Elevated Alkaline Phosphatase

CLINICAL DIAGNOSTIC MANUAL

Alkaline phosphatase (ALP) is an enzyme present in various tissues, primarily the liver, bones, kidneys, and placenta. Elevated ALP levels in the blood can indicate increased activity or damage to the tissues where this enzyme is produced.

ALP is particularly useful for evaluating liver and bone diseases. Causes of elevated ALP can range from benign conditions to severe diseases requiring medical intervention.

Pathology	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Paget’s disease	Bone pain, bone deformities, fractures	History of bone pain, radiographs showing bone remodelling	Serum ALP measurement, radiographs, bone scan
Dietary vitamin D deficiency	Bone pain, muscle weakness, fractures	History of poor vitamin D intake, limited sun exposure	Serum ALP measurement, vitamin D, calcium, and phosphate levels
Bone metastases	Bone pain, pathological fractures, general weakness	History of primary cancer, persistent bone pain	Serum ALP measurement, imaging studies (X-rays, CT, MRI), bone scan
Primary or tertiary hyperparathyroidism	Muscle weakness, fatigue, bone pain, fractures, kidney stones	History of hypercalcaemia, elevated calcium levels	Serum ALP measurement, PTH, calcium, and phosphate levels, parathyroid imaging
Cholestasis	Jaundice, pruritus, abdominal discomfort, nausea	History of liver or biliary diseases, jaundice	Serum ALP measurement, liver function tests, abdominal ultrasound