Organic mood disorder: Sequelae of small vessel disease.

Sir,

Bipolar disorder predominantly begins in young adults, with evidence of bimodal presentation with a second peak in late life, i.e., beyond 50 years, wherein diagnosis is difficult.[1] Cerebrovascular lesions, ischemic variety, may be one of the etiological causes for such neuropsychiatric complication, and small vessel involvement may not present with typical stroke syndrome. 2 We present here a mood disorder, manic type secondary to small vessel disease.

A 64-year-old female was brought with complaints of memory disturbances and irritable behavior for 1 year. Onset was noted with giddiness and one episode with fall associated with loss of consciousness. She was managed conservatively for this.

During the last 1 month, she developed agitation in the form of singing and dancing, at times noticed to be muttering to self with inadequate sleep. She would claim that she is as good as “Lata Mangeshkar” in singing. Hence, she was referred to our unit. Other symptoms were overtalkativeness, jocularity, and irritable mood. She would make inappropriate comments (about her increased sexual urges) in front of relatives and accuse the husband of infidelity.

Comorbidities were diabetes mellitus and hypertension. No history of psychiatric illness in the patient (prior to this episode) or her first-degree family relatives was elicited. No history of convulsions/seizures was elicited.

On mental status examination, she had increased psychomotor activity, appeared overfamiliar, and overdressed. She was distractible with pressure of speech. She had delusion of infidelity and delusion of grandiosity claiming to have superpowers and having the most melodious voice in all over India. She also claimed God, and various actors were speaking to her directly, inferred as auditory hallucinations. Her mood was elated and irritable, but her affect was stable. Her judgment was impaired.

Physical examination showed blood pressure of 150/90 mmHg. Neurological evaluation was normal. Clinical testing for the frontal lobe showed impaired alternate hand sequence and a lack of concern, suggesting dorsolateral prefrontal and orbitofrontal area dysfunction. She performed well on clinical parietal lobe testing. Her mini-mental status score was 16 out of 30. Since the patient was inattentive, these findings are to be interpreted with caution. Neuropsychological evaluation and neurological intervention could not be done due to the patient's uncooperativeness.

Computerized tomography of the brain showed scattered ischemic foci in the bilateral frontal periventricular and left posterior parietal subcortical white matter and bilateral posterior capsule-ganglionic white matter. Magnetic resonance imaging of the brain also showed multiple small ischemic foci scattered in the bilateral subcortical and periventricular deep white matter in the frontoparietal regions and associated mild diffuse cerebral atrophy.

She was started on tablet sodium valproate 200 mg BD in view of irritability and impulsivity. Tablet aripiprazole 2.5 mg per day was added in view of mood-congruent psychotic symptoms, behavioral problems, and safer cardiac profile.[3] On increasing to 5 mg over a week, improvement of almost 50% was reported with decreased irritability although the delusion of infidelity and delusion of grandiosity persisted but with lesser intensity. The patient tolerated valproate well, and levels were not estimated.

Cerebral small vascular disease, of the gray and white matter, is a group of pathological process with myriad etiology.[4] Classical strokes such as hemiplegia may not be seen in lacunar and white matter lesions.[56] Although responsible for ischemic strokes in 25% of cases, the manifestations vary, such as the disorders of sensation, movement, sight, speech, balance, and coordination depending on the location of the lesion.[78]

We diagnosed her as an organic mood disorder secondary to the small vessel disease. This was considered due to the temporal relationship of the disinhibition, talkativeness, grandiosity with long-standing history of hypertension, history of falls as probable presentation of the lacunar infarcts, absence of past or family history of mood disorder, consistent features of behavioral change due injury to the frontal lobe and impaired functioning on clinical testing, and radiological findings justifying the deficits.

Late-onset mood disorder in the elderly is less reported and devoid of guidelines for its management.[9] A small vessel disease with such a presentation may be missed, as it may be devoid of a classical stroke-like presentation with neurological deficits. Further volume of data is necessary for understanding the relationship between such vascular lesions, consequential loss of function, and the ensuing presentations of mood episodes in the elderly.

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Conflicts of interest

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