Haemorrhagic Mycobacterium avium complex pericarditis presenting with cardiac tamponade in an immunocompetent woman

Background

Cardiac tamponade is a syndrome caused by an accumulation of fluid in the pericardial sac (pericardial effusion) that is characterised by resultant diastolic filling impairment of the ventricles, leading to a reduction in cardiac output.1 2 This syndrome is life-threatening and, if not diagnosed and treated promptly, could lead to cardiac arrest.1 2 This case highlights the important fact that the clinical presentation of cardiac tamponade is variable, and a good understanding of tamponade physiology is key to identifying and managing patients who present with atypical findings.

There are several causes of pericardial effusion which can lead to tamponade. Infectious causes are common. However, Mycobacterium avium complex (MAC)-induced pericardial effusion is extremely rare with very few cases documented to date.3 Furthermore, in the cases which have been documented, MAC-induced pericardial effusion is usually found in immunocompromised male patients.3

We present a rare case of MAC-induced pericardial effusion in an immunocompetent woman with no predisposing factors. Her case was even more interesting as she presented in a haemodynamically stable state despite having active tamponade from her large pericardial effusion. We explain the physiology behind her atypical presentation.

Case presentation

A young woman in her mid-40s with a medical history of hypertension presented with 10 days of a non-productive cough, worsening shortness of breath, chest tightness and pleuritic chest pain relieved by sitting up. She reported fevers of up to 103°F. She denied any nausea, vomiting or diarrhoea but did admit to decreased appetite.

On examination, she was ill appearing but in no acute cardiopulmonary distress. Her pulse was regular but tachycardic. She had normal heart sounds with no rubs, murmurs or gallops. She had no jugular venous distension. The pulmonary examination was unremarkable. She had no lymphadenopathy. The remainder of her examination was unremarkable. She was also normotensive, tachycardic up to 138 beats/min, afebrile and not hypoxic when evaluated in the emergency department.

Investigations

Initial ECG showed evidence of sinus tachycardia with a heart rate of 124 beats/min, low voltage QRS complexes and poor R wave progression. Chest X-ray showed evidence of an enlarged cardiac silhouette (see figure 1). Her complete blood count was significant for haemoglobin was 10.1 g/dL with a platelet count of 515/nL and a normal white cell count of 4.96/nL. Complete metabolic panel showed only mild transaminitis. C reactive protein, erythrocyte sedimentation rate and D-dimer were significantly elevated (see table 1).

Given her elevated D-dimer, dyspnoea and tachycardia, pulmonary embolism (PE) was a concern. CT angiogram of the chest was negative for PE but revealed a 5.4 cm pericardial effusion (see figure 2A). STAT echocardiogram showed a large pericardial effusion with findings positive for tamponade physiology (plethoric inferior vena cava, collapse of the right atrium and right ventricle).

Differential diagnosis

This patient’s large haemorrhagic pericardial effusion could have been caused by malignancy, tuberculosis (TB) or possible viral pericarditis, with MAC representing contamination. However, we argue against this as none of these differentials would explain this patient’s clinical course. The patient’s flow cytometry was negative, cytology was negative, breast biopsy was also negative and the lack of a recurrent nature was not in keeping with a malignant effusion with contamination. TB was ruled out as all her sputum samples were negative for M. tuberculosis (MTB), in addition to the fact that PCR and gene sequencing for MTB were negative on all samples tested (see table 1). Given the haemorrhagic nature, viral pericarditis was less likely. In addition, testing for common viruses, including coxsackie virus on the pericardial and respiratory samples, was negative. Hence, the large haemorrhagic pericardial effusion, recurrent fevers, inflammation and necrotising granulomas seen on histopathology, growth of MAC in multiple pericardial samples and a positive QuantiFERON-Gold test in the setting of negative PCR for MTB made a localised MAC-induced pericardial effusion the most likely diagnosis in this case.

Treatment

She underwent emergency pericardiocentesis, during which 1 L of bloody pericardial fluid was drained (see table 1 for analysis). There was a concern for possible malignancy or tuberculous pericardial effusion. The patient was isolated, and serial sputum cultures were sent for acid-fast bacilli (AFB) staining. Immunoglobulin levels were measured and found to be normal. Rheumatological workup (table 1) was unremarkable; HIV, and hepatitis C and B were non-reactive.

Repeated echocardiogram and CT of the chest post-pericardiocentesis revealed residual moderate pericardial effusion (figure 2B), multiple small pulmonary nodules and bilateral breast lesions. There was a concern for malignancy. Symptoms persisted despite treatment with colchicine. Though she continued to spike fevers, blood cultures were negative, and serial sputum cultures were negative as well. On day 4 of admission, she underwent a right video-assisted thoracoscopic surgery (VATS) procedure with pericardial window and chest tube insertion.

During the procedure, the pericardium was noted to be tense and thickened posteriorly but not to the degree that warranted excision. A 400 mL of serous fluid was drained. Samples of the pericardium were also sent for microbiology and pathology. Inspection within the pericardial cavity revealed loculated fibrous material, which required blunt dissection to create a continuous cavity.

A decision to perform pericardiectomy, in this case, was not considered. This procedure is associated with a higher mortality and complication rate than a pericardial window and is usually indicated in cases of constrictive pericarditis, which this patient did not have.4 Hence, the risk of performing such a procedure greatly outweighed any benefits and was not performed. Furthermore, loculations found on thoracotomy could be removed by simple adhesiolysis through blunt dissection. No tight fibrous bands were found that would have required the removal of the pericardium.

Postoperatively, she did well, and chest X-rays showed no evidence of pneumothorax with minimal drainage from the chest tube. She was started on indomethacin 50 mg orally every 8 hours. Her pericardial drain and pleural chest tubes were removed.

Postoperatively, her fevers and her chest pain resolved. AFB stains were all negative initially, cytology was negative, and viral studies for coxsackie and adenovirus from pericardial fluid were negative. Flow cytometry on pericardial fluid was also negative. Cultures from the pericardial fluid showed no growth initially.

Her initial QuantiFERON-Gold test was positive. However, all sputum cultures were negative for MTB, and PCR/gene sequencing for MTB was negative. Her symptoms resolved with drainage of her pericardial effusion and the use of non-steroidal anti-inflammatory drugs (NSAIDs) before discharge. Infectious disease specialists involved in the case from the beginning agreed that the patient had a negative PCR for MTB; thus, they effectively ruled out active and latent TB. However, given her initial positive QuantiFERON-Gold test, there was a plan to have it repeated and to closely monitor her in the outpatient setting.

She was discharged to complete an extended course of NSAIDs with plans for follow-up of her breast and pulmonary lesions as well as her pending cultures.

Outcome and follow-up

Her pericardial fluid cultures later grew MAC confirming a diagnosis of a localised MAC-induced haemorrhagic pericarditis complicated by cardiac tamponade. Infectious disease specialists evaluated her in the outpatient setting for latent TB. Her repeat QuantiFERON-Gold test was negative, and the patient’s symptoms had resolved. As such, latent TB was determined to be unlikely and the initial QuantiFERON-Gold test was likely a false positive from her MAC infection at the time.

Infectious disease specialists agreed that since the patient was immunocompetent and was already showing significant clinical resolution with pericardial fluid drainage and NSAIDs alone, it was not worthwhile to subject this patient to the toxic side effects associated with an extended course of anti-mycobacterial medications.

Three months after her discharge, she was feeling better after having some residual chest discomfort. She had a biopsy of her right breast lesion, which was found to be benign. A repeat CT of the chest revealed a stable small 6 mm right upper lobe nodule, resolution of her previous smaller multiple pulmonary nodules and minimal fluid around the pericardium (figure 2C). The patient continues to do well and has had complete resolution of her symptoms and no recurrence of her effusion since being drained.

She has had several repeat CT scans of the chest which have shown resolution of her multiple pulmonary nodules, which were seen on scans during her illness. Her 6 mm right upper lobe nodule is stable in size. Given the fact that she is low risk for lung cancer, close monitoring with serial imaging was the appropriate plan. It is possible that it represents a post-inflammatory change.

The patient was also evaluated by oncology in the outpatient setting, who determined that malignancy was unlikely in this case and did not advise for further oncological workup.