ID 2 (2).pptx

PHAS 6300 Family Practice Infectious Diseases 2 bacteria Some notable Bacteria Shigella Salmonella S. pneumoniae Neisseria meningitidis Listeria monocytogene s  Causative agent Shigella sonnei (most common in US)...

PHAS 6300 Family Practice Infectious Diseases 2 bacteria Some notable Bacteria Shigella Salmonella S. pneumoniae Neisseria meningitidis Listeria monocytogene s  Causative agent Shigella sonnei (most common in US) Shigella flexneri Shigella dysenteriae Shigellosis Epidemiology The human intestinal tract represents the major reservoir of Shigella Shigella is both more common and more dangerous in the pediatric population  Transmission Fecal-oral route Shigellosis Symptoms Colonic dysentery Lower abdominal pain, abdominal cramps, explosive watery diarrhea that progresses to mucoid and bloody diarrhea with tenesmus, fever, chills, anorexia, malaise and headaches.  Shigellosis Diagnosis Stool culture + Fecal WBCs and RBCs Sigmoidoscopy may reveal punctate areas of ulceration and inflammation Treatment Oral hydration/ electrolyte replacement Avoid antimotility drugs (Loperamide) Antibiotics (Fluoroquinolones) only if fever high, dysentery is severe, and stool culture is positive  Nontyphoidal Salmonella Causative agent: Salmonella enteriditis Salmonella typhimurium Notes Very common foodborne infection. Linked to poultry, eggs, milk, contact with reptiles and other exotic pets Nontyphoidal Salmonella Symptoms Malaise Headaches Nausea Vomiting Fever Abdominal cramping Diarrhea that may become bloody ‘Pea soup’ diarrhea (brown- green color) Typhoid fever (AKA enteric fever) Causative agent Salmonella enterica serotype typhi Transmission Fecal-oral Linked to poor sanitation Endemic in parts of Latin America, Asia and Africa Typhoid fever (AKA enteric fever) Symptoms Enteric fever Chills, abdominal pain, fever Pea soup diarrhea Sometimes bloody diarrhea Rose spots – faint pink or salmon colored macular rash that spreads from Salmonella (Typhoidal and nontyphoidal) Diagnosis Stool culture Stool studies + for fecal WBCs and RBCs Treatment Oral hydration/ electrolyte replacement Typhoidal – Antibiotics Antibiotics only prescribed for nontyphoidal if fever high, dysentery is severe, and stool culture is positive Acute bacterial meningitis Common bacteria Streptococcus pneumoniae  most common overall Neisseria meningitidis  most common for patients aged 10-19 years old Listeria monocytogenes  increased incidence in immunocompromised populations including > 50 y/o, HIV, chemotherapy, others Acute bacterial meningitis Symptoms Triad of meningitis: Fever, headache, nuchal rigidity Meningeal symptoms Headache, fever, neck stiffness, photosensitivity, chills, nausea, vomiting, Severe disease Confusion, altered mental status, seizures Acute bacterial meningitis Physical exam Neck stiffness + Brudzinski / Kernig signs Petechial rash on the skin or mucus membranes + meningeal signs suggests N meningitidis  Diagnosis Treatment Lumbar Antibiotics puncture and Vancomycin Acute CSF and bacterial examination Ceftriaxone for meningiti Head CT can be most patients considered for (empiric tx) s some patients if there is a Dexamethasone possibility of an intracranial mass Quiz time! Viruses Influenza Epidemiology Other high risk Usually occurs in the fall or comorbidities winter in temperate Asthma climates Morbid obesity Children have the highest rates of infection Immune deficiency Individuals >65 are at the Diabetes highest risk for Any diseases affecting: complications Lungs 80-90% of deaths Heart 50-70% of Liver CNS hospitalizations Influenza Symptoms Signs Abrupt onset of fever, Generally few chills, headache, malaise, Possibly some myalgias, headache, pharyngeal injection, flushed face or rhinorrhea, congestion, conjunctival redness pharyngitis, substernal Cervical soreness lymphadenopathy Vomiting and diarrhea are and tracheal not common but occurs in tenderness is 10-20% of children possible, but more common in children. Elderly patients may present with confusion Influenza Treatment Prognosis Supportive treatment Generally excellent in Oseltamivir (Tamiflu) healthy individuals If previously healthy The duration of the presenting within 48 uncomplicated illness hours of symptoms is 1-7 days onset) Most fatalities are due Or if pregnant, hospitalized, or have a to bacterial pneumonia high risk of or exacerbations of complications other diseases  Rabies Causative agent Rhabdovirus Transmission Infected saliva from rabid animal bites Bats are most common Also common in raccoons skunks and foxes Rabies symptoms Prodrome CNS stage Prodrome Encephalitis Pain, paresthesias or Delirium, pruritus at or near hydrophobia, the bite hypersalivation Nonspecific symptoms: fever, Paralysis malaise, headache, Acute ascending nausea, vomiting paralysis similar to Guillain Barré  Rabie s Diagnosis Animal observation PCR of saliva Pets that bite but are behaving Serum anti- normally can be monitored for rabies 7-10 days after a bite antibodies Wild animals that bite humans Immunofluoresc should be decapitated and the head shipped to a lab for ent staining of testing Skin biopsy Raccoons, skunks, bats and CSF foxes that bite humans should be presumed to be rabid.  Rabies Treatment of animal bites suspicious for rabies Wound irrigation with soap and water 100% effective if initiated within 3 hours Postexposure prophylaxis HCDV (Rabies vaccine) (4 shot series over 2 weeks) HRIG (Rabies immune globulin) Symptomatic patients There is no established management The vast majority of cases are fatal.  Zika Virus Epidemiology Common in Central and South America Transmission Aedes mosquito bites Can also be spread sexually  oral, vaginal or anal Can also be spread via maternal-fetal route Zika Virus Symptoms Most infected people are asymptomatic Possible symptoms: Low-grade fever, lymphadenopathy maculopapular pruritic rash, arthralgias, conjunctivitis, hyperemia and petechiae of the hard palate Hematospermia in males  Zika Virus Associated conditions Diagnosis Serum or urine Congenital Zika syndrome Zika virus IgM is the initial test Microcephaly of choice Intracranial cerebral malformation PCR can be Ocular lesions used as a Congenital contractures/ screening in hypertonia pregnant women Guillain-Barré syndrome Other permanent neurological Infectious Mononucleosis (Mono) Causative agent Clinical Manifestations Epstein-Barr virus Pharyngitis, fever, fatigue, pharyngitis (EBV) aka Human Tonsillar exudate/ petechiae Herpes Virus 4 of the hard palate Lymphadenopathy Usually posterior cervical but Transmission can be anterior Saliva: ‘The kissing Splenomegaly, sometimes hepatomegaly disease’ Maculopapular rash in ~5% Especially if given amoxicillin or ampicillin Epidemiology 90% of adults of are Infectious Mononucleosis (Mono) Diagnosis Treatment Heterophile antibody Generally test (monospot) is supportive test of choice Corticosteroids in Serum EBV specific very severe antibodies disease. Peripheral smear may Avoid excessive/ show “Downey cells” - atypical dangerous exercise lymphocytes x 1 month to reduce risk of splenic rupture Rare complications of EBV Splenic rupture Malignancies Airway obstruction Lymphomas (secondary to Nasopharyngeal lymphadenitis carcinomas Hemolytic anemia Gastric carcinomas Thrombocytopenia Hairy leukoplakia Cytomegalovirus (CMV) AKA Human herpes Clinical manifestations virus 5 Usually asymptomatic in Transmission immunocompetent Can cause ‘CMV Body fluids or mononucleosis’ maternal-fetal fever, cough, myalgias, arthralgias, rash Present in 70% of Tonsillar exudate, cervical people in the US. lymphadenopathy are rare  Cytomegalovirus (CMV) Secondary CMV reactivation Most common in immunocompromised people Clinical Manifestations CMV colitis CMV retinitis CMV esophagitis CMV Pneumonitis Cytomegalovirus (CMV) Diagnosis Management CMV mononucleosis Primary IgM antibodies to CMV disease Supportive Reactivation CMV IgG antibodies to CMV Severe or Tissue biopsy – Owl’s eye reactivation appearance. Especially useful if Antivirals CMV related GI or lung disease (Gancicovir) Quiz time 2 Human Immunodeficiency virus (HIV) The hallmark of symptomatic HIV infection is immunodeficiency caused by continuing viral replication and infection of immune cells. The virus can infect all cells expressing the CD4 receptor, which HIV uses to attach to the cell. Human Immunodeficiency virus The cell principally infected is the CD4 (helper-inducer) lymphocyte, which directs many other cells in the immune network. However, HIV can infect any cell with CD4 receptors, including macrophages, dendritic cells, and monocytes.  HIV With increasing duration of infection, the number of CD4 lymphocytes falls and immunodeficiency worsens. Some of the immunologic defects, however, are explained not by quantitative abnormali ties of lymphocyte subsets but by qualitative defects in HIV associated infections HIV associated diseases Certain infections may occur at any CD4 count, while others rarely occur unless the CD4 lymphocyte count has dropped below a certain level.  Candidiasis Causative agent Candida albicans Part of the normal GI and GU flora Most common opportunistic pathogen Symptoms depend on the location of the infection Diagnosis Can be made with a Potassium hydroxide (KOH) smear Usual findings are budding yeast, hyphae and psuedohyphae  Oral candidiasis Symptoms Unpleasant taste Mouth dryness Signs Psuedomembranous candidiasis White plaques that can be scraped off Erythematous Red friable plaques  Oral candidiasis Treatment Clotrimazole troches Oral fluconazole if not improving Ketoconazole cream for angular cheilitis  Esophageal candidiasis Epidemiology Very rare among non- immunocompromised Rare with CD4>200 Common with CD5