Bone Flashcards
A 62-year-old male is found to have an alkaline phosphatase (ALP) level of 152 U/L (N 32–91). Laboratory studies performed last year showed an ALP level of 134 U/L. The review of systems today is negative, including for pain, nausea, and dyspnea. You note that his AST and ALT levels are in the normal range, and a gamma-glutamyl transaminase level is also normal.
Which one of the following would be the most appropriate next step in the evaluation? (check one)
Plain radiography of the skull, pelvis, and tibia
Right upper quadrant ultrasonography
A full-body CT scan
A HIDA scan
A radionuclide bone scan
Plain radiography of the skull, pelvis, and tibia
Paget disease of bone is the second most common metabolic bone disorder after osteoporosis and has a lifetime prevalence of 1%–2% in the United States. Only 30%–40% of patients have symptoms such as bone pain at diagnosis. Most patients are diagnosed after an incidental finding of elevated alkaline phosphatase (ALP) on routine laboratory studies or by plain films performed for another reason. When an elevated ALP level is found in an asymptomatic patient, other liver function tests such as a gamma-glutamyl transaminase level should be performed to evaluate for hepatobiliary pathology. If negative, this should be followed by plain radiography of the skull and tibia, and an enlarged view of the pelvis to assess for lytic lesions and cortical thickening. If plain radiography is consistent with Paget disease of bone, a radionuclide bone scan is performed to assess the full extent of the disease. Bisphosphonates are the first-line treatment in active disease, which is signified by bone pain, hearing loss, and lytic lesions. Right upper quadrant ultrasonography, a full-body CT scan, and a HIDA scan would not be the most appropriate next step in the evaluation.
