Hypoparathyroidism

Also called Underactive parathyroid, Low calcium

Too little parathyroid hormone, so calcium falls. Usually a complication of thyroid surgery, and severe low calcium is an emergency.

What it is

Underactivity of the parathyroid glands, which control calcium, causing a low blood calcium level.

The commonest cause by far is damage to or removal of the glands during thyroid or neck surgery. It also occurs as an autoimmune condition, sometimes alongside Addison's disease, and in 22q11 deletion syndrome.

Low calcium makes nerves and muscles irritable. Mild cases cause tingling around the mouth and in the fingers; severe cases cause muscle spasms, seizures, and dangerous heart rhythms.

**Severe symptomatic hypocalcaemia is a medical emergency** needing intravenous calcium, and it is most likely in the first days after neck surgery, which is why calcium is checked afterwards and why new tingling in that period must be reported immediately rather than at the follow-up appointment.

Treatment is calcium and activated vitamin D, usually alfacalcidol or calcitriol, for life. Ordinary vitamin D supplements are not sufficient, because the missing hormone is needed to activate vitamin D in the kidney. That distinction is important and easily muddled.

Long-term treatment carries its own risk: too much calcium and activated vitamin D deposits calcium in the kidneys, causing kidney stones and kidney damage, so monitoring is lifelong.

Signs you might notice

Tingling or pins and needles around the mouth, in the fingers and toes.

Muscle cramps, twitching and spasms, particularly of the hands and feet.

Anxiety, irritability, low mood, poor concentration and memory.

Fatigue.

Dry skin, brittle nails, coarse hair.

Severe: carpopedal spasm, where the hands and feet cramp into a fixed position; laryngeal spasm causing difficulty breathing; seizures; and abnormal heart rhythms.

**999** for spasms affecting breathing, seizures, or severe generalised cramping.

Urgent: new tingling or cramping in the days after thyroid or neck surgery. Report it the same day.

Chronic low mood and brain fog in someone on treatment is often under-recognised as being related to calcium control.

How it can affect day-to-day life

This is one of the few endocrine conditions where replacement does not restore normal physiology, and many people never feel fully well even with numbers in range. That is a real and validated experience, and being believed about it matters.

Calcium tablets have to be spread through the day and are a large daily burden; timing them around meals and other medicines, particularly levothyroxine and iron, matters.

Illness, vomiting, diarrhoea and diuretics all destabilise calcium, and there should be a written plan for what to do when unwell.

An emergency card and a clear treatment plan should be carried, because the symptoms of low calcium are easily mistaken for anxiety or hyperventilation in an emergency department.

Regular monitoring of calcium, kidney function and urine calcium is essential, and is sometimes reduced to an annual blood test when it should be more.

Pregnancy substantially changes calcium requirements and needs specialist management.

Supporting someone well

Report new tingling or cramping after neck surgery the same day.

Understand that ordinary vitamin D is not the treatment; activated vitamin D is.

Take calcium doses spread through the day as prescribed, and separate them from levothyroxine and iron.

Carry an emergency card explaining the condition and the treatment.

Have a written sick day plan for vomiting, diarrhoea or acute illness.

Keep monitoring appointments, including kidney function and urine calcium, not just blood calcium.

Ask for endocrinology follow-up rather than management by repeat prescription alone.

Take persistent brain fog and low mood seriously and raise it; it is a recognised part of the condition.

Plan pregnancy with specialist input.

Where to get help

999 for spasms affecting breathing, seizures or severe cramping.

A GP practice and endocrinology for ongoing management.

The surgical team in the days after neck surgery.

Pituitary Foundation and Thyroid UK cover related endocrine conditions and support.