Primary hypoparathyroidism in the dog: diagnosis and treatment
6-year-old male Miniature Schnauzer with episodes of tremors, stiffness, facial rubbing and one generalised seizure. Not on treatment and no toxin exposure.
| Parameter | Result | Reference |
|---|---|---|
| Ionised calcium | 0.68 mmol/L | 1.20–1.40 |
| Phosphorus | 8.4 mg/dL | 2.5–6.0 |
| Creatinine | 0.9 mg/dL | 0.5–1.5 |
| Albumin | 3.2 g/dL | 2.6–4.0 |
| PTH | < 0.3 pmol/L | 0.5–5.8 |
What is the diagnosis and the appropriate maintenance treatment?
chevron_right Show answer and explanation
A. Renal secondary hyperparathyroidism: renal diet and phosphate binders
There would be azotaemia and a high PTH. Here creatinine is normal and PTH undetectable.
B. Nutritional secondary hyperparathyroidism: correct the diet
It occurs in young animals on calcium-poor diets (e.g. meat only), with high PTH and normal or slightly low calcium, not with severe hypocalcaemia and undetectable PTH.
C. Primary hypoparathyroidism: supplement with oral calcium alone
The diagnosis is right, but without PTH the gut barely absorbs calcium because vitamin D is not activated. Oral calcium alone is not enough: calcitriol is needed.
D. Primary hypoparathyroidism: calcitriol and oral calcium after stabilising with IV calcium gluconate
Correct. Ionised hypocalcaemia with hyperphosphataemia, normal renal function and inappropriately low PTH is diagnostic. Stabilise with slow IV calcium gluconate under ECG monitoring and maintain with calcitriol and oral calcium, aiming for calcium at the low end of the range.
lightbulb Key takeaway
Always interpret PTH alongside ionised calcium: with hypocalcaemia, a 'normal' or low PTH is inappropriate. On calcitriol, aim for low-normal calcium and monitor frequently at first to avoid hypercalcaemia.
Test yourself with 10 random questions
Clinical pathology · 100 questions, a different test every time
Related questions
Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.