Sandbox : anmol
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Hyperparathyroidism Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Anmol Pitliya, M.B.B.S. M.D.[2]
Classification
| Classification of hyperparathyridism | |||
|---|---|---|---|
| Features | Primary hyperparathyroidism | Secondary hyperparathyroidism | Tertiary hyperparathyroidism |
| Pathology | Hyperfunction of parathyroid cells due to hyperplasia, adenoma or carcinoma. | Physiological stimulation of parathyroid in response to hypocalcaemia. | Following long term physiological stimulation leading to hyperplasia. |
| Cause | |||
| Associations | May be associated with multiple endocrine neoplasia. | Usually due to chronic renal failure or other causes of Vitamin D deficiency. | Seen in chronic renal failure. |
| Serum calcium | High | Low/Normal | High |
| Serum phosphate | Low/Normal | High | High |
| Management | Usually surgery if symptomatic. Cincacalcet can be considered in those not fit for surgery. | Treatment of underlying cause. | Usually cinacalcet or surgery in those that don't respond. |
Causes
Overview
Hyperparathyroidism is caused by an increase in concentration of parathyroid hormone in serum. There are three type of hyperparathyroidism including primary, secondary and tertiary hyperparathyroidism. The are an array of different causes for all types of hyperparathyroidism.
Causes of Primary hyperparathyroidism
Causes of primary hyperparathyroidism are as follows:
Common causes
- Parathyroid adenoma
- Usually single gland affected
- Sometimes multiple gland affected
Less common causes
- Parathyroid hyperplasia
- Parathyroid carcinoma
- Familial isloated hyperparathyroidism
- Radiation exposure (due to development of parathyroid adenoma or parathyroid hyperplasia)
- Celiac disease
Genetic causes
- HRPT2 gene mutations:
- HRPT2 gene code for parafibromin protein.
- HRPT2 gene mutations are found in a type of familial hyperparathyroidism, hyperparathyroidism-jaw tumor (HPT-JT) syndrome.
- HRTP2 gene mutations increases risk of parathyroid carcinoma.
- Cyclin D1 gene (CCND1)/PRAD1 gene:
- PRAD1 (parathyroid adenoma 1) is a protooncogene located on chromosome 11q13.
- Cyclin D1 gene translocation and oncogene action observerd in 8% of adenomas
- Cyclin D1 gene overexpression is pbserved in 20% to 40% of parathyroid adenomas
- MEN1 gene:[1]
- MEN1 is a tumor supressor gene on chronosome 11q13.
- Somatic loss of single MEN1 allele is observed in 25% to 40% of sporadic parathyroid adenomas.
Causes of secondary hyperparathyroidism
Causes of secondary hyperparathyroidism are as follows:
Common causes
- Chronic renal failure (leading to parathyroid hyperplasia)
- Vitamin D deficiency
Less common causes
- Severe calcium deficiency
- Gastric bypass surgery, particularly roux-en-Y gastric bypass (RYGBP)
- Malabsorption syndrome
Causes of tertiary hyperparathyroidism
Causes of tertiary hyperparathyroidism are as follows:
Common causes
- Chronic renal failure (leading to parathyroid hyperplasia)
- Renal transplant patients
Less common cause
- Long standing celiac disease[2]
Pathogenesis
Associated conditions
- Hypercalcemia
- Chronic renal failure
- Osteitis fibrous cystica
- Osteoporosis
- Osteomalacia
- Osteoarthritis
- Brown tumor
- Multiple endocrine neoplasia type 1, type 2A, and type 4
- Familial isolated hyperparathyroidism
- Neonatal severe hyperparathyroidism
- Familial hypocalciuric hypercalcemia
- Hyperparathyroid-jaw tumor syndrome
- Pancreatitis
Natural history, Prognosis and Complications
Natural history
- Primary hyperparathyroidism usually develops in the fifth decade of life, in post-menopausal women and starts as asymptomatic hypercalcemia in presence of increased parathyroid hormone.
- If left untreated, some of patients with hyperparathyroidism may develop marked hypercalcemia, marked hypercalciuria, cortical bone demineralization and nephrolithiasis.
- These complications resolves after the treatment.
- Untreated complication may be fatal.
Complications
Complications of primary hyperparathyroidism are due to hypercalcemia. Common complications of primary hyperparathyroidism include:
- Bone related complication:[3]
- Brown tumor
- Osteitis fibrous cystica
- Osteoarthritis
- Osteomalacia
- Osteoporosis
- Cardiac complications:
- Left ventricular hypertrophy
- Cardiac calcific deposits in the myocardium
- Aortic and mitral valve calcification
- Endocrine complications:
- Pancreatitis
- Parathyroid crisis
- Gastrointestinal complications:[4]
- Peptic ulcer disease
- Neuromuscular complications:
- Pregnancy related complications:
- Neonatal hypoparathyroidism
- Psychiatric complications:
- Depression
- Renal complications:
- Nephrolithiasis
- Nephrocalcinosis
References
- ↑ Westin G, Björklund P, Akerström G (2009). "Molecular genetics of parathyroid disease". World J Surg. 33 (11): 2224–33. doi:10.1007/s00268-009-0022-6. PMID 19373510.
- ↑ Maida MJ, Praveen E, Crimmins SR, Swift GL (2006). "Coeliac disease and primary hyperparathyroidism: an association?". Postgrad Med J. 82 (974): 833–5. doi:10.1136/pgmj.2006.045500. PMC 2653933. PMID 17148709.
- ↑ Bandeira F, Cusano NE, Silva BC, Cassibba S, Almeida CB, Machado VC, Bilezikian JP (2014). "Bone disease in primary hyperparathyroidism". Arq Bras Endocrinol Metabol. 58 (5): 553–61. PMC 4315357. PMID 25166047.
- ↑ Corlew DS, Bryda SL, Bradley EL, DiGirolamo M (1985). "Observations on the course of untreated primary hyperparathyroidism". Surgery. 98 (6): 1064–71. PMID 3878002.