USMLE STEP 3 BIOSTATS FINAL STUDY
GUIDE 2026 COMPLETE SOLVED
QUESTIONS 100% CORRECT
◉Malaria. Answer: -hemolysis, GI complaints
-blood smear shows the parasite
-tx with quinine or doxy
◉Malaria prophy. Answer: -atovoquone/proguanil daily
-mefloquine weekly (side effects include neuropsych, sinus brady,
QT prolongation)
-daily doxy (not the best answer on USMLE though)
◉Nocardia. Answer: -branching, gram positive filaments (like
actinomyces!) that are weakly acid fast
-seen in immunocompromised pt.s
-starts in lungs then disseminates to any organ, skin and brain are
most common
-CXR and cx
-tx with TMP/SMX
,◉Actinomyces. Answer: -normal immune system w/ facial or dental
trauma
-dx with gram stain and confirm with anaerobic cx
-branching, filamentous bacteria (LIKE nocardia!)
-tx with PCN
◉Histoplasmosis. Answer: -Ohio and Mississippi River valleys
-associated with bat droppings from caves
-viral syndrome, lung disease, oral and palate ulcers, splenomegaly
-disseminated disease enters bone marrow and causes pancytopenia
(can look like TB)
-acute pulmonary dx does NOT require tx
-disseminated dx is treated with amphotericin
◉Blastomycosis. Answer: -rural Southeast
-broad budding yeast
-bone lesions are common
-tx with amphotericin or itraconazole
◉Broad ass yeast in the south. Answer: blasto: tx with itra
, ◉Non-con head CT. Answer: r/o hemorrhage
◉Contrast head CT. Answer: AV malformations or tumor
◉Cr cutoff for CT with contrast. Answer: 1.5
◉What meds need to be d/c-ed before CT?. Answer: Metformin
(restart 48 hours after)
◉No MRI with gad in whom?. Answer: renal failure (Cr>1.5)
◉When is MRI best?. Answer: -demyelinating diseases
-posterior fossa, base of skull, orbits
-acoustic neuromas, pituitary tumors, small brain tumors
-bone tumors, osteomyelitis, joint spaces, aseptic necrosis of femoral
head
-spinal cord and spinal column problems
◉When are nuclear scans best?. Answer: -HIDA scan to evaluate
biliary obstruction v. acute cholecystitis, and biliary leaks postop;
NOT best choice for eval of gallstones
-bone scan: metastatic bone lesions, delayed fractures, osteomyelitis
and avascular necrosis of femoral head
GUIDE 2026 COMPLETE SOLVED
QUESTIONS 100% CORRECT
◉Malaria. Answer: -hemolysis, GI complaints
-blood smear shows the parasite
-tx with quinine or doxy
◉Malaria prophy. Answer: -atovoquone/proguanil daily
-mefloquine weekly (side effects include neuropsych, sinus brady,
QT prolongation)
-daily doxy (not the best answer on USMLE though)
◉Nocardia. Answer: -branching, gram positive filaments (like
actinomyces!) that are weakly acid fast
-seen in immunocompromised pt.s
-starts in lungs then disseminates to any organ, skin and brain are
most common
-CXR and cx
-tx with TMP/SMX
,◉Actinomyces. Answer: -normal immune system w/ facial or dental
trauma
-dx with gram stain and confirm with anaerobic cx
-branching, filamentous bacteria (LIKE nocardia!)
-tx with PCN
◉Histoplasmosis. Answer: -Ohio and Mississippi River valleys
-associated with bat droppings from caves
-viral syndrome, lung disease, oral and palate ulcers, splenomegaly
-disseminated disease enters bone marrow and causes pancytopenia
(can look like TB)
-acute pulmonary dx does NOT require tx
-disseminated dx is treated with amphotericin
◉Blastomycosis. Answer: -rural Southeast
-broad budding yeast
-bone lesions are common
-tx with amphotericin or itraconazole
◉Broad ass yeast in the south. Answer: blasto: tx with itra
, ◉Non-con head CT. Answer: r/o hemorrhage
◉Contrast head CT. Answer: AV malformations or tumor
◉Cr cutoff for CT with contrast. Answer: 1.5
◉What meds need to be d/c-ed before CT?. Answer: Metformin
(restart 48 hours after)
◉No MRI with gad in whom?. Answer: renal failure (Cr>1.5)
◉When is MRI best?. Answer: -demyelinating diseases
-posterior fossa, base of skull, orbits
-acoustic neuromas, pituitary tumors, small brain tumors
-bone tumors, osteomyelitis, joint spaces, aseptic necrosis of femoral
head
-spinal cord and spinal column problems
◉When are nuclear scans best?. Answer: -HIDA scan to evaluate
biliary obstruction v. acute cholecystitis, and biliary leaks postop;
NOT best choice for eval of gallstones
-bone scan: metastatic bone lesions, delayed fractures, osteomyelitis
and avascular necrosis of femoral head
