Wednesday, January 27, 2016

A MECHANICAL FALL IN AN ELDERLY PATIENT

An 81-year-old woman is bought into the accident and emergency department by ambulance
from a local nursing home. As a long-term resident of the home she is an active
participant in daily activities, and is usually self-caring and independent. Yesterday
evening, she sustained a witnessed mechanical fall, tripping over the walking stick of
another resident.

Despite a small graze to the right side of the head, there was no loss of
consciousness and the patient reassured care home staff that she was fine. An incident
report was filed. During the night the patient took paracetamol for pain control of a
headache but no further action was taken.


In the morning, she complained of continued headache and the care staff noted a general
listlessness and drowsiness. During the course of the day this progressed, and the patient
was found slumped in her chair before lunch, rousable only to strong verbal commands.
Staff were worried and called an ambulance.

Examination
On inspection the patient had a superficial graze to the right side of her forehead. Her
Glasgow Coma Scale (GCS) was 11 (motor 5, eyes 3, speech 3). She was apyrexial, pulse
76 regular, normotensive with a normal cardiovascular examination. There was no focal
neurological deficit, and both pupils were equal and reactive. An unenhanced computed
tomography (CT) scan was performed (Figure)





ANSWER
This is a single unenhanced image from a cranial CT scan at the level of the basal ganglia.
There is an area of asymmetry between the inner table of the skull and the brain in the left
cerebral hemisphere. This is more dense than adjacent brain parenchyma but not as dense as
the calcified bones of the skull. It conforms to the skull in a concave shape and is predominantly
homogeneous in appearance. The adjacent sulci are effaced, as they are not traceable
to the brain surface compared to the contralateral side. There is also slight effacement of
the left lateral ventricle with some mild midline shift to the right. The brain parenchyma
demonstrates preserved grey/white matter differentiation, and there is some generalized
cerebral atrophy, demonstrated by increased sulcal spaces seen in the normal right cerebral
hemisphere. These findings are in keeping with a subdural haemorrhage with mass effect.
Subdural haemorrhage is defined as a collection of blood in the space between pia mater
and dura mater of the leptomeninges.


Laceration of the veins between the two inner layers of the meninges causes blood to
accumulate in the subdural space. Although there is an association with direct head
trauma and penetrating injury, subdural haematomas are most commonly seen within
the elderly population. The brain atrophies with age and becomes more mobile within the
skull. The bridging cortical veins are stretched, increasing the risk of both spontaneous
rupture and disruption after trivial head injury. Blood is free to track along the surface of
the brain within the subdural space and is limited only by the falx and tentorium cerebellum.
Cranial CT demonstrates a concave haematoma that, unlike an extradural haemorrhage,
crosses suture lines within the skull.

The haematoma can have a varied attenuation
pattern depending on whether it is an acute, subacute or chronic subdural haemorrhage.
For example, Figure demonstrates bilateral chronic subdural haemorrhages. In some
cases where there is rebleeding, layering of old and fresh blood can be seen, demonstrating
an acute-on-chronic picture. These types of intracranial bleeds tend to be venous in aetiology and blood accumulates slowly in the subdural space.

Treatment depends on the neurological deficit caused by the haemorrhage.
Patients commonly present with headache, sleepiness and personality change, but if the bleed is large, the conscious level can fluctuate.

Signs and symptoms of  raised intracranial pressure can occur late and should alert clinicians to the need of urgent evacuation and decompression via a burr hole in a specialist neurosurgical
centre. Patients can make a full recovery.

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