Primary hyperparathyroidism. The radiograph of the skull commonly shows osteopenia with a speckled appearance - the so called "pepper pot skull". In primary hyperparathyroidism, typically there is hypercalcaemia, low phosphate and raised alkaline phosphatase.

Causes of hyperparathyroidism are:

1.Diffuse hyperplasia 10-40%

2.Single adenoma 50-80%

3.Multiple adenomas 10%.

4.Parathyroid Carcinoma 2%