CALCIUM ON THE SPINAL CORD
What would cause deposits of calcium on the cervical spinal cord? What tests would you run, and what treatment would you suggest? The patient, who has had two surgical procedures to remove the calcium, suffers from multiple joint pain, numbness, pain, and tingling in both legs. Tinel and Phalen's signs are positive.
—R.O. Waiton, DO, Los Gatos, Calif.
Small isolated calcium deposits are nonspecific and often secondary to local trauma. However, very large or widely disseminated extraskeletal calcium deposits consistent with “metastatic calcification” suggest a broad differential diagnosis that includes renal failure and calciphylaxis, a hypercalcemic state (such as milk-alkali syndrome, sarcoidosis, hyperparathyroidism, and hypervitaminosis D), or a hyperphosphatemic state (such as can be seen with tumoral calcinosis and cell lysis). A paraneoplastic syndrome, various rheumatologic conditions (including systemic sclerosis, dermatomyositis, and lupus), and numerous inherited disorders are also possible (Ehlers-Danlos syndrome, Werner's syndrome, and pseudoxanthoma elasticum). I cannot determine from your question whether the calcium deposits are limited to the cervical spinal cord or not, but your patient's symptoms could go along with many of the aforementioned disorders in addition to primary cord involvement. The presence of positive Tinel and Phalen's signs suggests median nerve entrapment (carpal tunnel syndrome), which can be associated with systemic conditions, such as hypothyroidism and end-stage renal disease, but doesn't necessarily imply a unifying diagnosis.
Workup should include a complete history and physical exam. Suggested lab studies might include an assessment of renal function, serum calcium (ionized or corrected for albumin), phosphate, alkaline phosphatase, and parathyroid hormone. Depending on initial results and your suspicion for the various disorders suggested, also consider a complete blood count; vitamin D, serum bicarbonate, thyroid-stimulating hormone, urinary calcium excretion, antinuclear antibody, and creatine kinase determinations; and SCL-70 antibody study, etc. X-rays or a bone scan might better define the extent of tissue calcification.
Treatment depends on the etiology identified by the workup. The case report of a patient with tumoral calcinosis whose presentation was very similar to the one described might be worth a look (Br J Neurosurg. 2005;19:185-190).
—Daniel G. Tobin, MD (115-13)
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