Pericardial disease: Pathology review

Two people came to the emergency department. One of them is 55 year old Pamela who has sharp retrosternal chest pain that gets worse when she breathes in. On chest auscultation, a friction rub can be heard. The other person is 43 year old Thomas, who had been in a car accident and now presents severe hypotension and on physical examination, his neck veins are distended, his heart rate is really high. On chest auscultation there’s barely audible heart sounds. An ECG was ordered for both individuals. Pamela had ST-segment elevation in several leads and also PR depression, while Thomas has low-voltage QRS complexes.

Okay, based on what we know about the individuals, we can assume that both suffer from pericardial disease. But first, a bit of physiology. The pericardium is a sac that covers the heart and the roots of the great vessels. The pericardium has two layers, an inner serous layer and an outer fibrous layer. The space between the two layers is the pericardial cavity that cushions the heart from any kind of external jerk or shock - like a shock absorber. The pericardium also fixes the heart to the mediastinum, to prevent it from twisting, so that the large vessels don’t get pinched shut.

Now for pericardial disease, we should start by talking about inflammation in the pericardium, which is called pericarditis. People who develop pericarditis are also at risk of developing a pericardial effusion where the inflammation causes fluid to accumulate around the heart.

Pericarditis is in most cases idiopathic. It can also be due to a viral infection, like Coxsackie B virus. Pericarditis can also be seen in autoimmune diseases, like rheumatoid arthritis or systemic lupus erythematosus, because the immune system attacks our own tissues, including the pericardium. For your exams, other high yield causes include myocardial infarction and Dressler syndrome which occurs several weeks after a myocardial infarction. Basically, when heart cells die in a myocardial infarction, it attracts white blood cells to the area, leading to massive inflammation that also involves the serous pericardium. Another cause is uremia, which is when blood levels of urea gets really high and this usually happens due to kidney failure. The high levels of urea irritate the serous pericardium, making it secrete a thick pericardial fluid that’s full of fibrin strands and white blood cells. Cancers like lung cancer and lymphoma can also lead to pericarditis, due to metastasis that reach the pericardium, irritating it. Finally, there’s radiation therapy that can also lead to pericarditis.