Parasitic Infections- Exam 2 Flashcards by Johannah Crumpton

______ is primarily Entamoeba histolytica. What is the mode of transmission? what is the host?

Amebiasis

fecal-oral route but can occur through sexual contact

humans

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In toxoplasmosis, IgM is ____, IgG is _____

acute

chronic

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____ is found worldwide, mainly in subtropical/tropical areas due to crowding, poor sanitation, poor nutrition

Amebiasis

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What is the typical incubation of amebiasis?

2-4 weeks

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gradual onset diarrhea, abd pain, bloating, usually afebrile
PE - abd distension, abd tenderness, hyperperistalsis, hepatomegaly
Microscopic hematochezia is commonly found
Periods of remission-recurrence may last for weeks
What am I?

mild/moderate amebiasis

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colitis, dysentery with 10-20 bloody/watery stools per day
High fevers, prostration, vomiting, abd pain
PE - abd distension, abd tenderness, hepatomegaly, hypotension
Hematochezia is common

What am I?

moderate/severe amebiasis

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______ is MC in young children, pregnant pts, malnourished, pts on steroids

moderate/severe amebiasis

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What are the acute complications associated with amebiasis?

necrotizing colitis, intestinal perforation, mucosal sloughing, hemorrhage, death
Mortality rates > 40%

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What are the chronic complications associated with amebiasis?

chronic diarrhea with weight loss, bowel ulcerations, amebic appendicitis

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_____ is the MC extraintestinal manifestation of amebiasis. What are some s/s? More common in men or women?

Amebic Liver Abscess

Abdominal pain, fever, enlarged/tender liver, anorexia, wt loss

MC seen in men; can occur without any hx of colitis
Can rupture–often fatal if rupture occurs

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How do you dx intestinal amebiasis? What test should you order?

Stool Microscopy/O&P - E. histolytica
trophozoites and cysts
Stool antigen test
Stool PCR for parasitic DNA/RNA

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How do you dx hepatic amebiasis? What test should you order?

*Anti-amebic antibodies - serological
test; almost always +
*Stool O&P or antigen - often negative
*Imaging - US or CT of liver

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What is the treatment for amebiasis?

Initial - metronidazole (10 days) or tinidazole (3 days)
Eliminates E. histolytica trophozoites

Followed by - paromomycin x 7 days
PO aminoglycoside
Eliminates E. histolytica cysts
May be only tx if pt has no s/s

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How do you prevent amebiasis?

Avoid fruits, vegetables, and
water in endemic areas

Especially in Central/South America, India,
Indonesia, tropical and
sub-Saharan Africa

Handwashing
Boiled water
Thoroughly cooked food

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_____ is caused by Giardia lamblia. Where is it commonly found?

Giardiasis

found worldwide, especially in areas with poor sanitation

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______ is the MC intestinal protozoal pathogen in US

Giardiasis

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What are some risk factors for Giardiasis?

Travelers to Giardia-endemic areas
-Tropical regions with poor sanitation

Swallowing contaminated water during
wilderness or recreation travel

Men who have sex with men

Immunocompromised

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______ their cysts can survive weeks-months in the environment
Can survive in chlorinated water
May see outbreaks in households, daycares
Hosts - humans, dogs, cats, numerous wild animals

What am I?
What is the incubation period?

Giardiasis

1-3 weeks

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Giardiasis is not discernible in ___ of patients. Asymptomatic cyst passers are ___ of patients

50%- No discernible infection

10%- Asymptomatic cyst passers

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Profuse watery diarrhea, weight loss, dehydration
Usually afebrile with no vomiting
May require hospitalization due to dehydration

What am I?

acute diarrheal syndrome of giardiasis

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Diarrhea - daily or in remitting-recurring cycles that may alternate with constipation
Greasy or frothy, foul-smelling stools; no blood, mucus, or pus
-May see malabsorption - decreased protein, fats, vitamins
Abdominal cramps, bloating, flatulence, nausea, malaise; no fever or vomiting
Symptoms can persist weeks to months

What am I?

Chronic Diarrheal Syndrome related to giardiasis

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What is the correct procedure to dx giardiasis? What will the stool microscopy O&P show?

Stool Microscopy/O&P
—-Positive for cysts and trophozoites
—–No blood or leukocytes
*Stool antigen assay for Giardia
*Stool PCR for Giardia

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What is the treatment for giardiasis? For patients 1-3yrs? for less than 12 months?

tinidazole 2 g PO x 1 dose

nitazoxanide 500 mg PO BID x 3 days

metronidazole 500 mg PO BID x 5-7 days

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_____ interferes with normal reproduction cycle of Cryptosporidium and Giardia

Nitazoxanide (Alinia)

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SE of ____ are usually minimal - GI upset, headache, dizziness, discolored (bright yellow) urine

What are the SE of Nitazoxanide (Alinia)?

_____ have a fecal- oral route of transmission, worldwide distribution and are commonly found in HIV+ pts and swimming pool outbreaks

Cryptosporidiosis

Can be in HIV+ and immunocompetent pts as well, found in 65-97% of surface waters, often see outbreaks in daycares and households. What am I? What is a clinical pearl associated with this protozoa?

Cryptosporidiosis **swimming pool outbreaks

Fecally contaminated food, water, or hands Cysts can survive years in the environment Can survive in chlorinated water Often see outbreaks in communities, households, daycares - highly infectious Hosts - humans, numerous animals What am I? How long is the typical incubation?

Cryptosporidiosis 1-14 days

5-10 days of diarrhea; other s/s for up to 2 weeks Watery, nonbloody diarrhea N/V, abdominal pain and cramping Low-grade fever is possible May have milder or asymptomatic course What am I?

acute Cryptosporidiosis

typically have chronic presentation Chronic diarrhea - frequent, foul-smelling stools Malabsorption and weight loss Extraintestinal disease Pulmonary infiltrates and dyspnea Biliary tract infection and sclerosing cholangitis What am I?

HIV/AIDS pt with Cryptosporidiosis

How do you dx Cryptosporidiosis? What will stool O&P show?

Stool microscopy/O&P with acid-fast stain ----No blood or leukocytes **Stool antigen assay for Cryptosporidium **Stool PCR testing

**What is the treatment for acute Cryptosporidiosis?

**Acute form is self-limiting; may use supportive tx

What is the treatment for Cryptosporidiosis for immunosuppressed patients or persistent cases?

**Nitazoxanide or paromomycin Consider adding azithromycin if severe symptoms or refractory to tx

______ is associated with Cyclospora cayetanensis

Cyclosporiasis

Fecal-oral route Ingestion of oocyst form of parasite Worldwide distribution Endemic to Haiti, Peru, Nepal Often linked to foodborne outbreaks in US from imported produce What am I?

Cyclosporiasis

**Cyclosporiasis what is the clinical pearl? What is the typical incubation?

MC in imported **fresh produce 2-14 days

May see a flu-like prodrome Watery diarrhea, nausea and abdominal cramping Fatigue, malaise, anorexia Fever present in 25% Symptoms usually present for 2+ weeks May remit and relapse for months What am I?

symptomatic cyclosporiasis

What would immunocompromised patients who have contracted cyclosporiasis present like?

How do you dx Cyclosporiasis?

**Stool microscopy/O&P with acid-fast stain Colonoscopy with biopsy

What is the treatment for Cyclosporiasis? include both first and second line

First line: **TMP-SMX (Bactrim) 160/800 BID x 10 days Long-term, 3x/wk prophylactic treatment can reduce recurrence in AIDS pts Second-line options (also for 7 days) Ciprofloxacin (Cipro) - may not be as effective as TMP-SMX Nitazoxanide (Alina) - not as well studied, seems effective May be good for pts with sulfa allergy

_____ is caused by Trichomonas vaginalis

Trichomoniasis

_____ is sexually transmitted, worldwide and very common cause of GU infections. What is the most common pt demographic?

Trichomoniasis Especially common in non-Hispanic black females

Name all the ways you can get trichomoniasis. What is the typical incubation?

sexually transmitted- MC contact with moist, contaminated cloths, toilet seats, specula mothers to newborn during birth 5-28 days

Frothy, yellow or green nonmalodorous vaginal discharge Vulvovaginal discomfort, abdominal pain Dysuria, dyspareunia, pruritus inflamed vaginal mucosa and cervix with punctate hemorrhages “Strawberry Cervix” May have milder or asymptomatic course Does NOT usually have an odor What am I?

Trichomoniasis

What is the classic presentation of trichomoniasis in males?

Dysuria Scant, thin urethral discharge

How do you dx trichomoniasis?

Wet prep of vaginal or urethral secretions -------Presence of motile, flagellated organisms **Nucleic acid assay (PCR)

What will a wet prep of trichomoniasis look like?

Presence of motile, flagellated organisms

What is the treatment for trichomoniasis?

**Tinidazole or Secnidazole - 2 g PO x 1 dose Alternative - metronidazole 500 mg PO BID x 1 week Refractory - tinidazole 2 g PO QD x 14 d, +/- vaginal boric acid or paromomycin Must also treat all sexual partners!

____ is fecal-oral, ingestion of cysts in undercooked meat, transplacental, or from infected organ/blood donor.

Toxoplasmosis

_____ is caused by Toxoplasma gondii

Toxoplasmosis

**_____ is worldwide and one of the leading causes of deaths from foodborne illness in the US

Toxoplasmosis

Toxoplasmosis is more concerning in ____ and _____ pts

pregnant or immunosuppressed pts

Name some ways you can contract toxoplasmosis. What is the typical incubation?

Fecal-Oral Transmission- CATS!!! Ingestion of infected meat Transplacental infection Infected donor transmission 1-2 weeks

mono-like - fever, malaise, sore throat, HA, myalgias, LAD, HSM Rare - hepatitis, meningoencephalitis, polymyositis, retinochoroiditis What am I? What percentage is asymptomatic?

primary toxoplasmosis infection of a normal person 80-90% will have no symptoms

MC---encephalitis with necrotizing brain lesions Fever, HA, signs of focal brain lesion May also see retinochoroiditis, pneumonitis, myocarditis What am I?

primary toxoplasmosis infection of an immunocompromised person

In toxoplasmosis the overall risk of infection (increases/decreases) as pregnancy progresses. Severe infection risk (increases/decreases) as pregnancy progresses

risk of infection increases severe infection decreases

stillbirths, spontaneous abortions possible seizures, psychomotor retardation, deafness, hydrocephalus fever, jaundice, HSM, V/D, pneumonitis, myocarditis, retinochoroiditis What am I?

congenital toxoplasmosis infection

**congenital toxoplasmosis infection will present as _____ in teenagers/young adults

retinochoroiditis

Serum IgM and IgG antibody detection Which Ig would be present acutely vs. lifelong? ID of parasite on tissue biopsy PCR of amniotic fluids, blood, CSF, other body fluids Culture of body fluids How do you dx ______?

toxoplasmosis

Is toxoplasmosis screening recommended in pregnancy?

NOT recommended

What is the treatment for toxoplasmosis in an immunocompetent person?

not necessary in acute disease

What is the treatment for prolonged/severe toxoplasmosis in an immunocompetent person?

2-4 wks: pyrimethamine + lecovorin + sulfadiazine OR clindamycin

Give _____ to a pregnant person with toxoplasmosis to reduce the transmission risk

Spiramycin

What is the treatment for toxoplasmosis in an immunocompromised/fetal patient?

pyrimethamine + sulfadiazine Pyrimethamine is teratogenic - not used in early pregnancy

What is the cause of malaria? most severe?

**Plasmodium falciparum, P. vivax, P. ovale, P. malariae, P. knowlesi

_____ bite of infected Anopheles female mosquito in endemic areas

malaria

Where is the highest rate of transmission of malaria?

Sub-saharan Africa

What is the typical incubation of malaria?

9-14 days

Sporozoites injected into the bloodstream, travel to liver Hepatocytes become infected, release merozoites Merozoites infect erythrocytes Becomes disseminated through bloodstream Pathogenesis of ____

malaria

The prodome phase of malaria presents with ___ and ____

HA and fatigue

High fever, chills, sweats malaise, anorexia, fever abdominal pain, N/V/D myalgias, arthralgias chest pain, dry cough seizures, HA Exam - may be benign May show signs of anemia, jaundice, mild HSM What am I?

paroxysm stage of malaria Initially sporadic episodes, but may become regular (48-72 hrs) without tx

Risk for falciparum malaria is greatest within ______ of exposure

2 months important to ask about recent travel!!!

Severe illness, organ dysfunction, or high parasite load Peripheral parasitemia >5% or >200,000 parasites/mcL altered consciousness, repeated seizures, coma (“cerebral ______”) severe anemia, hemolysis, DIC, other bleeding abnormalities hypotension and shock ARDS, pulmonary edema jaundice, hepatic dysfunction acute kidney injury acidosis, hypoglycemia secondary bacterial infections (pneumonia, Salmonella) What am I?

Complications/ severe malaria

How do you dx malaria?

**Giemsa-stained blood smears PCR/Rapid Assays

Name some things malaria treatment depends on

The type (species) of the infecting parasite **The area where the infection was acquired and its drug-resistance status The clinical status of the patient Any accompanying illness or condition Pregnancy status Drug allergies, or other medications taken by the patient

What is the 1st line for susceptible (non-falciparum) malaria?

Chloroquine or Hydroxychloroquine resistance is increasing **check region to figure out what treatment is best

What is the 1st line for Falciparum and resistant non-falciparum malaria?

ACTs Artemether-lumefantrine (Coartem) Artesunate-amodiaquine (Camoquin)

What is the first line treatment for severe malaria?

IV artesunate - must be obtained from CDC

T/F: All patients with malaria should be hospitalized

TRUE, ALL patients should be hospitalized

Chloroquine Quinine/Quinidine Mefloquine (Lariam) Primaquine What class? What do they treat?

Quinoline derivatives malaria

Atovaquone-proguanil (Malarone) is considered ______. Treats _____.

antifolate malaria

_____ have activity against the erythrocytic stage of infection of malaria

Quinoline Derivatives

______ MOA accumulates in parasite food vacuole and complexes with heme, preventing heme breakdown and allowing cytotoxic free heme to accumulate

Chloroquine

_____ is the first line for tx and prophylaxis of susceptible malaria pathogens.

chloroquine

Chloroquine clears fever in _____ hrs and parasitemia in ____ hrs. What is a common SE?

24-48 hours 48-72 hours pruritis

______ drug of choice for elimination of dormant liver cysts (P. vivax, P. ovale) and is used after tx with chloroquine or quinine

Primaquine

_____ is often used for prophylaxis - can be dosed weekly. Greater problems with toxicity when used therapeutically

Mefloquine

_____ is derived from the bark of the South American cinchona tree MOA - Antimalarial MOA not well understood; _____ is a class IA antiarrhythmic agent

quinine/quinidine

_____ interferes with folate metabolism, blocking nucleic acid synthesis

Atovaquone-proguanil (Malarone)

______ is derived from leaves of Artemisia annua, an herb used in Chinese medicine. MOA - encourage formation of free radicals that damage parasite; active against all forms

Artemether-lumefantrine (Coartem)

_______ has the fastest parasite clearance times of any antimalarial. Rapid absorption, rapid onset. Short half-life - not good for chemoprophylaxis, and only given in combo regimens

Artemether-lumefantrine (Coartem)

How should you choose the best antimalarial prophylaxis?

based on the country the pt is visiting how soon are they leaving are they pregnant?

____, ___ and ____ only have to be started 1-2 days before travel, and continued 7 days after return. NOT safe in pregnancy

Atovaquone-proguanil Doxycycline Primaquine

_____ and ______ are dose once weekly, have to start 1-2 weeks before travel, continued 4 weeks after return, safe to use in pregnancy

chloroquine and mefloquine

What are some malaria prevention strategies?

Prophylactic Antimalarial Drugs Insect repellent sprays (DEET, Picardin, PMD, IR 3535) Insecticide-treated netting

Tapeworms are common in ____, ____ and ____

beef, pork and fish

Slightly higher incidence in sub-Saharan Africa, Central and South America Lives in intestine; can reach several feet in length ingestion of cysts in undercooked meat What am I?

Tapeworms (Taeniasis)

What is the typical incubation of tapeworms?

2-3 months 5-6 weeks for fish (more common in freshwater fish)

_____ prolonged infection causes B12 deficiency

fish tapeworm

____ MC finding are proglottids in stool

tapeworms

May be asymptomatic May have abdominal pain, nausea, diarrhea, flatulence, hunger, wt loss Eosinophilia is possible MC finding - proglottids in stool Fish - prolonged infection causes B12 deficiency What am I?

intestinal tapeworm

Altered cognition, psychiatric s/s, seizures, HA, focal neuro deficits Important cause of epilepsy in Latin America, SE Asia What am I?

invasive- cysticerosis tapeworms

How do you dx tapeworms?

Microscopic identification of proglottids and eggs in feces

What is the treatment for intestinal tapeworms?

praziquantel (Biltricide) PO x 1 dose albendazole 400 mg x 3 days

Why is Neurocysticercosis controversial? What is the treatment? More common after eating _____

Clearance of cysts vs. inflammatory response to dead/dying pathogens albendazole +/- corticosteroids pork

_____ allows increased calcium to enter parasitic cells, causing muscle spasms and paralysis and leading to worm detachment from host

Praziquantel (Biltricide)

_____ are Ancylostoma duodenale, Necator americanus

hookworms

____ are transcutaneously transmitted, Larvae penetrate skin and migrate through bloodstream to lungs, eventually ending up in the intestines

hookworms

____ are MC in tropical and subtropical regions, 1 billion worldwide

hookworms

Larvae in soil penetrate host skin and migrate through bloodstream to lungs, Larvae penetrate alveoli and move up bronchial tree to mouth,Larvae are swallowed and mature in intestine What am I? What is the incubation?

hookworms 4-8 weeks

pruritic maculopapular rash at site of infection fever, wheezing, dry cough Bloating, abdominal pain, anorexia, nausea, diarrhea Can also see low protein, anemia In children - may lead to cognitive delay and impaired growth What am I?

Hookworms

How are hookworms dx?

Stool microscopy/O&P - microscopic eggs in feces Rapid stool PCR testing increasingly available Often also see anemia, blood in stool, hypoalbuminemia

What is the treatment for hookworms?

**Albendazole 400 mg x 1 dose Mebendazole 100 mg BID x 3 d - lower cure rates also need treatment for anemia and low protein as appropriate

_____ inhibits helminth microtubule formation and glucose uptake. _____ should be taken with a high-fat meal or snack

Benzimidazoles Albendazole (Albenza) : may cause elevated LFTs and/or, in long-term tx, neutropenia or agranulocytosis

_____ is associated with Enterobius vermicularis

Pinworms (Enterobiasis)

Fecal-oral route; person-to-person via ingestion of eggs Contact with hands or perianal region of an infected pt, food or fomites that have been contaminated by infected pt, or infected bedding or clothing Autoinfection is possible Worldwide distribution What am I? What is the MC population?

Pinworms (Enterobiasis) **MC in school-age children

Eggs hatch in duodenum Larvae migrate to cecum where they mature to adulthood Female worms migrate through the rectum to the perianal skin to lay eggs at night What am I? What is the incubation period?

Pinworms (Enterobiasis) 1-2 months

-Perianal pruritus, especially nocturnal May see excoriation and secondary impetigo of perianal skin Children may also have insomnia, restlessness, enuresis Majority of patients are asymptomatic What am I?

Pinworms (Enterobiasis)

How do you dx pinworms? Are eggs found in the feces?

Scotch tape test”/“Paddle test” - in early AM eggs are NOT found in feces

What is the treatment for pinworms? What are pt education point?

Albendazole x 1 dose or mebendazole x 1 dose repeat in 2 weeks Tx of infected family members and close contacts Washing bed sheets, clothing Avoid perianal scratching Education on hand hygiene

What is the treatment for a pregnant pt with pinworms?

Pyrantel pamoate preferred if pregnant

_____ anticholinesterase drug; depolarizes neuromuscular cells and paralyzes the helminths

Pyrantel pamoate (Pin-Away)

____ is associated with Trichinella spiralis

trichinosis

______ is common with the ingestion of larvae from undercooked pork or other meat Typically in areas where pigs feed on garbage In US - primarily from ingesting wild game

Trichinosis

Larvae found in cysts in muscle tissue Gastric acid releases larvae from cysts Larvae travel to intestine and mature into adults, where they breed and create new larvae New larvae invade and travel via the bloodstream to muscle tissues, where they encyst Hosts - humans, mulitple animals What am I? What is the typical incubation?

Trichinosis 1-7 days

V/D, abdominal pain Usually lasts < 1 wk larvae migration Fever, myalgias, periorbital edema, eosinophilia May see HA, cough, dyspnea, hoarseness, dysphagia, rash, eye hemorrhages Peak in 2-3 wks; can last for 2 months Severe - signs of muscle involvement Muscle pain and weakness Myocarditis, pneumonitis, encephalitis What am I?

Trichinosis

How do you dx trichinosis?

Elevated serum muscle enzymes (CK, LDH, AST) ELISA assay 2+ weeks after infection - cross-reactive with other parasites Muscle biopsy

What is the treatment for a mild trichinosis infection?

supportive care (analgesics, antipyretics, bed rest, steroids)

What is the treatment for a systemic trichinosis infection?

-albendazole 400 mg BID x 8-14 days or mebendazole 500 mg TID x 13-14 days, +/- steroids

_____ is associated with Ascaris lumbricoides

Roundworms (Ascariasis)

Fecal-Oral transmission Ingestion of eggs in contaminated food or water, or exposure via fomites Worldwide distribution MC in warm climates with poor sanitation Heavy infections MC in children migrates throughout the body and causes cough and urticaria

Roundworms (Ascariasis)

Eggs hatch in small intestine and become larvae Larvae invade the mucosa and are carried via the bloodstream to the lungs Larvae mature further in the lungs, migrate across alveolar mucosa, and travel up the bronchial tree to the mouth Larvae are then swallowed and travel again to the small intestine, where they fully mature Hosts - humans, dogs What am I? What is the typical incubation?

Roundworms (Ascariasis) 6-8 weeks

Fever, eosinophilia Pulmonary - Dry cough, dyspnea, chest pain May see eosinophilic pneumonia +/- eosinophilia Bloating, decreased appetite, obstruction Pancreatitis, appendicitis, cholangitis May be coughed up, vomited up, or passed rectally May migrate and emerge through nose or anus asymptomatic in up to 85% of patients What am I?

Roundworms (Ascariasis)

How do you dx Roundworms (Ascariasis)?

Stool microscopy/O&P - microscopic eggs in feces Emergence of adult worms (cough, nose, anus, feces)

What is the treatment for Roundworms (Ascariasis)? Pregnant patient?

Albendazole 400 mg x 1 dose Mebendazole x 1 dose (500 mg) or 3-day regimen (100 mg BID) If pregnant - pyrantel pamoate