Bacterial pericarditis most often presents in a nonspecific pattern in the young child, and the practitioner should strongly consider the diagnosis when evaluating patients with unexplained tachycardia and tachypnea. Fever, agitation, and precordial chest pain are common presenting symptoms. The pericardial friction rub is the pathopneumonic physical finding in older patients, but diminished heart sounds rather than a friction rub may be found in patients with large effusions. Most pediatric cases of bacterial pericarditis present in children younger than 2 years of age and classic signs are not present, such as a friction rub or chest pain. Practitioners, therefore, should have a low index of suspicion in toxic patients. They should workup patients with tachycardia out of proportion to the fever and respiratory distress not fully explained by a septic or pulmonic process.

Pericardial effusions develop rapidly in patients with acute bacterial pericarditis. Cardiac filling is impaired as pericardial fluid accumulates, producing signs of congestion and diminished cardiac output. Patients with rapid accumulation of fluid will present with cardiogenic shock. Conversely, congestive symptoms, such as hepatomegaly, jugular venous distention, and pulmonary edema, will predominate in patients with a slower accumulation of pericardial fluid. Patients with constrictive pericarditis resulting from viral myopericarditis, cat-scratch disease, tuberculosis, or sequelae of purulent pericarditis may also present with congestive heart failure. In patients with tamponade, systemic perfusion is maintained by an increase in heart rate and systemic vascular resistance. The increased systemic vascular resistance produces a narrow pulse pressure, as opposed to a wide pulse pressure commonly seen in severe sepsis. Ultimately, in patients with purulent pericarditis, if the effusion remains undrained, systemic hypotension and cardiovascular collapse will result.