Pulmonary Aspergillosis, Mucormycosis, and Actinomycosis Co – Infection in a Diabetic Patient

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Pulmonary Aspergillosis, Mucormycosis, and Actinomycosis Co-Infection Presenting as a Cavitary Lesion in a Patient with Diabetes

Introduction

Pulmonary infections caused by opportunistic fungi and bacteria pose significant diagnostic and therapeutic challenges, particularly in immunocompromised patients. This case report presents a rare instance of co-infection involving three distinct pathogens – Aspergillus, Mucor, and Actinomyces – in a diabetic patient, manifesting as a cavitary lung lesion. The complexity of this case underscores the importance of comprehensive diagnostic approaches and tailored treatment strategies in managing such intricate infections.

Case Presentation

A 52-year-old male with type 2 diabetes mellitus presented with a 2-month history of fever, cough, expectoration, and muscle soreness. Initial chest computed tomography (CT) revealed a large irregular cavitary lesion in the right upper lobe (RUL), accompanied by a small amount of pleural effusion. Following one week of antibacterial therapy, while the lobar pneumonia showed partial resolution, a lung abscess became evident.

Clinical Findings and Initial Investigations

Physical examination revealed slightly diminished breath sounds in the right lung compared to the left, with moist rales audible bilaterally. Laboratory investigations showed elevated leukocyte count (15.31 × 10⁹/L), increased serum creatinine (178 mmol/L), and hypoxemia (PaO₂ 66.6 mmHg). The patient’s glycemic control was suboptimal, with a glycosylated hemoglobin level of 8.3%. Initial microbiological tests, including serum procalcitonin, fungal glucan, and Cryptococcus capsule antigen tests, were negative. However, a serum galactomannan (GM) test was positive (0.56).

Diagnostic Procedures and Findings

Bronchoscopic examination revealed purulent sputum obstructing the RUL bronchus. Bronchoalveolar lavage fluid (BALF) analysis showed a positive GM test (4.51), confirming aspergillosis infection. The patient was initiated on meropenem and voriconazole for two weeks. Follow-up CT imaging demonstrated an irregular thick-walled cavity in the RUL. Despite continued oral voriconazole therapy, subsequent bronchoscopy one month later revealed complete obstruction of the RUL bronchus by a granulomatous neoplasm. The BALF GM test remained positive (1.78), and pathological examination identified both Mucor and Aspergillus species.

Therapeutic Challenges and Management

The confirmation of mucormycosis necessitated the addition of amphotericin B or posaconazole to the treatment regimen. However, the patient declined these options due to pre-existing renal dysfunction. Despite ongoing treatment with meropenem and posaconazole, the patient’s condition deteriorated, with persistent fever, worsening respiratory symptoms, and rising serum creatinine levels (260 mmol/L). Repeat bronchoscopy showed complete obstruction of the RUL bronchus by a yellowish granulomatous mass that moved with respiration. BALF GM test remained elevated (5.09), and histopathological examination revealed Aspergillus mycelia within a background of Actinomyces.

Definitive Treatment and Outcome

After six months of unsuccessful medical management, the patient underwent pulmonary lobectomy. Postoperative pathological examination confirmed the presence of a mycotic mass consisting primarily of Aspergillus. Following surgical intervention, the patient achieved clinical remission.

Discussion

This case highlights several critical aspects in the management of complex pulmonary infections:

  1. Diagnostic Complexity: The co-infection of three distinct pathogens – Aspergillus, Mucor, and Actinomyces – presented significant diagnostic challenges. The overlapping clinical and radiological features of these infections necessitated a combination of imaging studies, microbiological tests, and histopathological examination for accurate diagnosis.

  2. Role of Bronchoscopy: Serial bronchoscopic examinations proved invaluable in both diagnosis and monitoring disease progression. The visualization of bronchial obstruction and collection of BALF samples were crucial for identifying the causative organisms.

  3. Therapeutic Considerations: The management of this complex co-infection required a multifaceted approach, including antifungal therapy, antibacterial treatment, and ultimately surgical intervention. The patient’s renal dysfunction further complicated treatment decisions, limiting the use of potentially nephrotoxic antifungal agents.

  4. Importance of Glycemic Control: The patient’s poorly controlled diabetes likely contributed to the development and progression of these opportunistic infections, underscoring the importance of strict glycemic control in preventing such complications.

  5. Diagnostic Utility of GM Testing: Serial GM testing in both serum and BALF samples played a crucial role in monitoring disease activity and treatment response, despite its limitations in distinguishing between different fungal infections.

  6. Pathological Findings: Histopathological examination provided definitive evidence of the co-existing infections, with characteristic features of Aspergillus (septate hyphae), Mucor (broad, aseptate hyphae), and Actinomyces (sulfur granules with filamentous bacteria) observed in different specimens.

Imaging Features

The radiological evolution of the disease process, as demonstrated by serial CT scans, provided valuable insights into the progression of the infection:

  1. Initial CT: Revealed a large irregular cavitary lesion in the RUL with associated pleural effusion.

  2. Post-antibiotic CT: Showed partial resolution of lobar pneumonia but development of a lung abscess.

  3. Follow-up CT: Demonstrated an irregular thick-walled cavity in the RUL, consistent with fungal infection.

  4. Late-stage CT: Revealed bilateral pneumonia with persistent cavitation in the RUL, accompanied by consolidation and air bronchograms.

Bronchoscopic Findings

The bronchoscopic examinations revealed the progressive nature of the infection:

  1. Initial bronchoscopy: Showed purulent sputum obstructing the RUL bronchus.

  2. One-month follow-up: Revealed complete obstruction of the RUL bronchus by a granulomatous neoplasm.

  3. Subsequent examination: Demonstrated a yellowish granulomatous mass completely obstructing the RUL bronchus, with movement noted during respiration.

Pathological Features

Histopathological examination provided definitive diagnosis:

  1. Mucor: Characterized by broad, aseptate hyphae with right-angle branching.

  2. Aspergillus: Identified by septate hyphae with acute-angle branching.

  3. Actinomyces: Recognized by sulfur granules containing filamentous bacteria.

Management Challenges

The management of this complex case presented several challenges:

  1. Drug interactions and side effects: The need for multiple antimicrobial agents increased the risk of adverse effects and drug interactions.

  2. Renal dysfunction: Limited the use of amphotericin B, a potentially effective treatment for mucormycosis.

  3. Patient compliance: The patient’s refusal of certain treatment options complicated management.

  4. Diagnostic uncertainty: The overlapping features of the three infections delayed definitive diagnosis and appropriate treatment.

Conclusion

This case of pulmonary co-infection with Aspergillus, Mucor, and Actinomyces in a diabetic patient illustrates the diagnostic and therapeutic challenges posed by complex opportunistic infections. The successful management of such cases requires a multidisciplinary approach, combining advanced diagnostic techniques, tailored antimicrobial therapy, and when necessary, surgical intervention. The case also highlights the importance of maintaining strict glycemic control in diabetic patients to prevent such complications. Early recognition, accurate diagnosis, and prompt initiation of appropriate treatment are crucial in improving outcomes for patients with such complex infections.

doi.org/10.1097/CM9.0000000000000468

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