*4.2.3 Diagnostic approach*

	- 1.Hyperparathyroidism (Primary and tertiary)
	- 2.Malignancy: Approximately 80% of these cases are caused by increased PTH-related peptide (most often squamous cell carcinoma of lung/head/ neck) which is a protein that mimics PTH. 20% of cases is due to direct bone invasion.
	- 3.Medications: Vit A/D excess, increased calcium intake (milk-alkali syndrome, chronic renal failure), teriparatide, lithium, thiazide diuretics, TPN
	- 4.Granulomatous diseases:- Such as sarcoidosis, TB, fungal infections
	- 5.Rhabdomyolysis
	- 6.Addison's disease
	- 7.Paget's disease
