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Epilepsy in older people poses several additional problems for the provision of services compared with the rest of the population:

• Diagnostic difficulties, especially in differentiating syncope attacks from seizures.
• Susceptibility to anti-epileptic drug (AED) side effects and toxicity, and increased likelihood of interaction with other medication.
• Social difficulties e.g. increased impact of driving restrictions.
• Physical restrictions to lifestyle; seizures that cause falls are more likely to cause injury in older people.
• Multidisciplinary service requirements in the community, including liaison nurse, social worker and occupational therapist.

Epidemiology

• Almost a quarter of people with newly diagnosed epilepsy are over 60 years old.
• In one UK study the overall prevalence of epilepsy in people aged over 60 was 11.8 per 1000 and the overall annual incidence in those over 60 was 117 per 100,000.
• Most new seizures in elderly patients are partial in onset with or without secondary generalisation. Idiopathic epilepsy is rarely detected later in life.
• Cerebrovascular disease is the most common cause of seizures in patients over 60 years old who are newly diagnosed with epilepsy.

Aetiology of epilepsy in the elderly

• Underlying factors can be identified in a greater proportion of elderly patients than younger patients, including cerebrovascular disease, dementia and tumours.
• Cerebrovascular disease is the most common underlying factor.
• Dementias of non-vascular origin give rise to seizures that are often easy to control. Alzheimer's disease and epilepsy often coexist.
• The most common tumours found to produce seizures in later life are gliomas, meningiomas, and metastasis. Seizures often have focal features but elderly patients do not always show neurological signs.
• Trauma is common in old age and older people are more likely to develop post-traumatic epilepsy. Subdural haematoma is a potentially treatable cause of epilepsy in elderly people.
• Other possible underlying causes are hypertensive encephalopathy and cerebral vasculitis.

Presentation

• A reliable history and a witnessed event are generally of more value than investigations.
• There may be a history of trauma with evident bruises, cuts or burns.
• There may be a witness report of pallor, cyanosis, abnormal movements, tongue biting, urinary incontinence, and impaired conscious level, or postictal features, e.g. confusion, headache, drowsiness, and Todd's paresis.
• The majority of de-novo seizures in elderly people are partial in onset with or without secondary generalisation.

Differential diagnosis

• Common problems that need to be considered include cardiac arrhythmias, hypoglycaemia, postural hypotension, carotid sinus sensitivity, adverse drug effects and vasovagal episodes.
• The differential diagnosis of seizures in the elderly includes :
  • Neurological: transient ischaemic attack, transient global amnesia, migraine, narcolepsy, restless legs syndrome
  • Cardiovascular: vasovagal syncope, orthostatic hypotension, cardiac arrhythmias, structural heart disease, carotid sinus syndrome
  • Seizures resulting from anoxic brain injury may occur with respiratory as well as cardiac disease.
  • Infection
  • Endocrine/metabolic: renal failure, hypothyroidism, hypoglycaemia, hyperglycaemic non-ketotic states, electrolyte disturbances (e.g. hyponatraemia, hypokalaemia, hypocalcaemia) and hepatic impairment
  • Sleep disorders: obstructive sleep apnoea, hypnic jerks, rapid eye movement sleep disorders
  • Psychological: non-epileptic psychogenic seizures.
  • The peak incidence of first seizures related to alcohol withdrawel occurs in late adult life.
  • Drug-induced seizures are most likely to be associated with use of more than one drug, high doses and coexisting illness. Drugs reported to cause seizures include antihistamines, antidepressants, antipsychotics and hypoglycaemic drugs.
• Complex partial seizures presenting as confusion may be misdiagnosed as psychiatric symptoms.
• Transient global amnesia: anterograde amnesia that resolves fully within 24 hours, with no neurological or cognitive sequelae.
• Sleep disorders: patients may only suffer night-time seizures.
• Hypothyroid neuropathy can be confused with partial seizure activity.
• Psychogenic non-epileptic attack disorder (NEAD) may present for the first time in later life, but this is unusual.

Investigations

• Investigations will depend on the presentation but include ECG, ambulatory ECG, carotid and basilar artery ultrasound, orthostatic blood pressure measurement, and routine biochemical and haematological screening can help differentiate between possible underlying causes.
• Initial blood tests should include full blood count, ESR, glucose, renal function, electrolytes, calcium and thyroid function tests.
• Neuroimaging to detect intracerebral lesions. MRI is usually the preferred investigation, being more accurate than CT, with the exception of subarachnoid haemorrhage.
• EEG: less specific and sensitive than neuroimaging in the investigation of epilepsy in elderly people.2 EEG abnormalities in healthy elderly individuals are common. EEG can occasionally help to identify seizure type. The diagnosis of non-convulsive status epilepticus can be confirmed when continuous epileptiform activity is recorded in a confused patient.

Management

• The NICE guidance recommends that the choice of treatment, access to investigations and the importance of regular monitoring of effectiveness and tolerability are the same for older people as for the general population.
• An elderly person suspected to have had new onset seizures should ideally be referred to an epilepsy specialist for rapid assessment and initiation of treatment if indicated.
• Education of patients, carers and relatives about cause, cautions and treatment of seizures.
• Treatment for provoked seizures should be directed towards the underlying cause.
• Whether treatment should be started after a single unprovoked seizure remains controversial.
• Calcium and vitamin D supplements should be considered in view of the increased risk of osteoporosis with AED treatment. Some authorities recommend calcium and vitamin D supplements and regular bone density measurements for elderly patients at particular risk of osteoporosis.

Antiepileptic drugs

• Low-dose drug regimens can help keep to a minimum adverse effects and drug interactions. Most elderly patients require smaller doses than younger adults. Adverse effects can be kept to a minimum by starting with a low dose and titrating slowly.
• Elderly patients are more at risk of side-effects and idiosyncratic reactions.
• Long-term antiepileptic drug treatment is an independent risk factor for osteoporosis.
• Drugs with a high risk of neurotoxicity should be avoided.
• Few clinical trials of AEDs have been performed specifically in the elderly. It has been recommended that lamotrigine or valproate should be considered as first choice with carbamazepine as second choice.
• Valproate is a suitable alternative as it is well tolerated in the elderly and implicated in fewer interactions than is carbamazepine or phenytoin.
• Elderly people may be particularly susceptible to the sedative and behavioural effects of phenobarbital.

Complications

• The post-ictal phase is frequently extended in elderly patients and can contribute to physical injury sustained during seizure activity. Falls, burns, fractures, lacerations, strains, and severe bruising can greatly reduce quality of life.
• Those affected often lose confidence and independence. Poor mobility and impaired self-confidence can result in admission to residential care.
• Mortality rates in older patients with epilepsy are high, particularly for those who present in status epilepticus. Rates of sudden unexpected death are also higher than average for the elderly.

Prognosis

• Most older patients will remain seizure-free on antiepileptic drug monotherapy. Complete seizure control can be expected in about 70% of elderly patients. Inadequate seizure control should raise the suspicion of poor adherence or progressive neurodegenerative disease.
• Older people who present with a single seizure are more likely than younger individuals to have a further seizure.