Protozoal Infections Flashcards
A malaria-like illness in a patient from New England…
Babesiosis (Protozoa)
A 40-year-old immigrant from Brazil presents with various constitutional symptoms and prominent muscle pain, especially near her heart. She’s tachycardic and arrythmic. Imaging studies reveal a dilated heart, megaesophagus, and megacolon. She dies two days later due to an arrythmia.
Chagas Disease Trpanosoma cruzi (Protozoa) -endemic in Central/South America Rubin: Acute chagas may cause fatal myocarditis Chronic chagas is associated with cardiac failure and GI disease
A child presents with abrupt onset of abdominal cramping and frequent, foul-smelling stools. The chronic form of this bug causes malabsorption, weight loss, and growth retardation.
Giardiasis Giardia lamblia (Protozoa) -more common in warmer climates with crowded, unsanitary environments
You’re doing medical work in Africa and a patient tells you that about a week ago he developed a red spot on his shoulder. Now he has a fever, and you discover splenomegaly and lymphadenopathy. He works several jobs as a game warden, fisherman, and cattle herder. The man seems apathetic and a little dazed. You worry that he might soon develop a severe meningoencephalitis because he probably has been infected with…
Trypanosoma brucie (Protozoa) “African Trypanosomiasis” or “sleeping sickness” -those occupations are at risk -caused by bite from tsete flies -Africa 3 Stages: 1) Primary chancre (the red spot from the fly bite…) 2) systemic infection (fever, splenomegaly…) 3) severe meningoencephalitis characterized by apathy and many other CNS symptoms
A woman from India develops paroxysms of fever, chills, and severe headache while visiting in the United States. Physical examination reveals hepatosplenomegaly. Labs show anemia and hyperbilirubinemia. Her urine is dark, and a urine dipstick is positive for hemoglobin. The patient develops tonic-clonic seizures and becomes comatose. What pathogen is most likely responsible?
Plasmodium faciparum (Protozoa) Malaria -paroxysms of chills and high fever -hepatosplenomegaly -mostly afflicts people in tropical countries Pathogenesis Review Plasmodium organisms infect RBCs, which rupture and release parasites, hemoglobin. Thus, anemia. Phagocytosis by macrophages leads to monocyte/macrophage hyperplasia and hepatosplenomegaly. Some of the released hemoglobin is excreted in the urine. Parasitized RBCs adhere to capillary endothelium, producing microinfarcts in the brain and heart.
Chronic diarrhea in an immunocompromised host… Organisms visible microscopically as “blebs attached to the luminal surface of epithelium.”
Cryptosporidiosis Cryptosporidum parvum (Protozoa) -Unique feature: Extracellular parasite. Reproduces on luminal surface of most of GI tract, remains attached to epithelium.
A premature infant develops seizures in the nursery and dies a few days later. Autopsy reveals necrosis with calcification in the brain.
Toxoplasmosis Toxoplasma gondii (Protozoa) Congential Infection -cerebral calcifications and marked hydrocephalus
A 25-year-old man, who recently returned from a trip to Central America, presents with severe right upper quadrant pain. Imaging shows a cystic cavity, and biopsy reveals stuff that looks like anchovy paste.
Amebiasis Entamoeba histolytica (Protozoa) -tropical areas with poor sanitation This bug has lytic actions on the liver and/or colon. In the colon, it produces ulcers shaped like a bottleneck and presents with a wide range of abdominal symptoms. Liver abscess is a major complication.
A 50-year-old man, who recently returned from a trip to Africa, complains of darkening of his skin…
Leishmaniasis Leishmania (Protozoa) 1) Cutaneous leishmaniasis -ulcers with sharp, raised borders -usually localized, but disseminated in immunocompetent host 2) Mucocutaneous leishmaniasis -develops years after cutaneous version; ulcer forms at mucocutaneous junction 3) Visceral leishmaniasis (Kala Azar) -light skinned persons develop darkening of skin
