Infectious pericarditis (purulent and tuberculous)

Acute pericarditis is inflammation of the pericardium, most often viral or idiopathic, presenting with pleuritic chest pain relieved by sitting forward, a pericardial friction rub, and diffuse ST elevation with PR depression. Treatment is an NSAID plus colchicine, and the main hazards are effusion, tamponade, and recurrence.

Constrictive pericarditis is a rigid, often calcified pericardium that impairs diastolic filling, causing predominantly right-sided heart failure. It follows pericardial injury (post-surgical, tuberculous, radiation, or idiopathic), is distinguished from restrictive cardiomyopathy by hemodynamic and imaging features, and definitive treatment is pericardiectomy.

Cardiac tamponade is life-threatening compression of the heart by a pericardial effusion, impairing diastolic filling and cardiac output. It presents with hypotension, distended neck veins, and pulsus paradoxus, is confirmed by echocardiography, and is treated by urgent pericardiocentesis; avoid vasodilators and aggressive diuresis.

Pericardial effusion is accumulation of fluid in the pericardial space, ranging from an incidental finding to life-threatening tamponade. Its hemodynamic effect depends on the rate of accumulation rather than volume alone, and management ranges from observation and treating the cause to pericardiocentesis for tamponade or large symptomatic effusions.

Tuberculosis, caused by Mycobacterium tuberculosis, remains a leading global cause of infectious death and presents as latent infection, primary/secondary pulmonary disease, or extrapulmonary and disseminated (miliary) disease. Diagnosis rests on AFB smear, NAAT, and mycobacterial culture (the gold standard), and drug-susceptible active disease is treated with a four-drug regimen (isoniazid, rifampin, pyrazinamide, ethambutol) for 2 months followed by isoniazid plus rifampin for 4 to 7 months.

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, identified by an acute rise in SOFA score of 2 points or more in a patient with known or suspected infection. Survival depends on recognizing the pattern early and completing the hour-1 bundle: lactate, blood cultures before antibiotics, broad-spectrum antibiotics such as cefepime 2 g IV every 8 hours, and 30 mL/kg crystalloid for hypotension or a lactate of 4 mmol/L or higher.

Septic shock is the subset of sepsis with hypotension requiring vasopressors to maintain a mean arterial pressure above 65 mm Hg plus a serum lactate above 2 mmol/L despite adequate fluid resuscitation, carrying in-hospital mortality of 40% or higher. Management is a timed sequence: 30 mL/kg crystalloid bolus, blood cultures and broad-spectrum antibiotics within 1 hour, norepinephrine titrated to MAP >=65, and escalation to a second vasopressor and stress-dose hydrocortisone when hypotension persists.

Bacteremia is the presence of viable bacteria in the blood, confirmed by positive blood cultures, that ranges from transient and clinically silent to the trigger for sepsis and septic shock requiring urgent source identification and antimicrobial therapy.

Community-acquired pneumonia is a lower respiratory tract infection acquired outside the hospital that is diagnosed by a compatible clinical syndrome plus a new infiltrate on chest imaging, risk-stratified with CURB-65 or the Pneumonia Severity Index to guide site of care, and treated with empiric antibiotics chosen by site of care and comorbidity, escalating to cover MRSA or Pseudomonas aeruginosa when risk factors are present.

Empyema is frank pus or a culture/Gram-stain-positive bacterial infection of the pleural space, most often complicating pneumonia, that requires prompt drainage plus antibiotics rather than antibiotics alone.

Infective endocarditis is microbial infection of the endocardium, usually a heart valve, producing vegetations that cause valve destruction, embolism, and systemic infection. Diagnosis uses the modified Duke criteria combining blood cultures and echocardiography, and treatment is prolonged targeted intravenous antibiotics with surgery for complications.