Neurological disease

Published on 02/03/2015 by admin

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17 Neurological disease

Approach to the patient

A detailed history and examination guide the choice of investigations that will enable you to answer the three questions that are key to formulating a diagnosis:

Imaging plays a key role in diagnosis.

Alterations in consciousness

Coma is a state of unrousable unresponsiveness (often defined as a Glasgow Coma Score (GCS) of 8 or less; Table 17.1). GCS is a useful and reliable standardized tool, especially for serial measurements, but be aware of limitations, e.g. tetraparetic patients or those with tracheostomy.

Table 17.1 Glasgow Coma Score (GCS)

Category Response Score
Eye opening (E) Spontaneous 4
To speech 3
To pain 2
Nil 1
Speech/verbal response (V) Appropriate and orientated 5
Confused 4
Inappropriate words 3
Incomprehensible sounds 2
Nil 1
Motor response (M) Obeys commands appropriately 6
Localizes to pain 5
Withdraws to pain 4
Flexes to pain 3
Extends to pain 2
Nil 1

GCS = E + V + M. Minimum score 3, maximum score 15.

Coma is a life-threatening emergency. Assessment must be swift and comprehensive, and occur in tandem with life support measures and initial investigations (Box 17.1, p. 624, and see Fig. 20.21 (p. 722)).

Initial assessment

Neurological examination. This is helpful to lateralize signs, to determine the level of pathology and to assess integrity of brainstem reflexes.

Acute confusional state (delirium)

Delirium is characterized by abnormalities of perception and cognition, often without a decrease in the level of consciousness. Impairment in consciousness, if present, can vary and fluctuates with confusion, usually being worse at night. It is very common, especially in elderly hospitalized patients. There are a wide variety of causes, often occurring in combination, in a patient vulnerable by virtue of age or impaired cognitive reserve. Common causes include systemic infection, hypoxia, electrolyte imbalance, liver or renal failure, and drug/alcohol intoxication or withdrawal (especially anticonvulsants, anxiolytics, opiates), as well as brain injury, encephalitis/meningitis or deficiency states such as Wernicke–Korsakoff encephalopathy.

Delirium should be distinguished from dementia, aphasia and psychosis. Dementia can also predispose to the development of periods of delirium with intercurrent illnesses. In dementia there is no clouding of consciousness, the patient is alert, and there is less likely to be agitation or rapid fluctuations.

Stroke

Stroke is characterized by the sudden onset of focal neurological symptoms caused by interruption of the vascular supply to a region of the brain (ischaemic stroke) or intracerebral haemorrhage (haemorrhagic stroke). It is a common cause of mortality and physical disability.

Paramedics and members of the public are encouraged to make the diagnosis of stroke on a history and simple examination (the ‘FAST’ test):

image N.B. Stroke is a medical emergency and prompt treatment can improve prognosis.

Clinical evaluation

Onset is acute (a gradual or stuttering onset may indicate a mass lesion) and characterized by negative rather than positive symptoms (e.g. numbness rather than tingling).

Ask about preceding trauma or neck/facial pain (may indicate dissection) and use of anticoagulants (cerebral haemorrhage). Identify vascular risk factors.

General physical examination

Stroke is primarily a clinical diagnosis, supported by imaging.

Thrombolysis (Box 17.3)

image N.B. Every minute counts. The benefit of thrombolysis decreases with time, even within the 4.5-hour window.

Box 17.3

(Amended from Adams HP, et al. 2007)

Thrombolysis in acute ischaemic stroke

Thrombolysis improves long-term morbidity after an ischaemic stroke but is associated with an increased risk of acute haemorrhage. Maximal benefit of thrombolysis is achieved if it is given as soon as possible, although benefit may be derived if administered up to 4.5 hours after the start of symptoms. The short time window and need for prior MRI/CT to exclude haemorrhage or massive infarction require urgent action. Intra-arterial thrombolysis and mechanical disruption of clot are occasionally employed in specialist centres.

Further management

Subsequent management aims to reduce complications, lower the risk of further events and ensure adequate rehabilitation.

Identification of embolic source

Transient ischaemic attacks (TIAs)

This is a transient episode of neurological dysfunction caused by focal brain, spinal cord or retinal ischaemia without acute infarction. The previous definition with its arbitrary 24-hour time scale is no longer used, as the end point is now tissue injury. Examples include anterior circulation — sudden transient loss of vision in one eye (amaurosis fugax), aphasia, hemiparesis; or posterior circulation — diplopia, ataxia, hemisensory loss, dysarthria, transient global amnesia.

The ABCD2 score can help to stratify stroke risk in the first 2 days.

Age > 60 years 1 point
BP > 140 mmHg systolic and/or > 90 mmHg diastolic 1 point
Clinical features  
Unilateral weakness 2 points
Isolated speech disturbance 1 point
Other 0 points
Duration of symptoms (mins)  
> 60 2 points
10–59 1 point
< 10 0 points
Diabetes  
Present 1 point
Absent 0 points

A score of < 4 is associated with a minimal risk, whereas > 6 is high-risk for a stroke within 7 days of a TIA.

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