uncontrolled diabetes mellitus complications

Diagnostic Delay in Pulmonary Mucormycosis Despite Empirical Antibiotics

Pulmonary mucormycosis remains a rare but life-threatening fungal infection, particularly in elderly patients with uncontrolled diabetes mellitus. Two recent case reports from 2025 and 2026 highlight the diagnostic challenges and critical importance of early intervention in this population. In both cases, patients presented with persistent respiratory symptoms and imaging findings that mimicked bacterial pneumonia, leading to delayed recognition of mucormycosis until bronchoscopy and histopathological confirmation were performed.

Overlapping Symptoms and Imaging Findings That Mimicked Bacterial Pneumonia

In April 2025, a 71-year-old male with a history of uncontrolled diabetes mellitus, hypertension, and Parkinson’s disease was referred to a pulmonary medicine clinic after failing to improve with empirical antibiotic therapy for a week of fever, cough, and breathlessness. Imaging revealed a cavitary lesion in the left upper lobe, prompting further investigation. Bronchoscopy with bronchoalveolar lavage and biopsy confirmed pulmonary mucormycosis caused by Rhizopus species, a fungus commonly associated with this infection.

The patient’s clinical presentation—fever, cough, dyspnea, and hemoptysis—was nonspecific and overlapped with common bacterial pneumonias. This overlap is a recurring theme in mucormycosis cases, particularly in immunocompromised individuals. The delay in diagnosis underscores the need for high clinical suspicion in patients with uncontrolled diabetes and persistent respiratory symptoms despite appropriate antibiotic treatment.

Histopathological Confirmation and the Critical Role of Bronchoscopy

Diagnosis of pulmonary mucormycosis relies on a combination of imaging, bronchoscopy, and histopathological examination. In both reported cases, initial sputum evaluations—including bacterial culture, KOH mount, AFB smear, and CBNAAT—were inconclusive. Contrast-enhanced CT scans revealed consolidation with internal necrosis, and bronchoscopy identified endobronchial lesions or cavitary lesions, prompting biopsy.

Histopathological examination confirmed the presence of broad, aseptate hyphae with right-angle branching, characteristic of mucormycosis. These findings, combined with the patient’s risk factors, led to the definitive diagnosis. The importance of early bronchoscopy cannot be overstated, as it allows for direct visualization of the airway and tissue sampling, which is critical for accurate diagnosis and timely initiation of antifungal therapy.

Antifungal Therapy and Glycemic Control in a Multidisciplinary Approach

Treatment for pulmonary mucormycosis typically involves intravenous liposomal amphotericin B, followed by oral posaconazole. In the 2025 case, the patient was started on liposomal amphotericin B, with subsequent transition to oral posaconazole. Glycemic control was optimized, and surgical intervention was considered but deferred due to clinical improvement. Over time, the patient demonstrated gradual clinical and radiological improvement, with complete resolution observed over two months.

A similar approach was described in a 2026 case report from Egypt, where a 74-year-old man with poorly controlled diabetes mellitus presented with cough, hemoptysis, and non-resolving consolidation. After bronchoscopy and biopsy confirmed endobronchial mucormycosis, the patient was treated with intravenous amphotericin B followed by oral posaconazole, along with strict glycemic optimization. This case also highlighted the significance of early bronchoscopy and histopathological confirmation in patients with persistent consolidation and negative sputum results.

Risk Factors and Prognosis

Uncontrolled diabetes mellitus is a major risk factor for mucormycosis, particularly pulmonary mucormycosis. The infection is associated with high morbidity and mortality due to rapid tissue necrosis and vascular invasion. Delays in diagnosis are common, with mortality rates exceeding 50–80% in various series, depending on the extent of disease and underlying comorbidities.

Early initiation of antifungal therapy, combined with control of underlying risk factors such as diabetes, is essential for favorable outcomes. Multidisciplinary management—including infectious disease specialists, pulmonologists, and surgeons—is often required to optimize patient care and improve survival.

Key Takeaways and Future Directions

• High clinical suspicion: Mucormycosis should be considered in patients with uncontrolled diabetes and non-resolving pneumonia, even in the absence of typical risk factors.
• Early bronchoscopy: Bronchoscopy with biopsy is essential for definitive diagnosis, particularly when sputum evaluations are inconclusive.
• Prompt antifungal therapy: Early initiation of liposomal amphotericin B or other effective antifungal agents is crucial to improving outcomes.
• Multidisciplinary management: Collaboration among specialists is necessary to address both the fungal infection and underlying comorbidities.

As mucormycosis remains a rare but severe infection, ongoing research and clinical awareness are vital to improving diagnostic accuracy and treatment outcomes in this vulnerable patient population.

Consult your healthcare provider for personalized medical advice and management.