So Sakamoto is an emergency physician in Japan focused on high-quality emergency department care, transitions of care, bedside decision-making, and education at the emergency–primary care interface in ageing populations.
Japan is one of the world’s most rapidly ageing societies. Chronic subdural haematoma (CSDH), increasingly encountered in everyday clinical practice here, may offer a glimpse of what healthcare systems elsewhere will face as their populations age.
The textbook patient with CSDH might be an older person who sustained a head injury several weeks earlier. Yet this is often not the patient I see. Instead, the story may be quieter: “He is not walking as well.” “She has started falling.” “His memory seems worse.” “She is less active.” Or simply: “Something has changed.”
A CT scan eventually reveals the haematoma.
A history of head injury is helpful, but its absence should not reassure us. In older people, a fall may have been forgotten, or the injury may have seemed too trivial to mention. Indeed, a clear history of head trauma cannot be identified in 30–50% of patients with CSDH.¹ Asking about trauma matters; relying on it does not.
A disease of an ageing society
In an ageing society, it increasingly sits at the intersection of ageing, falls, frailty, medication, and functional decline.
Japan’s experience illustrates how CSDH changes as populations age. Toi and colleagues analysed 63,358 patients with newly diagnosed CSDH in a Japanese national administrative database. Patient numbers peaked among those in their 80s, and impaired consciousness became increasingly common with advancing age. At discharge, 28.4% had a modified Rankin Scale score of 3–6 — ranging from requiring assistance with daily activities to death.²
CSDH can therefore no longer be regarded simply as a neurosurgical consequence of head trauma. In an ageing society, it increasingly sits at the intersection of ageing, falls, frailty, medication, and functional decline.
There is another assumption worth challenging: that CSDH is benign because it is treatable. It is certainly treatable. Gait disturbance, cognitive impairment, and reduced consciousness caused by the haematoma can improve dramatically after evacuation. CSDH is consequently familiar as an important cause of potentially reversible cognitive decline.
But treatable does not mean benign.
Among older patients with CSDH, Miranda and colleagues reported mortality of 26.3% at six months and 32% at one year, substantially higher than might be expected after treatment of a supposedly benign condition.³ Japanese authors have similarly questioned the traditional perception of CSDH as a benign disease, particularly in older patients.⁴ Perhaps the haematoma is telling us something beyond what we see on the CT scan.
Look beyond the haematoma
An older person who develops CSDH may also have frailty, impaired gait, recurrent falls, cognitive decline, polypharmacy, or exposure to anticoagulant or antiplatelet therapy. The haematoma may therefore be more than an isolated intracranial lesion. It may be a marker of vulnerability.
This changes the questions we should ask.
Not only, “How should we treat this haematoma?” but also, “Why did this patient become vulnerable enough for this to happen?”
And when we find a haematoma, we should look beyond it to the vulnerability that allowed it to occur.
Why did they fall? Has their mobility deteriorated? Could medication be contributing? Are antithrombotic drugs still appropriately indicated, with their benefits and risks regularly reviewed? Are impaired vision, cognition, or the home environment increasing the risk of another fall?
These questions are particularly relevant to primary care, where vulnerability can be recognised longitudinally — often before a haematoma develops. Reviewing falls risk, mobility, frailty and medication is not merely aftercare following CSDH; it may be part of preventing the next event.
The lesson from Japan is therefore not simply that clinicians should think of CSDH more often in older patients.
We should suspect it even without a memorable head injury. We should not confuse treatability with benignity. And when we find a haematoma, we should look beyond it to the vulnerability that allowed it to occur.
As populations around the world continue to age, what is commonplace in Japan today may become commonplace elsewhere tomorrow.
The first clue to CSDH may not be a history of head injury, but the quiet observation that ‘Something has changed.’
And perhaps the most important consultation for CSDH takes place long before the haematoma exists.
References
1. Adhiyaman V, Asghar M, Ganeshram KN, Bhowmick BK. Chronic subdural haematoma in the elderly. Postgrad Med J. 2002;78(916):71–75.
2. Toi H, Kinoshita K, Hirai S, et al. Present epidemiology of chronic subdural hematoma in Japan: analysis of 63,358 cases recorded in a national administrative database. J Neurosurg. 2018;128(1):222–228.
3. Miranda LB, Braxton E, Hobbs J, Quigley MR. Chronic subdural hematoma in the elderly: not a benign disease. J Neurosurg. 2011;114(1):72–76.
4. Uno M, Toi H, Hirai S. Chronic Subdural Hematoma in Elderly Patients: Is This Disease Benign? Neurol Med Chir (Tokyo). 2017;57(8):402–409.
