Parasitic Infections Overview PDF

MANAGEMENT OF PARASITIC INFECTIONS BY: Dr. OKIDI OSCAR P’OKELLO SCHISTOSOMIASIS Schistosomiasis (Bilharziasis) Disease of the large intestine and the urinary tract due to infestation by a Schistosoma blood fluke. Causes: The larvae form (cercariae) of Schistosoma penetrate the skin fr...

MANAGEMENT OF PARASITIC INFECTIONS BY: Dr. OKIDI OSCAR P’OKELLO SCHISTOSOMIASIS Schistosomiasis (Bilharziasis) Disease of the large intestine and the urinary tract due to infestation by a Schistosoma blood fluke. Causes: The larvae form (cercariae) of Schistosoma penetrate the skin from contaminated water and they migrate to different parts of the body, usually the urinary tract (Schistosoma haematobium) and the gut (S. mansoni) Clinical features of Schistosomiasis S. haematobium (urinary tract) Painless blood stained urine at the end of urination - terminal haematuria Frequent and painful micturition In females: low abdominal pain and abnormal vaginal Discharge Late complications: fibrosis of bladder and ureters with increased UTI risks, hydronephrosis (excess fluid in kidneys), infertility Clinical features of Schistosomiasis S. mansoni (gastrointestinal tract) Abdominal pain, frequent stool with blood-stained mucus, hepatomegaly Chronic cases: hepatic fibrosis with cirrhosis and portal hypertension, haematemesis/melena are frequent  Schistosomiasis Differential diagnosis Cancer of the bladder (S. haematobium) Dysentery (S. mansoni) Investigations History of staying in an endemic area (exposure to water bodies) Urine examination (for S. haematobium ova) Stool examination (for S. mansoni ova) Rectal snips (for S. mansoni)  Management of Schistosomiasis TREATMENT Praziquantel 40 mg/kg single dose Refer patient if they develop obstruction or bleeding Prevention Avoid urinating or defecating in or near water Avoid washing or stepping in contaminated water Effective treatment of cases Clear bushes around landing sites LEISHMANIASIS  LEISHMANIASIS A chronic systemic infectious disease transmitted by the bite of a sand fly. Cause: Flagellated protozoa Leishmania species Clinical features of Leishmaniasis Visceral Leishmaniasis (Kala-azar) Chronic disease characterized by fever, hepatosplenomegaly, lymphadenopathy, anaemia, leucopenia, progressive emaciation and weakness Fever of gradual onset, irregular, with 2 daily peaks and alternating periods of pyrexia The disease progresses over several months and is fatal if not treated After recovery from Kala-azar, skin (cutaneous) leishmaniasis may develop  Clinical features of Leishmaniasis Cutaneous and Mucosal Leishmaniasis (Oriental sore) Starts as papule, enlarges to become an indolent ulcer Secondary bacterial infection is common  Leishmaniasis Differential diagnosis Other causes of chronic fever, e.g. brucellosis (For dermal leishmaniasis) Other causes of cutaneous lesions, e.g. leprosy Investigations Stained smears from bone marrow, spleen, liver, lymph nodes, or blood to demonstrate Leishman Donovan bodies Culture of the above materials to isolate the parasites Serological tests, e.g. indirect fluorescent antibodies Leishmanin skin test (negative in Kala-azar) Treatment of Leishmaniasis Cutaneous Leishmaniasis (all patients) Frequently heals spontaneously but if severe or persistent, treat as for Visceral Leishmaniasis below Visceral Leishmaniasis (Kala-azar): All patients Combination: Sodium stibogluconate 20 mg /kg per day IM or IV for 17 days Plus paromomycin 15 mg/kg [11 mg base] per day IM for 17 days  Treatment of Leishmaniasis Alternative first line treatment is: Sodium Stibogluconate 20 mg/kg per day for 30 days (in case paromomycin is contraindicated) In relapse or pregnancy Liposomal amphotericin B (e.g. AmBisome) 3mg/kg per day for 10 days In HIV+ patients Liposomal amphotericin B 5 mg/kg per day for 8 days  Treatment of Leishmaniasis Post Kala-Azar Dermal Leishmaniasis (PKDL) Rare in Uganda Sodium Stibogluconate injection 20 mg/kg/day until clinical cure. Several weeks or even months of treatment are necessary Note: Continue treatment until no parasites detected in 2 consecutive splenic aspirates taken 14 days apart Patients who relapse after a 1st course of treatment with Sodium stibogluconate should immediately be retreated with Ambisome 3 mg/kg/day for 10 days  Leishmaniasis Prevention: Case detection and prompt treatment Residual insecticide spraying Elimination of breeding places TRYPANOSOMIASIS  Human African Trypanosomiasis (Sleeping Sickness) A disease caused by trypanosomes (a protozoa) and transmitted to humans by several species of tsetse fly Cause: Trypanosoma rhodesiense (mostly in the Central and Eastern regions of Uganda) Trypanosoma gambiense (mostly in West Nile region)  Human African Trypanosomiasis Clinical features May be history of tsetse fly bite and swelling at site of bite after 7-14 days (more often in T. rhodesiense, rarely in T.Gambiense) T. Rhodesiense Incubation is 2-3 weeks Early stage (haemolymphatic stage): headache not responding to common analgesics, fever, generalised lymphadenopathy, joint pains Late stage (meningoencephalitis stage): after some weeks, neurological and psychiatric symptoms like apathy, day sleepiness, paralysis, seizures If not treated: cachexia, lethargy, coma and death within 3-6 months  Human African Trypanosomiasis T. gambiense Similar to the rhodesiense but less acute and with slower progression Incubation can last several years  Human African Trypanosomiasis Differential diagnosis Malaria, meningitis TB, HIV/AIDS Investigations Blood: Slides for trypanosomes CSF: For trypanosomes, lymphocyte count Aspirate from chancre/lymph node: for trypanosomes  Human African Trypanosomiasis Management This is based on the findings of the CSF analysis, determining the stage of disease. To determine the medicine of choice, the disease is divided into two stages: early and late stage  Human African Trypanosomiasis STAGE FEATURES Early CSF is normal (first) Lymphocytes 15 years –– Nifurtimox/ Elfornithine combination therapy (NECT) –– Nifurtimox: 5 mg/kg every 8 hours orally for 10 days (15 mg/kg/day) –– Plus Eflornithine 200 mg/kg 12 hourly for 7 days (400 mg/kg/day). Dilute Eflornithine dose of 200 mg/kg into 250 ml of distilled water and administer the infusion over at least 2 hours (50 drops/minute) –– Infusions are given slowly to prevent convulsions Relapses IV melarsoprol 2.2 mg/kg once daily for 10 days  Treatment of Trypanosomiasis Note: Corticosteroids: Should be given to patients with late trypanosomiasis on melarsoprol who may have hypoadrenalism - the steroids may also reduce any drug reactions Do not give hydrocortisone after day 24, even though the melarsoprol treatment is not yet complete If prednisolone is used instead of hydrocortisone, the anti-inflammatory action is similar but the correction of the hypoadrenalism will be much less marked Suramin: Do not use this medicine for early or late stage T. gambiense treatment in onchocerciasis- endemic areas as it may cause blindness in any onchocerciasis-infected patients by killing the filariae in the eye  Treatment of Trypanosomiasis Prevention: Trapping of tsetse flies Clearing of bushes around homes and paths Early detection and treatment of cases END