Thiamine deficiency as a differential diagnosis for severe fatigue in terminally ill cancer patients

Patients with advanced cancer present various symptoms as their disease progresses. Among these, fatigue is a frequent symptom in patients with advanced cancer and is associated with decreased quality of life (QOL). However, there are few reports regarding its association with thiamine deficiency (TD).

We report a case in which we found TD in a patient with advanced lung cancer who presented with weight loss, significant fatigue, and appeared to have a worsening general condition, for whom symptoms were dramatically improved within a short period of time by intravenous administration of thiamine.

The patient was a 76-year-old woman who had been diagnosed with lung cancer and liver metastases 6 months earlier. Due to interstitial pneumonia, she was not a candidate for chemotherapy and so palliative care was started. At 8 months after initial diagnosis, the patient complained of fatigue during a medical examination, so a blood sample was taken. A week later, she visited the hospital with a cane. She felt extremely fatigued and was unable to stand, but results from the previous blood test revealed that a TD. The fatigue disappeared 15 minutes after intravenous administration of thiamine and she was able to return home without the cane.

Fatigue is a frequent symptom in advanced cancer patients, and TD may be the underlying cause. Inclusion of TD in the differential diagnosis may contribute to improving patient QOL.