Page 474 - Textbook of Pathology, 6th Edition

458 of acute pericarditis already described. Included under this
are: tuberculous pericarditis, chronic adhesive pericarditis,
chronic constrictive pericarditis, and the pericardial plaques.
1. TUBERCULOUS PERICARDITIS. Tuberculous peri-
carditis is the most frequent form of granulomatous
inflammation of the pericardium. The lesions may occur by
one of the following mechanisms:
i) Direct extension from an adjacent focus of tuberculosis.
ii) By lymphatic spread e.g. from tracheobronchial lymph
nodes, chronic pulmonary tuberculosis or infected pleura.
The exudate is slightly turbid, caseous or blood-stained
with sufficient fibrin. Tubercles are generally visible on the
pericardial surfaces and sometimes caseous areas are also
visible to the naked eye.

Microscopically, typical tuberculous granulomas with
caseation necrosis are seen in the pericardial wall. The
lesions generally do not resolve but heal by fibrosis and
Figure 16.34 Fibrinopurulent pericarditis. The pericardium is covered calcification resulting in chronic constrictive pericarditis.
with pink serofibrinous exudates. The space between the layers of the
pericardium contains numerous inflammatory cells, chiefly PMNs. 2. CHRONIC ADHESIVE PERICARDITIS. Chronic
adhesive pericarditis is the stage of organisation and healing
by pyogenic bacteria (e.g. staphylococci, streptococci and by formation of fibrous adhesions in the pericardium
pneumococci) and less frequently by fungi and parasites. The following preceding fibrinous, suppurative or haemorrhagic
infection may spread to the pericardium by the following pericarditis. The process begins by formation of granulation
routes: tissue and neovascularisation. Subsequently, fibrous
i) By direct extension from neighbouring inflammation e.g. adhesions develop between the parietal and the visceral
in empyema of the pleural cavity, lobar pneumonia, infective layers of the pericardium and obliterate the pericardial space
SECTION III
endocarditis and mediastinal infections. (Fig. 16.35,A). Sometimes, fibrous adhesions develop
ii) By haematogenous spread. between the parietal pericardium and the adjacent
iii) By lymphatic permeation. mediastinum and is termed as adhesive mediastinopericarditis.
iv) Direct implantation during cardiac surgery. Chronic adhesive pericarditis differs from chronic
Generally, fibrinous or serofibrinous pericarditis precedes constrictive pericarditis in not embarrassing the function of
the development of purulent pericarditis. The amount of the heart. However, cardiac hypertrophy and dilatation may
exudate is variable and is generally thick, creamy pus, coating occur in severe cases due to increased workload.
the pericardial surfaces. 3. CHRONIC CONSTRICTIVE PERICARDITIS. This is
a rare condition characterised by dense fibrous or fibrocalcific
Microscopically, besides the purulent exudate on the thickening of the pericardium resulting in mechanical
pericardial surfaces, the serosal layers show dense interference with the function of the heart and reduced
Systemic Pathology
infiltration by neutrophils (Fig. 16.34). Purulent exudate cardiac output. The condition usually results from a long-
generally does not resolve completely but instead heals standing preceding causes, e.g.
by organisation resulting in adhesive or chronic i) Tuberculous pericarditis
constrictive pericarditis. ii) Purulent pericarditis
iii) Haemopericardium
4. HAEMORRHAGIC PERICARDITIS. Haemorrhagic iv) Concato’s disease (polyserositis)
pericarditis is the one in which the exudate consists of v) Rarely, acute non-specific and viral pericarditis.
admixture of an inflammatory effusion of one of the foregoing The heart is encased in 0.5 to 1 cm thick and dense
types alongwith blood. The causes are as under: collagenous scar which may be calcified. As a result, the heart
i) Neoplastic involvement of the pericardium fails to dilate during diastole. The dense fibrocollagenous
ii) Haemorrhagic diathesis with effusion tissue may cause narrowing of the openings of the vena
iii) Tuberculosis cavae, resulting in obstruction to the venous return to the
iv) Severe acute infections right heart and consequent right heart failure. In contrast to
The outcome of haemorrhagic pericarditis is generally chronic adhesive pericarditis, hypertrophy and dilatation do
similar to that of purulent pericarditis. not occur due to dense fibrous scarring. Instead, the heart
size is normal or smaller (Fig. 16.35,B).
B. Chronic Pericarditis
4. PERICARDIAL PLAQUES (MILK SPOTS, SOLDIERS’
Chronic pericarditis is the term used for tuberculous SPOTS). These are opaque, white, shining and well-
pericarditis and the healed stage of one of the various forms circumscribed areas of organisation with fibrosis in the