CASE SERIES |
https://doi.org/10.5005/jp-journals-11010-1102 |
Unveiling the Varied Faces of Melioidosis: A Case Series with Diverse Pulmonary Presentations
1Department of Respiratory Medicine, Velammal Medical College Hospital and Research Institute, Madurai, Tamil Nadu, India
2–5Department of Respiratory Medicine, Velammal College of Allied Health Sciences, Madurai, Tamil Nadu, India
Corresponding Author: Anand Rajendran, Department of Respiratory Medicine, Velammal Medical College Hospital and Research Institute, Madurai, Tamil Nadu, India, Phone: +91 9524108802, e-mail: dranandrajendran1994@gmail.com
Received: 16 November 2023; Accepted: 05 April 2023; Published on: 18 June 2024
ABSTRACT
Melioidosis, caused by the bacterium Burkholderia pseudomallei, is known for its protean clinical manifestations. It can manifest as acute, subacute, or even chronic presentation. While commonly associated with septicemia and localized infections, pulmonary involvement can present with a spectrum of variable patterns. This case series aims to shed light on the diverse pulmonary presentations of melioidosis, highlighting the challenges in diagnosis and management.
How to cite this article: Rajendran A, Ali NR, Manikandan E, et al. Unveiling the Varied Faces of Melioidosis: A Case Series with Diverse Pulmonary Presentations. Indian J Respir Care 2024;13(2):132–135.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient(s) for publication of the case report details and related images.
Keywords: Acute respiratory distress syndrome, Burkholderia pseudomallei, Case report, Empyema, Lung abscess, Mediastinal lymphadenopathy, Melioidosis
INTRODUCTION
Melioidosis, caused by gram-negative bacterium Burkholderia pseudomallei, is known for its protean clinical manifestations. South Asia has the largest melioidosis case burden accounting for more than half of the global burden up to 45%.1 While commonly associated with septicemia and localized infections, pulmonary involvement can present with a spectrum of variable patterns. This case series aims to shed light on the diverse pulmonary presentations of melioidosis, highlighting the challenges in diagnosis and management.
CASE 1: LUNG ABSCESS—THE MASQUERADER–ACUTE PRESENTATION
A 45-year-old male from Thoothukudi presented with a 2-week history of fever, productive cough, and dyspnea. He has been a known case of type II diabetes mellitus for the past 2 years but has not been on regular medications for the past 5 months. Chest X-ray revealed right upper and mid zone infiltrates with a cavity containing air-fluid level, mimicking pulmonary tuberculosis (Fig. 1A). Clinical examination revealed fever with a temperature of 101°F, heart rate of 115/minute, tachypnea with a respiratory rate of 25/minute, and room air saturation of 93%. Other system examinations were normal. His blood investigations revealed marked leukocytosis (total count of 15,600 cells/mm3—normal range of 4000–11,000 cells/mm) with a neutrophil predominance of 89%; C-reactive protein of 19.6 mg/dL (normal range—0–0.8 mg/dL). Sputum for acid-fast smear and GeneXpert were negative. Sputum culture showed normal oral flora. Initial intravenous broad-spectrum antibiotic therapy targeting common pathogens yielded minimal clinical improvement. High-resolution computed tomography (HRCT) thorax (Fig. 1B) showed right upper lobe cavitation with consolidation. Bronchoalveolar lavage (BAL) was done which was negative for acid-fast bacilli (AFB) stain and GeneXpert MTB. BAL bacterial culture grew B. pseudomallei (Fig. 1C), leading to a revised diagnosis of melioidosis. The antibiotic was escalated to intravenous ceftazidime every three times daily. He showed significant clinical and radiological improvement evidenced by chest X-ray (Fig. 1D) following intravenous ceftazidime and was finally discharged with oral doxycycline after 2 weeks of hospitalization.
Figs 1A to D: (A) Chest X-ray posterior–anterior view showed right upper and mid zone infiltrates with a cavity containing air-fluid level; (B) Axial section of CT thorax—lung window showed right upper lobe cavitation with consolidation with extensive tree-in-bud appearance in middle lobe; (C) Growth of B. pseudomallei on MacConkey agar showing creamy, nonhemolytic colonies with metallic sheen; (D) Repeat chest X-ray posterior–anterior view at the time of discharge showed near complete resolution of right upper and mid zone infiltrates
CASE 2: CHRONIC PULMONARY MELIOIDOSIS MASQUERADING AS LUNG MALIGNANCY—THE RADIOLOGIC ENIGMA
A 70-year-old female from Rameswaram with a history of diabetes mellitus presented with progressive dyspnea and loss of weight for the past 1 month. However, there was no history of fever or cough. Her blood routines were normal. Chest X-ray was relatively normal with suspected left retrocardiac opacity (Fig. 2A). Echocardiogram was normal. HRCT thorax revealed a focal soft tissue density lesion in the superior segment of the left lower lobe with bilateral emphysematous lung fields—suspicion of malignancy (Fig. 2B). The patient was initially started on broad-spectrum intravenous antibiotics (piperacillin–tazobactam 4.5 gm thrice daily plus levofloxacin 500 mg once daily). Computed tomography (CT)-guided biopsy of the left lower lobe lesion showed an acute suppurative process on histopathology, GeneXpert MTB was negative. Bacterial culture grew Burkholderia Pseudomonas. Later, antibiotics were escalated to injection ceftazidime 2 gm intravenously three times daily for 2 weeks. Post escalation, she had both clinical and radiological improvement and was discharged with oral sulfamethoxazole/trimethoprim (800/160 mg) two tablets twice a day for 3 months with daily folic acid 5 mg and was advised to review on an outpatient department (OPD) basis for repeat CT screening. Initially suspected as a primary lung malignancy, further investigation revealed necrotizing pneumonia caused by B. pseudomallei. This case underscores the need for a broad differential diagnosis, especially in regions endemic for melioidosis, even in the absence of overt septicemia.
Figs 2A to B: (A) Chest X-ray anteroposterior view was relatively normal with suspected perihilar left retrocardiac opacity; (B) Axial section of the CT thorax—lung window showed a focal soft tissue density lesion in the superior segment of the left lower lobe with bilateral emphysematous lung fields—suspicion of malignancy
CASE 3: EMPYEMA–SUBACUTE PRESENTATION
A 70-year-old male farmer from Nagercoil presented to our OPD with complaints of fever, right-sided pleuritic chest pain, and dry cough for the past 1 month. His past medical history revealed diabetes mellitus and systemic hypertension for which he was not on regular medications. He appeared febrile with a temperature of 101°F, a heart rate of 110 beats/minute, blood pressure of 100/60 mm Hg, a respiratory rate of 24/minute, and room air oxygen saturation of 94%. Physical examination revealed diminished breath sound in the right lower lung basal areas. Chest X-ray showed right lower zone haziness with cardiophrenic angle blunting (Fig. 3A). CT thorax with contrast revealed right-sided pleural effusion with split pleura sign suggestive of empyema (Fig. 3B). His blood routines were unremarkable except for leukocytosis (total count—15,600). He was started on intravenous antibiotics (piperacillin–tazobactam 4.5 gm thrice daily plus levofloxacin 500 mg once daily). Pleural fluid aspiration revealed exudative pleural effusion with neutrophil predominance for which pigtail insertion was done for drainage. Pleural fluid culture grew B. pseudomallei by which a diagnosis of melioidosis was made. So, antibiotics were escalated to injection meropenem 2 gm intravenous thrice daily for 2 weeks, leading to significant clinical and radiological improvement (Fig. 3C). Finally, the patient was discharged with oral doxycycline 100 mg twice daily and was advised to review on an outpatient basis.
Figs 3A to C: (A) Chest X-ray posterior–anterior view showing right lower zone haziness with cardiophrenic angle blunting; (B) CT thorax with contrast revealed right-sided pleural effusion with split pleura sign suggestive of empyema; (C) Chest X-ray during review (after 1 month) showed near complete resolution of effusion with residual pleural thickening
DISCUSSION
The pulmonary manifestations of melioidosis present a wide spectrum of clinical scenarios, ranging from acute pneumonia to chronic nodules and pleural effusion. Understanding these diverse presentations is crucial for clinicians in endemic regions such as the people residing in coastal areas as described in all our three cases and those encountering patients with relevant travel histories. This discussion delves into the key aspects of the pulmonary involvement in melioidosis, drawing insights from relevant literature.
Acute Pneumonia as a Predominant Presentation
One of the primary pulmonary presentations of melioidosis is acute pneumonia, which can closely mimic other common respiratory infections like tuberculosis.2 The severity of the pneumonia often leads to a misdiagnosis of community-acquired pneumonia (CAP). It is imperative for clinicians to consider melioidosis in the differential diagnosis, especially in areas where the bacterium B. pseudomallei is endemic. The importance of a high index of suspicion cannot be overstated as delays in appropriate treatment may contribute to increased morbidity and mortality associated with melioidosis. Cheng and Currie in their research have extensively highlighted the challenges associated with diagnosing melioidosis, given its varied clinical presentations, and stress the significance of tailored therapeutic approaches based on the severity and manifestation of the disease.3
Subacute Presentations with Pleural Involvement
In addition to acute pneumonia, melioidosis can manifest as subacute presentations involving the pleura. Pleural effusion, though relatively uncommon, adds a layer of complexity to the disease presentation. The involvement of the pleura may lead to delays in diagnosis due to the atypical nature of the symptoms. It is crucial for clinicians to consider melioidosis in the differential diagnosis of patients with unexplained pleural effusions, especially in regions where the disease is endemic. Dance in his article described the need for increased vigilance in recognizing atypical presentations, such as pleural effusion, and advocated for comprehensive surveillance strategies to understand the global distribution of this infectious disease.4
Asymptomatic Carrier States and Latent Pulmonary Nodules
An intriguing facet of melioidosis is the potential for individuals to serve as asymptomatic carriers, harboring latent pulmonary nodules. These carriers may remain undiagnosed unless incidentally discovered during routine imaging studies for unrelated conditions. The presence of latent nodules highlights the chronicity of melioidosis and raises questions about the long-term implications for asymptomatic carriers. Inglis et al. discussed the challenges of identifying asymptomatic carriers and underscored the importance of global perspectives in recognizing and managing melioidosis.5
Global Perspective and Collaborative Approaches
The global emergence of melioidosis necessitates collaborative efforts between clinicians, microbiologists, and public health authorities. A multidisciplinary approach is essential for effective surveillance, timely diagnosis, and appropriate management. The discussion around melioidosis should extend beyond the boundaries of endemic regions, considering the potential for travel-related cases and the evolving epidemiology of the disease.
CONCLUSION
Melioidosis continues to be a diagnostic challenge, particularly when presenting with diverse pulmonary manifestations. Clinicians in endemic regions should maintain a high index of suspicion, considering melioidosis in the differential diagnosis of pneumonia, lung nodules, or even incidentally discovered infiltrates. Timely recognition and appropriate treatment are crucial for improving outcomes in this potentially fatal infection.
ORCID
Anand Rajendran https://orcid.org/0000-0002-0823-2426
REFERENCES
1. Mohapatra PR, Mishra B. Burden of melioidosis in India and South Asia: challenges and ways forward. Lancet Reg Health Southeast Asia 2022;2:100004. DOI: 10.1016/j.lansea.2022.03.004
2. Veluthat C, Venkatnarayan K, Padaki P, et al. Case of melioidosis misdiagnosed as pulmonary tuberculosis. BMJ Case Rep 2021;14(5):e242499. DOI: 10.1136/bcr-2021-242499
3. Cheng AC, Currie BJ. Melioidosis: epidemiology, pathophysiology, and management. Clin Microbiol Rev 2005;18(2):383–416. DOI: 10.1128/CMR.18.2.383-416.2005
4. Dance DA. Melioidosis as an emerging global problem. Acta Trop 2000;74(2–3):115–119. DOI: 10.1016/s0001-706x(99)00059-5
5. Inglis TJ, Rolim DB, Sousa Ade Q. Melioidosis in the Americas. Am J Trop Med Hyg 2006;75(5):947–954. DOI: 10.4269/ajtmh.2006.75.947
________________________
© The Author(s). 2024 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.