Page 296 - Concise Pathology for Exam Preparation ( PDFDrive )

11 Disorders of the Heart 281

Causes:
(a) Acute viral illness
(b) Uraemia
(c) Myocardial infarction (postinfarction Dressler syndrome)
(d) Rheumatic fever
(e) Trauma
(f) Acute bacterial infections
Pathology:
• Pericardial surface is dry, granular
• Pericardial fluid appears thick yellow or cloudy because of abundant leukocytes and
erythrocytes
• During course of evolution fibrin may get digested or become organized
3. Purulent pericarditis
It is a consequence of invasion of the pericardial space by infective organisms, which
reach by the following routes:
a) Direct extension from neighbouring inflammation, eg, empyema, lobar pneumo-
nia, mediastinal infections, etc.
b) Seeding from blood
c) Lymphatic extension
d) Direct introduction during cardiotomy
Most common causative organisms are Staphylococci, Streptococci and Pneumococci.
The patient presents with high grade fever, rigors and a pericardial friction rub.
Pathology:
• Serosa reddened, granular and coated with exudate (thin creamy pus)
• Organization of exudate may lead to constrictive pericarditis
4. Haemorrhagic pericarditis
It is characterized by an exudate composed of blood mixed with fibrinous or suppura-
tive material. Its causes include
a) Malignant neoplastic involvement of the pericardium
b) Bacterial infections
c) Bleeding diathesis
d) Tuberculosis
e) Following cardiac surgery
5. Chylous pericarditis
This type of pericarditis occurs due to lymphatic obstruction.

Chronic Pericarditis
1. Tubercular/caseous pericarditis: Pericardial involvement occurs by direct spread
from a tuberculous focus in tracheobronchial lymph nodes and usually results in dis-
abling constrictive pericarditis.
2. Chronic adhesive pericarditis: Fibrinous, suppurative or haemorrhagic pericarditis heal
by organization and lead to formation of fibrous adhesions between parietal and visceral
pericardium. This is usually seen due to infection by pyogenic bacteria and tuberculosis.
3. Chronic constrictive pericarditis: Rarely the pericardial space may get filled with fi-
brous or fibrocalcific tissue which interferes with normal functioning of the heart. It is
usually a consequence of tuberculous, purulent or haemorrhagic pericarditis.

Q. Define heart failure. Discuss the types, common causes,
pathophysiology and clinical features of heart failure.
Ans. Heart failure is defined as a state in which the ventricles cannot maintain an adequate
cardiac output to meet the metabolic needs of the body.

Pathophysiology
• Cardiac output is a function of
• Preload, which refers to the volume and pressure of blood in the ventricles at the end
of diastole

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