Part 1 of 2 | MCQ in 2nd Part 2:
23M active IV heroin user p/w 4 d fever/headache/seizure. Temp 39.3, supple neck. Initial head CT (-). CSF: WBC 30 (60% L), TP 90, gluc n/l. Developed R arm/leg hemiparesis hospital day 5. MRI: large L>R b/l basal ganglia enhancing lesions ()

|Part 2 of 2 |
Routine CSF viral PCRs/bacterial/AFB/fungal Cxs (-). Blood Cxs, HIV, RPR, TEE (-). Lives in Missouri, no travel/other exposures. Continued to be highly febrile on cefepime/vancomycin/metronidazole. What is the most likely cause of his clinical presentation?

1/9
Only 37% got the correct answer, Mucor.

Learning points:

High risk of cerebral mucormycosis among people who inject drugs (PWID)
Unique basal ganglia involvement seen in these cases

Picture in MCQ taken from:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3590060/

2/9
We've recently discussed some of the infections seen among PWID https://twitter.com/WuidQ/status/1191477822579204104?s=20

Isolated cerebral mucromycosis is one these infections clinicians need to be aware of. \\

This MCQ was inspired by a case presented in our #idgrandrounds in 2015.

3/9
Common Mucor risk factors:
DM in DKA, steroids, hematologic malignancies, transplantation, neutropenia, trauma/burns

Common forms:
Rhino-orbito-cerebral | pulmonary | disseminated > GI
Cutaneous (trauma/burn)

Isolated Mucor:
Renal & cerebral seen in PWID

4/9
Isolated cerebral Mucor in PWID:

Predilection for the basal ganglia (uni-/bi lateral)

Case series: 20 of 22 patients have basal ganglia involvement
https://www.ncbi.nlm.nih.gov/pubmed/7888545 

68 patients w/ isolated cerebral Mucro 82% PWID, 71% basal ganglia
https://www.ncbi.nlm.nih.gov/pubmed/30415043 

5/9
Why the basal ganglia?
Mucor, highly angioinvasive. Tissue infarction/necrosis, path hallmarks.

https://academic.oup.com/cid/article/45/11/1522/335289
Contaminated injection microvascular injury from injected drug seeding to highly vascularized area (small penetrating arterioles/collaterals)

6/9
Need to have a high index of suspicion (can lead to early dx & tx)

Can present like typical meningitis (fever, mental status change, headache); but almost 50%,hemiparesis
Rapidly progressive course despite abx
Brain biopsy is diagnostic (only 38% had culture)

7/9
High mortality rate

65% mortality rate, survival a/w receipt of amphotericin & stereotactic aspiration https://www.ncbi.nlm.nih.gov/pubmed/30415043 

Among 70 patients: delay in antifungals (>6 days after dx) led to a 2-fold mortality increase https://academic.oup.com/cid/article/47/4/503/303246

8/9
Other answers:

CNS Toxo is highly unusual in people w/o HIV/immunosuppression
Although VZV PCR can miss intracranial VZV vasculopathy, most lesions are in gray-white matter junction
Case lacks findings c/w rabies: hydrophobia, aerophobia, exposure, etc

9/9
In summary:

Need to be aware of isolated cerebral Mucor among PWID (high index of suspicion, rapid course, stroke-like presentation, basal ganglia lesions)
Early suspicion, early Tx and Dx life saving!

9/9 EXTRA

In patients w/ cerebral Mucor (like in this featured case), would you use high dose ampho (10 mg/kg/day)?
https://academic.oup.com/jac/article/70/11/3116/2364014

@FungalDoc @GermHunterMD @ShohamTxID @CarlosdelRio7 @PaulSaxMD @RazonableMD @DocWoc71 @BradCutrellMD @Cortes_Penfield

Thank you for your response @FungalDoc @BradSpellberg @TxID_Edu @jdcooperid @FarhanFazal10.

I remember, this patient unfortunately expired despite higher dose ampho. By the time brain biopsy done & showed molds, might have been too late already.