Low calcium levels in the blood serum

Aetiology

• Chronic kidney disease
• Congenital absence (DiGeorge syndrome)
• Destruction (surgery, radiotherapy, malignancy)
• Autoimmune
• Hypomagnesaemia - calcium release from cells is dependent on magnesium
• Idiopathic
• Pseudohypoparathyroidism and pseudo-pseudohypoparathyroidism

Clinical features

Symptoms

• Paresthesia - fingers, toes, perioral
• Muscle cramps, tetany
• Muscle weakness
• Fatigue
• Bronchospasm or laryngospasm
• Fits

Signs

• Chovestek’s sign - gentle tapping over the facial nerve causes twitching of the ipsilateral facial muscles
• Trousseau sign - inflation of the sphygmomanometer cuff above systolic pressure for 3 min induces tetanic spasm of the fingers and wrist