Specimen Name Result Units Range
Plasma Sodium 144 mmol/L (135-145)
Potassium 4.3 mmol/L (3.5-5.5)
Chloride 98 mmol/L (100-109)
Bicarbonate 28 mmol/L (22-32)
Anion Gap 22 mmol/L (7-17)
Glucose 6.2 mmol/L (3.8-5.5)
Urea 5.0 mmol/L (2.7-7.2)
Creatinine 110 μmol/L (60-110)
Phosphate 0.47 mmol/L (0.80-1.45)
Total Calcium 3.34 mmol/L (2.10-2.55)
ALP 235 U/L (30-110)

36yo male attended ED with left #femur (mid-shaft) incurred during soccer practice.

[View Skeletal XRays]
Hyperparathyroidism
  • high Ca++ / normal PO4
  • widespread bone lytic lesions ∝ ↑reabsorption
  • nephrocalcinosis/renal stones, ectopic calcification, constipation
  • pathalogical # mid-shaft L.femur - not visible on films shown
    ≅ Throckmorton's (John Thomas) sign positive

Parathyroid hormone:

  • ↑ Ca++ & PO4 reabsorption from bone
  • ↑ renal tubular Ca++ reabsorption
  • ↓ renal tubular PO4 reabsorption
  • ↑ Vit.D3 → indirect effects:
    • ↓ renal (PT) H+ secretion/HCO3- reabsorption
    • ↓ plasma pH → displaces Ca++ from plasma protein & bone
    • ↑ renal PO4 excretion → ↓[Ca++].[PO4] product facilitating further bone reabsorption

Hyper-parathyroidism causes:

  • hypercalcaemia with low-normal PO4
  • bone reabsorption with cystic changes
  • ectopic calcification
  • renal stones
  • overall rise in renal Ca++ excretion ∝ filtered mass

 

Causes of Hypercalcaemia

  • factitious - venous stasis, polycythaemia, dehydration, high plasma albumin
  • 1° hyperparathyroidism
    • solitary adenoma ≈ 80%
    • MEN I (*Z-E synd.), MEN II (*phaeochromocytoma)
  • malignancy
    • solid tumour with bony 2°'s - breast, prostate
    • ectopic parathormone - lung (≈ 10-15%), kidney
    • haematological malignancies - m. myeloma, leukaemia, lymphoma
  • vitamin D
    • vitamin D intoxication → ↑Ca++ & PO4
    • 1,25-(OH)2-D3 - sarcoid, TB, berylliosis
    • idiopathic hypercalcaemia of infancy
  • ↑ bone turnover - thiazides, hyperthyroidism, vitamin A intoxication
  • familial hypocaliuric hypercalcaemia - FHH
    • autosomal dominant → > 99% renal calcium reabsorption
    • PTH levels are usually normal
  • renal failure (2° hyperparathyroidism)
  • other causes - Addison's, phaeochromocytoma, IVT, lithium (≈10%)