Page 295 - Concise Pathology for Exam Preparation ( PDFDrive )

280 SECTION II Diseases of Organ Systems

(c) Drugs (emetrine, cyclophosphamide, adriamycin and catecholamines)
(d) Metabolic diseases (cardiac amyloidosis, hemochromatosis and glycogen storage
diseases)
(e) Neuromuscular diseases (Friedreich ataxia and muscular dystrophies)
(f) Infiltration by leukaemias and carcinomas
(g) Connective tissue diseases (rheumatoid arthritis, systemic sclerosis and drug induced)

Q. Write briefly on diseases of the pericardium.

Ans. Pericardium
• The visceral pericardium is a simple layer of mesothelial cells and the parietal pericardium
is made of fibrous and elastic tissue. It is usually about 2 mm thick and well innervated.
• Diseases of the pericardium are usually secondary to or associated with other cardiac
and systemic diseases.
• Normally, no more than 30–50 mL of thin, clear, straw-coloured fluid is seen in pericar-
dial sac.
• Pericardial cavity may undergo distension by fluid (effusion), blood (haemopericar-
dium) or pus (purulent pericarditis). When significant fluid accumulates in the pericar-
dial cavity, it can cause cardiac tamponade, which is characterized by rapidly declining
cardiac output progressing to cardiogenic shock.
• Pericarditis (inflammation of the pericardium) may be classified based on the onset
(acute or chronic) and aetiology (serous, fibrinous, purulent, haemorrhagic and chylous).

Classification of Pericarditis
1. Classification of pericarditis based on onset:
a) Acute
b) Chronic
2. Classification of pericarditis based on aetiology:
a) Acute nonspecific (idiopathic)
b) Infective (bacterial, viral, tubercular, fungal or other infections)
c) Immunologic (rheumatic fever or other connective tissue disorders)
d) Neoplastic
e) Metabolic (uraemia, myxoedema or gout)
f) Traumatic (including post–cardiac surgery)

Acute Pericarditis
1. Serous pericarditis
Accumulation of serous fluid which differs from transudate of hydropericardium in hav-
ing increased protein content and higher specific gravity.
Causes:
(a) Viral infection, eg, mumps, coxsackie A or B
(b) Rheumatic fever
(c) Rheumatoid arthritis, Systemic Lupus Erythematosus (SLE) and scleroderma
(e) Uraemia
(f) Involvement by a malignant tumour
(g) Tuberculous pericarditis in early stage
Pathology:
• Usually the volume of the fluid does not exceed 50–200 mL.
• There is infiltration of epicardial and pericardial surfaces by scant neutrophils, lym-
phocytes and histiocytes.
• Clear, watery fluid; specific gravity , 1.015
2. Fibrinous and serofibrinous pericarditis
Fibrinous (bread and butter) pericarditis is the most common type of pericarditis. It
may resolve or lead to adhesive pericarditis. A pericardial frictional rub can be elicited
when it is active.

mebooksfree.com