HISTOPLASMOSIS OSPE

Question 1

Specimens:

Answer 1

Sputum, aspirate from bone marrow & lymph node, Scrapings from dermal or mucosal ulcers, blood and
biopsies from lymph nodes and other organs.

Question 2

Direct microscopy:

Answer 2

SMEAR/SPUTUM:
Giemsa or wright stains.
yeast appears as Oval, budding cell measuring 2-4μm

Histopathological staining (PAS, Giemsa or GMS stain) :tiny oval yeast cells with narrow based budding within macrophages

Question 3

Culture:Gold standard

Answer 3

SDA, blood agar and BHI agar with cyloheximide and chloramphenicol

Question 4

At 25°C:

Answer 4

• Mycelial phase
• Produces white to buff brown colonies, consist of 2 types of conidia or spores:
• Tuberculate macroconidia- typical thick walls and finger-like projections
• Microconidia are smaller, thin, and smooth-walled.

Question 5

At 37°C: yeast form

Answer 5

(creamy white colonies), which is best developed in special media like Kelley’s media.

Question 6

SKIN TEST

Answer 6

Histoplasmin skin test

Question 7

X-RAY

Answer 7

Diffuse pulmonary infiltration due to acute pulmonary histoplasmosis

Question 8

CASE

Answer 8

A 69-year-old male with no known significant past medical history presented with 2 months of shortness of breath, dry cough, subjective fevers, and an unintentional 20-pound weight loss. Review of symptoms was also notable for constant, diffuse headaches and nausea without vomiting or abdominal pain. She has a painless ulcer on her tongue and positive for HIV with CD4 count of 75. Her serum is nonreactive in the VDRL test. Biopsy of the
lesion revealed yeasts within macrophages.

Question 9

REFER SLIDES