Page 605 - Concise Pathology for Exam Preparation ( PDFDrive )

590 SECTION II Diseases of Organ Systems

Manifestations (Flowchart 21.2)

Severe hyperparathyroidism of primary or secondary (chronic renal failure) type

Oversecretion of parathyroid hormone

Increased osteoclastic resorption of bone

• Susceptibility to fractures, skeletal deformities and joint pains
• Dysfunction as a result of deranged weight bearing
• Osteitis fibrosa cystica
Note: The bony changes may disappear after cure of primary hyperparathyroidism
(removal of functioning adenoma).
FLOWCHART 21.2. Clinicopathological manifestations of hyperparathyroidism

Biochemical Abnormalities
Excessive circulating levels of PTH, hypercalcaemia, hypophosphataemia and hypercalciuria

X-Ray

• Cortical bone affected more severely than cancellous bone, focal areas of erosion of cortical
bone (subperiosteal resorption) frequently seen along radial surface of phalanges of index
and middle fingers.
• Loss of lamina dura at the roots of teeth is another diagnostic feature.

Pathology
• Minor degree of generalized bone rarefaction to prominent areas of bone destruction
(lytic lesion) with cyst formation
• Increased number of bizarre osteoclasts at the surface of moth-eaten trabeculae and
cortex
• Replacement of bone and bone marrow by fibrosis
• In cancellous bone, osteoclasts tunnel in and dissect along the length of trabeculae to
create the appearance of rail road tracks (dissecting osteitis)
• Microfractures and microhaemorrhages occur in the marrow cavity inducing an in-
flux of macrophages and repair tissue. There is formation of masses of reactive tissue
called Brown tumours (highly vascular tissue with abundant haemosiderin), which
may undergo cystic degeneration (osteitis fibrosa cystica or von Recklinghausen
disease of bone).

Q. Enlist the salient clinicopathological features of renal osteodystrophy.
Ans. Salient features of renal osteodystrophy (metabolic bone disease):
• Encompasses a number of skeletal abnormalities appearing in patients of chronic renal
failure or patients on long-term dialysis.
• More common in children.
• Clinical symptoms of bone disease in advanced renal failure appear in less than 10% of
the patients.
• Radiological and histological changes are observed in fairly large proportion of
cases.

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