I have a 56y/o female with history of bipolar, controlled for many years with Lithium until 2 years ago, changed to trileptal due to weight gain and had been very stable until May. She began to have chest pain and PCP ordered a thallium scan. During the scan she became severly anxious and within 24 h decompensatedinto an acute psychosis requiring hospitalization. During course of hospital stay she was given Haldol 5mg and subsequently suffered some rigidity and systolic BP >200. There were no CPK elecations or temp elevation. The internal medicine physician believes she suffered NMS and subsequently she had a paranoid delirium. She continues to show signs of organicity with periodic confusion, expressive aphasia, and inability to communicate any meaningful manner. However, she is alert, not agitated, and sleeping at night. She has had 2 neurological consultations, both of which believe there are elements of organicity but are unable to assign an etiology. Her EEG is normal, but MRI is read as probably chronic ischemic white matter changes, slightly more advanced than patients of this age. No focal intracranial abnormalities are identified.

Could thallium be implicated? Any Suggestions? Please Advise.

Dwight L. Bearden, M.D.

While we cannot provide specific clinical recommendations, below is general information regarding thallium poisoning.

The amount of thallium administered in a stress test is miniscule—thousands of times less than the amount required for even minimal toxicity.

Cases of true thallium poisoning typically present with a constellation of symptoms, some occurring within hours of toxic exposure, and others occurring up to several weeks later. The classic triad of thallium poisoning is:

--acute gastroenteritis, occurring within hours of exposure
--painful peripheral neuropathies, occurring within days of exposure
--alopecia, appearing two to four weeks after exposure

While mental status changes can occur in some cases of thallium poisoning, they tend to present days or weeks after exposure, and should not be seen acutely.

In suspected cases of thallium poisoning, the diagnosis can be confirmed through measuring a 24-hour urine thallium level. The normal 24-hour urine thallium level is under 2 mcg/L, with toxicity occurring at levels greater than 200 mcg/L.


Further Reading:
Misra UK, Kalita J, Yadav RK, Ranjan P. Thallium poisoning: emphasis on early diagnosis and response to haemodialysis. Postgrad Med J 2003;79:103-5.