Histoplasma capsulatum; Histoplasmosis

Question 1

Patient presentation

Answer 1

travel history weight loss, night sweats, cough, fatigue and headaches

crackles on auscultation

increase neutrophil count, increased lymphocytes, increased monocytes

Question 2

Where is organism commonly acquired?

Answer 2

along Ohio Mississippi valleys; central and South America, India, Africa and southeaster Asia

Question 3

Where does organism grow?

Answer 3

in soil contaminated with bat, pigeon, bird droppings

Question 4

who has higher risk of acquiring?

Answer 4

construction workers, agriculture workers, spelunkers, immunocompromised

Question 5

treatments

Answer 5

Oral intraconazole (>4 weeks pulmonary symptoms)

Severe infections: amphotericin B

Question 6

Lab Culture demonstrates

Answer 6

dimorphism- organism grows as mold at 25C

in tissues at 37C organism appears as yeast

Question 7

Lab stain demonstrates

Answer 7

GMS shows yeast seen in macrophages (tissue phase)

Grocott methenamine silver (GMS) stain is commonly used for the identification of fungi on cytosmears and tissue sections.

Question 8

Lab skin test

Answer 8

DTH Delayed-type hypersensitivity (DTH) skin testing

Question 9

causes weight loss/cachexia

Answer 9

cytokine response, TNF alpha

Question 10

reactivation occurs under what conditions

Answer 10

immunosuppressed - HIV, transplant, TNF-alpha inhibitors

Question 11

pathology

Answer 11

inhaled spores enter lungs in which alveolar macrophages trap them and they change to yeast form. they are transported to lymph node where they can lie latent forming a granuloma. within time calcified fibrinous granulomas with caseous necrosis in the lungs hilarious and mediastinal areas are demonstrated and may also be seen spleen, liver, bone marrow

Question 12

Lab Xray demonstrates

Answer 12

multiple bodular infiltrates/ enlarged hisar and mediastinal nodes and popcorn calcification