Ans d 

Clinical features of Hyperparathyroidism are

1. Subperiosteal bone erosions
2. Primary Hyperthyroidism  is defined as hypercalcaemia in the presence of an unsuppressed and therefore relatively, or absolutely, elevated PTH level. Elevated calcium and elevated PTH are important  in diagnosis of PTH
3. The presence of kidney stones remains the most common clinical manifestation of symptomatic PHPT.
4. It is associated with a low serum phosphate in the setting of normal creatinine and vitamin D levels

Ref Bailey and Love Page 826

 Some useful questions can be bought here  MCQs and EMQs in Surgery: A Bailey & Love Revision Guide, Second Edition 

Some uncommon disorders associated with hyperparathyroidism include

peptic ulcers, pancreatitis, and bone disease

central nervous system symptoms 

Causes of Primary Hyperparathyroidism are

1. Parathyroid Adenoma -75% (can be localised by Sestamibi scanning)

Management of primary hyperparathyroidism

Patients with symptomatic primary hyperparathyroidism as manifested by kidney stones, renal dysfunction, or osteoporosis should undergo parathyroidectomy.

If the patient is asymptomatic and detected to have high parathyroid levels then surgery is done only if

1. age is less than 50
2. very high excretion of calcium in urine
3. low creatinine clearance
4. kidney stones
5. high serum calcium