Cardiac tamponade causes

Causes
Cardiac tamponade occurs when the pericardial space fills up with fluid faster than the pericardial sac can stretch. If the amount of fluid increases slowly (such as in hypothyroidism) the pericardial sac can expand to contain a liter or more of fluid prior to tamponade occurring. If the fluid occurs rapidly (as may occur after trauma or myocardial rupture) as little as 100 ml can cause tamponade.

Causes of increased pericardial effusion include hypothyroidism, trauma (either penetrating trauma involving the pericardium or blunt chest trauma), pericarditis (inflammation of the pericardium), iatrogenic trauma (during an invasive procedure), and ventricular rupture.

Cardiac tamponade is caused by a large or uncontrolled Pericardial effusion, that is the buildup of fluid inside the pericardium. This commonly occurs as a result of:
 * Chest trauma (both blunt & penetrating)
 * Myocardial rupture
 * Malignancy
 * Uraemia
 * Pericarditis
 * During cardiac surgery
 * Aortic dissection
 * Anticoagulant therapy.

The effusion can occur rapidly (as in the case of trauma or myocardial rupture), or over a more gradual period of time (as in cancer). The fluid involved is often blood, but pus is also found in some circumstances

Myocardial rupture is a somewhat uncommon cause of pericardial tamponade. It typically happens in the subacute setting after a myocardial infarction (heart attack), in which the infarcted muscle of the heart thins out and tears. Myocardial rupture is more likely to happen in the elderly, females, patients with hypertension, and individuals without any previous cardiac history who suffer from their first heart attack and are not revascularized either with thrombolytic therapy or with percutaneous coronary intervention or with coronary artery bypass graft surgery. These patients more often have single vessel disease without development of collaterals.