A 55-year-old male patient was admitted to the hospital with complaints of fever, cough, chest tightness, and paroxysmal palpitations for 1 week. He had a history of TB infection of the lungs 2 years ago. He received routine first-line anti-TB therapy for over 8 months (including isoniazid, rifampin, ethambutol, and pyrazinamide) and was discharged.
At admission, the patient has discontinued anti-TB treatment and was not taking any medication, including hormone preparations, to control other chronic diseases. Additionally, he denied a history of diabetes, hypertension, or tumors. Notably, he reported several sudden chest pain episodes lasting for a few seconds, accompanied by dizziness and amaurosis during the past week. He underwent a general clinical examination at a local outpatient community hospital setting. Previous medical records showed temporary sinus bradycardia with premature atrial beats on electrocardiogram (ECG) (Figure 1A), which spontaneously recovered to a normal rhythm after rest.
Based on physical examination at admission, he had a height of 169 cm, body mass index of 18.13 kg/m2, temperature of 36.9 C, respiration rate of 18 breaths/min, blood pressure of 109/64 mmHg, and mild malnutrition. No anemia or palpable superficial node enlargement were detected. ECG showed a type II second-degree sinoatrial block (Figure 1B). However, the patient had no specific symptoms other than mild palpitations and chest tightness; therefore, an atropine challenge test was not performed. Lung auscultation revealed scattered pulmonary rhonchi and mild rales in both lungs. Chest radiography revealed fibrotic tuberculous lesions without acute processes. Blood biochemical tests revealed a white blood cell count of 8.06 x 109/L, polymorphonuclear neutrophils level of 96.2%, and high-sensitivity C-reactive protein level of 106.0 mg/L, indicating the presence of infection or inflammation. Other biochemical tests revealed a creatine kinase (CK) level of 109 IU/L, CK-MB level of 16 IU/L, and cardiac troponin I level of 0.02 ng/ml. In addition, serological tests for Hepatitis B, syphilis, and HIV were negative.
Given that the condition of the patient was stable, the emergency physician initially diagnosed the patient with recurrent TB or cardiovascular diseases and prescribed over-the-counter remedies, including dextromethorphan hydrobromide and traditional cough syrup, to relieve cough and reduce sputum and recommended that the patient visits the Specialty Hospital of Infectious Diseases the following day for a further comprehensive examination of the lungs and heart. Unfortunately, after returning home, the patient suddenly experienced severe chest pain, dyspnea, and cardiac arrest at midnight and died after unsuccessful resuscitation attempts. Following the request of the patient's family and the law of China, the body was delivered for a forensic autopsy to examine the cause of the unexpected death.
The autopsy revealed that the epicardium of the right auricle and right atrium were studded with slightly off-white tubercles (Figure 2A). The cut surface of the myocardium showed irregular gray-white lesions on the ventricular wall (Figure 2B). The main trunk of the left coronary artery showed the presence of atheromatous plaques with lumen stenosis (<25%). All other branches of the coronary artery were normal, and there was no evidence of pleural or pericardial involvement. Multiple white nodules, 1-2 mm in diameter, were observed with partial calcification in cut sections of the lungs. The hilar lymph nodes were grayish-white in color and enlarged. No significant abnormalities were observed in any other organ. Histological examination of the sinus node region revealed granulomas, focal fibrosis, and fatty infiltration (Figure 2C). The myocardium also showed a broad context of fibrosis with infiltrated lymphocytes, many Langhans giant cells, and caseating epithelioid granulomas (Figure 2D). Although acid-fast bacillus was not detected in the myocardium, tubercle bacillus deoxyribonucleic acid (DNA) was confirmed by real-time polymerase chain reaction (PCR) on formalin-fixed lung tissue. Tubercle bacilli were detected in the granulomatous areas of the lung tissue using Ziehl-Neelsen (ZN) staining (Figure 3).