Cause:
Acute: 90% are idiopathic; also uremic, bacterial from a subdiaphragmatic abscess (Nejm 1967;276:1247), post-MI, viral especially coxsackie, postsepticemic (Ann IM 1973;79:194), mycoplasma (Ann IM 1977;86:544), or malignancy invading pericardium
Chronic: tuberculosis, sarcoid
Pathophys:
The stiffening causes restriction of ventricular diastolic filling; increased heart rate must compensate for decreased stroke volume; can tolerate 1-3 L if slowly accumulates, only 300-400 cc if rapid accumulation
Paradoxical pulse if constrictive (exaggeration >10 mm Hg of normal drop of systolic BP with inspiration) due to impaired venous return and normal increased pulmonary vascular volume w inspiration (Mod Concepts Cardiovasc Dis 1978;47:109, 115)
Coxsackie viral type probably is the most common cause and occurs in late summer and fall like other enteroviruses
Sx:Dyspnea; chest pain, often pleuritic and better when sits up
Si:
Ascites, poor heart sounds, no PMI, tachycardia; pleural effusions on left more often and larger than on right, unlike CHF (Nejm 1983;308:696)
In constrictive pericarditis: increased CVP with Kussmaul's si, r/o RV infarction; rapid Y descent and rebound, r/o infiltrating myocardiopathy, eg, amyloid. Paradoxical pulse >10 mm Hg, r/o asthma, RV myocardial infarction (Nejm 1983;309:551)
Lab: Noninv:EKG ST elevation, and/or PR depressions in limb and precordial leads, which exclude early repolarization; early repolarizaton usually has precordial lead (STs) or limb (PRs) involvement only; Ts invert only after STs back to normal. May show electrical alternans, ie, alternate QRSs have higher and lower voltages
Echo shows pericardial fluid and may show tamponade hemodynamics
Xray:Chest shows large heart, "boot-shaped." CT may show calcifications in 27% of constrictive types, usually chronic, 2/3 w/o a dx, occasionally is tbc (Ann IM 2000;132:444)
Rx:ASA, ibuprofen, or other NSAID rx, or steroids if NSAID intolerant × 4 wk, plus colchicine 0.6 mg po bid × 1 then qd × 6 mo, prevents recurrence (Arch IM 2005;165:1987)
If constrictive, tap under echo or EKG guidance; pulmonary edema can develop if tap too much too fast leading to an overload of a deconditioned heart (Nejm 1983;309:595); if constrictive and chronic, surgical pericardectomy