Disorders of Calcium Metabolism Tutorial Flashcards
55M - South Asian, aches and pains, proximal myopathy (muscle weakness)
His GP performed some blood tests:
Normal renal function
Serum calcium 2.10 (reference range 2.15 – 2.60 mmol/L)
Serum phosphate 0.8 (reference range: 0.80 – 1.40 mmol/L)
25 hydroxyvitamin D 10 (reference range : 70 – 150 nmol/L)
PTH 20 (reference range: 1.1 – 6.8 pmol/L).
What is the diagnosis?
Low Calcium and Vit D High PTH (trying to compensate for low serum Ca2+)
Hypocalcaemia - secondary to low vitamin D levels
Secondary Hyperparathyroidism - vitamin D deficiency
Low Vit D in adults = osteomalacia
Low Vit D in children = rickets
What risk factors does he have for developing this?
Ethnicity - South Asian (melanin reduces UVB absorption from the sun)
Diet: Chapatis - contain phytates that binds to vit D contributing to Vit D deficiency
What treatment should be offered?
Vitamin D replacement - inactive tablet form given as his renal function is normal (25-OH vit D)
Can be given:
Ergocalciferol (Vit D2) - plant derived
Cholecalciferol (Vit D3) - animal derived, long acting
Inactive given because the body can regulate the activation process
55M - South Asian, loin pain, worse on passing urine, microscopic haematuria on a urine dipstick
His GP checked some blood tests:
Normal renal function
Serum calcium 2.90 (reference range: 2.15 – 2.60 mmol/L )
Serum phosphate 0.6 (reference range: 0.80 – 1.40 mmol/L)
25 hydroxyvitamin D 84 (reference range: 70 – 150 nmol/L)
PTH 12 (reference range: 1.1 – 6.8 pmol/L).
What is the diagnosis?
High PTH and high Ca2+
Hypercalcaemia secondary to phyerparathyroidism
Primary hyperparathyroidism - e.g. parathyroid adenoma
What is the cause of his loin pain?
What are the symptoms of hypercalcaemia?
Loin pain = renal stones (cholicky pain)
Stones; diarrhoea; nephrogenic diabetes insipidus = dehydration, polyuria, polydipsia; abdominal pains; dyspepsia; increased bone turnover; depression
How should he be treated?
Ultrasound scan to find the gland with the adenoma, then parathyroidectomy to remove it
Kidney stones - ultrasound treatment to break it down, many fluids to reduce formation of more kidney stones
55F -Tired, aches and pains all over her body for several months, low mood, more constipated
History: left mastectomy and adjuvant radiotherapy for breast cancer 3 years ago
Her GP checks some blood tests:
Normal renal function
Serum calcium 3.00 (reference range: 2.15 – 2.60 mmol/L )
Serum phosphate 1.00 (reference range: 0.80 – 1.40 mmol/L)
25 hydroxyvitamin D 70 (reference range: 70 – 150 nmol/L)
PTH <1.1 (reference range: 1.1 – 6.8 pmol/L).
Hypercalcaemia due malignancy (as the PTH is low as it should be so not an issue with PTG)
Metastases in the bone activates osteoclasts
PTH-like peptides that act on the PTH receptors and activate them = leads to hypercalcaemia
How should she be treated?
Chemo - for the cancer
Calcitonin - reduces serum Ca2+
Rehydration to help reduce calcium level
Bisphosphinate - inhibit osteoclasts
