What pericarditis is and what causes it
Pericarditis is inflammation of the pericardium. The two normally slippery layers become irritated, swollen, and roughened, so they rub against each other instead of gliding. In much of the world the most common cause is presumed viral infection (or simply unidentified, called idiopathic), often following a cold or stomach bug a week or two earlier.
Other causes include bacterial infection (notably tuberculosis in many regions), autoimmune diseases like lupus, kidney failure, cancer, radiation, and injury to the heart. A special form, Dressler syndrome, appears weeks after a heart attack or heart surgery as a delayed immune reaction. When inflammation spills into the heart muscle as well, it is called myopericarditis — a combination we'll flag because it raises the stakes.
The classic story: pain, rub, ECG, markers
The hallmark is chest pain with a very particular character. It is sharp and stabbing rather than the heavy pressure of a heart attack. It is pleuritic — worse with a deep breath, coughing, or lying flat — and it characteristically eases when the person sits up and leans forward. The pain often spreads to the left shoulder or the ridge of the trapezius muscle, a clue that points specifically to the pericardium.
On the stethoscope, the inflamed surfaces produce a pericardial friction rub — a scratchy, creaky, leather-on-leather sound, often in three phases per heartbeat. It is the single most specific physical sign of pericarditis, though it can come and go from hour to hour and is easy to miss.
The ECG gives a second strong clue. Because the inflammation is spread diffusely over the whole heart surface, pericarditis classically shows widespread, concave-upward [[st-elevation|ST elevation]] across most leads — unlike a heart attack, where ST elevation is confined to the leads facing one blocked artery. A drooping PR segment is another supportive sign. Blood tests usually show raised inflammatory markers such as C-reactive protein.
Making the diagnosis — 2 of these 4 features needed:
[1] Chest pain — sharp, pleuritic, eased by leaning forward
[2] Friction rub — scratchy 3-phase sound on auscultation
[3] ECG changes — widespread concave ST elevation + PR depression
[4] New/worse effusion — fluid seen on echocardiography
Worked example — a 30-year-old, 10 days after a cold:
Pain sharp, better sitting forward ........ feature [1] YES
Scratchy rub at left sternal border ....... feature [2] YES
ECG: ST up in nearly all leads ............ feature [3] YES
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3 of 4 present -> diagnosis = acute pericarditisCourse and what helps
Most viral and idiopathic pericarditis is self-limited and settles over a couple of weeks. The cornerstone of treatment is anti-inflammatory: high-dose NSAIDs (such as ibuprofen) plus colchicine, which both speeds recovery and cuts the chance of recurrence. Rest from strenuous exercise is advised while inflammation is active. A minority of people have recurrent pericarditis, with the pain returning weeks or months later.