Hypophosphataemia

1) Decreased intake

• Malnutrition

2) Decreased GI absorption

3) Increased excretion

• Renal loss (decreased reabsorption)
  • Increased PTH
  • Myeloma
  • Fanconi syndrome
  • ARF diuretic phase
  • Cisplatin
  • Post obstructive diuresis
• Hyperparathyroidism (PTH decreases phosphate reabsorption)
• Malignancy

4) Acute intracellular shifting of phosphate (To intracellular)

• Acute leukaemia (taken up by new cells)
• Post parathyroidectomy
  • Hungry bone syndrome
  • Large deposition of Calcium and phosphate in bone
• Respiratory alkalosis

Clinical manifestations

Diverse effects range from irritability to coma and may lead to

• Respiratory failure
• Cardiac failure
• Rhabdomyolysis
• Ileus
• Impaired phagocytosis
• Haemolysis
• Thrombocytopenia
• Metabolic encephalopathy

Correction

Oral is safest. Remember calcium supplementation to prevent hypocalcaemia

• Oral – skim milk 1mg elemental phosphorus per ml
• IV – 2.5mg/kg over 6 hours