Page 473 - Textbook of Pathology, 6th Edition

A. HYDROPERICARDIUM (PERICARDIAL EFFUSION).  TABLE 16.11: Classification of Pericarditis. 457
Accumulation of fluid in the pericardial cavity due to non-
inflammatory causes is called hydropericardium or A. ACUTE PERICARDITIS
pericardial effusion. Normally, the pericardial cavity contains 1. Serous pericarditis
30 to 50 ml of clear watery fluid. Considerable quantities of 2. Fibrinous or serofibrinous pericarditis
fluid (up to 1000 ml) can be accommodated in the pericardial 3. Purulent or fibrinopurulent pericarditis
cavity without seriously affecting the cardiac function if the 4. Haemorrhagic pericarditis
accumulation is slow. But sudden accumulation of a smaller B. CHRONIC PERICARDITIS
volume (up to 250 ml) may produce deficient diastolic filling 1. Tuberculous pericarditis
of the cardiac chambers (cardiac tamponade). Pericardial 2. Chronic adhesive pericarditis
effusion is detected by cardiac enlargement in the X-rays and 3. Chronic constrictive pericarditis
by faint apex beat. 4. Pericardial plaques (milk spots, soldiers’ spots)
The various types of effusions and their causes are as
follows:
1. SEROUS PERICARDITIS. Acute pericarditis may be
1. Serous effusions. This is the most common type accompanied by accumulation of serous effusion which
occurring in conditions in which there is generalised oedema differs from transudate of hydropericardium in having
e.g. in cardiac (in CHF), renal, nutritional and hepatic causes. increased protein content and higher specific gravity. Its
The serous effusion is clear, watery, straw-coloured with various causes are as under:
specific gravity less than 1.015 (transudate). The serosal i) Viral infection e.g. coxsackie A or B viruses, influenza
surface is smooth and glistening.
virus, mumps virus, adenovirus and infectious mono-
2. Serosanguineous effusion. This type is found following nucleosis.
blunt trauma to chest and cardiopulmonary resuscitation. ii) Rheumatic fever.
3. Chylous effusion. Milky or chylous fluid accumulates iii) Rheumatoid arthritis.
in conditions causing lymphatic obstruction. iv) Systemic lupus erythematosus.
4. Cholesterol effusion. This is a rare type of fluid accumu- v) Involvement of the pericardium by malignant tumour in CHAPTER 16
lation characterised by the presence of cholesterol crystals the vicinity e.g. carcinoma lung, mesothelioma and
such as in myxoedema. mediastinal tumours.
vi) Tuberculous pericarditis in the early stage.
B. HAEMOPERICARDIUM. Accumulation of pure blood The fluid accumulation is generally not much and ranges
in the pericardial sac is termed haemopericardium. The from 50 to 200 ml but may rarely be large enough to cause
condition must be distinguished from haemorrhagic cardiac tamponade.
pericarditis in which there is escape of small quantities of
blood into the pericardial cavity. Massive and sudden Microscopically, the epicardial and pericardial surfaces The Heart
bleeding into the sac causes compression of the heart leading show infiltration by some neutrophils, lymphocytes and
to cardiac tamponade. The causes of haemopericardium are histiocytes. The fluid usually resorbs with the resolution
as under: of underlying disease.
i) Rupture of the heart through a myocardial infarct.
ii) Rupture of dissecting aneurysm. 2. FIBRINOUS AND SEROFIBRINOUS PERICARDITIS.
iii) Bleeding diathesis such as in scurvy, acute leukaemias, The response of the pericardium by fibrinous exudate is the
most common type of pericarditis. Quite often, there is
thrombocytopenia. admixture of fibrinous exudate with serous fluid. The various
iv) Trauma following cardiopulmonary resuscitation or by causes of this type of pericarditis are as follows:
laceration of a coronary artery.
i) Uraemia
ii) Myocardial infarction
PERICARDITIS
iii) Rheumatic fever
Pericarditis is the inflammation of the pericardial layers and iv) Trauma such as in cardiac surgery
is generally secondary to diseases in the heart or caused by v) Acute bacterial infections.
systemic diseases. Primary or idiopathic pericarditis is quite The amount of fluid accumulation is variable. The cardiac
rare. Based on the morphologic appearance, pericarditis is surface is characteristically covered by dry or moist, shaggy,
classified into acute and chronic types, each of which may fibrinous exudate which gives ‘bread and butter’ appearance.
have several etiologies. Acute and chronic pericarditis has Clinically, these cases manifest by friction rub. In less
further subtypes based on the character of the exudate extensive cases of fibrinous or serofibrinous pericarditis,
(Table 16.11). there is complete resorption of the exudate. In cases with
advanced fibrinous exudate, pericarditis heals by
A. Acute Pericarditis organisation and develops fibrous adhesions resulting in
adhesive pericarditis.
Acute bacterial and non-bacterial pericarditis are the most
frequently encountered forms of pericarditis. These may have 3. PURULENT OR FIBRINOPURULENT PERICARDI-
the following subtypes: TIS. Purulent or fibrinopurulent pericarditis is mainly caused