From the Guidelines
Low parathyroid hormone (PTH) levels, known as hypoparathyroidism, are primarily caused by factors such as hypercalcemia, increased vitamin D levels, diabetes mellitus, and increasing age, as well as conditions like adynamic bone disease, which can be associated with low PTH levels in patients with chronic kidney disease 1.
Causes of Low PTH
The causes of low PTH levels can be multifactorial and include:
- Hypercalcemia, which can suppress PTH production
- Increased vitamin D levels, which can also suppress PTH production
- Diabetes mellitus, which can affect PTH levels
- Increasing age, which can be associated with decreased PTH production
- Adynamic bone disease, a condition characterized by low bone turnover, which can be associated with low PTH levels in patients with chronic kidney disease 1
- Other factors such as hypomagnesemia, which can impair PTH secretion, and certain medications, including chemotherapy drugs and cinacalcet, which can suppress PTH production
Clinical Implications
Low PTH levels can have significant clinical implications, including an increased risk of mortality, as hypoparathyroidism has been found to be an independent predictor of mortality in several studies 1. Additionally, low PTH levels can be associated with hypocalcemia symptoms, including muscle cramps, tingling, seizures, and cardiac arrhythmias. Treatment of low PTH levels typically focuses on calcium and vitamin D supplementation to maintain normal calcium levels, while addressing the underlying cause of the low PTH levels when possible.
Diagnosis and Management
The diagnosis and management of low PTH levels require careful consideration of the underlying cause, as well as the patient's overall clinical condition. In some cases, a bone biopsy may be necessary to diagnose conditions such as adynamic bone disease or aluminum toxicity, which can be associated with low PTH levels 1. The management of low PTH levels should prioritize the maintenance of normal calcium levels, as well as the treatment of any underlying conditions that may be contributing to the low PTH levels.
From the Research
Causes of Low PTH
- Congenital absence or hypoplasia of the parathyroids, as seen in DiGeorge syndrome 2
- DiGeorge-like syndrome (DGLS), a rare genetic disorder with similar clinical manifestations to DiGeorge syndrome, can also lead to hypoparathyroidism 3
- Thyroid abnormalities, such as thyroid gland dysgenesis, may be associated with DiGeorge syndrome and potentially contribute to low PTH levels 2
- Benign thyroid nodules, as seen in a rare case of DGLS, can be associated with hypoparathyroidism 3
- Non-functional parathyroid gland, as reported in a case of DGLS with hypoparathyroidism and thyroid nodules 3