cardiac tamponade and constrictive pericarditis? - scorpinme

[ArchivalUser]

ok... sometimes those UW folks make mistakes then...

[ArchivalUser]

Constrictive pericarditis occurs when a thickened fibrotic pericardium, of whatever cause, impedes normal diastolic filling. This usually involves the parietal pericardium.

Acute and subacute forms of pericarditis (which may or may not be symptomatic) may deposit fibrin, which may, in turn, evoke a pericardial effusion. This often leads to pericardial organization, chronic fibrotic scarring, calcification, and restricted cardiac filling.

The clinical symptoms and classic hemodynamic findings can be explained by the fact that early diastolic filling becomes rapid and that elevation and equalization of the diastolic pressures in all of the cardiac chambers restrict late diastolic filling. This leads to venous engorgement and decreased cardiac output.

The normal pericardium is composed of 2 layers: the tough fibrous parietal pericardium and the smooth serous visceral pericardium. Usually, approximately 50 mL of fluid (plasma ultrafiltrate) is present in the intrapericardial space to minimize friction during cardiac motion. In constrictive pericarditis, early ventricular filling during the first third of diastole is unimpeded, but, afterwards, the stiff pericardium affects flow and hemodynamics. That is, ventricular pressure decreases rapidly early and then increases abruptly to a level that is sustained until systole. All cardiac diastolic pressures become nearly equal. This limits end-diastolic volume, which, in turn, decreases stroke volume and cardiac output.
Elevated jugular venous pressures

Sinus tachycardia is common while the blood pressure is normal or low

A pericardial knock, which corresponds with the sudden cessation of ventricular filling early in diastole

o Pulsus paradoxicum (paradoxus) is a variable finding and, if present, rarely exceeds 10 mm Hg unless a concomitant pericardial effusion with an abnormally elevated pressure exists.
o The Kussmaul sign (ie, elevation of systemic venous pressures with inspiration) is a common nonspecific finding, but this sign is also observed in patients with right ventricular failure, restrictive cardiomyopathy, right ventricular infarction, and tricuspid stenosis, although, importantly, not in patients with cardiac tamponade.

[ArchivalUser]

The following are common etiologies

Idiopathic
Infectious (bacterial)
Radiation-induced
Postsurgical

[ArchivalUser]

CARDIAC TAMPONADE

Cardiac tamponade is a clinical syndrome caused by the accumulation of fluid in the pericardial space, resulting in reduced ventricular filling and subsequent hemodynamic compromise. Cardiac tamponade is a medical emergency.

3 phases of hemodynamic changes in tamponade.


Phase I: The accumulation of pericardial fluid causes increased stiffness of the ventricle, requiring a higher filling pressure. During this phase, the left and right ventricular filling pressures are higher than the intrapericardial pressure.

Phase II: With further fluid accumulation, the pericardial pressure increases above the ventricular filling pressure, resulting in reduced cardiac output.

Phase III: A further decrease in cardiac output occurs, which is due to equilibration of pericardial and left ventricular (LV) filling pressures.

The underlying pathophysiologic process for the development of tamponade is markedly diminished diastolic filling because transmural distending pressures are insufficient to overcome the increased intrapericardial pressures.

Distended neck veins are a common feature in patients with tamponade.

The Beck triad or acute compression triad : increased jugular venous pressure, hypotension, and diminished heart sounds.
Pulsus paradoxus or paradoxical pulse:
This is an exaggeration (>12 mm Hg or 9%) of the normal inspiratory decrease in systemic blood pressure.
To measure the pulsus paradoxus, patients are often placed in a semirecumbent position; respirations should be normal. The blood pressure cuff is inflated to at least 20 mm Hg above the systolic pressure and slowly deflated until the first Korotkoff sounds are heard only during expiration. At this pressure reading, if the cuff is not further deflated and a pulsus paradoxus is present, the first Korotkoff sound is not audible during inspiration. As the cuff is further deflated, the point at which the first Korotkoff sound is audible during both inspiration and expiration is recorded. If the difference between the first and second measurement is greater than 12 mm Hg, an abnormal pulsus paradoxus is present.

Kussmaul sign paradoxical increase in venous distention and pressure during inspiration.

Ewart sign
Also known as the Pins sign, this is observed in patients with large pericardial effusions.
It is described as an area of dullness, with bronchial breath sounds and bronchophony below the angle of the left scapula.

The y descent
The y descent is abolished in the jugular venous or right atrial waveform.
This is due to an increase in intrapericardial pressure, preventing diastolic filling of the ventricles

For all patients, malignant diseases are the most common cause of pericardial tamponade. Tamponade can occur as a result of any type of pericarditis.

[ArchivalUser]

Chest radiography findings may show cardiomegaly, water bottle“shaped heart, pericardial calcifications, or evidence of chest wall trauma