Page 386 - Concise Pathology for Exam Preparation ( PDFDrive )

13 The Lung 371

Clinical Features

• Insidious onset with progressively increasing dyspnoea and dry cough.
• Hypoxaemia, clubbing and cyanosis are seen in later stages.
• The disease course is variable; mostly the patient worsens despite immunosuppressants.

Q. Write briefly on cryptogenic organizing pneumonia.
Ans. Salient features of cryptogenic organizing pneumonia
• A disease of unknown aetiology in which patient presents with cough and dyspnoea
• X-ray shows patchy peribronchial and subpleural consolidation
• Microscopy shows polypoid bits of loose connective tissue in the bronchioles, alveoli
and alveolar ducts (Masson bodies). No interstitial fibrosis is seen and most patients
recover after being given steroids for 6 months or longer.

Q. Write briefly on pulmonary involvement in autoimmune diseases.
Ans. Lungs can be involved in the following autoimmune diseases:
1. Rheumatoid arthritis
• Involved in 30–40% patients
• May present as chronic pleuritis, pleural effusion, interstitial pneumonitis or fibrosis
and follicular bronchiolitis
2. Scleroderma or systemic sclerosis
Diffuse interstitial fibrosis and pleural involvement
3. SLE
Transient infiltrates, pneumonitis and pleural involvement

Q. Write in detail on the clinicopathological features of sarcoidosis.
Ans. Sarcoidosis is a systemic disease of unknown cause characterized by formation of
noncaseating granulomas in different tissues and organs.

Aetiopathogenesis
Unknown; but consensus is that disordered immune regulation, genetic predisposition
and presence of certain environmental agents may all contribute.

Immunological Abnormalities
• Intra-alveolar and interstitial accumulation of CD41 T cells leads to increased CD4:CD8
T cells ratio.
• Increased levels of T-cell-derived T H 1 cytokines such as IL2 and IFN g, results in T cell
expansion and macrophage activation.
• Increased levels of other cytokines like IL-8, TNF, macrophage inflammatory protein
1a (MIP1 a), which recruit additional T cells and monocytes and contribute to the
formation of granulomas.
• Anergy to candida and common skin antigens like purified protein derivative (PPD) and
polyclonal hypergammaglobulinaemia may be seen.

Genetic Association

Familial clustering of cases and association with certain HLA haplotypes (HLA-A1 and
HLA-B8)

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