Metagenomic next-generation sequencing in diagnosing rhino-orbital-cerebral mucormycosis presenting as cerebral Infarction: a case series and diagnostic analysis of seven patients

TL;DR

This study shows how metagenomic sequencing can help diagnose a rare fungal infection that mimics a brain stroke, especially in diabetic patients.

Contribution

This is the first case series to demonstrate the use of metagenomic next-generation sequencing for early diagnosis of ROCM presenting as cerebral infarction.

Findings

All seven patients with ROCM presented with cerebral infarction confirmed by MRI.

mNGS detected Rhizopus species in cerebrospinal fluid, confirming ROCM diagnosis.

Despite treatment, the mortality rate was 85.7%, highlighting the need for early diagnosis.

Abstract

Rhino-orbital-cerebral mucormycosis (ROCM) is a rare, rapidly progressive, and fatal invasive fungal infection. This case series is the first to systematically characterize ROCM presenting primarily as cerebral infarction on imaging and highlights the value of metagenomic next-generation sequencing (mNGS) in the early diagnosis of such critical and atypical cases.

All seven patients had diabetes mellitus, with six concurrently presenting with ketoacidosis. Universal clinical features included fever and a fixed, dilated pupil. Most patients exhibited facial swelling (6/7, 85.7%) and visual impairment (5/7, 71.4%). Cerebral infarction was confirmed by head magnetic resonance imaging (MRI) in all individuals.

The diagnosis was confirmed in all cases by the detection of Rhizopus species sequences via mNGS of cerebrospinal fluid (CSF). Six patients received treatment with amphotericin B cholesteryl sulfate complex, and two of these also underwent surgical debridement. Ultimately, only one patient survived, yielding a mortality rate of 85.7% (6/7).

ROCM should be highly suspected in diabetic patients presenting with acute cerebral infarction accompanied by fever and facial or ocular symptoms. mNGS enables rapid and early etiological diagnosis of ROCM, which is crucial for improving outcomes. Earlier diagnosis, combined antifungal therapy, and surgical intervention may be associated with better prognosis.

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