Invasive Rhinocerebral Aspergillosis in a Patient With Poorly Controlled Diabetes Mellitus: A Clinical Challenge

Invasive rhinocerebral aspergillosis (IRCA) is a rare but devastating fungal infection that can progress silently until significant tissue destruction occurs. It most often affects immunocompromised individuals, particularly those with poorly controlled diabetes mellitus. Frontal sinus involvement is uncommon, yet it poses a high risk of intracranial spread and severe neurological complications. We describe a 74-year-old woman with long-standing, poorly controlled type 2 diabetes mellitus (HbA1c 14.1%), referred for unstable glycemic control and subtle cognitive changes. Cranial imaging revealed left frontal sinus opacification with posterior wall erosion and intracranial extension. She was started on empirical amphotericin B and broad-spectrum antibiotics. Endoscopic sinus surgery confirmed posterior table dehiscence with dural exposure, and cultures identified Aspergillus fumigatus. Due to amphotericin B-related nephrotoxicity, antifungal therapy was transitioned to isavuconazole and later to oral voriconazole. With optimized insulin therapy and close multidisciplinary follow-up, the patient recovered fully, showing radiologic improvement one month after discharge. This case highlights the strong association between poor glycemic control and invasive fungal infections. Frontal sinus involvement demands early recognition and aggressive treatment to prevent intracranial complications. Isavuconazole offered effective antifungal coverage with better renal safety in this setting. IRCA can be subtle in its early stages, but rapidly becomes life-threatening once intracranial extension occurs. Early diagnosis, coordinated multidisciplinary care, and strict metabolic control are key to achieving favorable outcomes in these patients.