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Parasitic Diseases Flashcards

1
Q

first-line tx for severe malaria

A

Artemisinin Derivatives (artemether-lumefantrine, artesunate)

**Retains activity vs all spp

  • SEs: hemolysis can occur after IV admin (post-artesunate delayed hemolysis) - can occur >7 days after infusion
  • resistance noted to be appearing in SE Asia (esp Cambodia)

Chloroquine (4-aminoquinolone)

in areas of known chloroquine sensitivity (i.e. Central America, Panama Canal)

  • SEs: pruritis (palms, soles, scalp), cardiac and CNS tox w/ IV tx
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2
Q

SEs of 4-aminoquinolones (antimalarials)

  1. chloroquine
  2. mefloquine
  3. quinine/quinidine
A
  1. pruritis (palms, soles, scalp), cardiac, CNS
  2. dizziness, diarrhea, N/V. Neuropsych = most serious
  3. cinchonism (combo of tinnitus, deafness, HA, visual disturbances, dysphoria, vomiting, postural hypotension). Cardiac tox (postural hypotension, QT prolongation, ventricular arrhythmias)
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3
Q

First line for malaria ppx (or tx for uncomplicated falciparum/unknown spp) in region w/ chloroquine resistance

A

atovaquone (an 8-aminoquinolone) + proguanil

Also w/ activity vs: Babesia, toxo, crypto, leishmaniasis, trichomonas

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4
Q

General dx of intestinal, liver, keratitic amebae

A

two stages: trophozoite (active feeding stage) or cysts (infectious resting form)

  • intestinal - both forms can be visualized via microscopy of stool sample. Preferred = stool Ag or PCR. Can see on histopath using PAS or H&E
  • liver - imaging (u/s, CT), serology most helpful, or can aspirate and use PCR
  • keratitis - corneal scraping for microsopy and cx
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5
Q
A

Entamoeba histolytica (diff to distinguish from other spp)

(L = trophozoite w/ ingested RBCs; R = cyst)

  • cyst - 12-15um; trophozoite - >20um
  • will see trophozoites only in abscesses
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6
Q

chronic severe diarrhea in children and IC adults

a cause of cholangitis in AIDS

A

cryptosporidium

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7
Q

Dx of Giardia

A
  • usually via demonstration of cysts in stool (occasionally trophozoite)
    • 11-12um, oval, 4 nuclei
    • trichrome, iron-hematoxylin stains
    • variable shedding - requires multiple stool samples
  • bx tissue - trichrome/Giemsa stain
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8
Q

opportunistic intestinal pathogens

(HIV-assoc diarrhea, as well as diarrhea in other IC pts)

A

think of intestinal coccidia and microsporidia

= cryptosporidium, cyclospora, cystoisospora, sarcocystis

*obligate intracellular pathogens

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9
Q

protozoan infection w/ myositis and fever

Malasia

A

sarcocystitis

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10
Q

Free-Living Amebae Pathogens

A
  • Naegleria fowleri
  • Acanthamoeba
  • Balamuthia mandrillaris
  • Sappinia pedata (new, emerging)
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11
Q

dx of acanthamoeba

A

can be cx on nutrient agar w/ layer of GN bacteria (they feed on bacteria and act as hosts for legionella, MAC, listeria)

most reliable = 18S rDNA sequencing

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12
Q

Geo spread of malaria

  • falciparum
  • vivax
  • ovale
  • malariae
A
  • all tropical regions (densest in Sub-Sarahan Africa)
  • most prevalent in Asia (also Central/South America, Middle East, N Africa)
  • Africa, Asia
  • limited to SE Asia
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13
Q

Which malaria spp persist in liver as hypnozoites and cause relapse?

A

vivax, ovale

“It’s not OVer!”

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14
Q
A

P falciparum

  • parasitised RBCs not enlarged
  • RBCs containing mature trophozoites
  • total parasite biomass = circulating parasites + sequestered parasites
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15
Q
A

P vivax (ring, trophozoites, schizonts)

  • parasites prefer young RBCs
  • RBCs enlarged
  • all stages present in peripheral blood
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16
Q
A

P malariae (ring, trophozoites, schizonts)

  • parasites prefer old RBCs
  • pRBCs not enlarged
  • all stages present in peripheral blood
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17
Q

Epi of Trypanosomal brucei sbb

  • favors riverine vegetation
  • favors savannah
A
  • Tb gambiense
  • Tb rhodesiense

related to outdoor activities

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18
Q

Most often detection of helminthic diseases

A

ID adult worm, egg, or larvae

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19
Q

Soil transmitted helminths/nematodes (roundworms)

A
  • Ascaris lumbricoides
  • Necator americanus
  • Ancylostoma duodenale
  • Trichuris trichiura
  • Strongyloides
  • Enterobius (pinworm)
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20
Q

raccoon exposure

severe encephalitis (eosinophilic) or ocular infection

A

Baylisascaris procyonis (roundworm)

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21
Q

Taiwan, Thailand

eating snails

eosinophilic meningitis

A

angiostrongyliasis (caused by molluscun-borne rat lungworm)

humans = incidental hosts

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22
Q

Dracunculiasis - epi, life cycle, infection

A
  • epi - poor communities in rural areas
    • Chad, Ethiopia, Mali
  • transmitted via small crustacean vector (Cyclops spp) - seasonal
  • larvae swallowed in stagnant water → swallowed and penetrate through gut wall into abd cavity/retroperitoneum → females induce a blister, which forms an ulcer, causing person to stick leg in water, where female emerges from SQ tissue
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23
Q

Vector for wuchereria bancrofti

A

mosquitos (culicine most common; also Aedes in Pacific Islands, Anopheles in Africa)

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24
Q

vector for Onchocerca volvulus

A

blackfly - Simulium damnosum

requires running water for larval development, so transmission occurs in close prox to water sources

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25
Q

vector of loa loa

A

deer fly (Chrysops spp) = day biters

West and Central Africa

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26
Q

natural hosts and epi of Fasciola hepatica

A

found in sheep-rearing areas (highest prevalence in Bolivia, Peru)

acq by ingestion of water/leafy plants that grow in fresh water

humans = accidental hosts

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27
Q

schistosoma spp w/ terminal spine

A

S haematobium

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28
Q

schistosoma spp that looks like the rising sun

A

S japonicum

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29
Q

Schistosoma spp with subterminal spine

A

S mansoni

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30
Q

intestinal trematode (fasciolopsis buski = giant fluke)

how transmitted

A

snails are important vectors

ingestion of raw watercress, bamboo, water chestnuts

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31
Q

alveolar echinococcus hosts

A

E multilocularis

definitive host = raccoons, foxes, domestic dogs

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32
Q

Stain most useful for ID of blood parasites

A

Giemsa stain

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33
Q

Timing of blood samples to coincide w/ peak time of microfilaremia

Day (1000-1400)

Night (2200-0200)

Anytime

A
  • Day: Loa loa
  • Night: W bancrofti, B malayi, B timori
  • Anytime: Onchocerca, Mansonella
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34
Q

Key areas of distribution for P vivax

A

Korea

former Soviet Union

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35
Q

Fever patterns of malaria

  1. erythrocyte cycle duration = 48hrs. Fever pattern = irregular tertian fever
  2. ”” = 48hrs. Fever pattern = tertian fever
  3. same as #2
  4. ”” = 72hrs. Quartan fever
  5. ”” = 24hrs. Quotidian fever
A
  1. P falciparum
    1. fever w/ no clear pattern. sounds “false”
  2. P vivax
  3. P ovale
  4. P malariae
    1. malariae is “meh” about fever (only occurs every 4 days or so)
  5. P knowlesi
    1. every day you “knowlesi” the fever is coming
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36
Q

Mgmt of complicated malaria

A

ideal = IV artesunate

alt: quinine or chloroquine

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37
Q
A

Romana sign

u/l palpebral edema at site of inoculation of T cruzi (Chagas)

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38
Q

Acute and Chronic phases of Chagas

A
  • Acute: fever, inflammation @ inoculation site (Romana sign if involves conjunctiva), local LAD, HSM
  • Chronic:
    • cardiac - biventricular HF, electrical abnormalities, thromboembolic disease, apical aneurysm
    • GI - megaesophagus or megacolon, motility dysfunction
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39
Q

morphologic features of babesiosis (via thick/thin smear, stained via Wright or Giemsa)

A
  • infected RBCs are normal sized
  • no intracellular pigment
  • delicate rings w/ varying morphologies
  • multiply infected RBCs
  • extracellular forms common (NOT seen in malaria)
  • maltese cross (rare)
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40
Q

Toxoplasma Dx

A

serology, PCR, tissue all available

  • IgG+/IgM- : past infection, NOT acute
  • IgG-/IgM+ : likely acute infection
  • if both IgG and IgM+ : could be either acute or chronic. IgM Abs can remain + for up to 12mos

in adv HIV or SOT: helpful to have IgG results prior to tx, as they can be misleading when IS. Will go with clinical picture most often + histo or PCR

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41
Q

Tx of toxoplasma

A
  • Immunocompentent: self-limited. If end-organ disease, can use pyrimethamine + sulfadiazine + leucovorin x2-4wks
  • Immunocompromised: either TMP/SMX or dapsone+pyrimethamine or atovaquone x6wk minim until reconstitution
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42
Q
  • from drinking water or swimming pools (R to chloronation)
  • Immuncompetent: asx - acute - subacute - chronic high V watery diarrhea (can continue d/t autoinfection from poor hand hygiene)
  • Immunocompromised: profound D and severe wasting
    • can have biliary tract involvement (acalculous chole, cholangitis, pancreatitis)
A

cryptosporidium

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43
Q

Dx cryptosporidium

A

Ag detection assays (DFA, ELISA)

NAAT

stool microscopy (4um) via mAF stain

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44
Q

Tx of cyclospora

A

TMP/SMX

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45
Q

Tx of cystoisospora

A

TMP/SMX

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46
Q
A

giardia duodenalis

  • left: trophozoite
    • pear-shaped, 2 nuclei, flagella
  • righ: cyst
    • 10-14um, mature w/ 4 nuclei, immature w/ 2 nuclei
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47
Q

granulomatous skin lesion in midface/nose → wks-mos of HA, F, visual changes, behavioral changes, focal deficits, increased ICP

A

balamuthia mandrillaris

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48
Q

two organisms that will show feeding tracks if cultured on a lawn of nonnutrient agar covered with enteric bacteria (E coli)

A

Acanthamoeba

Naegleria

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49
Q

Early: eosinophilia + F + dry cough/SOB/CP

Most pathology after 6-8wks: malnutrition, pancreatic/hepatobiliary d/t obstruction, intestinal obstruction rare

A

consider ascaris infection

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50
Q

50-70 x 40-50 um from stool sample

A

Ascaris lumbricoides

Tx: albendazole x1 dose

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51
Q

recurrent rectal prolapse

A

tichuris trichiura

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52
Q

chronic abdominal pain

eosinophilia

iron deficiency anemia

A

think hookworms (necator, ancylostoma)

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53
Q

migratory urticarial rash

fast moving

may have periumbilical purpura

A

larva currens w/ strongy

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54
Q

co-infection a/w strongy hyperinfection

A

HIV

HTLV-1

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55
Q

clinical manifestations of loa loa

A
  • calabar swelling - angioedema of face and exposed extremities
  • myalgias, arthralgias, fatigue
  • “eye worm” - migration to conjunctiva
  • endomyocardial fibrosis leading to myocarditis
  • immune-complex nephropathy
  • encephalitis (? d/t rx w/ DEC)
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56
Q
A

calabar swelling of R hand d/t angioedema from loa loa worm traveling through SQ tissue

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57
Q

Mazzotti reaction

A

fever, urticaria, swollen/tender LN, tachycardia/hypotension, edema, abdominal pain, followed by fatal encephalopathy ~7 days posttx w/ DEC

d/t rapid killing by DEC of microfilaria in high burden loa loa infection → acute severe inflammatory reaction

**also occurs w/ Onchocerciasis

pretreat w/ albendazole or apheresis

also avoid DEC in individuals co-infected w/ onchocerciasis (tx oncho first, then can tx w/ DEC afterwards)

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58
Q

What and where

A

S japonicum

China and SE Asia

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59
Q

What and where

A

S mekongi

Mekong river basin (Cambodia to Laos)

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60
Q

What and where

A

S haematobium

sub-Saharan and Northern Africa

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61
Q

What and Where

A

S intercalatum

western/central Africa

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62
Q

What and where

A

S mansoni

sub-Saharan Africa and S America

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63
Q

Tx of schistosomiasis

A
  1. praziquantal = gold standard
    1. not recommended unless dx microscopy and/or serology
    2. not initiated until at least 6wks from presumed exposure (need full adult maturation, as PZQ doesn’t work vs larval stages)
    3. exposes parasite Ag to host immune system
  2. Adult disintegration can release a bunch of eggs
    1. expulsion by peristalsis
  3. confirm cure w/ egg excretion surv 2-6mos
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64
Q

complications of chronic infection with fasciola hepatica

A
  • biliary
    • pain, cholangitis, cholelithiasis, obstructive jaundice, pancreatitis
    • sclerosing cholangitis
    • biliary cirrhosis
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65
Q

General tx of parasitic disease

  • nematodes
  • trematodes
  • cestodes
A
  • nematodes (roundworms) - albendazole (except for…)
    • strongy - ivermectin
    • wuchereria - DEC
    • loa loa - DEC (except co-infection w/ oncho or w/ heavy burden)
    • oncho - ivermectin (avoid DEC)
  • trematodes (flukes) - PZQ
    • except fasciola - triclabendazole
  • cestodes (tapeworms) - albendazole and/or PZQ
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66
Q

IC pt w/:

  • encephalitis w/ mass lesions
  • HSM
  • F
  • myocarditis
A

chagas (T cruzi)

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67
Q

IC pt w/:

  • visceral or cutaneous disease noted (reactivation)
  • visceral - F, HSM, pancytopenia
A

leishmania

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68
Q

IC pt w/:

  • encephalitis w/ mass lesions
  • pneumonitis
  • retinitis
A

toxoplasma

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69
Q

dx and tx of microsporidia

A
  • dx: modified trichrome stain, calcofluor white, IFA
  • tx: albendazole
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70
Q

punctate keratoconjunctivitis (contact lens use, after eye surgery, bathing in hot springs)

A

Many spp of microsporidia (including vittaforma corneae)

*a microsporidia (obligate intracellular fungi) - produces extracellular infective spores

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71
Q

Encephalitozoon intestinalis

A
  • watery diarrhea
  • biliary disease
  • disseminated disease (liver, kidney, lung, sinuses)

*a microsporidia (obligate intracellular fungi) - produces extracellular infective spores

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72
Q

enterocytozoon bieneusi

A
  • watery diarrhea
  • biliary disease (cholangitis, acalc chole)

*a microsporidia (obligate intracellular fungi) - produces extracellular infective spores

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73
Q
  • flask-shaped ulcerations in GI tract
  • can have extraintestinal (liver, brain) in young men
A

Entamoeba histolytica

wide range of presentation: asx, traveler’s diarrhea (common cause), colitis, ameboma, extraintestinal (liver, brain)

74
Q

Dx and Tx

A

Balantidium coli = the only ciliated pathogen of humans. Single-celled, huge cell (70um x 200um)

  • WW (esp Central/S America, SE Asia, Papua New Guinea)
  • a/w ingestion of contaminated pig feces

Tx: tetracycline, metronidazole

75
Q

Dx and Tx

A

Entamoeba histolytica

  • Dx:
    • stool Ag testing (>90% sens for intestinal dz)
    • stool OP (50% sens for colitis and abscess). Poor spec (unable to d/w histolytica from non-path dispar and diarrhea-only moshkovskii)
    • Serology - helpful in liver abscess (95% sens), and in intestinal (85% sens)
  • Tx: tinidazole or metro then paromomycin
76
Q

20um

A

cystoisospora

77
Q

10um

A

cyclospora

78
Q

4um

A

cryptosporidium

79
Q

protracted watery diarrhea

peripheral eos (the ONLY protozoa that does this)

A

cystoisospora belli (20um)

80
Q
  • protracted diarrhea (often w/ abrupt N/V, fever) often a/w bloating, flatus
  • anorexia, wt loss, fatigue later
  • food-assoc outbreaks - usually imported (fresh fruits and vegetables - raspberries, lettuce, herbs)
  • tropical/subtropical - esp from Nepal, Peru, Guatemala
A

cyclospora cayetanensis

In NA - most cases from imported food

(oocysts immature when first shed, require days-wks to sporulate and become infectious; P2P therefore unlikely)

81
Q

protracted watery diarrhea

cattle workers, daycare outbreaks

water supply outbreaks (R to chlorine) = #1 cause of water park/swimming pool outbreaks

A

cryptosporidium

82
Q

when to suspect intestinal protozoan infection

A

protracted (wks-mos) watery diarrhea

and/or:

  • h/o travel (domestic or foreign)
  • recreational water activities
  • altered immunity
  • exposure to group care (daycare)
83
Q

subacute granulomatous encephalitis

chronic granulomatous keratitis (contact lens, LASIK)

soil, water exposure

enters via LRT or broken skin

seen in IC hosts

A

acanthamoeba

84
Q

fulminant meningoencephalitis

warm freshwater exposure

A

naegleria folweri

85
Q

Typical presentations of T cruzi in IC pts (AIDS, SOT)

A
  • AIDS: primarily reactivation neuro disease - acute, diffuse, necrotic meningoencephalitis. Focal CNS (similar to toxo)
  • SOT: F, HSM, myocarditis (usually mos post-tx)
86
Q

What is this?

Dx and Tx?

A

Chagas disease

Acute disease: ID parasites in blood

Chronic: IgG Abs (2 tests rec for dx)

Tx: benznidazole or nifurtimox

87
Q
  • acute: w/in 1 wk of infection, persists for 8wks. F, local LAD, unilateral painless periorbital edema
  • indeterminate stage: serology+ but not evidence of dz
A

Chronic: dilated CM, megaesophagus

Chagas disease (tryp cruzi)

88
Q

Tx of African trypanosomiasis

A

must do CSF analysis to decide (if >5 WBC = late stage)

  • early:
    • W Africa (gambiense) - pentamidine
    • E Africa (rhodesiense) - suramine
  • late:
    • W Africa - eflornithine+nifurtimox;
    • E Africa - melarsoprol (co-admin w/ steroids to reduce rate of reactive encephalopathy)
89
Q

unique lab finding with African trypanosomiasis

A

elevated IgM

  • d/t persistent changing of their outer surface protein (contains as many as 1000 genes encoding different variant surface glycoprotein)
  • each trypanosome expresses one VSG at a time. But individual parasites can spont switch VSG
90
Q

chancre at bite site + regional LAD

clears, then for wks: F, HSM, LAD, faint rash, HA

late: AMS, neuropsych/sleep d/o, terminal somnolent state

A

African trypanosomiasis (sleeping sickness)

tse tse fly

Trypanosoma brucei gambiense (W Africa)

rhodesiense (E Africa)

91
Q

Tx of visceral leishmaniasis

A

(L donovani, L infantum chagasi) = amastigotes in macrophages go to local LNs then hematogenously spread to liver, spleen, BM

Dx: intracellular amastigotes in BM or splenic aspirate. Can dx w/ serology.

Tx: LAMB (miltefosine for donovani)

92
Q

Tx of mucosal leishmaniasis

A

(usually L (V) braziliensis, also guyanensis, panamensis) = slow, progressive, destructive

IV antimony or IV liposomal AMB or PO miltefosine

93
Q

Tx of cutaneous leishmaniasis

A
  • If L (V) braziliensis, guyanensis, panamensis:
    • tx systemically w/ PO miltefosine (fluc or keto, but not FDAa)
    • or IV pentavalent antimony (LAMB, but not FDAa)
  • if none of the above:
    • ok to obs as long as few lesions, <5cm, not on face/fingers/toes/genitals, and a normal host
94
Q

Dx of leishmaniasis

A

Standard = amastigotes in tissue using Giemsa

  • Cutaneous = edge of ulcer: scraping, aspirate, punch
  • Visceral = BM, LN, splenic aspirates (PCR)

touch prep under oil - look for amastigotes

culture - triple N media (wks to grow)

Histo via punch bx

PCR fairly sensitive

95
Q

chronic cutaneous ulceration, usually painless

induration, scaliness, central depression, raised border

papule –> nodule –> ulcerative lesion –> atrophic scar

usually self-resolves. Can see reactivation w/ friction

A

cutaneous leishmaniasis

96
Q

Leishmaniasis spp likely to cause visceral disease

A
  • L infantum chagasi
  • L donovani
97
Q

Leishmaniasis spp likely to cause mucosal disease

A

L braziliensis (also subgenus Viannia guyanensis, L V panamensis)

98
Q
A

Leishmania life cycle

  1. Promastigote - extracellular, in sandfly. Long. +flagella. large central nucleus w/ band-shaped kinetoplast
  2. Amastigote - intracellular (macrophages). Round/oval. Wright-Giemsa stain = small, rod-shaped kinetoplast
99
Q
A

Babesiosis

  • Transmission - Ixodes tick. NE and upper MW.
  • Sx - Co-infection w/ Lyme/anaplasma. Transfusion important source. HA, F/C, myalgias. Severe disease in HIV, asplenia
  • Labs - anemia, thrombocytopenia, mild increased LFTs. nl/l/h WBCs
  • Dx - small ring forms in RBCs, PCR
  • Tx - azithromycin + atovaquone. XChange for severe disease
100
Q

Tx of P vivax or P ovale

A
  • chloroquine x3 days –> then primaquine x14 days (gets rid of hypnozoites)

OR

  • tafenoquine

**check G6PD prior to primaquine or tafenoquine

101
Q

Tx of P falciparum

(or uncomplicated knowlesi)

A
  • Uncomplicated: chlor sens area - chloroquone; chlor R area - atovaquone/progaunil (Malarone)
  • Severe: IV artesunate
102
Q

malaria ppx in pregnant women in area of chloroquine resistance

A

mefloquine

**beware of SEs: neuro sx, hallucinations, anxiety/depression

103
Q

Malaria ppx

  • Central America, Middle East
  • Everywhere
A
  • chloroquine (the only places w/ chloroquine sensitive malaria)
  • atovaquone/proguanil, or doxy. Can use mefloquine (but not in SE Asia)
104
Q

Dx of Malaria

A
  • Ag capture (95% sens for falciparum; 85% for other spp), smear

tx if no other explanation for fever in traveler. Repeat testing can help confirm (12-24hrs)

105
Q
A

P falciparum

banana-shaped gametocyte

106
Q
A

P malariae

band form

(also seen in P knowlesi)

107
Q
A

P ovale

mature schizont

6-12 merozoites

108
Q
A

P vivax or ovale

enlarged infected RBCs

Schuffner’s dots

109
Q

presentations of complicated malaria

A
  • cerebral malaria
  • respiratory distress/pulm edema
  • severe anemia (hct <15% kids; <20% adults)
  • renal failure
  • hypoglycemia
  • shock, acidosis
  • jaundice
  • bleeding d/o (evidence of DIC)
  • ***usually w/ falciparum (when parasitemia >20%). In absence of end-organ damage, cutoff for severe dz = >10% parasitemia
110
Q

General labs and sx of uncomplicated malaria

A

fevers/chills, HA, fatigue

abdominal pn w/ 20% as presenting sx

thrombocytopenia in 50%, mild anemia in 30% (+may see hemolysis w/ TBili and LDH), no leukocytosis usually

111
Q

Malaria with shortest incubation period

also most lethal (can infect RBC of ANY age)

A

falciparum. knowlesi

***generally w/ higher parasitemia

Note:

  • pref younger RBCs - vivax
  • pref older RBCs - malariae
112
Q

Stages of Malaria parasite

A
  • Sporozoites - infective stage from mosquito
  • Liver schizont - asx replicative stage (become 10-30k merozoites)
  • Hypnozoite - dormant liver stage (in vivax and ovale). Releases merozoites weeks-mos after primary infection
  • Merozoites - infects RBCs and develops into ring-stage trophozoites. Matures into schizonts, which release merozoites –> infects more RBCs
  • Gametocytes - infective stage for mosquitos
113
Q

MCC of fever in returned traveler

A

MALARIA

M falciparum = medical emergency

114
Q

typically more ill than P malariae (d/t high parasitemia), but with morphologic similarities

Myanmar, Phillipines, Indonesia, Thailand

A

P knowlesi

115
Q

eosinophilia + F + elevated AST/ALT in child

A

consider visceral larva migrans (toxocariasis)

116
Q

abdominal pain after sushi

A

think anisakis

117
Q

eosinophilic meningitis

A

angiostrongylus (most common)

118
Q

muscle pain + eosinophilia

A

trichinella

119
Q

SQ nodules

A

onchocerca volvulus

(nonpainful, vascular fibrous nodules)

120
Q

gram negative sepsis after TNF inhibitor

A

strongy hyperinfection

121
Q

itchy feet return to tropics

A

ground itch d/t hookworms

122
Q

allergic sx after trauma

A

echinococcus

123
Q

crab/crayfish + pulm sx + eos

A

paragonimus

124
Q

freshwater exposure + eosinophilia

A

schistosomiasis

125
Q

Gnathostoma spinigerum and hispidum clinical picture

dx and rx

A
  • skin: migratory, painful SQ swellings (q few 2wks); creeping eruption/cutaneous larva migrans
  • tissue: visceral, eosinophilic meningoencephalitis, radiculomyelitis, ocular disease
  • empiric dx or via bx. No Ab test.
  • Rx: 3+ wks of albendazole
126
Q

dx of toxocariasis

A
  • clincal + Ab (ELISA via serum or IO fluid)

**IgG only supportive - many individuals have prior exposure

  • Tx: usually self-limited disease. Acute VLM/OML - albend + steroids
127
Q
  • fever, eos, HM + wheezing/PNA/SM. 2-5yo
  • retinal lesions (look like solid tumors). 10-15yo

acq via animal feces ingestion

raccoon + CNS disease (eos meningitis)

A

toxocariasis

  • visceral larva migrans
  • ocular larva migrans

raccoon + CNS (eos meningitis)/more severe: baylisascariasis

128
Q
  • invasion of worm = pain, vomiting
  • allergic reaction to worm = mild urticaria, itchy sensation back of throat, anaphylactic shock

raw/undercooked seafood (WW)

A

anisakis

***ok if food frozen for a few days first (do not eat fresh off the dock)

129
Q
A

trichinellosis

130
Q

MC parasitic cause of eosinophilic meningitis

a/w ingestion of snails/slugs (often eaten on vegetables) or paratenic hosts (freshwater shrimps, crabs, frogs)

SE Asia, pacific basin, Caribbean

A

angiostrongylus cantonensis

131
Q

abdominal cramps, diarrhea (if heavy infection)

striated muscle involvement: severe muscle pain, periorbital edema

eosinophilia

+/- fever, urticaria

hunting pig, boar, horse - “wild game”

A

trichinellosis

  • larvae released from cysts by gastric acid and migrate to striated muscle, encyst, then live in “nurse cells”
  • adults invade small bowel
132
Q

clinical manifestations of loiasis

A
  • asx microfilaremia
  • non-spec: fatigue, urticaria, arthralgias/myalgias
  • calabar swelling
  • eyeworm
  • end organ (rare): endomycocardial, encephalopathy, renal failure
133
Q

progressive cognitive dysfunction

nodding seizures (esp when children start to eat)

growth stunting

tanzania, south sudan, northern uganda

A

Nodding syndrome

a/w onchocerciasis

134
Q

Dx and tx of onchocerciasis

A
  • serology (anti-filarial, onchocerca-specific)
  • parasitologic: skin snips, nodulectomy
  • Tx: ivermectin, moxidectin (FDA appr 2018 - longer 1/2-life)
  • alt = doxy x6wks (kills endosymbiotic Wolbachia bacteria, kills adult worms)
135
Q

ocular manifestations of onchocerciasis

A

punctate keratitis, sclerosing keratitis, chorioretinitis

136
Q

Dx lymphatic filariasis (W bacrofti, B malayi)

A
  • Def: ID of microcilariae in nighttime blood, detection of circulating Ag in blood (only Wb), ID of adult worm (by tissue bx or u/s “filaria dance sign”)
  • Presumptive: compatible clin picture + positive antifilarial Abs
  • Tx: DEC
137
Q

paroxysmal nocturnal asthma

pulmonary infiltrates

peripheral blood eos (>3k)

elevated serum IgE

likely d/t excessive immune response to microfilariae in lung vasculature

A

tropical pulmonary eosinophilia

138
Q

clinical presentations of W bacrofti, B malayi

A

asx

lymphangitis - retrograde

lymphatic obstruction (lymphedema, elephantiasis, hydrocele)

139
Q

tx of filariasis

A
  • lymphatic filariasis (Wuchereria, Brugia), loa loa - DEC
  • onchocerciasis - ivermectin

when to avoid DEC: loa w/ high microfilaremia (leads to encephalopathy and death); oncho (leads to severe skin inflammation and blindness)

140
Q

Body location (adults and microfilariae) of the following filarial infections:

  • Wuchereria bancrotti, Brugia malayi - lymphatic filariasis (mosquitoes)
  • loa loa - eyeworm (Chrysops flies)
  • onchocerciasis - river blindness (blackflies)
A
  • adults - lymphatics; microfil in blood (at night)
  • adults - SQ tissues (moving); microfil - blood (day)
  • adults - SQ tissues (nodules); microfil - skin
141
Q

child in MW - no travel hx

plays in sandbox

pet dog

F, HSM, wheezing, eos

A

toxocara canis (visceral larval migraines)

142
Q

peri-anal itching

fecal/oral route

A

Enterobius vermicularis (pinworm)

Dx: scotch tape test; eggs with one flat side

Tx: albendazole, mebendazole, or pyrantel pamoate in single dose followed by another in 2wks

tx all members of household

143
Q

dx and tx of strongy

A

serology = TOC

stool o/p: low sens

Tx: ivermectin

144
Q

life-cycle and dx

heavy infections = loose/freq stools, tenesmus, occ frank blood, rectal prolapse in children

A

trichuris trichiura (whipworm)

dx = eggs are football shaped w/ two polar plugs

145
Q

clinical presentations of hookworms (ancylostoma duodenale and necator americanus)

A
  • MAJOR cause of anemia and protein loss (b/c of plasma loss)
  • pneumonitis a/w wheezing, dyspnea, dry cough
  • urticarial rash
  • mild abd pn (they’re chewing on GI mucosa)

if sensitized: papulovesicular dermatitis at entry site “ground itch” –> worms migrate laterally leads to cutaneous larvae migrans

146
Q
A

ascaris lumbricoides

eggs in stool - once they migrate to gut (makes 200k/day)

*will not find eggs until 2-3mos after pulm sx occur (they are just migrating at this time)

tx w/ albendazole or mebendazole

147
Q

can cause the following syndromes

  • abdominal distention/pain or intestinal obstr
  • eosinophilic pneumonitis w/ transient infiltrates
  • cholangitis and/or pancreatitis (aberrant migration)

note this is dx if boards show barium swallow w/ silhoutte of worm

A

ascaris lumbricoides

148
Q

lifecycle of intestinal nematodes (roundworms)

A
  • strongy, hookworms: skin (pruritic rxn) –> lungs (can have Loeffler’s syndrome) –> gut
  • ascaris (ingestion of eggs): gut –> liver –> lungs (MCC of Loeffler’s) –> gut
149
Q

Acq of nematodes (roundworm)

  • which obtained via ingestion of eggs from fecally contaminated food/soil?
  • which via direct penetration of skin?
  • which via ingestion of larvae in food?
  • which via vector transmission?
A
  • ascaris, trichuris, enterobius, toxocara
  • hookworms, strongy
  • trichinella, angiostrongylus, anisakis
  • wuchereria, brugia, oncho, loa
150
Q

MC intestinal nematodes (roundworms)

A
  • ascaris lumbricoides
  • ancylostoma duodenale
  • necator americanus
  • trichuris trichiura
  • strongy
  • enterobius vermicularis
151
Q

pruritic rash

recently moved to… (e.g. FL)

A

anyclostoma braziliense (cutaneous larval migrans)

152
Q
A
  • Left: E granulosus
  • Right: E multilocularis - infiltrative, tumor-like growth, poorly demarcated, semi-solid nature. fox/rodent life cycle

boards may show large liver cyst w/ multiple daughter cysts = multilocularis (to confuse you w/ granulosus)

multilocularis will not have multiple loculations like granulosus grossly on imaging (only see loculations under micro)

153
Q

Tx of echinococcus granulosus

A

**depends on stage of liver cyst

Note to remember: tx w/ albendazole for several days prior to surgery or PAIR or FNA (usually 2D-1W prior, then 1-3mos after)

154
Q

How to DX?

A

Echinococcus granulosus

IgA ELISA = 85% sens for liver cysts (50% sens for lung cyst)

**if need FNA for dx –> start albendazole for a few days prior to prevent growth of spilled cystic material in the peritoneal cavity

155
Q

Presentations of echinococcus granulosis

  • most common
  • uncommon
A

most cysts in the liver (65%). 25% in the lung (RLL MC). The rest can appear anywhere

  • Common (occur w/ rupture of a cyst) - allergic sx/anaphylaxis. Cholangitis/biliary obstruction. Peritonitis. PNA
  • Uncommon: bone fracture. Mechanical rupture of heart w/ tamponade. Hematuria/flank pain (renal cysts)
156
Q

anatomy of echinococcus granulosus (hydatic cyst)

A

= watery vessel

  • outer acellular laminated layer - will see surrounding inflammatory response of fibrosis and chronic inflammation
  • inner, nucleated germinal layer (pluripotential tissue)
  • internal cystic fluid + daughter cysts
157
Q

acq of echinococcus granulosus

A

adult worms live in dog intestines

humans = accidental hosts

infection by ingestion of eggs in dog feces

158
Q

Tx of neurocysticercosis

A
  • Rx tx dec risk of future seizures, but inc immediate risk of seizures
  • If hyrdocephalus/diffuse edema: steroids+surgery. not antiparasitic therapy
  • if no inc ICP: 1-2 cysts - albendazole; >2 cysts - albendazole + praziquantel
  • start corticosteroids prior to antiparasitic tx
159
Q

Dx of neurocysticercosis

A
  • Def: tissue bx. Multiple cystic lesions w/ scolex on imaging. Retinal cysticercus on fundo
  • presumptive: suggestive lesions on imaging (be wary of single lesion, even if typical)
  • cysticercosis serology = supportive (sens if high burden of disease)
160
Q

2 effects of neurocysticercosis

(remember: d/t ingestion of eggs/larval form of solinium from human stool)

A
  1. pressure effect of cortical area (cysts usually grow slowly and push normal cells apart)
  2. inflammatory response to dying cyst –> scarring (most common)
161
Q

D latum

  • acquisition
  • sx
  • dx
  • tx
A
  • acq via ingestion of fish with larvae
  • B12 deficiency (~40% of pts)
  • DX: eggs/proglottids in stool
  • TX: praziquantel
162
Q

Taenia saginatum

  • acquisition
  • sx
  • dx
  • tx
A
  • acq via larvae in undercooked beef
  • few sx (though can grow up to 10m)
  • DX: eggs/proglottids in stool
  • TX: praziquantel
163
Q

Major Cestodes (flatworms/tapeworms)

  • basic info
  • Intestinal tapeworms:
  • Larval cysts:
A

all (except D latum) have suckers w/ surrounding hooklets on the scolex (head) to attach to intestine

have proglottid segments (contain repro organs)

  • Intestinal: taenia, diphyllobothrium latum
  • Larval cysts: taenia solium, echinococcus
164
Q

passing flat tissue fragments in stool

A

flatworm infection

very common complaint

165
Q

helminths a/w the following complications/syndromes

  • HTLV-1 infection
  • bladder cancer
  • appy
  • liver abscess
  • seizures
A
  • strongy (that is, diff to eradicate strongy if pt has HTLV-1; often require multiple ivermectin tx)
  • S. haematobium
  • enterobius
  • none - a/w protozoa
  • cystecercosis
166
Q

Metagonimus yokagawi

  • acquisition
  • sx
  • tx
A

(intestinal fluke)

  • ingestion of larvae in undercooked fish
  • sx: diarrhea and abdominal pain
  • tx: praziquantel
167
Q

Fasciolopsis buski

  • acquisition
  • sx
  • dx
  • tx
A

(intestinal fluke)

  • eating encysted larvae on aquatic vegetation
  • SX: depends on burden. Usually asx. Can see D, F, abd pn, ulceration, hemorrhage
  • DX: eggs in stool
  • TX: praziquantel
168
Q

Paragonimus westermani

  • life cycle (how acq)
  • common syndromes
  • dx
  • tx
A

(lung fluke)

  • eggs –> snails –> freshwater crabs/crayfish (in US - crayfish in MO)
  • acq via ingestion of undercooked seafood
  • adults migrate to lungs
  • SX:
    • Acute migration - fever, cough, D; migration through lungs - may dev chest pain
    • Chronic - chronic pulmonary symptoms (chronic PNA often a/w eos, can be confused w/ TB)
  • DX: sputum and/or stool exam for eggs
  • TX: praziquantel
169
Q

Clonorchis sinsensis

Opisthorchis viverrini

(both similar)

  • life cycle
  • common syndromes they cause
A

(liver flukes)

eggs –> snails –> freshwater fish

acq by ingestion of undercooked fish

develop in duodenum –> reside biliary ducts/GB/pancreatic ducts

**CMI doesn’t develop - repeated infections engender cumulative worm burden

***can live for 50yrs, making 2000 eggs/day

syndromes

  • biliary obstruction
  • cholelithiasis
  • cholangiocarcinoma
170
Q

dx and tx of fasciola hepatica

A
  • eggs in stool (low sensitivity), serology
  • triclabendazole (FDA-appr in 2019)
  • ***this is the only trematode that doesn’t respond well to praziquantel
171
Q

life cycle of fasciola hepatica

A

(liver fluke)

  • acq via eating encysted larvae on acquatic vegetation (eg water chestnuts) –> migrates through liver (RUQ pn, hepatitis) –> arrives at biliary ducts
  • matures over 3-4mos
  • can induce biliary obstruction
172
Q

when to consider schisto

A

freshwater exposure in endemic region

  • acute syndrome: F, abd pn, myalgias, eos, etc
  • chronic syndrome: abd/pelvic pn, blood in stool, diarrhea, portal HTN, hematuria, eos
173
Q
A
  1. S mansoni (lateral spine)
  2. S haematobium (terminal spine)
174
Q

Manifestations of chronic schisto

  • mansoni
  • haematobium
  • japonicum
A
  • mansoni (GI): granulmatous colitis, portal HTN, colonic ulceration
  • haematobium (GU): will see hematuria/pyuria. Granulomatous cystitis, bladder fibrosis/cancer, obstructive uropathy, calcified eggs in bladder wall. Immune complex nephrotic syndrome. Can see chronic genital disease as well (epididymitis, prostatitis; uterine abn)
  • japonicum: CNS disease (eggs to brain/spinal cord)
175
Q

Basics of Acute Schistosomiasis (Katayama Fever)

  • who
  • when
  • sx
  • labs
  • dx
A
  • occurs in previously unexposed hosts
  • occurs ~3-8wks (correlates w/ adult maturation and onset of egg-laying)
  • fever, myalgias, abd pn, HA, D, urticaria (can look quite ill)
  • striking eosinophilia, elevated AST and alk phos
  • no reliable way to confirm dx acutely (serology and OP often negative d/t few/no eggs in stool yet)
176
Q

Acute schistosomiasis (cercarial dermatitis/swimmer’s itch)

A

urticarial plaques/pruritic papules upon re-exposure to cercariae penetrating skin in a sensitized individual

usually just a nuisance - infection never takes

177
Q

Schistosomiasis life cycle

A
178
Q

Basic info re trematodes (flukes)

A
  • usually w/ two muscular suckers
  • usually hermaphroditic (except Schisto)
  • require intermediate hosts
  • praziquantal tx all (exc fasciola)
179
Q

List of Flukes

  • blood flukes
  • liver flukes
  • lung flukes
  • intestinal flukes
A
  • schistosoma (mansoni, japonicum, haematobium)
  • fasciola hepatica, clonorchis sinensis, opisthorchis viverrini
  • paragonimus westermani
  • fasciolopsis buski, metagonimus
180
Q

effect of schistosome flukes in the portal V system

A

releases eggs –> travel through GI wall and cause eosinophilic colitis

181
Q

The few exceptions of helminths that multiply within the host

A
  • strongyloides
  • paracapillaria
  • hymenolepis
182
Q

Groups of pathogenic helminths

A

(all eukaryotic, multicellular animals)

  • Phylum Platyhelminth - trematodes (flukes), cestodes (tapeworms)
  • Phylym Nematode (roundworms)

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