Fungal and Parasitic infections Flashcards

Question

What is Ascariasis?

Answer 1

CH 291: ASCARIS LUMBRICOIDES - Ascariasis - Roundworms - Most prevalent human helminthiasis in the world, topical areas - Highest rate in preschool/school-age children Transmission - Hand to mouth and ingestion of contaminated fruits and veggies

Answer 2

Patho - After ingestion, Ova hatch in the SI à larvae penetrate intestinal wall and migrate to the lungs hematogenously --> pulmonary ascariasis entering alveoli, bronchi and trachea --> swallowed and returned to SI as adult worms

Answer 3

Dx: 1. Stool exam + Kato-Katz thick smears – combination produces best diagnostic yield. Eggs in stool 2. Micro exam of fecal smears 3. Cbc – eosinophilia 4. Sputum analysis – larvae or Charcot-Leyden crystals (collections of crystalloid composed of eosinophilic proteins) 5. Abdominal UTZ – mechanical bowel obstruction depicting hypoechoic tubular structures with welldefined echogenic walls (worms)

Answer 4

Mgt 1. Mebendazole 500mg SD po 2. Albendazole 400mg SD po 3. Ivermectin 150-200 ug/kg po SD 4. Nitazoxanide 100mg po BID x 3d for 1-3yo; 200mg BID for 4-11yo; 500mg BID for adolescents 5. Piperazine citrate 75mkd x 2 d – DOC for intestinal/ biliary obstruction. Causes NM paralysis of the parasite and rapid expulsion of the worms 6. Surgery – for severe obstruction Prevention 1. Deworming programs 2. Improving sanitation and sewage facilities

Answer 5

- Pinworm - White threadlike worm - Perianal area - Humans are the only known host - Highest in 5-14yo, crowded living conditions IP: eggs embryonate within 6h and remain viable for 20d, matures to adult in 36-53d Transmission - Fecal-oral or ingestion - autoinoculation

Answer 6

Patho - Gravid female --> migrate to perianal area at night - Sx caused by mechanical stimulation and irritation, allergic reactions, and migration of the worms to anatomic sites where they can become pathogenic

Answer 7

CM 1. Nocturnal perianal pruritus 2. No eosinophilia 3. Complications: appendicitis, chronic salphingitis, PID, peritonitis, hepatitis, ulcerative GI lesions Dx: 1. Scotch tape swab: early AM to look for eggs Mgt: 1. Mebendazole 100mg SD, then repeat after 2 wks 2. Albendazole 400mg po SD then repeated after 2 wks - DOC 3. Pyrantel pamoate 11mg/kg tid x1d then repeat after 2 wks 4. Morning bathing, freq changing of bed sheets Prevention: 1. Repeat tx every 3-4mos if with repeated exposure 2. Good hand hygiene

Answer 8

CH 281: ENTAMOEBA HISTOLYTICA - Amebiasis - 2nd leading cause of parasitic death Transmission - Fecal oral route, oral-anogenital sex - Cysts are resistant to harsh environmental condition, chlorination, gastric acidity and digestive enzymes - Can be killed by heating water to 55C Patho - Ingestion of cysts à trophozoites (intestines) à tissue invasive and kill epithelial cells, neutrophils, monocytes, and macrophages - Trophozoite form causes intestinal and tissue invasion - Flask shaped ulcers - in the liver, causes abscesses

Answer 9

CM 1. 90% asx’c 2. Loose stools and fever, tenesmus, blood streaked stools, HABS 3. Amoebic colitis: (-) constitutional sx, colicky abd pain, freq bowel movt (6-8x), tenesmus 4. Liver abscess: rare, fever + tender hepatomegaly, abd distention - Fever is hallmark of amebic liver abscess CM 1. 90% asx’c 2. Loose stools and fever, tenesmus, blood streaked stools, HABS 3. Amoebic colitis: (-) constitutional sx, colicky abd pain,freq bowel movt (6-8x), tenesmus 4. Liver abscess: rare, fever + tender hepatomegaly, abd distention **Fever is hallmark of amebic liver abscess

Answer 10

Dx 1. Clinical + E.histolytica in stool microscopy (trophozoites) - Confirm cure, repeat stool exam 2 weeks after tx - heme(+) 2. CBC – moderate anemia, leukocytosis without eosinophilia 3. ESR high, elev ALP and transaminases, bilirubin 4. Low albumin 5. UTZ, CT or MRI – single abscess in the R hepatic lobe 6. Indirect hemmaglutination – most sn serologic test

Answer 11

Mgt: 1. Metronidazole 35-50 mkd TID x 7-10d 2. Tinidazole 50mkd OD x 3d (3-5d if liver abscess) Followed by: 3. Paromomycin – DOC. 25-35 mkd TID x7d 4. diloxanide furoate 20mkd TID x 7d - Diloxanide better because amebicidal vs trophozoite and cyst forms, even in asymptomatic carriers. Failure to administer this Rx will not eradicate infection 5. Iodoquinol 30-40 mkd TID x20d For asx’c intestinal colonization 6. Paromomycin, diloxanide furoate, iodoquinol 7. Surgery – for intestinal perforation or toxic megacolon 8. Liver abscess – metronidazole, tinidazole Prognosis: - Asymptomatic carrier state in most - Extraintestinal infection 5% mortality rate Prevention 1. Proper sanitation 2. Regular examination of food handlers

Answer 12

- Malaria - Predominant in SE Asia: P.vivax & falciparum - Incomplete immunity, allows reinfection 1. P. falciparum = fever variable = mature & immature RBC 2. P. vivax & ovale = 48h = immature RBC. Persists in liver -> relapse 3. P. malaria = 72h = mature RBC Patho - Anopheles female mosquito

Answer 13

2 phases: 1. Exoerythrocytic – hepatic cells, 1st phase 2. Erythrocytic – RBC; 2nd phase 4 Pathologic process in malaria: 1. Fever: RBC rupture --> parasitemia 2. Anemia: hemolysis, splenic sequestration, BM suppression 3. Immunopathologic events --> excessive proinflamm cytokines --> tissue anoxia, hypergammaglobulinemia, immunosuppression 4. Tissue anoxia --> obstruction to blood flow (adherence of infected RBC to endothelium) --> vascular leakage of blood, protein and fluid -- > cumulatively, these lead to cerebral, cardiac, pulmo, intestinal, renal and hepatic failure.

Answer 14

Transmission: - Blood transfusion, contaminated needles, transplacental

Answer 15

IP: P.falciparum=9-14d P.vivax=12-17d P.ovale=16-18d P.malariae=18-40d

Answer 16

CM: 1. Prodromal sx (2-3d): headache, fatigue, anorexia, myalgia, LG fever, chest pain, abd pain, arthralgia 2. Paroxysms of fever alternating with periods of fatigue, but otherwise relative wellness, chills, anemia, and splenomegaly 3. Uncomplicated malaria – fever with alternating fatigue but otherwise relatively well - HG fever, severe headache, sweats, myalgia - Nausea & vomiting, abdominal pain, diarrhea - Hepatosplenomegaly, pallor 4. Severe malaria – sz, impaired consciousness, prostration/weakness, poor UO, signs of pulmonary edema, abN spontaneous bleeding, signs of organ dysfunction, jaundice, hyperparasitemia (>2% parasitized RBC), severe anemia, metabolic abN (acidosis, hypoglycemia), hemoglobinuria 5. Congenital malaria – abortion, miscarriage, stillbirth, PT, IUGR, fever, restlessness, drowsiness, pallor, jaundice, poor feeding, v/d, cyanosis, hepatosplenomegaly

Answer 17

Dx 1. Always ask for travel hx (Malaysia, Indonesia, Singapore, PH: Palawan & Mindanao) 2. Microscopy – gold standard a. Thick smear: scan large # of RBC b. Thin smear: ID species, % infected RBC, tx response 3. CBC: anemia, thrombocytopenia, N or low leukocyte count 4. Elev ESR 5. PCR 6. Rapid diagnostic test kits – for: no microscopy center,

Answer 18

Mgt (DOH) 1. P. falciparum/malariae: medical emergency - Uncomplicated 1st line: 4 days tx as follows: Coartem (arthemeter 20mg-lumefantrine 120mg) on days 1-3 à primaquine 0.5 mg base/kg qd on day 4 - 2nd line tx/ Severe malaria: 7d quinine 10 mg base/kg q8 + Clindamycin 10 mg/kg BID x 7d Alt: Tetracycline 25 mkd po QID or Doxycycline 2.2mg/kg BID or 3d clindamycin 20mkd TID - Return visit at d14, 21, 28: monitor tx and failure - Iv tx until parasitemia <1% - Severe: 1st line: Artesunate 3mkdose in NaHCO3 2nd line: quinine 10 mg salt/kg LD then 10mg q12 MD + Clindamycin 10mkd BID x 7d 2. P. ovale/vivax 1st line: Uncomplicated: chloroquine 10 mg base/kg po on days 1-2 then 5 mg base/kg on day 3 + Primaquine 0.25 mkd SD x 1-14d - 2nd line: AL 20mg/120mg in 6 doses in 65h + Primaquine 0.25 mgbse/kg on D1 3. Artesunate : DOC for severe malaria

Answer 19

Complic P.falciparum is the most severe, most complications P.malariae is the mildest, most chronic 1. Severe anemia – most common 2. Cerebral malaria 3. Hypoglycemia 4. Circulatory collapse (algid malaria) 5. Sz 6. Thrombocytopenia 7. Renal failure, RD, algid malaria, bleeding diatheses 8. Splenic rupture – from P.vivax 9. Nephrotic syndrome – from P.malariae

Answer 20

Prevention 1. Chemoprophylaxis - Doxycycline 2mg/kg 100mg daily 2-3 days before à 4 weeks after - Mefloquine 250mg weekly, 1 wk before travel à 4 weeks after - Chloroquine 5mkdose po q7d (start 1 wk prior and continue 4 wks after exposure) 2. Avoid outdoors from dusk to dawn, permethrintreated mosquito netting, mosquito repellent (DEET >2mos old)