protozoa Flashcards
Parasites are divided to
- Protozoa
2. Helminthes
Protozoa infections are divided to
- GI infections
- CNS infections
- Hematologic infections
- other infections (visceral infections and STD)
Protozoa GI infections - bugs and diseases
- Giardia lamblia - giardiasis
- Entamoeba histolytica - amebiasis
- Cryptosporidium - diarrhea
Giardia lamblia - disease and symptoms / seen in
Giardiasis: 1. bloating 2. flatulence
3. foul smelling, fatty diarrhea
campers + hikers
Giardia lamblia - transmission / diagnosis / treatment
cysts in water
multinucleated trophozoites or cysts in stool
treatment: metronidazole
Entamoeba histolytica - disease and symptoms
Amebasis: 1. bloody diarrhea (dysentery)
- liver abscess (anchovy paste exudate)
- RUG pain
Entamoeba histolytica - transmission / treatment
cysts in water
treatment: metronidazole
or iodoquinol for asymptomatic cyst passers
- a luminal agent, eg. paromomycin) is also recommended to eradicate intestinal colonizationcyst
- drainage is not recommended
Entamoeba histolytica infection - diagnosis
- serology and/or
- trophozoites with RBCs in the cytoplasm
or cysts with up to 4 nuclei in stool
Cryptosporidium - disease and symptoms
severe nonbloody diarrhea in AIDS Mild disease (watery diarrhea) in immunocompoment
Cryptosporidium - transmission / diagnosis
oocysts in water
diagnosis: oocysts on acid-fast stain
Cryptosporidium - treatment/prevention
prevention by filtering city water supplies
notazoxamide in immunocompetent hosts
no clear treatment for AIDS patient
Protozoa - CNS infection - bugs and diseases
Toxoplasma gondi - toxoplasmosis
Naegleria fowleri - rapidly fatal meningoencephalitis
Trypanosoma brucei - African sleeping diseas
Toxoplasma gondi infection and symptoms
- Congenital toxoplasmosis –> classic triad of chorioretinitis, hydrocephalus, intracranial calcification
- reactivation in aids –> brain abscess
Toxoplasma gondi transmission
cysts in undercooked meat (MC)
oocysts in cat feces
crosses placenta
Toxoplasma gondi - diagnosis
serology
biopsy (tachyzoite)
CT/MIR ring-enhancing lesion
Trypanosoma brucei - disease and symptoms
African sleeping disease: 1. enlarged lymph nodes
2. recurring fever 3. somnolence 4. Coma
African sleeping disease - transmission / diagnosis
Tsetse fly, a painful bit
diagnosis: Trypomastigote in blood smear
African sleeping disease - treatment
suramin for blood-borne disease
melarsoprol for CNS penetration
Naegleria fowleri - diagnosis
amoebas in spinal fluid
Malaria - fever according to bug
P. vivax/ovale –> 48hr cycle (tertian: fever on first day and third day, thus fever are actually 48hr apart)
P. falciparum –> severe. irregular fever pattern
P. malariae –> 72 hr cycle (quartan)
other complications of malaria, beside general symptoms
occlude capillaries in brain (cerebral malaria), kidney, lung (esp with P. Falciparum)
Malaria - relapse vs recrudescence
Relapse occurs in P. vivax and P. ovale infection ressults from hypnozoites –> reactivation of hypnozoites in liver
Recrudescence occurs in P. malariae and P. falciparum infections and results from incomplete eradication of the parasites
Malaria - diagnosis
- Blood smear: trophozoites ring within RBCs, schizont containing merozoites
- Red granules (Schuffner stippling) through RBC cytoplasm seen with P. vivax/ovale
Malaria - treatment for every situation
- Chloroquine (for sensitive species)
- Mefloquine or atovaquone/proquanil (for resistant)
- IV quinidine or artesunate (If life threatening) –> test for G6PD
- P. vivax/ovale add primaquine for hypnozoite –> test for G6PD
Protozoa visceral infections - bugs and disease
- Trypanosoma cruzi –> Chagas disease
2. Leishmania donovani –> Visceral leishmaniasis (kala-azar), cutaneous leismaniasis
Leishmania donovani - disease and symptoms / aka
A. Visceral leishmaniasis (kala-azar): 1. spiking fevers 2. hepatosplenomegaly 3. pancytopenia B. cutaneous leismaniasis: 1. Skin ulcers
Leishmania donovani - transmission
sandfly
Visceral leishmaniasis (kala-azar) - diagnosis / treatment
macrphages contating amastigotes
amphotericin B
sodium stibogluconate
Trypanosoma cruzi - disease / map / transmission
Chagas disease
SOUTH AMERICA
transmission: Reduviid bug (kissing bug) feces, deposited in a painless bite
Chagas disease sign
ROMANA SIGN: unilateral periorbital swelling –> characteristic of acute stage
chagas disease - diagnosis / treatment
Trypomastigote in blood smear
- Benzidazole or nifurtimox
Protozoa sexual transmitted infections - bugs and disease / symptoms
Trichomonas vaginalis –> vaginitis –> foul-smelling, greenish discharge, itching and burning
bacterial vaginosis vs protozoal vaginitis according to
vaginitis: foul-smelling, greenish discharge, itching and burning
Bcterial vaginosis: gray vaginal discharge with fishy smell, nonpainful
Trichomonas vaginalis - outside human form
cannot exits outside human because it cannot form cysts
Trichomonas vaginalis - diagnosis / treatment
trophozoites (motile) on wet mount
strawberry cervix
- Metronidazole for patient and partner (prophylaxis)
treatment for all protozoal infections (except malaria)
Giardiasis –> Metronidazole
amebiasis –> metronidazole, iodoquinol for asymptomatic cyst passers
cryptosporidium –> prevention by filtering city water supplies, nitazoxanide in immunocompetent, no clear treatment for aids
Toxoplasma gondi –> Sulfadiazine+pyrimethamine
Naegleria fowleri –> Amphotericin B
Trypanosoma brucei –> Suramin for blood-borne disease or melarsoprol for CNS penetration
Babesia –> atovaquone + azithromycin
Tripanosoma cruzi –> Benzidazole or nifurtimox
Leishmania donovavi –> amphotericin sodium stibogluconate
trichomonas vaginalis –> Metronidazole for patient and partner (prophylaxis)
Babesiosis - epidimiology / diagnosis
ixode scapularis like lyme and anaplasmosis
thin blood smear: intraerythrocytic rings (Maltese cross)
Babsiosis - manifestation
- flu like
- if severe: ARDS, CHF, DIC, splenic rupture
- anemia, thrombocytopenia, increased bilirubinm LDH, LFTs
Babesia - treatment
- atovaquone + azithromycin
- Quinine + clindamycin (if severe)
RFs for severe babesiosis
- immonucompr
- splenectomy
- older than 50
complications of malaria in children
seizure, coma, hypoglycemia, met acidosis
complications of malaria in adults
jaundice, acute renal failure, acute pulm edema
C. parvum in immunocomprement
traveler’s diarrhea - prolonged, profuse, watery - self limited in 10-14 days
E. histolytica - most common symptom
asymptomatic (only 10% has colitis) `
malaria prevention
travelers new to endemic areas require chemoprophylaxis
atovaquone - proguanil, doxycycline or melfoquine (2 weeks prior to travels, continued during statyy, discont 4 weeks after returning
other measures to protect from mosquitos
toxoplasmic encephalitis - stereotactic brain biopsy
only if not respond to antibiotic