Parasitic Infections- Exam 2 Flashcards
______ 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
In toxoplasmosis, IgM is ____, IgG is _____
acute
chronic
____ is found worldwide, mainly in subtropical/tropical areas due to crowding, poor sanitation, poor nutrition
Amebiasis
What is the typical incubation of amebiasis?
2-4 weeks
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
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
______ is MC in young children, pregnant pts, malnourished, pts on steroids
moderate/severe amebiasis
What are the acute complications associated with amebiasis?
necrotizing colitis, intestinal perforation, mucosal sloughing, hemorrhage, death
Mortality rates > 40%
What are the chronic complications associated with amebiasis?
chronic diarrhea with weight loss, bowel ulcerations, amebic appendicitis
_____ 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
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
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
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
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
_____ is caused by Giardia lamblia. Where is it commonly found?
Giardiasis
found worldwide, especially in areas with poor sanitation
______ is the MC intestinal protozoal pathogen in US
Giardiasis
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
______ 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
Giardiasis is not discernible in ___ of patients. Asymptomatic cyst passers are ___ of patients
50%- No discernible infection
10%- Asymptomatic cyst passers
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
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
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
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
_____ interferes with normal reproduction cycle of Cryptosporidium and Giardia
Nitazoxanide (Alinia)
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?
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
More severe, prolonged symptoms
Chronic, fulminant watery diarrhea and weight loss
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
