Chronic subdural hematoma in the elderly: not a benign disease

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27th September 2010, Journal of Neurosurgery

An in-depth scientific article published in the Journal of Neurosurgery reveals that a fairly common disease in the elderly has a high mortality rate long after patients have undergone what is considered routine treatment. Chronic subdural hematoma in the elderly: not a benign disease reviews the cases of 209 patients with chronic subdural hematoma (CSDH).

Authors are Lucas Bernardes Miranda, MD, Ernest Braxton, MD, Joseph Hobbs, MD, and Matthew R. Quigley, MD, Department of Neurosurgery, Allegheny General Hospital, Pittsburgh. The accompanying editorial is authored by Kim J. Burchiel, MD, Department of Neurosurgery, Oregon Health and Science University, Portland, Oregon. The article and editorial are posted online here.

CSDH is relatively common, especially among the elderly, with an estimated incidence of 7.4/100,000 in that group. A CSDH is an old clot of blood on the surface of the brain beneath its outer covering. This is more common in the elderly because of normal brain shrinkage that occurs with aging. This shrinkage stretches and weakens the bridging veins, so that even minor head trauma can cause tearing of blood vessels over the brain surface, resulting in a slow accumulation of blood over several days to weeks. Left untreated, CSDH can cause severe physical, emotional, and cognitive impairments.

"CSDH is a frequently encountered problem in neurosurgical practice and the perception is that it is a benign disease, with easy-to-treat lesions. As such, the majority of neurosurgical literature has been limited to short-term outcome analysis, focusing primarily on types of surgical interventions, the effect of anticoagulants, and whether drains should be left in place. We believe our research is the first long-term analysis of CSDH in an elderly-only population," said Dr. Quigley.

The authors retrospectively reviewed the cases of 209 patients treated for CSDH at Allegheny General Hospital between September 2000 and September 2008. The neurological status on admission was normal in 166 patients, drowsy with mild deficits in 31, and comatose in 12. Additional key patient demographics:

- Gender: 132 men (63 percent), 77 women (37 percent)
- Mean patient age: 80.6 years (range 65-96 years)
- Medication: 48 patients were receiving antiplatelet agents, 31 were receiving Coumadin, and 2 were receiving both.
-Treatment: Bur holes in 21 patients, twist-drill closed-system drainage in 44, and craniotomies in 72. An additional 72 patients received conservative, nonsurgical treatment.

Mortality and Follow-up

- Thirty-five patients (16.7 percent died in the hospital, 130 were discharged to rehabilitation or a skilled care facility, and 44 returned home.
- Following discharge, the mean survival for the remaining 174 patients was 4.4 years.
- Long-term follow-up extended to a maximum of 8.3 years (mean 1.45 years).
- One hundred-forty (83 percent) of the patients returned to the clinic one month post discharge and their brain CT scans revealed either stable or improved status.
 

Noteworthy is that 72 patients underwent conservative treatment without surgical intervention. The authors found that survival was not related to the type of surgical intervention or to whether surgery was performed. Furthermore, the type of intervention, size of the CSDH, amount of shift, the presence of bilateral CSDHs, and anticoagulant use had no significant impact on the short- or long-term mortality. In the Cox proportional hazards model, only age and discharge to home were related to survival.

"While the 16.7 percent hospital mortality rate was just slightly higher than in other CSDH studies, what stood out was that this rate climbed to 26.3 percent and 32 percent respectively, at 6-month and 1-year follow-up, after what was considered successful treatment," said Dr. Quigley.

"Another surprising finding was that the hazard ratios derived from data showed that younger patients (age range 60-69 years) had the highest mortality rate, with the risk progressively diminishing in each successive decade to the tenth," added Dr. Burchiel.

The authors liken the continued increased mortality following apparently successful treatment of CSDH to the similar and widely reported phenomenon in patients who have undergone successful surgery for hip fracture. In light of the hazard ratio age findings, the authors surmise that if CSDH is indeed a "marker" of underlying disease, the younger one experiences this disease, the more compromised one's health will be relative to others in that age group.

"As with hip fracture, we assume that CSDH unmasks underlying medical conditions and exacerbates them. Although additional studies are required, given our long-term outcome findings, this disease should be reassessed by physicians and family members from a "benign" disease to one with potentially grave patient consequences," concluded Dr. Quigley.

Source: American Association of Neurological Surgeons (AANS)