Canine and Feline, Seventh Edition - 5-Fluorouracil Toxicosis PDF

Canine and Feline, Seventh Edition 1 5-Fluorouracil (5-FU) Toxicosis A...

Canine and Feline, Seventh Edition 1 5-Fluorouracil (5-FU) Toxicosis A iron, metaldehyde, mushrooms (Amanita, Antiemetic—maropitant 1 mg/kg IV, SC Galerina, and Lepiota spp.), sodium fluoroac- q24h; ondansetron 0.1–0.2 mg/kg IV etate (Compound 1080), strychnine. q6–12h; metoclopramide 0.1–0.5 mg/kg IV, ­ BASICS Metabolic—hepatic failure, hepatic SC q6–8h. OVERVIEW encephalopathy. GI protection—proton pump inhibitors, Antimetabolite, antineoplastic agent; it is Nervous—idiopathic epilepsy, meningitis, H2 blockers, sucralfate. metabolized to thymidine, which blocks the neoplasia. Analgesia—buprenorphine 0.005–0.03 mg/kg methylation reaction of deoxyuridylic and CBC/BIOCHEMISTRY/URINALYSIS IM or IV q6–12h, butorphanol 0.1–0.5 mg/kg thymidylic acids, resulting in thymine CBC—baseline, then continue to monitor SC, IV, or IM. deficiency; thymine is critical for DNA and q3–4 days post exposure for 21 days; monitor Antibiotic—broad-spectrum antibiotic to a lesser extent RNA replication; the result for echinocytes; leukopenia develops by day 7 therapy if total white blood cell count is is cell death due to interruption of normal and continues to day 13; thrombocytopenia below 2000. DNA and RNA synthesis; this mechanism develops by day 7 and can continue for 21 Bone marrow stimulation—filgrastim targets rapidly growing cells like bone marrow days; acute anemia due to blood loss can be (Neupogen®) 4–6 μg/kg SQ q24h. and intestinal crypts; 5-FU has various active secondary to bone marrow suppression by Transfusion therapy may be indicated if metabolites resulting in delayed clearance day 9, persisting until day 21. PCV 2 ng/mL one week following first half of gestation secondary hypoluteoidism may result from mating. Hypoluteoidism—serum PATHOPHYSIOLOGY prostaglandin exposure, prolonged stress, and progesterone level 200 bpm). individuals; heritability of susceptibility to vaccines. Visualization of fetal kidney and intestinal feline infectious peritonitis virus (FIPV) RISK FACTORS peristalsis indicates fetal maturity. suspected to be high. Cats with high coefficient of inbreeding Abdominal radiographs—after 45 days, can INCIDENCE/PREVALENCE (COI). Previous pregnancy loss. Previous evaluate fetal number, relative size, and Difficult to determine, as pregnancy may not history of reduced litter size. Evidence of position; also assess fetal death (gas pockets) be diagnosed early. Loss or resorption of one cystic endometrial hyperplasia (CEH) on or fetal malformation. or two conceptus within a litter is not ultrasound. Concurrent systemic disease or DIAGNOSTIC PROCEDURES uncommon. recent trauma. Older queens (over 6 years). Submit aborted, stillborn, mummified GEOGRAPHIC DISTRIBUTION Malnourishment. Unsanitary housing fetuses and fetal membranes (fresh or N/A conditions. Raw diets. refrigerated on ice) for gross necropsy, SIGNALMENT histopathology, cultures, and viral isolation. Increased incidence in queens >5 years old; Submit culture of reproductive tract or entire increased risk in purebred cats with high tract if removed (uterus, ovaries, oviducts). inbreeding. ­ DIAGNOSIS Submit samples from aborted and stillborn fetus for karyotyping. Pedigree analysis— SIGNS DIFFERENTIAL DIAGNOSIS evaluate COI. Evaluate cattery management Early pregnancy loss—failure to ovulate, General Comments for vaccination protocols, feeding regime, failure to conceive, chromosomal disorder, or Frequently no clinical symptoms other than sanitation procedures, and quarantine disorder of sexual development. Vaginal lack of pregnancy or reduced litter size. procedures. Nutrition—nutritional analysis discharge—pyometra, uterine stump of diet: of particular importance when queen Historical Findings pyometra, mucometra, vaginitis, neoplasia, is fed homemade and/or raw diet. Failure to deliver kittens at expected due date, cystitis, active labor or impending abortion, return to estrus sooner than expected trauma to urogenital tract. Mass or tissue PATHOLOGIC FINDINGS (approximately 45 days), discovery of fetal from vaginal vault—dystocia, neoplasia, Variable with etiology. tissues or placenta, behavior change, systemic hemorrhage/blood clot, uterine prolapse. illness. CBC/BIOCHEMISTRY/URINALYSIS Physical Examination Findings Generally normal. Inflammatory leuko- Signs range from normal to dehydration, ­gram with infection or systemic disease. ­ TREATMENT fever, abdominal straining, and discomfort to Anemia of pregnancy; hemoconcentration APPROPRIATE HEALTH CARE presence of purulent, mucoid, watery, or and azotemia may be seen with dehydration None, for noninfectious, stable queens; sanguineous vaginal discharge. or hypovolemia. primary hypoluteoidism—managed on CAUSES OTHER LABORATORY TESTS outpatient basis. Infectious Infectious Causes NURSING CARE Bacterial—organisms implicated in causing Cytology and bacterial culture of vaginal Inpatient management if systemically ill, abortion via ascending infection through the discharge, fetus, fetal membranes, or uterine debilitated, severely dehydrated, or for vaginal vault and cervix include E. coli, contents (aerobic and mycoplasma). medical management of ongoing fetal loss or Staphylococcus spp., Streptococcus spp., FeLV—test for antigens in queens using pyometra. Chlamydia spp., Pasteurella spp., Klebsiella spp., ELISA or indirect fluorescent antibody (IFA). ACTIVITY Pseudomonas spp., Salmonella spp., Mycoplasma FHV-1—IFA or PCR from corneal or Isolation for queens with infectious disease. spp., and Ureaplasma spp. Protozoal— conjunctival swabs, viral isolation from No activity restrictions for most; restrict Toxoplasma gondii. Viral— feline leukemia conjunctival, nasal, or pharyngeal swabs. activity as indicated if due to trauma.  Canine and Feline, Seventh Edition 3 (continued) Abortion, Spontaneous (Early Pregnancy Loss)—Cats A DIET hypertension leading to hemorrhage from CEH. Fair prognosis for successful Feed commercially available diet labeled for placental sites during parturition or at time of pregnancy with treatment for primary use in pregnancy. Correct diets with Cesarean section. Altrenogest can cause hypoluteoidism; significant monitoring inappropriate taurine or vitamin A concen­ agalactia and failure of parturition, leading to required for good outcome. Pregnancy loss trations. Avoid feeding raw meats or death of litter; discontinue use 2 days before due to genetic abnormalities likely to recur if allowing queens to hunt during pregnancy to due date. Caution with use of altrenogest queen is bred to tom with similar pedigree. reduce risk for ingestion of pathogenic with infectious processes or necrotic fetuses in bacteria and T. gondii. uterus; may keep infection within uterus, CLIENT EDUCATION causing metritis and systemic illness; monitor pregnancy often with ultrasound. PGF2α— Infectious diseases—verify vaccination side effects vomiting, hypersalivation, ­ MISCELLANEOUS status (vaccinate prior to pregnancy) and defecation, urination, and tachypnea; dose ASSOCIATED CONDITIONS disease surveillance measures; ensure use of dependent and self-limiting. Severe systemic disease otf any kind, quarantine facilities for pregnant queens and malnutrition. new arrivals. Breeding management—keep POSSIBLE INTERACTIONS detailed records of reproductive performance, Progesterone administration during AGE-RELATED FACTORS pedigree analysis, and social behavior of pregnancy associated with masculinization of Queens >6 years old—higher incidence of queens (including when not receptive to male). female fetuses; do not administer in first half lower litter size and infertility. Nutrition—advise feeding commercial cat of pregnancy and use with informed consent ZOONOTIC POTENTIAL food during pregnancy. Genetic disease— thereafter. Tocolytics associated with T. gondii. discuss COI and value of introducing new increased risk of dystocia, failure of placental genetics. Discuss risk of zoonotic disease separation, lack of milk production, and poor PREGNANCY/FERTILITY/BREEDING from T. gondii. maternal behavior for first days postpartum. Queens with previous pregnancy loss are at higher risk of subsequent pregnancy loss or SURGICAL CONSIDERATIONS ALTERNATIVE DRUG(S) infertility and should be monitored inten- Ovariohysterectomy (OHE) may be Dopamine agonists (e.g., cabergoline 5 μg/kg sively. considered if queen is systemically ill from PO q24h) can be used to lower progesterone uterine infection or deceased fetuses. If and facilitate uterine emptying. Use in SYNONYMS valuable breeding animal, Cesarean section conjunction with low dose of PGF2α. Pregnancy loss. Abortion. Fetal can be performed to remove deceased fetuses. mummification. Early embryonic loss. SEE ALSO Breeding, Timing. Sexual Development Disorders. ­ FOLLOW-UP ­ MEDICATIONS PATIENT MONITORING ABBREVIATIONS DRUG(S) OF CHOICE Serial ultrasound—follow pregnancy loss, CEH = cystic endometrial hyperplasia. Depends on etiology. Amoxicillin– uterine emptying, or viability of remaining COI = coefficient of inbreeding. clavulanic acid 13.75 mg/kg PO q12h—safe for fetuses; initially daily; decrease frequency FeLV = feline leukemia virus. pregnancy. Enrofloxacin 5 mg/kg/day PO— when stable, continue until birth (with partial FHV-1 = feline herpesvirus 1. excellent penetration to uterus; contraindicated loss) or uterus is free of fluid (complete FIPV = feline infectious peritonitis virus. if live fetuses present. Prostaglandin F2α abortion). Monitor health and attitude of FIV = feline immuno­deficiency virus. (PGF2α; dinoprost/Lutalyse®) 80–100 μg/kg queen. If live fetuses are present—delayed FPLV = feline panleukopenia virus. IM q8–12h—promotes uterine contractions, parturition my occur with progesterone or IFA = indirect fluorescent antibody. loss of corpus luteum, and cervical opening to terbutaline treatment; Cesarean section may OHE = ovariohysterectomy. expulse aborted materials. Tocolytics— be necessary. PGF2α = prostaglandin F2α. prevent uterine contractions: terbutaline PREVENTION/AVOIDANCE ­Suggested Reading 0.03–1.0 mg PO as needed based on tocodyna­ Institute infectious disease prevention, Lamm CG. Clinical approach to abortion, mometry (www.whelpwise.com); 0.03 mg/kg control, and surveillance. Replace subfertile stillbirth, and neonatal death in dogs and PO q8h if tocodynamometry not available. queens with more reproductively fit individ­ cats. Vet Clin North Am Small Anim Pract Hypoluteoidism—oral progestogene uals. Avoid exposure to abortifacient, 2012, (42)3:501–513. (altrenogest) 0.088 mg/kg PO q24h to teratogenic, or fetotoxic drugs. Serial Verstegen J, Dhaliwal G, Verstegen-Onclin K. maintain pregnancy; can monitor queen’s progesterone assays and fetal ultrasound Canine and feline pregnancy loss due to progesterone, as altrenogest will not interfere during next pregnancy. viral and non-infectious causes: a review. with progesterone assay. Theriogenology 2008, 70(3):304–319. POSSIBLE COMPLICATIONS Author Aime K. Johnson CONTRAINDICATIONS Loss of entire litter. Metritis, chronic Terbutaline—cardiac disease, pyometra, Consulting Editor Erin E. Runcan endometritis, uterine rupture, sepsis, shock. Acknowledgment The author and editors infectious disease, hypertension. Uterine pathology. Masculinization of Altrenogest—contaminated uterus with acknowledge the prior contribution of Milan female fetuses with progesterone therapy. Hess. systemically ill queen. Prostaglandin-cats with previously diagnosed respiratory disease. EXPECTED COURSE AND PROGNOSIS Poor prognosis for live kittens for current PRECAUTIONS litter, even with aggressive monitoring and  Client Education Handout Use of tocolytics requires accurate breeding treatment. May recur in future pregnancies available online dates to know when to stop treatment; most depending on cause and treatment. Poor successful in combination with tocodyna­ prognosis for normal pregnancy with severe mometry. Terbutaline can cause  4 Blackwell’s Five-Minute Veterinary Consult A Abortion, Spontaneous (Early Pregnancy Loss)—Dogs CAUSES Necropsy of aborted fetus, stillborn puppies, Infectious and placenta(s)—enhance chances of Brucella canis. definitive diagnosis. ­ BASICS Systemic or endocrine disease—problems Canine herpesvirus. DEFINITION Toxoplasma gondii, Neospora caninum. with maternal environment. Loss of a fetus because of resorption in early Mycoplasma and Ureaplasma. CBC/BIOCHEMISTRY/URINALYSIS stages or expulsion in later stages of pregnancy. Bacteria—Escherichia coli, Streptococcus, Usually normal. PATHOPHYSIOLOGY Campylobacter, Salmonella. Systemic disease, uterine infection, viral Direct—congenital abnormality, infectious Viruses—distemper, parvovirus, adenovirus. infection, or endocrine abnormalities—may disease, trauma. Uterine produce changes in CBC, biochemistries, or Indirect—infectious placentitis, abnormal Cystic endometrial hyperplasia and pyometra. urinalysis. ovarian function, abnormal uterine environ- Trauma—acute and chronic. OTHER LABORATORY TESTS ment. Neoplasia. Serologic testing—B. canis, canine SYSTEMS AFFECTED Ovarian herpesvirus, Toxoplasma, Neospora; collect Reproductive. Hypoluteoidism—abnormal luteal function serum as soon as possible after abortion; Any major body system dysfunction can in absence of fetal, uterine, or placental repeat testing for paired titers for canine adversely affect pregnancy. disease: progesterone concentrations 1 : 200 dystocia up to 22.3%. cabergoline. considered positive; titers 1 : 50–1 : 200 SIGNALMENT Hormonal Dysfunction suspicious. Hypothyroidism (less common). ◦ Agar gel immunodiffusion—differen­ Species tiates between false positives and true Hyperadrenocorticism. Dog positives in agglutination tests; detects Endocrine-disrupting contaminants Breed Predilections documented in human and wildlife fetal loss. cytoplasmic and cell surface antigens. Familial lymphocytic hypothyroidism Baseline T4 serum concentration— Fetal Defects hypothyroidism possible cause for fetal (Borzoi)—prolonged interestrus interval, Lethal chromosomal abnormality or organ wastage; role in pregnancy loss unclear. poor conception rate, mid-gestation abortion, defects. Serum progesterone concentration stillbirths. Many breeds at risk for hypothyroidism, RISK FACTORS (hypoluteoidism; if no infectious cause); dogs although evidence of role in abortion unclear. Exposure of brood bitch to carrier animals. depend on ovarian progesterone production Old age. throughout gestation (minimum of 2 ng/mL Mean Age and Range Hereditary factors. required to maintain pregnancy); determine Infectious causes, pharmacologic agents as soon as possible after abortion; in causing abortion, fetal defects—all ages. subsequent pregnancies, start weekly Cystic endometrial hyperplasia—usually >6 monitoring at week 3 (may be before years old. pregnancy documented with ultrasound); Predominant Sex ­ DIAGNOSIS start biweekly sampling around gestational Intact bitches. DIFFERENTIAL DIAGNOSIS age of prior loss. Pregnancy loss typically Differentiate infectious from noninfectious occurs during seventh week of gestation (see SIGNS causes—B. canis immediate and zoonotic Premature Labor). Historical Findings concern. Vaginal culture—B. canis with positive Failure to whelp on time. Differentiate resorption from infertility— serologic test; Mycoplasma, Ureaplasma, other Expulsion of recognizable fetuses or helped by early diagnosis of pregnancy. bacterial agents; all except B. canis can be placental tissues. History of drug use during pregnancy— normal flora, so diagnosis difficult from Decrease in abdominal size; weight loss. particularly during first trimester, or use of vaginal culture alone; limited benefit unless Anorexia, vomiting, diarrhea. drugs (e.g., dexamethasone, prostaglandins, heavy growth of single organism; Salmonella Behavioral changes. ketoconazole, griseofulvin, doxycycline, associated with systemic illness. Physical Examination Findings tetracycline, dantrolene) known to cause fetal IMAGING Sanguineous or purulent vulvar discharge. death. Radiography—identifies fetal structures Disappearance of previously documented Vulvar discharge during diestrus—may after 45 days of gestation; earlier determines vesicles or fetuses. mimic abortion; evaluate discharge and origin uterine enlargement but not uterine contents. Abdominal straining, discomfort. to differentiate uterine from distal reproduc­ Ultrasonography—identify uterine size and Depression. tive tract disease. contents; assess fluid and its consistency; Dehydration. assess fetal viability (heartbeats: normal, Fever. >200 bpm; stress, 280 bpm).  Canine and Feline, Seventh Edition 5 (continued) Abortion, Spontaneous (Early Pregnancy Loss)—Dogs A DIAGNOSTIC PROCEDURES Prostaglandin treatment—discuss side for consistency (increasing mucoid content Vaginoscopy—identify source of vulvar effects (e.g., abortion). prognostically good). discharge and vaginal lesions; use scope of Infectious disease—establish surveillance PGF2α—continued for 5 days or until most sufficient length (16–20 cm) to examine and control measures. of discharge ceases (range 3–15 days). entire length of vagina. B. canis—monitor after neutering and SURGICAL CONSIDERATIONS Cytologic examination, bacterial culture— OHE preferred for stable nonbreeding patients. antibiotic therapy; yearly serologic testing may reveal inflammatory process (e.g., uterine (identify recrudescence). infection): use guarded swab to ensure anterior Hypothyroidism—see Hypothyroidism. sample (distal reproductive tract is heavily PREVENTION/AVOIDANCE contaminated with bacteria), or collect Brucellosis, other infectious agents— secretions by transcervical catheterization. ­ MEDICATIONS surveillance programs to prevent spread to PATHOLOGIC FINDINGS DRUG(S) OF CHOICE kennel. Histopathologic examination and culture of Prostaglandin F2α (PGF2α; Lutalyse®, dinoprost OHE—for nonbreeding bitches. fetal and placental tissue—may reveal tromethamine)—uterine evacuation after Use of modified-live vaccines (e.g., some infectious organisms; tissue culture, particu- abortion; 0.05–0.1 mg/kg SC q8–24h; distemper, parvovirus), currently unavailable larly of stomach contents, may identify cloprostenol (Estrumate®, cloprostenol)—1–5 μg/ in United States. infectious bacteria. kg SC q24h; not approved for use in dogs, but POSSIBLE COMPLICATIONS adequate documentation for use; use only if all Untreated pyometra—septicemia, death. living fetuses expelled. Brucellosis—discospondylitis, endophthal­ Antibiotics—broad-spectrum agent mitis, uveitis, zoonotic. appropriate pending culture and sensitivity of ­ TREATMENT vaginal tissue or fetus. EXPECTED COURSE AND PROGNOSIS APPROPRIATE HEALTH CARE Progesterone (altrenogest) at 0.088 mg/kg Pyometra—recurrence during subsequent Most bitches should be isolated pending (1 mL/25 kg PO q24h); progesterone in oil cycle likely (up to 70%) unless pregnant. diagnosis. at 2 mg/kg IM q48–72h; progesterone CEH—recovery of fertility unlikely; Hospitalization of infectious patients (Prometrium®; 10 mg/kg PO q24h, adjust pyometra common complication. preferred. daily dosage based on serum progesterone)— Hormonal dysfunction—manageable; B. canis—highly infective; shed in high for documented hypoluteoidism only to heritability should be considered. numbers during abortion; suspected dogs maintain pregnancy; must have accurate due Brucellosis—guarded; extremely difficult to should be isolated. date to know when to discontinue therapy; eliminate infection even with neutering. Outpatient—medically stable patients with inadvertently prolonging gestation results in noninfectious pregnancy loss. fetal death. Partial abortion—attempt to salvage live CONTRAINDICATIONS fetuses; antibiotics indicated if bacterial Progestogen supplementation contraindicated ­ MISCELLANEOUS component. with endometrial or mammary gland disease. AGE-RELATED FACTORS NURSING CARE PRECAUTIONS Older bitches more likely to have CEH. Dehydration—isotonic crystalloid fluids, PGF2α—dose-related side effects related to electrolyte supplementation as indicated. ZOONOTIC POTENTIAL smooth muscle contraction, diminish with B. canis—can be transmitted to humans ACTIVITY each injection; panting, salivation, vomiting, (especially if immunosuppressed), particularly Partial abortion—cage rest, but effect on and defecation common; caution in brachyce­ when handling bitch and expelled tissues. reducing further abortion unknown. phalics; dosing critical (LD50 for Notify pathologists if B. canis is suspected. DIET dinoprost—5 mg/kg). Progesterone supplementation will prevent SEE ALSO No special considerations; abortions have Brucellosis. been associated with raw diets. whelping—administration needs to be discontinued before 2–3 days prior to due Hypothyroidism. CLIENT EDUCATION date; risk of masculinization of female fetuses Infertility, Female—Dogs. Critical for B. canis—if confirmed, euthanasia if used before day 45 of gestation. Premature Labor. recommended due to lack of successful Pyometra. treatment and to prevent spread; may try ALTERNATIVE DRUG(S) Oxytocin—1 U/5 kg SC q6–24h for uterine ABBREVIATIONS ovariohysterectomy (OHE) and long-term CEH = cystic endometrial hyperplasia. antibiotics with surveillance program for kennel evacuation; consider only where uterine evacuation solely through uterine contraction OHE = ovariohysterectomy. situations (monthly serology, culling any PGF2α = prostaglandin F2α. positive animals until three consecutive negative desired. tests are obtained); discuss zoonotic potential. ­Suggested Reading Primary uterine disease—OHE is indicated Verstegen J, Dhaliwal G, Verstegen-Onclin K. in nonbreeding patients; cystic endometrial Canine and feline pregnancy loss due to hyperplasia (CEH) is irreversible. ­ FOLLOW-UP viral and non-infectious causes: a review. Infertility or pregnancy loss—may recur in Theriogenology 2008, 70(3):304–319. PATIENT MONITORING Author Julie T. Cecere subsequent estrous cycles despite successful Partial abortion—monitor viability of Consulting Editor Erin E. Runcan immediate treatment; pedigree analysis may remaining fetuses with ultrasonography; monitor be beneficial in highly linebred animals if systemic health of dam for rest of pregnancy. pregnancy loss and small litter size due to Vulvar discharges—daily; for decreasing  Client Education Handout inbreeding depression. amount, odor, and inflammatory component; available online  6 Blackwell’s Five-Minute Veterinary Consult A Abortion, Termination of Pregnancy RISK FACTORS Treatment on day 6–10 of diestrus—may N/A have reduced efficacy compared to mid-gesta- tion, but can be less distasteful to client (less ­ BASICS discharge and recognizable fetuses are not DEFINITION passed). Termination of an unwanted pregnancy. May be ­ DIAGNOSIS Multimodal treatment improves efficacy of accomplished by drugs that alter embryo Confirm pregnancy first, ~60% of drugs given alone. transport in the oviduct, impeding establishment mismated bitches do not become pregnant: NURSING CARE of a pregnancy, and/or cause luteal regression, ◦ Abdominal palpation—bitch: 31–33 days N/A terminating an established pregnancy. Due to after luteinizing hormone (LH) surge; their possible side effects (cystic endometrial ACTIVITY queen: 21–25 days after breeding. hyperplasia, aplastic anemia, and bone marrow Normal ◦ Transabdominal ultrasound—bitch: >25 days suppression), drugs that impair embryonic after LH surge; queen: >16 days after breeding. DIET transit through the oviduct (estrogens) are not ◦ Abdominal radiographs—bitch: >45 days Avoid feeding prior to each treatment and for commonly used or recommended. after LH surge; queen: >38 days after breeding. 1–2 hours after treatments (reduces nausea PATHOPHYSIOLOGY ◦ Serum relaxin concentration in the bitch and vomiting). After fertilization the embryo travels the (>28 days after LH surge; Witness® Relaxin, CLIENT EDUCATION oviduct in a timely manner before entering the Synbiotics/Zoetis). Discuss patient’s reproductive future with uterus. Impaired embryo transport through DIFFERENTIAL DIAGNOSIS owner. If no litters are desired, then ovario­ the oviduct leads to embryonic degeneration Hydrometra. hysterectomy (OHE) is the best option. and implantation abnormalities. In the dog Mucometra. Discuss with client potential side effects of and cat, pregnancy maintenance is dependent Hematometra. treatment options; reach mutual agreement on progesterone production from the corpora Pyometra. on treatment plan. lutea. In dogs and cats, maintenance of the Pseudopregnancy. SURGICAL CONSIDERATIONS corpora lutea during the second half of CBC/BIOCHEMISTRY/URINALYSIS OHE recommended for patients with no gestation is also supported by prolactin (PRL). Within normal limits during first half of reproductive value or when owners do not Drugs that cause luteal regression, antagonize pregnancy in healthy patients. desire future litters. PRL, and/or compete with progesterone Decrease in hematocrit during second half receptors will terminate pregnancy. of pregnancy in bitches and queens is normal. SYSTEMS AFFECTED Recommended as screening tests prior to Cardiovascular. treatment in patients with suspected under­- Digestive. ­ MEDICATIONS lying disease. Neurologic (caused by drugs used for DRUG(S) OF CHOICE treatment). OTHER LABORATORY TESTS Confirmation of pregnancy before initiating Vaginal cytology—determines stage of any of treatment protocols suggested below is Reproductive. Respiratory. estrous cycle and presence of sperm (absence recommended. Duration of suggested does not rule out previous breeding). treatment may vary; treatments should be GENETICS Serum progesterone concentration deter­- N/A continued until abortion is complete. mines if female in diestrus and monitors Prostaglandin F2α (PGF2α)—causes luteal INCIDENCE/PREVALENCE luteal regression during treatment. regression with subsequent decline in N/A IMAGING progesterone concentration, cervical relax­- GEOGRAPHIC DISTRIBUTION Transabdominal ultrasound (method of ation, and uterine contractions. Higher doses N/A choice)—diagnose pregnancy and monitor necessary prior to day 28 of gestation. uterine evacuation during treatment. ◦ Bitch low dose protocol—10 μg/kg SC q6h SIGNALMENT Abdominal radiographs. for 7–10 days or until pregnancy termination. Species ◦ Bitch standard dose protocol—100 μg/kg DIAGNOSTIC PROCEDURES Dog and cat. N/A SC q8h for 2 days, then 200 μg/kg SC q8h Breed Predilections until pregnancy termination. PATHOLOGIC FINDINGS ◦ Queen low dose protocol—25 μg/kg SC N/A N/A q6h for 1–2 days, then 50 μg/kg SC q6h for Mean Age and Range 3–4 days (queen more resistant to luteolytic Postpubertal bitch and queen. effects of PGF2α than bitches; often higher Predominant Sex doses for longer periods are required). Female ­ TREATMENT ◦ Queen standard protocol—0.5–1 mg/kg SC q12h every other day (>day 40), or SIGNS APPROPRIATE HEALTH CARE 2 mg/cat SC q24h for 5 days (>day 33). Depends on stage of gestation: Physical examination before initiation of Cloprostenol (prostaglandin analogue): ◦ None. treatment. ◦ Bitch—2.5 μg/kg SC q8–12h every 48 ◦ Vaginal discharge. Monitor 30–60 minutes after treatment for hours until pregnancy termination (~6 days ◦ Fetal expulsion. side effects (vomiting, defecation, hypersaliva- after start of treatment). tion, hyperpnea, micturition, tachycardia). CAUSES Dexamethasone—mode of action Pregnancy status in early diestrus is unknown; Impaired oviductal transport. unknown: ultrasound confirmation of pregnancy not Luteal regression. ◦ Bitch—0.2 mg/kg PO q8–12h for 5 possible until ~4 weeks after breeding. Progesterone receptor antagonism. days, then decreasing incrementally from  Canine and Feline, Seventh Edition 7 (continued) Abortion, Termination of Pregnancy A 0.16 to 0.02 mg/kg over last 5 days; impaired liver function; side effects may PREVENTION/AVOIDANCE treatment failures not uncommon. include vomiting and anorexia; prolonged use OHE for bitches and queens not intended Cabergoline (PRL antagonist)—causes (>2 weeks) may cause coat color changes. for breeding. luteal regression: POSSIBLE INTERACTIONS Estrus suppression or confinement of ◦ Bitch—1.65 μg/kg SC q24h for 5 days or bitches and queens intended for breeding PGF2α and analogues—effect may be reduced 5 μg/kg PO q24h for 5 days (>day 40). by concomitant administration of progestins; during a later cycle to avoid mismating. ◦ Queen—1.65 μg/kg SC for 5 days (>day 30) use may enhance effects of oxytocin. POSSIBLE COMPLICATIONS or 5 μg/kg PO q24h for 5 days (>day 35). Cabergoline and bromocriptine—cabergo- Pregnancy termination may not be achieved after Bromocriptine (PRL antagonist)—causes line effects may be reduced with concomitant one treatment protocol and continuation or luteal regression: treatment with dopamine (D2) antagonists; change in treatment protocol may be necessary. ◦ Bitch—50–100 μg/kg IM/PO q12h for avoid concomitant treatment with drugs 4–7 days >day 35 (50% effective); common EXPECTED COURSE AND PROGNOSIS causing hypotension. Interestrous interval in bitches treated with side effect vomiting; reduce dose and give with meal. ALTERNATIVE DRUG(S) prostaglandins and PRL inhibitors may be Cloprostenol and cabergoline combination: The following drugs are recommended for shortened (~1 month). Queens may resume ◦ Bitch—cabergoline 5 μg/kg PO q24h for use in bitches but are not readily available in estrous behavior 7–10 days after pregnancy 10 days plus cloprostenol 2.5 μg/kg SC at the United States: termination. start of treatment or 1 μg/kg SC at start of ◦ Aglepristone (progestin and glucocorticoid Subsequent estrus fertility not affected. treatment and at day 5 of treatment; receptors antagonist)—10 mg/kg SC q24h treatment should be initiated >28 days for 2 days >14 days post-LH surge; highly post-LH surge. effective in preventing pregnancy (>95% ◦ Queen—cabergoline 5 μg/kg PO q24h treatment efficacy); abdominal ultrasound at 28–30 days essential to insure treatment ­ MISCELLANEOUS plus cloprostenol 5 μg/kg SC q48h (>30 days after breeding) until abortion success; if pregnancy still present, repeat ASSOCIATED CONDITIONS complete (~9 days). injection protocol. Mild reactions at N/A Cloprostenol and bromocriptine injection site have been reported; mild AGE-RELATED FACTORS combination: vaginal discharge may be observed; slight N/A ◦ Bitch—bromocriptine 30 μg/kg PO q8h risk (3.4%) of development of pyometra in field studies. ZOONOTIC POTENTIAL for 10 days plus cloprostenol 2.5 μg/kg SC ◦ Aglepristone and cloprostenol combina- N/A or 1 μg/kg SC at start of treatment and at day 5 of treatment; treatment should be tion—aglepristone (10 mg/kg SC) combined PREGNANCY/FERTILITY/BREEDING initiated >28 days post-LH surge. with cloprostenol (1 μg/kg SC) q24h for 2 N/A days >25 days’ pregnancy; pregnancy CONTRAINDICATIONS SYNONYMS terminated within 6 days. Side effects after PGF2α and analogues—animals with Induced abortion. treatment include vomiting and diarrhea; respiratory disease (bronchoconstriction); do vaginal discharge may be observed. SEE ALSO not administer intravenously. Use with ◦ Aglepristone (10 mg/kg SC q24h for Breeding, Timing. caution in brachycephalic breeds. 2 days) with intravaginal misoprostol Cabergoline and bromocriptine—avoid ABBREVIATIONS (200–400 μg depending on body size) daily CEH = cystic endometrial hyperplasia. administration in animals hypersensitive to until abortion complete; abortion complete ergot alkaloids; use with caution in patients LH = luteinizing hormone. within 7 days. Vomiting, diarrhea, polydip- OHE = ovariohysterectomy. with impaired liver function. sia, anorexia not observed with this regimen. Estrogens may cause cystic endometrial PGF2α = prostaglandin F2α. hyperplasia (CEH), pyometra, and bone PRL = prolactin. marrow suppression leading to pancytopenia. ­Suggested Reading PRECAUTIONS Eilts BE. Pregnancy termination in the bitch PGF2α and analogues—side effects dose ­ FOLLOW-UP and queen. Clin Tech Small Anim Pract dependent and include vomiting, defecation, PATIENT MONITORING 2002, 17:116–123. dyspnea, tachycardia, salivation, restlessness, In animals treated with luteolytic drugs Fieni F, Dumon C, Tainturier D, Bruyas JF. and anxiety; side effects subside within 60 (prostaglandins and PRL antagonists), Clinical protocol for pregnancy termination minutes; use extreme caution in dogs and cats progesterone assays and transabdominal in bitches using prostaglandin F2α. J Reprod with preexisting cardiopulmonary, liver, and ultrasound examinations should be performed Fertil Suppl 1997, 51:245–250. renal diseases. to monitor decrease of serum progesterone Author Jose A. Len Dexamethasone—polydipsia, polyuria, and concentration and complete evacuation of Consulting Editor Erin E. Runcan polyphagia are reported side effects; long- uterine contents. In patients treated with term administration can result in signs of progesterone receptor antagonist drugs, transabdominal ultrasound examinations are  Client Education Handout hyperadrenocorticism. recommended to monitor complete evacu­ available online Cabergoline and bromocriptine—should be administered with caution in patients with ation of the uterus.  8 Blackwell’s Five-Minute Veterinary Consult A Abscessation of function), tissue destruction, and/or organ system dysfunction caused by accumulation of exudates. ­ BASICS ­ DIAGNOSIS Historical Findings DEFINITION Often nonspecific signs (e.g., lethargy, DIFFERENTIAL DIAGNOSIS An abscess is a focal collection of purulent anorexia). Mass Lesions exudate within a confined tissue space or cavity. History of trauma or prior infection. Cyst—transiently painful, slower growing, PATHOPHYSIOLOGY Rapidly appearing painful swelling with or no overt signs of inflammation. Bacterial organisms may enter tissue by without discharge, if affected area is visible. Fibrous scar tissue—firm, nonpainful. penetrating trauma, spread from another Physical Examination Findings Granuloma—less painful, slower growing, source of infection (hematogenous or Determined by organ system or tissue firmer without fluctuant center. adjacent infected tissues), or migration of a affected. Hematoma/seroma—variable pain, contaminated object (e.g., plant awn). Classic signs of inflammation (heat, pain, nonencapsulated, rapid initial growth but Most often, bacteria are inoculated under swelling, and loss of function) associated with slows once full size attained, fluctuant the skin via puncture or bite wounds. specific anatomic location of abscess. initially, may become more firm over time. When bacteria or foreign objects persist in Inflammation and discharge from fistulous Neoplasia—variable growth, variable pain. tissue, purulent exudate accumulates. tract may be visible if abscess has ruptured to Draining Tracts If exudate not quickly resorbed or drained, an external surface. Fungal infection—blastomycosis, fibrous capsule forms to “wall off ” infection; Variably sized, painful mass of fluctuant to coccidioidomycosis, cryptococcosis, abscess may eventually rupture. firm consistency attached to surrounding histoplasmosis, sporotrichosis. With fibrous capsule—to heal, the cavity tissues. Mycobacterial disease. must fill with granulation tissue from which Fever common, but may be absent if Mycetoma—botryomycosis, actinomycotic causative agent may not be totally eliminated; abscess has ruptured. mycetoma, eumycotic mycetoma. may lead to chronic or intermittent discharge Sepsis or infection of body cavity (e.g., Neoplasia. of exudate from a draining tract. pyothorax) may be seen if abscess ruptures Phaeohyphomycosis. Sterile abscesses can occur when irritants internally. (injectable medications, venom) or inflamm­ CBC/BIOCHEMISTRY/URINALYSIS atory processes (pancreatitis, immune CAUSES CBC—normal, neutrophilia with or mediated, decreased blood supply) lead to Foreign objects. without left shift, neutropenia and local collection of purulent exudate. Pyogenic bacteria—Staphylococcus spp., degenerative left shift (severe infection). Escherichia coli, β-hemolytic Streptococcus Serum chemistry profile—depends on SYSTEMS AFFECTED spp., Pseudomonas, Mycoplasma and severity, system affected. Signs of cholestasis if Skin/exocrine—percutaneous (cats > dogs); Mycoplasma-like organisms (l-forms), pancreatic abscess causes obstruction, anal sac (dogs > cats). Pasteurella multocida, Corynebacterium, hyperglycemia if diabetes mellitus, etc. Reproductive—prostate gland (dogs > cats); Actinomyces spp., Nocardia, Bartonella. Urinalysis—pyuria (prostatic abscess). mammary gland. Obligate anaerobes—Bacteroides spp., Ophthalmic—periorbital tissues. OTHER LABORATORY TESTS Clostridium spp., Peptostreptococcus, Hepatobiliary—liver parenchyma. FeLV, FIV testing—recurrent or slow- Fusobacterium. Gastrointestinal—pancreas (dogs > cats). healing abscesses (cats). Noninfectious—pancreatitis, suture Respiratory—pulmonary parenchyma. Cerebrospinal fluid evaluation—increased reaction, vaccination, other injectable drug cellularity and protein with brain abscess. GENETICS administration, stinging insects, snake Adrenal function—hyperadrenocorticism. N/A envenomation, immune-mediated panniculitis, dermatitis, neoplasia (especially when blood IMAGING INCIDENCE/PREVALENCE Radiography—soft-tissue density mass in supply outgrown). N/A affected area, may reveal foreign material. RISK FACTORS GEOGRAPHIC DISTRIBUTION Ultrasonography—determine if mass is Anal sac—impaction, anal sacculitis. N/A fluid filled; may reveal foreign object; Brain—otitis interna, sinusitis, oral SIGNALMENT echogenic fluid suggests purulent exudate. infection. Echocardiography—pericardial abscess, Species Liver—omphalophlebitis, sepsis. endocarditis. Cat and dog. Lung—foreign object aspiration or CT or MRI—pulmonary or brain abscess. migration, bacterial pneumonia. Breed Predilections Mammary gland—mastitis. DIAGNOSTIC PROCEDURES N/A Periorbital—dental disease, chewing of Fine-Needle Aspiration Mean Age and Range wood or other plant material. Red, white, yellow, or greenish liquid. N/A Percutaneous—fighting, trauma, or Protein content >2.5–3.0 g/dL. surgery. Nucleated cell count—3,000–100,000 (or Predominant Sex Prostate gland—bacterial prostatitis. more) cells/μL; primarily degenerate Mammary glands (female); prostate gland (male). Immunosuppression—feline leukemia virus neutrophils, fewer macrophages, SIGNS (FeLV) or feline immunodeficiency virus lymphocytes. General Comments (FIV) infection, immunosuppressive chemo­- Bacteria—intra- and extracellular: Determined by organ system and/or tissue therapy, acquired or inherited immune system ◦ Gram stain to classify organism for affected. dysfunctions, underlying predisposing disease empiric therapy. Associated with combination of inflamm­ (e.g., diabetes mellitus, chronic renal failure, ◦ If causative agent not readily identified ation (pain, swelling, redness, heat, and loss hyperadrenocorticism). with a Romanowsky-type stain, acid-fast  Canine and Feline, Seventh Edition 9 (continued) Abscessation A stain to detect mycobacteria or Nocardia and Early drainage—to prevent further tissue POSSIBLE COMPLICATIONS periodic acid-Schiff stain to detect fungus. damage and abscess wall formation. Sepsis. Remove foreign objects(s), necrotic tissue, Peritonitis/pleuritis if intra-abdominal or Biopsy Sample should contain both normal and nidus of infection. intrathoracic abscess ruptures. abnormal tissue. Complications to discuss include progressive Compromise of organ function. Impression smears. tissue damage, necrosis, dehiscence of wound, Delayed evacuation may lead to chronic, Tissue—for histopathologic examination prolonged healing times in high-motion areas draining fistulous tracts. and culture. (axillary, inguinal). EXPECTED COURSE AND PROGNOSIS Necessary to confirm nodular panniculitis. Depends on cause, organ system involved, Culture and Susceptibility Testing and amount of tissue destruction. Affected tissue and/or exudate—aerobic and anaerobic bacterial and fungal. ­ MEDICATIONS Blood and/or urine if systemic disease. DRUG(S) OF CHOICE PATHOLOGIC FINDINGS Antimicrobial drugs that are effective against ­ MISCELLANEOUS Exudate-containing mass lesion accom­ infectious agent and penetrate site of infection. ASSOCIATED CONDITIONS panied by inflammation. Broad-spectrum agent—bactericidal with FeLV or FIV infection. Causative agent may be detectable. both aerobic and anaerobic activity until Immunosuppression. results of culture and sensitivity are known; Gram stain of exudate may guide therapy. AGE-RELATED FACTORS ◦ Dogs and cats—amoxicillin (22 mg/kg N/A PO q12h); amoxicillin–clavulanic acid ZOONOTIC POTENTIAL ­ TREATMENT (22 mg/kg PO q12h); clindamycin Mycobacteria and systemic fungal APPROPRIATE HEALTH CARE (5–10 mg/kg PO q12h); trimethoprim– infections carry some potential. Establish and maintain adequate drainage. sulfadiazine (15 mg/kg PO q12h). If prostatitis secondary to Brucella canis. Surgical removal of nidus of infection or ◦ Cats only—pradofloxacin (7.5 mg/kg PO q24 for 7 days). PREGNANCY/FERTILITY/BREEDING foreign object(s) if necessary. N/A Initiate appropriate antimicrobial therapy. ◦ Cats with Mycoplasma and L-forms— Outpatient—minor abscesses, localized doxycycline (5 mg/kg PO q12h). SEE ALSO infection, nodular panniculitis. Aggressive IV antimicrobial therapy— Actinomycosis and Nocardia. Inpatient—sepsis or systemic inflammation, sepsis, peritonitis, pyothorax. Anaerobic Infections. extensive surgical procedures, treatment Antimicrobials not required for confirmed Colibacillosis. requiring hospitalization. sterile abscesses. Mycoplasmosis. CONTRAINDICATIONS Nocardiosis/Actinomycosis—Cutaneous. NURSING CARE Sepsis and Bacteremia. Depends on location of abscess. N/A Apply hot packs to inflamed area as needed. PRECAUTIONS ABBREVIATIONS Use protective bandaging, Elizabethan N/A FeLV = feline leukemia virus. collar as needed. FIV = feline immunodeficiency virus. Accumulated exudate—surgical drainage, POSSIBLE INTERACTIONS N/A ­Suggested Reading debridement of necrotic tissue. Green CE, Goldstein EJC. Bite wound Sepsis, peritonitis, pyothorax—fluid ALTERNATIVE DRUG(S) infections. In: Greene CE, ed., Infectious therapy, antimicrobial therapy, intensive care. Sterile nodular panniculitis—corticosteroids. Diseases of the Dog and Cat, 4th ed. St. ACTIVITY Louis, MO: Elsevier Saunders, 2012, pp. Restrict until abscess has resolved and 528–542. adequate healing occurs. Singh A, Scott Weese J. Wound infections ­ FOLLOW-UP and antimicrobial use. In: Johnston SA, DIET Tobias KM, eds., Veterinary Surgery Small N/A PATIENT MONITORING Animal, 2nd ed. St. Louis, MO: Elsevier, CLIENT EDUCATION Monitor for progressive decrease in drainage, 2018, pp. 148–155. Correct or prevent risk factors. resolution of inflammation, and improvement Author Selena Lane Maintain adequate drainage and continue of clinical signs. Consulting Editor Amie Koenig antimicrobial therapy for adequate period of time. PREVENTION/AVOIDANCE Acknowledgment The author and editors SURGICAL CONSIDERATIONS Percutaneous abscesses—prevent fighting; acknowledge the prior contribution of Adam Appropriate debridement and drainage— consider castration to reduce roaming or J. Birkenheuer. may need to leave wound open to external aggressive behavior. surface; may need drain placement. Anal sac abscesses—prevent impaction; consider anal saculectomy for recurrent cases.  Client Education Handout ◦ Penrose drains must exit ventrally to Prostatic abscesses—consider castration. available online encourage drainage; may be bandaged, if bandage is changed regularly. Mastitis—prevent lactation (spay). ◦ If no ventral drainage, use active drains Periorbital abscesses—do not allow chewing (e.g., Jackson-Pratt drain). on foreign objects.  10 Blackwell’s Five-Minute Veterinary Consult A Acetaminophen (APAP) Toxicosis SIGNALMENT (alanine aminotransferase [ALT], aspartate Species transaminase [AST])—characteristic. As hepatic function becomes impaired— ­ BASICS Cats more often than dogs. decreased blood urea nitrogen (BUN), DEFINITION SIGNS cholesterol, and albumin, and increased Results from accidental animal ingestion or General Comments serum bilirubin. owner administration of over-the-counter Relatively common—owing to widespread Heinz bodies (cats)—prominent in RBCs acetaminophen-containing analgesic and human use. within 72 hours. antipyretic medications. Anemia, hemoglobinemia, and hemoglob­ Historical Findings inuria or hematuria. PATHOPHYSIOLOGY Depression. When the normal biotransformation Hyperventilation. OTHER LABORATORY TESTS mechanisms for detoxification (glucuronida- Darkened mucous membranes. Acetaminophen plasma, serum, or urine tion and sulfation) are saturated, cytochrome Signs may develop 1–4 hours after dosing. concentrations. P450–mediated oxidation produces a toxic IMAGING Physical Examination Findings metabolite (N-acetyl-p-benzoquinone imine) N/A Progressive depression. that is electrophilic, conjugates with glutathione, Salivation. DIAGNOSTIC PROCEDURES and binds to sulfhydryl groups, leading to Vomiting. N/A hepatic necrosis. Abdominal pain. Dogs Tachypnea and cyanosis or muddy mucous PATHOLOGIC FINDINGS Liver is most susceptible to toxicity. Methemoglobinemia. membranes—reflect methemoglobinemia. Signs commonly observed at exposures Pulmonary edema. Edema—face, paws, and possibly forelimbs; >75–100 mg/kg. Centrilobular necrosis and congestion of after several hours. Methemoglobinemia may develop at doses Chocolate-colored urine—hematuria and the liver. >200 mg/kg. Renal tubular edema and degeneration with methemoglobinuria; especially in cats. Icterus. proteinaceous tubular casts. Cats Cannot effectively glucuronidate; more Hypothermia. limited capacity for acetaminophen Shock. elimination than dogs. Death. Saturate glucuronidation and sulfation CAUSES ­ TREATMENT biotransformation routes. Acetaminophen toxicosis. APPROPRIATE HEALTH CARE Red blood cells (RBCs) are most susceptible With methemoglobinemia—must evaluate RISK FACTORS to oxidative injury following glutathione promptly. Nutritional deficiencies of glucose and/or depletion. With dark or bloody colored urine or sulfate. Develop toxic cytochrome P450 metabolite icterus—inpatient. Simultaneous administration of other at much lower doses than dogs. glutathione-depressing drugs. NURSING CARE Poisoned by as little as 50–60 mg/kg (often Gentle handling—imperative for clinically as little as one half tablet); deacetylation of acetaminophen to p-aminophenol (PAP) affected patients. Induced emesis and gastric lavage—useful causes oxidative damage to RBCs, rapidly producing methemoglobinemia by binding to ­ DIAGNOSIS within 4–6 hours of ingestion. Anemia, hematuria, or hemoglobinuria— sulfhydryl groups on hemoglobin. DIFFERENTIAL DIAGNOSIS Slower-developing hepatotoxicosis may not may require whole blood transfusion. Other Causes of Liver Injury Fluid therapy—maintain hydration and be fully expressed before development of fatal methemoglobinemia. Hepatotoxic mushrooms. electrolyte balance. Blue-green algae. Oxygen therapy may be needed. SYSTEMS AFFECTED Aflatoxins. Drinking water—available at all times. Hemic/lymph/immune—RBCs damaged Iron, copper, zinc. Food—offered 24 hours after initiation of by glutathione depletion, allowing oxidation Xylitol. treatment. of hemoglobin to methemoglobin. Cycad palms. Hepatobiliary—liver necrosis (more ACTIVITY Nonsteroidal anti-inflammatory drugs Restricted common in dogs). (NSAIDs). Cardiovascular (primarily cats)—edema of DIET face, paws, and (to lesser degree) forelimbs Other Causes of Methemoglobinemia N/A through undefined mechanism. Onions/garlic. Naphthalene. CLIENT EDUCATION GENETICS Chlorates. Warn client that treatment in clinically Cats—genetic deficiency in the glucuronide Nitrites. affected patients may be prolonged and conjugation pathway makes them vulnerable. Sulfites. expensive. Inform client that patients with liver injury INCIDENCE/PREVALENCE Phenol. Common drug toxicity in cats; less frequent Benzocaine. may require prolonged and costly management. in dogs. Propylene glycol (cats). SURGICAL CONSIDERATIONS GEOGRAPHIC DISTRIBUTION CBC/BIOCHEMISTRY/URINALYSIS N/A N/A Methemoglobinemia and progressively rising serum concentrations of liver enzymes  Canine and Feline, Seventh Edition 11 (continued) Acetaminophen (APAP) Toxicosis A PREVENTION/AVOIDANCE SYNONYMS Never give acetaminophen to cats. Paracetamol. Give careful attention to acetaminophen Tylenol®. ­ MEDICATIONS dose in dogs. SEE ALSO DRUG(S) OF CHOICE POSSIBLE COMPLICATIONS Poisoning (Intoxication) Therapy. Activated charcoal 1–2 g/kg PO with a Liver necrosis and resulting fibrosis—may cathartic; immediately after completion of ABBREVIATIONS compromise long-term liver function in ALT = alanine aminotransferase. emesis or gastric lavage. recovered patients. N-acetylcysteine (Mucomyst®) 140 mg/kg AST = aspartate transaminase. diluted in 5% dextrose injection (D5W) as EXPECTED COURSE AND PROGNOSIS BUN = blood urea nitrogen. loading dose PO/IV; then 70 mg/kg diluted Rapidly progressive methemoglobinemia— D5W = 5% dextrose injection. in D5W PO/IV q6h for 7 additional treat- serious sign. NSAID = nonsteroidal anti-inflammatory ments. Large overdoses may require up to 17 Methemoglobin concentrations ≥50%— drug. treatments. grave prognosis. PAP = p-aminophenol. S-adenosylmethionine (SAMe) as a Progressively rising serum liver enzymes RBC = red blood cell. glutathione donor; 40 mg/kg PO × 1 dose, 12–24 hours after ingestion—serious concern. SAMe = S-adenosylmethionine. then 20 mg/kg q24h PO × 7 days. Expect clinical signs to persist 12–48 hours; INTERNET RESOURCES Added benefit of using methylene blue, death owing to methemoglobinemia possible https://www.aspca.org/pet-care/ cimetidine, and/or ascorbic acid is contro- at any time. animal-poison-control versial. Dogs and cats receiving prompt treatment that reverses methemoglobinemia and ­Suggested Reading CONTRAINDICATIONS prevents excessive liver necrosis—may Plumb DC. Acetaminophen. In: Plumb DC, Drugs that contribute to methemoglobinemia recover fully. ed., Plumb’s Veterinary Drug Handbook, or hepatotoxicity. Dogs—death as a result of liver necrosis 9th ed. Ames, IA: Wiley-Blackwell, 2018, PRECAUTIONS may occur within 72 hours. pp. 6–8. Drugs requiring extensive liver metabolism or Cats—death as a result of methemoglobine- Plumlee KH. Hematic system. In: Plumlee biotransformation—use with caution; expect mia occurs 18–36 hours after ingestion. KH, ed., Clinical Veterinary Toxicology. St. their half-lives to be extended. Louis, MO: Mosby, 2004, p. 59. Schell MM, Gwaltney-Brant S. OTC drugs. POSSIBLE INTERACTIONS In: Poppenga RH, Gwaltney-Brant SM, eds., Drugs requiring activation or metabolism by Small Animal Toxicology Essentials. Chichester: the liver have reduced effectiveness. ­ MISCELLANEOUS Wiley-Blackwell, 2011, pp. 231–233. ASSOCIATED CONDITIONS Sellon RK. Acetaminophen. In: Peterson ME, Keratoconjunctivitis sicca may develop in Talcott PA, eds. Small Animal Toxicology, small-breed dogs as a sequela. 3rd ed. St. Louis, MO: Elsevier, 2013, pp. ­ FOLLOW-UP 423–429. AGE-RELATED FACTORS Stockham SL, Scott MA. Fundamentals of PATIENT MONITORING Young and small dogs and cats—greater risk Veterinary Clinical Pathology, 2nd ed. Continual clinical monitoring of methemo­ from owner-given single-dose acetaminophen Oxford: Blackwell, 2008, p. 186. globinemia—vital for effective management; medications. Author Lisa A. Murphy laboratory determination of methemoglobin PREGNANCY/FERTILITY/BREEDING Consulting Editor Lynn R. Hovda percentage every 2–3 hours. Imposes additional stress and higher risk on Serum liver enzyme activities (ALT, ALP) exposed animals. every 12 hours; monitor liver damage.  Client Education Handout available online  12 Blackwell’s Five-Minute Veterinary Consult A Acidosis, Metabolic effects of catecholamines. In mildly acidemic Toxins—ethylene glycol, salicylate, conditions (pH >7.2), effects of increased paraldehyde, methanol intoxication. sympathetic stimulation predominate and Hyperphosphatemia (see Hyperphos- ­ BASICS result in mild increase in heart rate and cardiac phatemia)—raises AG. At a pH of 7.4, each DEFINITION output. More severe acidemia (pH 1 year after treat- discontinue drug until ulcers resolve, then blastomycosis in dogs. J Vet Intern Med ment; a second course of azole treatment 2011, 25:440–445. restart at half the previous dose. cures most patients; drug resistance has not Spector D, Legendre AM, Wheat J, et al. Amphotericin B Toxicity been observed. Antigen and antibody testing for the Only absolute contraindication to therapy With early detection of blastomycosis, the diagnosis of blastomycosis in dogs. J Vet is anaphylaxis, but major limiting factor is prognosis in cats appears similar to dogs. Intern Med 2008, 22:839–843. cumulative nephrotoxicity. Author Daniel S. Foy Monitor serum creatinine concentration Consulting Editor Amie Koenig throughout therapy—elevation above normal or 20% greater than baseline considered significant. ­ MISCELLANEOUS  Client Education Handout ZOONOTIC POTENTIAL available online Yeast form is not spread from animals to humans, except through bite wounds; ­ FOLLOW-UP inoculation of organisms from dog bites has PATIENT MONITORING occurred. Serum chemistry—monthly to monitor for Avoid cuts during necropsy of infected dogs hepatic toxicity, or if anorexia develops. and avoid needle sticks when aspirating lesions.  182 Blackwell’s Five-Minute Veterinary Consult Blepharitis B erythematosus (SLE), SH, drug eruption. Type IV (cell mediated)—contact and flea bite hypersensitivity; drug eruption. ­ BASICS ­ DIAGNOSIS Bacterial DEFINITION Hordeolum—localized abscess of eyelid DIFFERENTIAL DIAGNOSIS Inflammation of outer (skin) and middle glands, usually staphylococcal; may be external Clinical signs are diagnostic. (muscle, connective tissue, and glands) (sty in young dogs, glands of Zeis) or internal CBC/BIOCHEMISTRY/URINALYSIS portions of eyelid, usually with secondary (in old dogs, meibomian glands). Generalized Usually normal unless metabolic cause (e.g., inflammation of palpebral conjunctiva. bacterial blepharitis and meibomianitis—usually diabetic dermatosis). PATHOPHYSIOLOGY Staphylococcus or Streptococcus. Bartonella OTHER LABORATORY TESTS Inflammation—immune mediated, henselae—chronic blepharoconjunctivitis in cats. Indicated for systemic disorders, including infectious, endocrine mediated, self- and Pyogranulomas. SH—young and old dogs. hypothyroidism. external trauma, parasitic, radiation, Neoplastic nutritional. Inflammatory response often DIAGNOSTIC PROCEDURES Sebaceous adenomas and exaggerated because conjunctiva is rich in Eye examination—inciting cause, corneal adenocarcinomas—from meibomian gland. mast cells and densely vascularized. ulcer, foreign body, distichia, ectopic cilia, Squamous cell carcinoma—white cats. Meibomian gland dysfunction—bacterial keratoconjunctivitis sicca (KCS). Ancillary Mast cell—may appear as swollen, hyper­- lipases alter meibomian lipids and plug gland; ocular tests— fluorescein, Schirmer tear test. emic lesion. produce irritating fatty acids, enhance Thorough history and dermatologic exam: bacterial growth, and destabilize tear film. Other ◦ Cytology—deep skin scrape, conjunctival External trauma—eyelid lacerations, scrape, or exudate from glands and pustules. SYSTEMS AFFECTED thermal or chemical burns. Mycotic— ◦ Wood’s light evaluation, dermatophyte Ophthalmic dermatophytosis; systemic fungal granulomas. culture. ◦ KOH preparation. ◦ Intradermal SIGNALMENT Parasitic—demodicosis; sarcoptic mange; skin testing, other testing for hypersensitivity- See Causes. Cuterebra and Notoedres cati. Note: Demodex induced disease. ◦ Consider referral to a injai has a propensity for sebaceous glands dermatologist for refractory cases. Aerobic SIGNS and can be associated with meibomian gland bacterial culture and sensitivity—of exudate Serous, mucoid, or mucopurulent ocular dysfunction in dogs, including chalazia and from skin, conjunctiva, expressed meibomian discharge. Blepharospasm. Eyelid granulomatous blepharitis. Chalazia—ster- glands, or pustules; often will not recover hyperemia, edema, and thickening. ile, yellow-white, painless meibomian gland Staphylococcus from patients with chronic Pruritus. Excoriation. Depigmentation— swellings caused by granulomatous inflamma- meibomianitis and suspected SH. Immuno­ skin, hair (in Siamese-type cats with color