Page 132 - Concise Pathology for Exam Preparation ( PDFDrive )

5 Diseases of Immunity 117

Heart

• �Involved in systemic amyloidosis (immunocyte dyscrasias) and appears enlarged and firm

• �Focal subendocardial accumulation within the myocardium with pressure atrophy of
muscle fibres may induce ECG abnormalities
Other organs

• �Adrenals: Demonstrate deposits along basement membrane of cortical cells in zona
glomerulosa
• �GIT: Early lesions affect blood vessels but later submucosa, muscularis and sub-serosa

can be affected
• �Tongue: Undergoes enlargement (pseudo tumour formation or macroglossia)

• �Respiratory tract: Shows diffuse involvement of large and small bronchioles
Clinical Features

• �Early, nonspecific: Weakness, loss of weight and light-headedness
• �Renal involvement: Nephrotic syndrome (proteinuria), renal failure and uraemia

• �Cardiac involvement: Conduction disturbances, arrhythmias, restrictive cardiomyopa-

thy, congestive cardiac failure and constrictive pericarditis

• �Tongue involvement: Hampers speech and swallowing
• �GIT involvement: Diarrhoea, malabsorption and digestive disturbances

Diagnosis
Depends on demonstration of amyloid by:
• �FNAC of abdominal fat

• �Biopsy of kidney (in case of renal involvement), rectum or gingiva
Investigations for Primary Amyloidosis
• �Serum/urine electrophoresis
• �Immunoelectrophoresis
• �Bone marrow aspiration

Q. Differentiate between primary and secondary amyloidosis.

Ans. Contrasting features of primary and secondary amyloidosis are enlisted in Table 5.14.

Q. Write briefly on primary or congenital immune deficiency diseases.

Ans. Caused by mutations in genes involved in lymphocyte maturation or function.
TABLE 5.14. Contrasting features of primary and secondary amyloidosis
Features Primary amyloid � Secondary amyloid
Biochemical composition AL (light chain proteins); lambda chains AA, derived from larger precursor SAA
more than kappa
Associated diseases Plasma cell dyscrasias such as multiple Chronic inflammation, autoimmune dis-
myeloma, B cell lymphoma eases, cancers
Pathogenesis Stimulus n monoclonal B cell-proliferation Stimulus n chronic inflammation n
n excess of light chains n partial degra- activation of macrophages n cytokines
dation n insoluble AL fibril n partial degradation n insoluble AA
Incidence More common in developed countries Common worldwide
Distribution Kidney, heart, bowel, nerves Kidney, liver, spleen, adrenals
Stains Specific immunoassays with anti-kappa Immunoassays with anti-AA
antibodies
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