Pericarditis is the inflammation involving the sac that covers the heart (inflammation of the pericardium).
It can be due to infection (bacteria, viruses, TB etc), heart attack, autoimmune diseases (eg. SLE, rheumatic diseases), kidney failure, trauma, injury, certain medications, radiation etc.
Most of the patients will recover without much complication. Some, however, will develop complications related directly to pericarditis (eg. Pericardial effusion, constructive pericarditis, chronic recurrent pericarditis), or indirectly due to the underlying medical conditions eg, SLE, heart attack, infection.
Diagnosis is by careful history, clinical examination and some noninvasive investigations like ECG, CXR, blood test, echocardiography or CT scan.
Treatment is mainly symptomatic with pain killer and anti-inflammatory medications, or/and treatment directed at its underlying cause.
Finally the symptom of chest pain on lying and during inspiration might not necessary due to pericarditis. Simple chest wall muscle injury/strain, or pleurisy (inflammation of the lung covering sac) might give rise to similar complaints at times.
Dr Chee
