Parasitic infections Flashcards
How does infection by Giardia occur?
Ingestion of cysts in contaminated water or food
What are the characteristic symptoms of Giardia?
Acute onset of diarrhea Abdominal cramps Bloating Flatulence Sulfuric belching
Stools–profuse and watery at first, but later greasy and foul smelling–Steatorrhea
Weight loss
What is the tx for guard?
Metronidazole
What individuals are mostly affected by Cryptosporidiosis?
Immunocompromised hosts–Chronic diarrhea
What are sources of Cryptosporidium?
C. parvum–Dairy calves, young lambs and goats
Water supply and swimming pools–Oocytes have an extreme tolerance to chlorine
Severity and duration of cryptosporidium is dependent on what?
Immune status of host
Immunocompetent–> cryptosporidia cause a self-limiting, usually watery, diarrhea lasting 10-14 days
Immunocompromised–> cryptosporidiosis is more severe–often chronic and incurable illness that can be life-threatening
What is the tx for cryptosporidiosis?
Fluid and electrolyte support
Nitazoxanide in immunocompetent host shortens the duration of symptoms
What is the pathogenic entamoeba species?
E. histolytica
How does E. histolytica spread through the body?
Trophozoites penetrate the intestinal wall and get into the portal circulation
What can result from hematogenous spread of E. histolytica?
Hepatic disease
-Abscess formation within liver—can rupture into the pleural space
What is the presentation for E. histolytica that has caused hepatic disease?
Persisting fever
RUQ or epigastric pain and/or shoulder pain
What are the 2 forms of E. histolytica?
Cyst stage–infective form
Trophozoite stage–form that causes invasive disease
What is the tx for E. histolytica?
Metronidazole
What are the 2 Taenia tapeworms and where do they come from?
T. saginata–beef tapeworm
T. solium–pork tapeworm
What is released from the tania solium penetrating the intestinal wall and allows travel to the striated muscles, brain, liver, and other organs where they develop into cysticerci?
Oncospheres
What is Cysticercosis?
Tissue infection with larval cysts of the cestode T. solium–pt serves as an intermediate host for the parasite
What is a major complication of taenia solium infection?
Neurocysticercosis–CNS infection that causes intracerebral lesions–causing mass effects, seizures, or both
What tapeworm can be caused by ingestion of freshwater fish?
Diphyllobothrium latum
What are the symptoms seen with D. Latum infection
Normally asymptomatic but some pts can have weakness, dizziness, salt craving, diarrhea, and intermittent abdominal pain
Prolonged infection can lead to macrocytic anemia–megaloblastic anemia resulting from deficiencies of vitamin B12 and folate
What are the symptoms seen with ascaris lumbricoids?
Nonproductive cough
Chest discomfort
Fever
Eosinophilia that disappear often by the time the worms reach maturity
Severe cases
-Dyspnea and an eosinophilic pneumonia–Loffler syndrome– with transient patchy infiltrates seen on X-ray
What are complications seen with chronic ascariasis?
Intestinal obstruction
Obstruction of bile and pancreatic ducts
Appendicitis
Intestinal perforation
What is the lifecycle of Ascaris?
Infective eggs swallowed–larvae hatch, invade intestinal mucosa and carried to portal circulation —to the lungs
Larvae mature in the lungs–penetrate the alveolar walls, ascend the bronchial tree to the throat–> then swallowed
What are some complications seen with trichuris (whipworm) infection?
Frequent, painful passage of stool that contains a mixture of mucus, water, and blood
Rectal prolapse can occur
Children can become severely anemia and have growth retardation
What are the 2 hookworms (ankylostomiasis)?
Ancylostoma duodenale
Necator americanus
