A 63-year-old female developed unexplained
hyperglycemia and
glycosuria during administration of a
total parenteral nutrition regimen on which she had been stable for several months. Because the patient had no history of diabetes or evidence of an
infection,
chromium deficiency was considered. Plasma
chromium level was 0.1 microgram/dl (laboratory reference interval: 1.8-3.8 micrograms/dl). Fourteen days of supplemental intravenous
chromium chloride (200 micrograms/day) allowed complete withdrawal of exogenous
insulin with no further
hyperglycemia or
glycosuria. Correction of unexplained
glucose intolerance following vigorous
chromium supplementation indicates that the patient had
chromium deficiency. Subsequent plasma
chromium levels remained unchanged, possibly reflecting the sensitivity limits of the assay that was used, the uncertainty that exists regarding appropriate reference intervals for this
element, and the fact that plasma levels do not always correlate with total body stores. The patient did not manifest
peripheral neuropathy, which was present in one of the two previously reported cases, nor
encephalopathy, which was reported in the other. We conclude that this patient developed
chromium deficiency as a result of inadequate administration of
chromium in the parenteral formula (6 micrograms/day) plus excessive enteric losses, and she presented with
glucose intolerance as the only clinical manifestation of the deficiency. Caution should be exercised when interpreting plasma
chromium in patients with suspected deficiency.