Van: Parasitic Infections

Van: Parasitic Infections Tuesday, October 29, 2024 11:41 PM Parasitic Infections: Protozoa & Ectoparasite Infection Trichomoniasis General Info Trichomonas vaginalis (protozoan) Prevention Treatment (Adult) • Male partners should also receive treatment • Don’t want them to be carriers • Consistent and correct use of condoms • Metronidazole • Take w/ food • BBW for carcinogenicity → Limit use to approved indications only • Tinidazole • Take w/ food • BBW for carcinogenicity → Limit use to approved indications only; avoid chronic use • Patients advised to abstain from sex until they and their sex partners are treated; test for other STIs Giardiasis Giardia lamblia (protozoan) • Infection occurs via ingestion of cysts • Good hand hygiene • Food and water precautions • Safe sex practice • Metronidazole – off-label • Tinidazole – preferred • Nitazoxanide • Take w/ food • Rehydration therapy Amebiasis Entamoeba histolytica • Infection occurs (protozoan) via ingestion of cysts • Good hand hygiene • Rehydration therapy • Food and water precautions • Treat even if asymptomatic (unless E. dispar) • Avoid sexual practices that may • Symptomatic intestinal and extraintestinal disease: lead to fecal exposure • Metronidazole or Tinidazole • THEN ○ (Luminal amebicide) Paromomycin ▪ Take w/ food ○ Asymptomatic: Paromomycin Cryptosporidiosis Cryptosporidium spe. • Infection occurs (protozoan) via ingestion of oocysts • Good hand hygiene • Hand sanitizer does not kill • Use soap + water • Avoid contaminated bodies of water • Food and water precautions • Safe sex practice • No pools if having diarrhea Scabies Sarcoptes scabiei (ectoparasitic mite) • Avoid direct contact w/ infested • 1st line: persons/pets or their clothing, • Topical permethrin 5% cream to entire body (except face, bedding, etc. mucous membranes, and eyes), leave on for 8-14 hours • All close contacts should be before removing (shower or bath); reapply 1 week later checked and treated • Ivermectin appropriately • Spinosad 0.9% suspension • ± Topical corticosteroids or antihistamines PRN itching Lice • Ectoparasite Pediculus humanus • Avoid direct contact w/ infested • 1% permethrin lotion (OTC) – use with nit combs corporis/capitis (causing body persons/pets or their clothing, • Spinosad 0.9% (if lice resistant to permethrin, Rx) lice and head lice respectively) bedding, etc. • Calamine lotion for itching • Other members of the family should be treated Notes • DIAGNOSIS • Stool microscopy with direct fluorescent Ab • DIAGNOSIS • 1. Stool microscopy = non-definitive • 2. EIA or PCR = confirmatory • May resolve on its own in 7-14 days in healthy people • Rehydration therapy, avoid lactose-containing products • Nitazoxanide • DIAGNOSIS • Identifying characteristic rash (burrows), skin scrapings Malaria • 4 predominant Plasmodia species that cause malaria ○ P. falciparu ○ P. vivax ○ P. malariae ○ P. ovale (protozoa) • Diagnosis: Microscopy • Chemoprophylaxis Principle ○ Recommended for all those travelling to areas where malaria exposure possible ○ All options are equally effective if no resistance present (>90%) ○ Malarone has fewer AE’s; although more costly ○ Short-term travel ▪ Malarone, also primaquine/tafenoquine for traveling to places with P. vivax ○ Long-term travel ▪ Mefloquine (Qweek dosing), also chloroquine/hydroxychloroquine but there is possible resistance ○ G6PD testing prior to Tafenoquine, Primaquine → cause hemolytic anemia in patients with G6PD deficiency ○ Sun sensitivity is large concern for doxycycline ○ Psychiatric patients: avoid mefloquine, tafenoquine Drug AEs Chloroquine (Aralen®) Serious: QT prolongation • Weekly dosing (good choice for long trip) • Patients may already be on hydroxychloroquine for rheumatoid arthritis • Ok in all trimesters of pregnancy (DOC) • Widespread resistance Weekly • May exacerbate psoriasis • Dosing must start 1-2 weeks prior and continue for 4 weeks after return (not a good choice for last-minute travelers or for short trips) Mefloquine (Lariam®) Insomnia, abnormal dreams, dizziness, seizure • Weekly dosing (good choice for long trips) • DOC in pregnancy for chloroquine resistant areas • • • • Atovaquone/ Proguanil (Malarone®) Common: GI issues, headache, N/V • • • • No resistance issues Ok for imminent departure/shorter trips Well-tolerated Pediatric strength tablets available • Last line in pregnancy, breastfeeding • Not recommended in severe renal impairment (CrCl <30mL/min) • High cost Daily Doxycycline (Vibramycin®) Photosensitivity • • • • No resistance issues Ok for imminent departure May prevent other infections Tend to be least expensive • Contraindicated in pregnancy and age < 8 y/o • Must continue dosing for 4 weeks after return (not a good choice for short trip) • Not recommended in women who are prone to vaginal yeast infections Daily Primaquine Abdominal pain, GI upset, QT prolongation • Highly effective medication against sensitive P. vivax (good choice for travel to places with >90% P. vivax) • Ok for imminent departure or short trips • Must test for G6PD deficiency Daily • Contraindicated in pregnancy • Cannot be used by women who are breastfeeding (unless the infant has also been tested for G6PD deficiency) Tafenoquine (Arakoda®) Headache, diarrhea, back pain • Ok for imminent departure or short trips • Must test for G6PD deficiency • Contraindicated if history of psychiatric illness • (i.e. history of psychotic disorders or current psychotic symptoms)/breastfeeding (when the infant is found to be G6PD deficient or if G6PD status of the infant is unknown) • Cannot be used by pregnant women/children Hydroxychloroquine (Plaquenil®) Pros Cons Resistance developing Contraindicated if history of psychiatric illness Not recommended if certain cardiovascular diseases or seizures Dosing 2 weeks prior & continue for 4 weeks after return (not a good choice for last-minute travelers or for short trips) Dose Weekly Daily then weekly • Treatment ○ Rapid malaria diagnosis, especially of P. falciparum, is essential because antimalarial therapy given within 48 to 72 hours can decrease risks of highmortality complications such as hypoglycemia, pulmonary edema, and renal failure ○ Artemisinin-based antimalarials → treat P. falciparum malaria ▪ Only artemether-lumefantrine (Coartem®) approved for use in US • Administer with full meal to improve absorption. May crush tablets and mix with 5-10 mL of water, administer to patient, rinse container with water and administer contents to the patient, followed by food/drink if possible. Repeat dose if vomiting occurs within 2 hours of administration. • Generally safe for use in pregnancy • Monitoring: ECG if on other QT prolonging agents • Drug interactions: CYP3A4 inhibitors/inducers & grapefruit juice • Contraindications: concurrent use with strong CYP3A4 inducers (such as rifampin, carbamazepine, phenytoin, St. John’s wort); hypersensitivity to any component of the formulation • AE’s >30%: headache, anorexia, dizziness, asthenia, arthralgia and myalgia • Patients ≥35 kg: ○ Four tablets at hour 0 and hour 8 on the first day ○ Then 4 tablets twice daily on day 2 and day 3 (total of 24 tablets per course) • Indications: ○ Treatment of acute, uncomplicated malaria infections due to Plasmodium falciparum, including geographical regions where chloroquine resistance has been reported ▪ IV artesunate • DOC for the treatment of severe malaria • Can be used in infants, children, and pregnant women • Well-tolerated; but rare, delayed post-artemisinin hemolytic anemia noted • If not in stock, should consider interim treatment with an effective oral antimalarial while obtaining IV artesunate emergently from a commercial source • Preferred antimalarial for interim oral treatment: artemether-lumefantrine (Coartem® ) • Artemether-lumefantrine (Coartem® ): preferred follow-on treatment after IV artesunate