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Histoplasmosis
Seven Carson
February 21, 2016

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A female patient, age 75 by the name of Jane Doe (Alias) had been admitted to the
hospital’s emergency room feeling weak and dizzy. She had indicated she has not been feeling
well for the past 8 weeks. At this time she was in an immunosuppressed state, due to her
previous splenectomy and the methotrexate she was taking for her rheumatoid arthritis. Blood
was then collected by the attending nurse and sent to the in house lab and for examination. After
the specimens arrived a CBC (complete blood count) was then ordered. Her only outstanding
results were a high hemoglobin of 16.6 g/dl (reference range is 11.8-15.8 g/dl), a hematocrit of
48.5% (35.0-45.0%), and a WBC (white blood cell) count of 20.8x10^3 (4.0-11.0x10^3/uL). A
manual review was then
performed on her blood.
The results yielded a low
neutrophil count of 12%
(40-75%), a high band
count of 14% (0-11%), and
a high lymphocyte count of
75% (15-50%). A little bit
later after her admittance a
urine sample was collected
for a routine dipstick with a
reflex to culture. Table 1-1
shows the abnormal results,
while her normal results were excluded. A urinalysis is a great way to identify a bacterial or
fungal infections microscopically; however, a reflex to culture was not triggered due to the lack
Table 1-1
Test Test Result Reference range
Color Dark Yellow Yellow
Clarity Slightly Cloudy Clear
Bilirubin Small Negative
Ketones Trace Negative
Blood Small Negative
Protein 30 mg/dl Negative to Trace
Urobilinogen ≥8.0 EU/dl 0.2-1.0 EU/dl
Red Blood Cell Count 4-10 per hpf 0-3 per hpf
Bacteria Moderate Negative to Few

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of WBCs and the nitrite was negative. A blood culture was then ordered, one anaerobe and one
aerobe. After 5 days of incubation the blood showed no growth for bacteria. The next day a test
for influenza A and B was ordered, but came up negative.
Early that morning she was drawn again, but now as an inpatient. A PT (prothrombin)
was run and turned up prolonged with a result of 13.6 seconds (9.4-11.8 seconds). Another CBC
was run this time it had metamyelocytes and myelocytes present with results of 1.0% and 2.0%
respectively (0% for both). A CMP (complete metabolic profile) was also run, however the
results were abnormal I deemed them unnecessary to mention. Blood samples were also sent to
our reference lab for antibody testing. She was positive for a Blastomyces antibody, positive for a
Coccidioides, and positive for the M band of Histoplasma along with a titer of 1:128. The M
band’s significance is that it appears in the patient’s sera during acute infection and is often
present in chronic infections of Histoplasmosis. A titer greater than or equal to 1:32 is also
suggestive, but not diagnostic, of infection (Kauffman, 2007).
Now on day 3, she was tested once again with a CBC and CMP. The CBC’s results were
mostly with the normal reference range, with only her WBC count and MCH being outstanding.
The CMP was fairly similar to her previous day’s results. Later that morning more blood samples
were sent out to our reference lab, while we set up multiple cultures. One culture was sputum.
We started by grading the sputum and after it was deemed acceptable we plated it. Later it turned
up with moderate growth of Candida albicans (yeast), and a lack of the normal respiratory flora.
Day 4 yielded similar results on her morning routine CBC and CMP. Then another blood
culture was collected, which yielded no organism after 5 days. A fungal culture was prepared for
the reference lab and ourselves.

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Day 5 her CBC’s WBC, hematocrit, and MCH were a little on the high end, with results
of 11.8x10^3, 46.0%, and 32.6 pg respectively. Her CMP was similar to yesterday. A
Clostridium difficile by PCR was then ordered with the results turning up negative.
On days 6, 7, 8, 9, 10, and 11 a PT, CMP, and CBC were drawn on those mornings. Her
PTs were prolonged with times of 16.8 seconds, 30.6 seconds, 21.1 seconds, 22.2 seconds, 21.0
seconds, and 17.4 seconds respectively (9.4-11.8 seconds is normal). Her CBCs and CMPs were
similar to the day before. By day 8 her blood counts were becoming normal.
On day 12 the doctor diagnosed her with Disseminated Histoplasmosis capsulati.
Disseminated Histoplasmosis is the most severe form that can occur with the fungus
Histoplasma capsulatum. This variety can affect nearly any part of your body including: mouth,
liver, central nervous system, skin, and even adrenal glands. If left untreated disseminated
Histoplasmosis is usually fatal (Centers for Disease Control and Prevention, 2015). It has a
higher rate of fatality to young children, elderly, and people with an immunodeficiency. Possible
symptoms include: fever, muscle aches, headaches, chills, dry cough, joint pain, rash, or chest
discomfort. In chronic cases the symptoms can mimic tuberculosis, which can include coughing
that brings up blood or weight loss.
The fungus can often be found in bird and bat droppings. It is transmitted by the spores
becoming airborne from disturbed infected soil. Commonly it occurs in the Mississippi and Ohio
river valleys. People with occupations involving soil are at a greater risk of inhaling the spore.
Jobs such as landscapers, gardeners, farmers, gardeners, and cave explorers are at the higher risk
(Mannselis, 2015).

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Macroscopically on Sabouraud Dextrose Agar (SDA) the
fungus appears as a white to brown or pink with a fine dense
cotton texture (Figure 1-1). On the reverse side it will appear white
or sometimes yellow to orange-tan. It is usually mature within 15-
20 days, but may take up to 8 weeks to grow out. The fungus does
not survive well in clinical specimens, so it can be difficult to
isolate. DNA probes are the preferred form of identification.
Microscopically at 25-30˚C, young cultures appear as septate
hyphae bearing pear-shaped, smooth occasionally spiny micro
conidia on short branches or directly on the sides of the hyphae. When it is in this early stage the
fungus can be confused for Blastomyces dermatitidis. Several weeks later they will develop
large, thick-walled, round macro conidia (Figure 1-2). At 35˚C small round or oval budding cells
and occasional abortive hyphae may be seen (Larone, 2002).
On day 15 she was then additionally diagnosed with cellulitis of her right upper limb. On
days 12-19 she was monitored with routine CBCs and CMPs, later being discharged on day 19.
With this being a fungal infection she would have needed to take antifungal medications.
Intravenous medications are typically the stronger and more preferred course of action, instead of
a pill form.
Figure 1-1
Figure 1-2

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Works Cited
Centers for Disease Control and Prevention. (2015, November 21). Histoplasmosis. Retrieved February
21, 2016, from Centers for Disease Control and Prevention:
http://www.cdc.gov/fungal/diseases/histoplasmosis/
Kauffman, C. A. (2007, January). Histoplasmosis: a Clinical and Laboratory Update. Retrieved March 28,
2016, from American Society for Microbiology: http://cmr.asm.org/content/20/1/115.full
Larone, D. H. (2002). Medically Important Fungi a Guide to Identification (4th ed.). Washington D.C.:
American Society for Microbiology Press.
Mannselis, M. L. (2015). Texbook of Diagnostic Microbiology (5th ed.). New York: Saunders.