Elevated alkaline phosphatase

Elevated alkaline phosphatase is a condition where the levels of alkaline phosphatase exceed that found in a reference range. It can be associated with certain medical conditions.^[1] or syndromes (e.g. Hyperphosphatasia with mental retardation syndrome, HPMRS)

If it is unclear why alkaline phosphatase is elevated, isoenzyme studies using electrophoresis can confirm the source of the ALP. Heat stability also distinguishes bone and liver isoenzymes ("bone burns, liver lasts").

Liver

• Liver (Liver ALP):
  • Cholestasis, cholecystitis, cholangitis, cirrhosis, hepatitis, fatty liver, sarcoidosis, liver tumor, liver metastases, drug intoxication
    • N.B. concurrently elevated GGT (gamma glutamyl transpeptidase) helps rule in favor of liver metastasis (rather than bone, kidney, etc.) when assessing spread of cancer.
  • Drugs: e.g. verapamil, carbamazepine, phenytoin, erythromycin, allopurinol, ranitidine

Bone/skeletal

• Bone disease (Bone ALP):
  • Paget's disease,^[2] osteosarcoma, bone metastases of prostatic cancer (High / very high ALP values)
  • Other bone metastases
  • Renal osteodystrophy
  • Fractured bone
  • Multiple myeloma (only when associated with fractures)

• Skeletal involvement of other primary diseases:
  • Osteomalacia, rickets, vitamin D deficiency, (Moderate rise)
  • Malignant tumors (ALP originating from tumor)
  • Renal disease (secondary hyperparathyroidism)
  • Primary hypothyroidism

and many more causes

Cancer

As carcino-placental alkaline phosphatase (Reagan's isoenzyme)

• Breast carcinoma
• Colon cancer
• Hodgkin lymphoma

Other

• Lung cancer
• Chlorpropamide therapy
• Infectious mononucleosis
• Pancreatic carcinoma
• Polycythemia vera
• Myelofibrosis
• Leukemoid reaction to infection
• Women using hormonal contraception
• Pregnancy
• Transient hyperphosphatasaemia of infancy: benign, often associated with infection
• Seminoma^[3]

References