1 infec 56 - tabish60102

[ArchivalUser]

A 27-year-old man has a 3-week history of fever, headache, malaise, decreased appetite, a dry cough, and a 1.3-kg (3-lb) weight loss. His symptoms began 1 week after a 1-month trip to help construct homes in rural Mexico. Seven or eight members of the construction group have developed similar symptoms. The patient's medical history is unremarkable.

On physical examination, temperature is 37.4 °C (99.3 °F), pulse rate is 74/min, respiration rate is 20/min, and blood pressure is 142/88 mm Hg. The head, eyes, ears, nose, and throat are normal. Diffuse crackles are heard throughout all lung fields. Cardiac, abdominal, and neurologic examinations are normal. The extremities are normal.

Laboratory Studies
Hemoglobin

14.5 g/dL (145 g/L)
Hematocrit

44%
Leukocyte count

9200/μL (9.2 × 109/L)
Platelet count

325,000/μL (325 × 109/L)
Blood urea nitrogen

18 mg/dL (6.43 mmol/L)
Serum creatinine

1.0 mg/dL (88.42 µmol/L)
Serum electrolytes

Normal
Serum aspartate aminotransferase

71 U/L
Serum alanine aminotransferase

95 U/L
Serum total bilirubin

0.9 mg/dL (15.39 µmol/L)
Urinalysis

Normal

A chest radiograph shows diffuse reticulonodular infiltrates throughout both lung fields with enlarged mediastinal lymph nodes. CT-guided lung biopsy samples demonstrate early granulomatous inflammation; stains for bacteria, mycobacteria, and fungi are negative.

Which of the following pathogens is most likely causing this patient's findings?

A Mycobacterium tuberculosis
B Aspergillus fumigatus
C Staphylococcus aureus
] D Histoplasma capsulatum

[ArchivalUser]

dd

[ArchivalUser]

(Correct Answer = D)
Key Point
Deep fungal infections such as histoplasmosis are a risk to travelers to endemic areas.

This patient's epidemiologic data, clinical presentation, and laboratory findings are most consistent with histoplasmosis from exposure to a high inoculum. This type of histoplasmosis has occurred in the midwestern United States for some time, and similar point source epidemics have been identified more recently in Central America. The constructions sites that the patient and his colleagues worked on presumably contained areas where bird or bat droppings promoted the growth of Histoplasma capsulatum in the soil.

Although Mycobacterium tuberculosis can cause miliary disease, it is unlikely that multiple persons would become infected at the same time. Aspergillus fumigatus is unlikely to cause these findings in an immunocompetent person. Staphylococcus aureus would have caused a much more acute and severe disease, especially when the pulmonary disease is this extensive.

[ArchivalUser]

THERE IS ONE MORE IMP INFEC THAT PRESENTS LIKE TB AND HISTOPLASMA?