One Patient With Bipolar Depression and Medically Unexplained Pain Symptoms Despite Treatment

A 62-year-old woman with a diagnosis of major depressive disorder presented with mood symptoms characterized by depression, anhedonia, poor appetite, fatigue, insomnia, and suicidal ideation for about 2 weeks. About 10 years prior, she had the first episode of major depression and attempted suicide by swallowing a large amount of detergent. Total gastrectomy was performed to save her life. No specific physical illness and substance abuse were identified. She complained about severe pain beneath the gingiva from about 7 years ago without any medical findings. She was treated with venlafaxine 150 mg/day and quetiapine 200 mg/day for years but still had many recurrences of major depression, especially during severe gingiva pain attacks. Upon admission, duloxetine 60 mg/day plus estazolam 2 mg/day were prescribed. During day 14 of her hospital stay, however, there were no clinical improvements in her mood and pain symptoms. Therefore, olanzapine was added and titrated to 10 mg/day for augmentation therapy. For treatment of refractory depression, her family was invited to clarify her prior psychiatric and medical history. Surprisingly, manic episode characterized by euphoric mood, overspending, increased psychomotor activity, and decreased sleep were present in the past. Under the impression of bipolar disorder, duloxetine was tapered and only olanzapine was kept. Her gingiva pain improved dramatically within 2 days after duloxetine withdrawal. Finally, she was discharged from our acute ward and received outpatient follow-up on day 28.

Unipolar depression and pain can provoke and perpetuate one another; this has been investigated by several previous studies.^1,2 However, the association between bipolar depression and pain has not yet been extensively studied. Recently, a few studies provided a better understanding between pain and bipolar depression.^3,4 Bipolar depression patients are significantly more likely than normal individuals to suffer from at least moderate pain.³ In one study, roughly two-thirds of the women with bipolar depression suffered concomitant pain, whose localizations arose at multiple sites, while the most common location of pain was in the back.⁴ Furthermore, head, neck, limb, and joint locations had also been reported in the same study.⁴ Antidepressants are known to predispose bipolar depression patients to manic switches and to increase the risk of suicide in the absence of a mood stabilizer.⁵ On the other hand, if antidepressants could lead to a worsening of pain when mood swings still need more large-scale studies to support this point of view. The case shown above presented medically unexplained pain beneath the gingiva, which was never reported in prior studies and may mislead a delayed diagnosis and treatment of bipolar disorder and even a poor prognosis.