Chronic subdural haematoma in an elderly patient with a manic episode

To the Editor

A 79-year-old lady with a history of bipolar affective disorder (BPAD) was admitted to hospital with a manic relapse. This episode occurred in the context of the death of her husband. She had previously been well for many years and was not taking psychotropic medication. Her medical history included hypertension, hyperlipidaemia, hypothyroidism and osteoporosis. She was not on any anticoagulant or antiplatelet medication.

The day following her admission, she had an unwitnessed fall with a head strike. Computed tomography of the brain (CT-B) at the time was unremarkable for acute pathology. Following this fall, she developed a delirium which was investigated and considered secondary to a urinary tract infection (UTI) and constipation. Her condition gradually improved with the treatment of her UTI and commencement of an antipsychotic and short-term benzodiazepine use, and she was discharged home two weeks after admission.

During the first week after discharge, her son expressed concerns about ongoing fluctuating attention. This was initially attributed to resolving delirium and mania. However, following further concerns about headache and worsening confusion, another CT-B was ordered, which revealed an acute-on-chronic subdural haematoma (SDH; see Figure 1). She was referred to the local emergency department where she had no focal neurological signs on serial examinations. Urgent referral to neurosurgery was made and she underwent a dual mini-craniotomy two days later and was discharged home. She had a second spontaneous SDH five weeks later with further neurosurgery and full recovery.

Figure 1.

Non-contrast CT brain with evidence of acute-on-chronic subdural haematoma.

Falls in hospital are a leading contributor to morbidity and mortality. Risk factors include old age, cognitive impaitment, agitation, and sedating medication, all of which are commonplace in old age psychiatry. Chronic SDH occurs due to the slow accumulation of blood in the subdural space. This usually arises following head trauma, but atraumatic SDH can occur (Yang and Huang, 2017). Chronic SDH can develop following a normal CT-B, especially if the scan occurs immediately following the head injury (Matsuda et al., 2008). Focal neurological signs may be delayed, and many patients may present with non-specific symptoms such as nausea, headache and confusion. Doctors may be falsely reassured by ‘normal’ neurological examinations as well as initial normal CT-B (Snoey and Levitt, 1994).

It is imperative that psychiatrists consider diagnostic overshadowing when treating elderly patients. Availability bias may result in neurological symptoms and signs being attributed to psychiatric conditions. In individuals with ongoing headache, nausea or confusion following a fall, a repeat CT-B should be considered, even if the initial CT-B was normal.