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Difficulty: Very hardInfectious Diseases

Match each clinical vignette describing a systemic or opportunistic infection with the most appropriate primary therapeutic management.

  • A 38-year-old male with untreated HIV (CD4 count 30 cells/mm³) presents with 2 months of fever, significant weight loss, and hepatosplenomegaly. Bone marrow aspirate reveals narrow-based budding yeast cells enclosed within mononuclear phagocytes.Induction with intravenous liposomal amphotericin B, followed by maintenance oral itraconazole
  • A 72-year-old male resident of Rhode Island presents with an acute febrile illness, profound fatigue, and dark urine. Peripheral smear reveals hemolytic anemia and atypical intraerythrocytic tetrad forms (Maltese crosses).Antimicrobial therapy with oral atovaquone plus oral azithromycin
  • A 28-year-old immunocompetent female returning from an archaeological dig in the San Joaquin Valley develops a low-grade fever, dry cough, and painful subcutaneous erythematous nodules on her anterior shins. Chest radiograph demonstrates a focal pulmonary infiltrate.Observation and supportive care with regular clinical follow-up
  • A 64-year-old male renal allograft recipient presents with progressive confusion and a cavitary pulmonary infiltrate. Brain MRI reveals a ring-enhancing lesion. Stereotactic biopsy shows filamentous, branching, Gram-positive bacilli that are weakly acid-fast.Prolonged antimicrobial therapy with high-dose intravenous trimethoprim-sulfamethoxazole
  • A 59-year-old female with poorly controlled type 2 diabetes mellitus presents with facial pain, proptosis, and a necrotic ulceration on the hard palate. Biopsy demonstrates broad, non-septate hyphae branching at right angles.Emergent surgical debridement combined with intravenous liposomal amphotericin B

Answer

The correct matches are: 1) Disseminated Histoplasmosis with liposomal amphotericin B followed by itraconazole; 2) Babesiosis with atovaquone and azithromycin; 3) Uncomplicated Coccidioidomycosis with observation and supportive care; 4) Disseminated Nocardiosis with high-dose trimethoprim-sulfamethoxazole; 5) Rhinocerebral Mucormycosis with emergent surgical debridement and liposomal amphotericin B.
Each clinical vignette provides pathognomonic clues to a specific infectious disease requiring a distinct management strategy. Disseminated histoplasmosis (intracellular yeast in macrophages) requires amphotericin B induction followed by itraconazole. Babesiosis (intraerythrocytic tetrads/Maltese crosses) is treated with atovaquone and azithromycin. Primary coccidioidomycosis in an immunocompetent host with erythema nodosum represents a self-limited infection that requires only observation. Nocardiosis (weakly acid-fast, branching Gram-positive rods causing brain abscesses in transplant recipients) is treated with prolonged high-dose trimethoprim-sulfamethoxazole. Finally, mucormycosis (broad, non-septate, right-angle branching hyphae in a diabetic patient) is an aggressive angioinvasive fungal infection that universally requires both emergent surgical debridement and liposomal amphotericin B.

Step-by-Step Solution

1
Analyze each clinical vignette to identify the specific pathogen based on epidemiology, host immune status, and microscopic characteristics.
The vignettes describe: 1) Histoplasma capsulatum, 2) Babesia microti, 3) Coccidioides immitis, 4) Nocardia species, and 5) Mucorales.
Accurate identification relies on synthesizing pathognomonic clues: intracellular yeast in a patient with AIDS, intraerythrocytic tetrads in a Northeast US resident, Valley fever with erythema nodosum, weakly acid-fast branching rods in a transplant recipient, and broad right-angle hyphae in a diabetic.
2
Determine the definitive guideline-directed management for each identified infection.
Identify the standard therapies: Histoplasmosis requires amphotericin B/itraconazole, Babesiosis requires atovaquone/azithromycin, mild Coccidioidomycosis requires observation, Nocardiosis requires trimethoprim-sulfamethoxazole, and Mucormycosis requires surgery and amphotericin B.
Matching the pathogen to its targeted therapy assesses understanding of antimicrobial stewardship, opportunistic infection management, and situations where surgical intervention or watchful waiting is indicated.
3
Pair the clinical vignettes with their corresponding therapeutic management strategies.
The pairs are logically connected based on the diagnostic and therapeutic reasoning in previous steps.
This confirms the ability to translate complex diagnostic data directly into clinical decision-making.

Key Concept

Identification and targeted management of severe and opportunistic infectious diseases based on distinct microbiological, epidemiological, and host immune factors.
Estimated Time:3m 0s
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Topics

Infectious Diseases

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