Vascular

CASE 44: tranSient arm WeaKneSS

history

A 71-year-old man presents to the emergency department with weakness and numbness in his left arm. The symptoms came on suddenly while he was in the garden 2 h ago. His vision was not affected and he thinks the weakness in his arm has now resolved. He has had no previous episodes and has no history of trauma to his head or neck. He is currently on medication for hypertension and is a lifelong smoker.

examination

The blood pressure is 130/90 mmHg and the pulse rate is regular at 90/min. Heart sounds are normal and the chest is clear. Abdominal examination is normal. Neurological examination does not show any neurological deficit. A right-sided carotid bruit is heard.

Questions

•What is the diagnosis?

•What are the risk factors?

•How should this patient be investigated?

•What are the complications of surgery?

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100 Cases in Surgery

ANSWER 44

A transient ischaemic attack (TIA) is defined as a brief episode of neurologic dysfunction (i.e. paralysis, paraesthesiae or speech loss) resulting from focal temporary cerebral ischaemia not associated with permanent cerebral infarction. Eighty per cent of cerebrovascular incidents are caused by emboli, with the majority of infarctions in the carotid territory.

!Risk factors

•hypertension

•Smoking

•Diabetes mellitus

•atrial fibrillation

•raised cholesterol

Patients should undergo the following investigations:

•Full blood count, ESR

•Electrocardiogram

•Imaging of the carotid, which can be done by:

•Duplex ultrasonography: this technique combines B mode ultrasound and colour Doppler flow to assess the site and degree of stenosis; this is now the investigation of choice in most centres

•Magnetic resonance angiography

•Spiral CT angiography

•Angiography: intra-arterial angiography of the carotid arteries is associated with a 1–2 per cent risk of stroke and is now mainly a historical diagnostic modality that is rarely used

•CT head scan: to delineate areas of infarction and exclude haemorrhage in an acute presentation with stroke

•Echocardiogram – if a cardiac source for emboli is suspected

A stenosis of more than 70 per cent in the internal carotid artery is an indication for carotid endarterectomy in a patient with TIAs (Figure 44.1). The procedure should be carried out as soon as possible and within 2 weeks of the symptoms to prevent a major stroke. Stenting of the carotid artery is now performed as an alternative to endarterectomy in some centres, but evidence to date suggests that this technique is less effective than endarterectomy and may be associated with an increased rate of neurological complications.

!Risks of surgery

•neck haematoma (5 per cent)

•Cervical and cranial nerve injury (7 per cent): hypoglossal, vagus, recurrent laryngeal, marginal mandibular and transverse cervical nerves

•Stroke (2 per cent)

•myocardial infarction

•False aneurysm: rare

•infection of prosthetic patch: rare

•Death (1 per cent)

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Vascular

Figure 44.1 internal carotid artery stenosis (arrow) on angiography.

KEY POINTS

•Symptomatic carotid stenosis of >70 per cent should be considered for carotid endarterectomy.

•patients with ongoing symptoms should be treated urgently.

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