INTRODUCTION: Pleuropulmonary amebiasis is an uncommon manifestation of hepatic Entamoeba histolytica infection. Amebiasis is typically seen in inhabitants of or travelers to developing countries and pleuropulmonary complications are estimated to occur in approximately 20% of patients with amebic liver abscesses. We describe an unusual case of an active duty soldier stationed in Liberia who presented with fever and abdominal pain and was subsequently diagnosed with pleuropulmonary amebiasis.
CASE PRESENTATION: A 52-year-old active duty US Army soldier stationed in Liberia presented with two weeks of fever (103°F), right upper quadrant abdominal pain and bloody diarrhea. Laboratory analysis revealed leukocytosis with a white blood cell count 32,600/mcL (76% segmented neutrophils, 16% lymphoctyes, 1% eosinophils, 7% monocytes) and a hematocrit of 25.8 g/dL. Colonoscopy revealed edema, erythema and colonic ulcerations. After admission to the hospital, the patient developed dyspnea, a productive cough (green-gray sputum) and right sided pleuritic chest pain. Chest x-ray revealed an elevated right hemi-diaphragm with an associated right pleural effusion. Computed tomography (CT) scan of the chest and abdomen revealed multiple liver abscesses with the largest abscess (7cm × 7cm) eroding through the right hemi-diaphragm leaving a 2.75cm defect. A large loculated right pleural effusion crossed the midline anterior to the vertebral bodies causing lateral displacement of the mediastinum (Fig 1 & 2). He was empirically treated with Metronidazole and immediately evacuated to Walter Reed Army Medical Center for further care. Repeat chest X-ray and CT scan of the chest revealed progressive enlargement and loculation of his pleural effusion. Diagnostic thoracentesis revealed opaque, brown fluid with WBC 113,400 cu/mm, RBC 45,360 cu/mm, pH 6.4, LDH 65, 659 U/L, total protein 2.6 g/dL and glucose 41 mg/dL. Serum antibodies were positive for Entamoeba histolytica. Transthoracic echocardiography revealed a minimal pericardial effusion with ejection fraction of 70% and mild tricuspid regurgitation. The patient underwent surgical decortication and chest tube drainage as definitive treatment for the empyema. He was treated with a course of Paromomycin and Metronidazole resulting in clinical and radiologic improvement.
DISCUSSIONS: Entamoeba histolytica is the third leading cause of parasitic-related mortality world-wide with over 100,000 deaths annually. Pleuropulmonary complications are the second most common cause of extra-intestinal disease and may present with delayed symptoms. Clinical findings of an elevated hemi-diaphragm, pleural effusion, lung abscess or pulmonary consolidation should suggest the diagnosis, yet these presentations can frequently be mistaken for diseases such as tuberculosis, bacterial lung abscess, lobar pneumonia or malignancy. The direct rupture of an amebic liver abscess into the pleural space causing a thoracic empyema is rare. Early therapy with anti-bacterial, anti-parasitics and pleural emypema drainage will shorten the disease course, yet complications secondary to hepatic abscess rupture can arise including hepatopleurobronchial fistula or purulent pericardial effusion leading to cardiac tamponade. Rarely the rupture of an abscess into the inferior vena cava can cause pulmonary thromboembolic disease with right ventricular hypertrophy and dilatation leading to congestive heart failure or cor-pulmonale.
CONCLUSION: Pleuropulmonary amebiasis can be a fatal disease. Clinicians must have high suspicion for this diagnosis in patients from endemic areas who present with the aforementioned symptomology. The different imaging modalities will assist in revealing the invasiveness of this disease as symptoms will not always be consistent with the extent of disease. Empiric therapy with anti-parasitics can modify disease progression and should be the standard of care.
DISCLOSURE: Anita Shah, No Financial Disclosure Information; No Product/Research Disclosure Information