Parathyroid disorders

Parathyroid disorders
Overview
Classification Hyperparathyroidism Familial hypocalciuric hypercalcemia Hypoparathyroidism Pseudohypoparathyroidism
Diagnosis
Differentiating Parathyroid Disorders

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Usama Talib, BSc, MD [2]

Synonyms and keywords:

Classification

Parathyroid disorders

Hyperparathyroidism

Familial hypocalciuric hypercalcemia

Hypoparathyroidism

Parathyroid hormone resistance diseases

Primary

Secondary

Tertiary

Post-surgical

Autoimmune

Genetic defects associated

Functional

Pseudohypoparathyroidism

Acrodysostosis

Blomstrand chondrodysplasia

Pseudohypoparathyroidism type 1

Pseudohypoparathyroidism type 2

Acrodysostosis type 1

Acrodysostosis type 2

Type 1A

Type 1B

Type 1C

Pseudopseudohypoparathyroidism

Diagnosis

Disorder		Laboratory findings
		Parathyroid hormone	Serum calcium	Serum phosphate	Other findings
Hyperparathyroidism	Primary hyperparathyroidism	↑	↑	↓/Normal	Normal/↑ calcitriol
	Secondary hyperparathyroidism	↑	↓/Normal	↑	--
	Tertiary hyperparathyroidism	↑	↑	↑	--
Familial hypocalciuric hypercalcemia		Normal/↑	Normal/↑	--	↓ Urinary calcium/creatinine clearance ratio
Hypoparathyroidism		↓	↓	↑	↓ 1,25 Dihydroxy vitamin D Normal urinary cAMP Normal urinary phosphate
Pseudohypoparathyroidism	Type 1A	↑	↓	↑	↓ 1,25 Dihydroxy vitamin D ↓ Urinary cAMP ↓ Urinary phosphate
	Type 1B	↑	↓	↑	↓ 1,25 Dihydroxy vitamin D ↓ Urinary cAMP ↓ Urinary phosphate
	Type 1C	↑	↓	↑	↓ 1,25 Dihydroxy vitamin D ↓ Urinary cAMP ↓ Urinary phosphate
	Pseudopseudohypoparathyroidism	Normal	Normal	Normal	--
	Type 2	↑	↓	↑	↓ 1,25 Dihydroxy vitamin D Normal urinary cAMP ↓ Urinary phosphate
Acrodysostosis	Acrodysostosis type 1	↑	↓	↑	Multiple hormone resistance
	Acrodysostosis type 2	↑	↓	↑	Multiple hormone resistance
Blomstrand chondrodysplasia		↑	↓	↑	↓ Urinary phosphate ↑ Urinary cAMP

Differentiating Parathyroid Disorders

• Parathyroid disorders usually cause an symptoms due to derangement in serum calcium. So, parathyroid disorders are differentiated within themselves and others on the basis of serum calcium levels.

Hypercalcemia

Repeat (Check ionized calcium or calcium corrected for albumin)

Hypercalcemia confirmed

Measure intact parathyroid hormone (PTH)

↑ PTH

Mildly ↑ PTH

↓ PTH

Hyperparathyroidism

Urinary calcium creatinine ratio

Measure parathyroid hormone-related protein (PTHrP) and vitamin D metabolites

↑ serum phosphate History of renal transplantation

↓/Normal phosphate levels

↑ Urinary calcium creatinine ratio

↓ Urinary calcium creatinine ratio

Tertiary hyperparathyroidism

Primary hyperparathyroidism

Familial hypocalciuric hypercalcemia

↑ PTHrP

↑ 1,25-dihydroxy vitamin D

↑ 25-hydroxy vitamin D

↓ 1,25-dihydroxy vitamin D

Normal PTHrP and vitamin D metabolites

Humoral hypercalcemia of malignancy

Chest X-ray, ACE levels

Hypervitaminosis D

History of high milk intake, excess calcium intake for treating osteoporosis or dyspepsia

Serum protein electrophoresis

Mammography

Check medications

Check for malignancies

Bilateral hilar lymphadenopathy, ↑ ACE levels

Milk-alkali syndrome

Multiple myeloma

Breast cancer

Sarcoidosis

Lithium induced hypercalcemia

Thiazide diuretic induced hypercalcemia