ICD-10 Diagnosis Code E21.0

Primary hyperparathyroidism

Diagnosis Code E21.0

ICD-10: E21.0
Short Description: Primary hyperparathyroidism
Long Description: Primary hyperparathyroidism
This is the 2017 version of the ICD-10-CM diagnosis code E21.0

Code Classification
  • Endocrine, nutritional and metabolic diseases
    • Disorders of other endocrine glands (E20-E35)
      • Hyperparathyroidism and other disorders of parathyroid gland (E21)

Information for Medical Professionals

Diagnostic Related Groups
The diagnosis code E21.0 is grouped in the following Diagnostic Related Group(s) (MS-DRG v33.0)


Convert to ICD-9 Additional informationCallout TooltipGeneral Equivalence Map
The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.
  • 252.01 - Primary hyperparathyroid

  • Familial primary hyperparathyroidism
  • Fibrous dysplasia of bone
  • Hyperparathyroidism-jaw tumor syndrome
  • Osteitis fibrosa cystica generalisata
  • Osteodystrophy
  • Parathyroid hyperplasia
  • Primary hyperparathyroidism
  • Primary water-clear cell hyperplasia

Index of Diseases and Injuries
References found for the code E21.0 in the Index of Diseases and Injuries:

Information for Patients

Parathyroid Disorders

Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.

If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.

If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders, or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

  • Calcium - ionized
  • Calcium - urine
  • Calcium blood test
  • Hypercalcemia - discharge
  • Hyperparathyroidism
  • Hypoparathyroidism
  • Parathyroid adenoma
  • Parathyroid biopsy
  • Parathyroid cancer
  • Parathyroid gland removal
  • Parathyroid hormone (PTH) blood test

[Read More]

Familial isolated hyperparathyroidism Familial isolated hyperparathyroidism is an inherited condition characterized by overactivity of the parathyroid glands (hyperparathyroidism). The four parathyroid glands are located in the neck, and they release a hormone called parathyroid hormone that regulates the amount of calcium in the blood. In familial isolated hyperparathyroidism, one or more overactive parathyroid glands release excess parathyroid hormone, which causes the levels of calcium in the blood to rise (hypercalcemia). Parathyroid hormone stimulates the removal of calcium from bone and the absorption of calcium from the diet, and the mineral is then released into the bloodstream.In people with familial isolated hyperparathyroidism, the production of excess parathyroid hormone is caused by tumors that involve the parathyroid glands. Typically only one of the four parathyroid glands is affected, but in some people, more than one gland develops a tumor. The tumors are usually noncancerous (benign), in which case they are called adenomas. Rarely, people with familial isolated hyperparathyroidism develop a cancerous tumor called parathyroid carcinoma. Because the production of excess parathyroid hormone is caused by abnormalities of the parathyroid glands, familial isolated hyperparathyroidism is considered a form of primary hyperparathyroidism.Disruption of the normal calcium balance resulting from overactive parathyroid glands causes many of the common signs and symptoms of familial isolated hyperparathyroidism, such as kidney stones, nausea, vomiting, high blood pressure (hypertension), weakness, and fatigue. Because calcium is removed from bones to be released into the bloodstream, hyperparathyroidism often causes thinning of the bones (osteoporosis). The age at which familial isolated hyperparathyroidism is diagnosed varies from childhood to adulthood. Often, the first indication of the condition is elevated calcium levels identified through a routine blood test, even though the affected individual may not yet have signs or symptoms of hyperparathyroidism or hypercalcemia.
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