Disorders of Parathyroid gland

Adenoma 

Causes of secondary hyperparathyroidism

1. Chronic renal failure
2. Malabsorption syndrome
3. Vitamin D deficiency
4. Medullary carcinoma thyroid

Adenoma 

• Hyperparathyroidism is the most common cause of surgically correctable hypercalcemia.
• Surgery is the most common treatment for primary hyperparathyroidism and provides a cure in about 95 percent of all cases. A surgeon will remove only those glands that are enlarged or have a tumor (adenoma).
• Primary hyperparathyroidism is a surgical disease and operation is required for the hyperfunctioning gland (A single hyperfunctioning adenoma accounts for approximately 90% cases)

Radial border of middle phalanx

However subperiosteal resorption is seen in all the options provided but option (C) is most characteristic and thus most correct

Subperiosteal bone resorption characteristically affects the phalangeal tufts, the radial aspect of the proximal and middle phalanges of the fingers, the metatarsals, the rib margins, the lamina dura, and the medial margins of the proximal humerus, femur, and tibia.

Resorptive changes on both the periosteal and endosteal sides in hyperparathyroidism mainly affect the middle phalanges and are most common on the radial side.

Subperiosteal resorption along the radial margin of the phalanges is virtually pathognomonic. (REF: Differential diagnosis in conventional radiology by Francis A. Burgener, Martti Kormano, Tomi Pudas 3rd edition fig 1.3)

Radiological features of hyperparathyroidism

• Osteopenia
• Loss of lamina dura

Brown’s tumours

Subperiosteal erosion of radial border of middle phalanx

• Salt and pepper pot skull
• Basket weave appearance of cortex

Ans. is C. i.e. Hyperparathyroidism

Subperiosteal bone resorption is an early and virtually pathognomonic sign of hyperparathyroidism, and this finding is marked by marginal erosions with adjacent resorption of bone and sclerosis.

• Brown tumors: These are focal areas of bone resorption where the bone has been replaced by fibrous tissue and osteoclasts. 
• In the spine, appearance of horizontal bands of sclerosis in the vertebral bodies adjacent to the vertebral end plates result in Rugger Jersey spine appearance.
• Chondrocalcinosis or calcification of the cartilage

Ans.A. Hyperparathyroidism

The salt and pepper appearance of the skull is a radiologic feature of hyperparathyroidism.

This appearance is due to the resorption of the trabecular bone in the skull and replacement of the resorbed bone by a newly formed connective tissue causing loss of integrity in the shape of skull bones.

Other radiologic features of hyperparathyroidism include:

• Brown tumors: These are focal areas of bone resorption where the bone has been replaced by fibrous tissue and osteoclasts. 

• In the spine, the appearance of horizontal bands of sclerosis in the vertebral bodies adjacent to the vertebral endplates results in the Rugger Jersey spine appearance.

• Chondrocalcinosis or calcification of the cartilage.

• Subperiosteal bone resorption characteristically involving the radial side of the middle phalanx of the middle finger, medial proximal tibia, and lateral end of the clavicle.

• Extracellular volume depletion
• Hypotension
• Hypokalemia
• Hyponatremia
• Hypochloremia
• Metabolic alkalosis
• Hypomagnesemia
• Hypercalcemia
• Hyperuricemia

• • Advanced primary hyperparathyroidism pathognomonic radiologic findings, which are best seen on x-rays of the hands and are characterized by subperiosteal resorption.
  • The skull also may be affected and appears mottled with a loss of definition of the inner and outer cortices.
  • Brown or osteoclastic tumors and bone cysts also may be present.
  • Brown tumors of the long bones and associated subperiosteal bone reabsorption, distal tapering of the clavicles and the classical, salt and pepper erosions of the skull were typical findings.

The patient in question has an increased serum Ca++, decreased serum phosphorus and increased values of alkaline phosphatase, suggests hyperparathyroidism.

Functions of parathyroid hormone:

• Parathyroid hormone acts on bone and causes to increase bone resorption and mobilise calcium. It also increases re absorption of calcium in the distal tubules of kidney. 
• It increases phosphate excretion in the urine and thereby depress plasma phosphate levels.
• It increases the formation of 1,25 dihydroxycholecalciferol which increases calcium absorption from the intestine.

Parathyroid hormone acts directly on bones to increase bone resorption and mobilize calcium. It  acts on the distal tubules of the kidney and increase calcium reabsorption. It  also increase phosphate excretion in the urine and decrease serum phosphate levels.
Hypoparathyroidism is associated with low calcium and high phosphate.

In chronic kidney disease, hyperphosphatemia and decreased renal production of 1,25-dihydroxycholecalciferol (1,25[OH]2D3) initially produce a decrease in ionized calcium.

The parathyroid glands are stimulated (secondary hyperparathyroidism) and may enlarge, becoming autonomous (tertiary hyperparathyroidism).

In osteomalacia and rickets, hypocalcemia acts as a stimulus to secondary hyperparathyroidism.

Vitamin D deficiency decreases GI absorption of calcium and phosphate, causing hypocalcemia and also hypomagnesemia. Decreased serum calcium will stimulate PTH secretion leading to the elevation of calcium level towards normal along with phosphaturia. Phosphaturia inturn will lead to hypophosphatemia.

Ans. is ‘d’ i.e., Secondary hyperparathyroidism with chief cell adenoma

Davidson states “In very small proportion of cases of secondary hyperparathyroidism continuous stimulation of the parathyroid may result in adenoma formation and autonomous PTH secretion. This is known as tertiary hyperparathyroidism”.

C i.e. Subperiosteal resorption of bone (phalanges)

All the options are the features of hyperparathyroidism but they are asking about the hallmark or characteristic feature which is ‑

• Subperiosteal Erosion of bone, particularly radial aspect of middle phalanx of middle & index finger.

A, B, C, i.e. Hyperparathyroidism, Poliomyelitis, Marfan syndrome

Osseous: hyperparathyroidism, thalassemia, Melnick–Needles syndrome.

Other causes of superior rib notching include poliomyelitis, osteogenesis imperfecta, neurofibromatosis, Marfan’s syndrome, collagen vascular disease, and hyperparathyroidism.

Answer is ‘a’ i.e. Parathyroid hyperplasia; ‘b’ i.e. Adenosis; ‘c’ i.e. MEN 1

Hyperparathyroidism is defined as elevated serum PTH due to increased secretion.

It is of two types.

a) Primary &

b) Secondary

with a rare third type – c) Tertiary

Primary hyperparathyroidism

• Primary hyperparathyroidism is due to intrinsic abnormality of one or more parathyroid glands:
• Single Adenoma         –>          83%
• Multiple Adenomas    —>          6%
• Hyperplasia                 —>        1%
• Carcinoma                   —>        1%

[To according to CSDT, this may vary in cliff books, but the general order is the same]

• Adenomas and hyperplasia of the parathyroid usually occur sporadically, but in few cases, they are part of familial syndromes

Familial syndromes associated with Primary Hyperparathyroidism

• MEN type 1-Wermer’s syndrome
• MEN type 2a – Sipple syndrome
• Familial hypocalciuric hypercalcemia

Secondary Hyperparathyroidism

• Sec. hyperparathyroidism is increased secretion of PTH by the parathyroids in response to a lowered serum ionized calcium level
• Causes

–         Chronic renal failure (most common cause)

–         Malabsorption syndrome

–         Vitamin D deficiency

–         Medullary carcinoma of the thyroid

Tertiary Hyperparathyroidism

Tertiary hyperparathyroidism follows long-standing secondary FIPT when the chronically stimulated parathyroid glands act independently of the serum calcium concentration.

Autonomous hypersecretion of PTH may persist despite the correction of the underlying condition.