Empeiria

Overactive parathyroid gland

Clinically: Primary hyperparathyroidism · also PHPT, primary HPT, overactive parathyroid, parathyroid adenoma

endocrine MONDO MONDO:0010837 unverified
This describes what this condition typically looks like. It is not a diagnosis and cannot tell you whether you have it -- patterns overlap, results vary between labs, and the same numbers mean different things in different people. Diagnosis usually rests on Calcium, total, interpreted alongside symptoms and history rather than read off a report. Note that a normal-looking result does not reliably rule this out -- see the caveats above.

unverified These explanations are written to be easy to read and have not yet been checked against a source. The ranges and measurement notes on this page show theirs.

definition unverified

One or more of the small parathyroid glands in the neck makes too much parathyroid hormone. This pushes blood calcium up, which over time can thin bones and cause kidney stones.

Excess parathyroid hormone (PTH) secretion from one or more overactive parathyroid glands, most often a single benign adenoma. Per the Fifth International Workshop (2022), it is diagnosed by an albumin-adjusted serum calcium above normal with an elevated or inappropriately high intact PTH on two occasions at least 2 weeks apart; a normocalcaemic variant has high PTH with normal calcium.

caveats unverified

Most people have no symptoms, and it is usually found on a routine blood test. In some people calcium stays normal while the hormone is high. Low vitamin D can also raise the hormone, so it has to be ruled out.

Most people have no symptoms, and it is usually found on a routine blood test. In some people calcium stays normal while the hormone is high. Low vitamin D can also raise the hormone, so it has to be ruled out.

No clinical version written yet.

The typical lab pattern

What the diagnosis rests on

The results a diagnosis is actually made on.

Calcium, total high — Fifth International Workshop (2022) diagnostic criterion: albumin-adjusted calcium above normal with a high or inappropriately normal PTH, twice at least 2 weeks apart. In the normocalcaemic variant, calcium is normal.
Consistent with it

Fits the picture, but not enough on its own.

Albumin either — Total calcium is adjusted for albumin before it is judged, as part of the standard work-up.
Phosphate low — Usually in the low-normal range; some people have a low phosphate. It is part of the standard work-up.
25-hydroxyvitamin D low ref 20–50 Low vitamin D is common in this condition and is checked. Vitamin D deficiency must be ruled out before diagnosing the normocalcaemic form, because it can raise PTH by itself.
Followed over time

Tracked once it is established.

Estimated glomerular filtration rate low ref ≥ 60 Kidney function is checked as part of the work-up. An eGFR or creatinine clearance below 60 mL/min is one of the guideline criteria for recommending surgery.

How it usually feels

Frequencies say how often a symptom accompanies this condition — not the other way round. Most people with any of these symptoms do not have this.