Hemophagocytic Lymphohistiocytosis due to Histoplasmosis

Lets turn up the heat:

45 YO HIV lost to f/u 5 year ago, with diarrhea and confusion. He is thin, slightly hypotensive and febrile to 103. Labs: pancytopenia, crypto ag -, ferritin 15k, fungal profile -, AFB/bacteria cx in blood -, Stool PCR -, CT scan w/nodes and ileus.

Cat Fan GIF

A very dedicated tech calls the fellow on call and says I think you need to look at this slide:

What is the diagnosis and what do you start him on?

Diagnosis is Hemophagocytic Lymphohistiocytosis due to Histoplasmosis. I know I am splitting hairs but HLH is only half right. His IL2 (CD25) was also very high with low NK cell activity. He met criteria for HLH:

HLH due to histo is maybe the most common cause of HLH in HIV patients. Another clue was this patient was hypotensive as Histo loves it some adrenal gland action and bowel causing his ileus. Here is a nice review from our neighbors up in Parkland:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4567100/

Typically we are taught for boards that this is endemic to the Ohio and Mississippi river valley regions but in actuality its spread is ubiquitous. This a recent map from the following reference showing that this a more common exposure than we think:

https://link.springer.com/article/10.1007/s11046-020-00431-2

Histo is acquired through inhalation of spores of Histoplasma capsulatum var. capsulatum (worldwide) or Histoplasma capsulatum var. duboisii (mostly Africa). Usually related to bat/bird poop/construction and is particularly nasty in immunosuppressed individuals.

It is a dimorphic fungi and outside the body. The mycelial phase is quite beautiful:

Most individuals who get Histo have no symptoms & may have a small granuloma but can be disseminated to any part of body but particularly likes bone marrow, GI tract, lymph nodes, spleen, adrenal glands. Like to cause elevated LDH, Alk pho, calcium, cytopenias, coagulopathy.

Dx: Mold grows at 25-30C and can take 6 wks, Yeast likes the body temp, grows faster. Fungal profile checks for Abs but not Ags. Histo Ab can indicate a chronic course or lung cavitary lesion. Urine ag sensitivity in AIDS is 95%, 85% for serum ag. Check if suspicion is high.

Treatment for acute/severe is Ampho B for 1-2 wks, then itraconazole for 6 weeks up to 1 year. Itra needs to be loaded for 3d prior to maintenance dose, 200mg TID for 3 days-> BID. Absorption depends on diet, liquid is better absorbed. Need to check itra levels in 1-2 weeks.

Our patient was started on dexamethasone and ampho and his BP improved and ileus improved after 3 days of ampho b. He is now on ART, itraconazole, and Bactrim and doing great!

Boom Gotcha GIF

Originally tweeted by Baylor Scott and White Infectious Disease (@BSWHTemple_ID) on 16 August, 2020.

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