Raised Alkaline Phosphatase Flashcards
What are the main differential diagnoses of raised alkaline phosphatase?
- Paget’s disease
- Vitamin D deficiency
- Bone metastases
- Primary or tertiary hyperparathyroidism
- Cholestasis
What suggests that Paget’s disease is the cause of raised alkaline phosphatase?
Deformity of skull or tibia
What confirms that Paget’s disease is the cause of raised alkaline phosphatase?
- Bone deformity on x-ray, especially on skull and tibia
- Increased urinary hydroxyproline
How is Paget’s disease managed?
Analgesics for bone pain. If not enough, try alendronic acid
What suggests that vitamin D deficiency is the cause of raised alkaline phosphatase?
- Diet history
- Decreased phosphate
What confirms that vitamin D deficiency is the cause of raised alkaline phosphatase?
- Decreased 1,25(OH)2 vitamin D level
- Normal calcium after oral vitamin D and calcium supplement
How is vitamin D deficiency managed?
- Dietary treatment
- Vitamin D and calcium supplements
What suggests that bone metastases are the cause of raised alkaline phosphatase?
- Normal phosphate
- Increased calcium and alkaline phosphate
What confirms that bone metastases are the cause of raised alkaline phosphatase?
Bone scan
What suggests that primary or tertiary hyperparathyroidism is the cause of raised alkaline phosphatase?
- Decreased phosphate
- History of secondary parathyroidism
What confirms that primary or tertiary hyperparathyroidism is the cause of raised alkaline phosphatase?
- Increased plasma parathyroid levels
- Increased calcium
What suggests that cholestasis is the cause of raised alkaline phosphatase?
Jaundice with pale stools and dark urine
How is it confirmed that cholestasis is the cause of raised alkaline phosphatase?
- Increased urine and serum bilirubin but no increased urobilirubinogen in urine
- Otherwise slightly abnormal LFTs
How is cholestasis managed?
- Colestyramine for pruritis
- Treat infections
- Relieve obstruction by stenting or surgery
