Review: cobalt toxicity and artificial metal hips

September 25, 2014, 1:28 pm

metal-hip-300x181

★★★★½

Systemic toxicity related to metal hip prostheses. Bradberry SM et al. Clin Toxicol 2014;52:837-847.

Abstract

As TPR has reported before, cobalt poisoning can cause hypothyroidism, cardiomyopathy, and neurotoxicity. Neurological manifestations include:

  • optic nerve damage and retinopathy with reduced visual acuity
  • bilateral nerve deafness and tinnitus
  • polyneuropathy (sensory and motor)
  • cognitive impairment and memory loss

A number of papers and case reports have described clinical cobalt toxicity related to metal-on-metal hip prostheses or revision of a failed ceramic prosthesis with metal parts. Although these cases are somewhat rare, missing the association can be catastrophic. Recently, a report in theNew England Journal of Medicine described a 59-year-old woman with bilateral metal-on-metal hip prostheses who received a heart transplant for severe progressive cardiomyopathy. She also developed hypothyroidism, initially attributed to previous treatment with amiodarone. Cobalt toxicity was not diagnosed until months after transplant surgery.

This superb paper describes and critically reviews that 18 cases in the medical literature of systemic toxicity in patients with metal hip prostheses. The authors — using somewhat vague criteria — determined that i 10 of these cases the systemic manifestations were probably related to cobalt exposure.

Some key take-home points from the paper.

  • metal ions released from hip prostheses impair osteocyte function and may contribute to implant failure
  • cobalt decreases uptake of iodine by the thyroid, leading to hypothyroidism and goiter
  • patients with hip implants at highest risk for cobalt toxicity are those whose failed ceramic prostheses have been revised using cobalt-containing metal parts
  • there is scant evidence supporting treating these patients with chelation

This is important reading. You’re not likely to see a case of this, but if you do you don’t want to miss the diagnosis. Bottom line: think cobalt toxicity if you see a patient with a metal hip and hypothyroidism, heart failure, and/or neurologic deficits.

Related posts:

You don’t need Dr. House to suspect cobalt toxicity in a patient with an artificial hip

Case report: cobalt toxicity following implantation of a metal hip prosthesis

Cognitive decline in patients with metal-on-metal hips: think cobalt toxicity

Neurological changes and hip prosthesis: consider cobalt toxicity

One Comment:

  1. milkshake Says:

    another metal to check in blood is chromium 3+, as a surrogate. Chromium 3+ has low toxicity but it is a common component of alloys used in implants. If you see the two together, it likely came from implant deterioration (rather than, for example, from contaminated food or drink).