Neurology Flashcards
What is the definition and epidemiology of Bell’s Palsy?
Bell’s Palsy is an idiopathic lower motor neurone facial (VII) nerve palsy. Annual incidence is around 15-40 per 100 000. Although idiopathic, it is preceded by an upper airway infection in 60%, suggesting a viral or post-viral aetiology.
What are the clinical features of Bell’s Palsy?
Patients have a prodrome of pre-auricular pain in some cases, followed by acute onset (hours/days) unilateral facial weakness and droop.
Fifty percent of patients experience pain or numbness in the face, neck or ear. Patients also experience hypersensitivity to sound (due to stapedius muscle paralysis), and tearing or drying of exposed eye. A loss of taste sense is uncommon.
On Examination:
There is lower motor neurone weakness of facial muscles (affects all the ipsilateral muscles of facial expression, and does not spare muscles of the upper part of the face as seen in UMN facial nerve palsy).
May elicit Bell’s phenomenon where the eyeball rolls up but eye remains open when trying to close eyes.
The ear should be examined for other causes (e.g, otitis media, herpes zoster infection).
What are the potential complications of Bell’s Palsy?
Corneal ulcers and eye infections are likely complications.
Aberrant reinnervation may also occur, e.g. blinking may cause contraction of the angle of the mouth due to simultaneous innervation of obicularis oculi and ori. Parasympathetic fibres may also aberrantly reinnervate causing ‘crocodile tears’ when salivating.
How can Bell’s Palsy be investigated?
Usually unnecessary, except to exclude Lyme serology and herpes zoster serology.
An EMG may show local axonal conduction block in facial canal. However, only useful >1 week after osnet.
How is Bell’s Palsy managed?
Protection of cornea with protective glasses/patches and artificial tears.
High-dose corticosteroids is beneficial if given within 72h of onset. It helps shorten time of recovery and improve long-term outcomes.
Antiviral agents such as acyclovir, have shown to improve long-term sequelae.
Surgical decompression can be done in patients that follow the following criteria
What is the definition and epidemiology of Dementia?
Dementia is the decline in cognitive function enough to interfere with daily life. Dementia is very common affecting 1 in 79, or 1 in 14 of those over the age of 65.
What are the different types/causes of Dementia?
The causes of dementia in order of prevalence are:
1. Alzheimer’s disease accounts for 65% of dementia cases - cortical atrophy in frontal, parietal and temporal areas caused by beta-amyloid plaques and neurofibrillary tangles.
- Dementia with Lewy bodies accounts for 15% of dementia in the UK. Affected neurones form Lewy bodies instead of tangles.
- Vascular dementia accounts for at least 10%, but possibly more with a mixed disease with Alzheimer’s. Caused by widespread small vessel disease within the brain (diabetes or hypertension), or due to mini-strokes.
- Other progressive intracranial pathology (e.g. brain tumour, MS, Pick’s disease, MND)
- Alcohol and drugs
- Rare infections and deficiencies (e.g. HIV-AIDS, syphilis, B vitamin deficiency)
What are the clinical features of Alzheimer’s Disease?
Patients usually have one or more of the risk factors, including advancing age, family history, genetics, Down’s syndrome, cerebrovascular disease, and hyperlipidaemia.
There can be said to be a pre-dementia stage for up to 8 years before criteria for AD is met. In this stage, patients noticeably lose their short-term memory, and have subtle problems with executive functions of planning, abstract thinking, semantic memory. Apathy (patient becomes passive, not wanting to perform daily activities, sleeping more) can also be noticed at this stage.
The hallmark of AD is memory decline with loss of recent memories first. Memory is usually affected first. Later language is affected with nominal dysphasia (difficulty naming people and objects). Spatial memory is also affected, causing disorientation, and misplacing items/often getting lost.
These all lead to a decline in Activities of Daily Living (ADL).
The patient has unremarkable initial physical examination, but in terminal disease may be unable to walk or speak.
What are the clinical features of Dementia with Lewy Bodies?
Intellectual symptoms due to cognitive decline similar to those of Alzheimer’s disease. However, patients are likely to develop issues with executive function, impaired attention, and visuospacial function before memory is affected.
Patients are also much more likely to develop parkinsonism, visual hallucinations and episodes of confusion.
What are the clinical features of Vascular Dementia?
As Alzheimer’s dementia can often co-occur with vascular dementia, it can be difficult to separate the two. Vascular dementia patients have risk factors of stroke including: obesity, age, hypertension and cigarette smoking, diabetes.
Patients present with problems with executive function such as problem solving, and signs of frontal cognitive syndrome (apathy, disinhibition, slowed processing of information, poor attention).
Patients tend to have better recall and fewer intrusions than those suffering from Alzheimer’s, though also suffer from memory impairment.
If dementia is caused my mini-strokes, impairment progresses in a stepwise way, with every mini-stroke.
How can dementia be investigated?
Blood tests such as:
• FBC - to rule out anaemia
• Metabolic panel - to exclude sodium, calcium and glucose levels causing the dementia
• Serum TSH - exclude hypothyroidism
• Serum B12 - as B12 deficiency can cause dementia.
Bedside cognitive testing will show cognitive impairments. The pattern of which can help differentiate the dementias, alongside a good history.
CT and MRI are useful, and can show characteristic changes for the different dementias.
What is the definition and epidemiology of Epilepsy?
Epilepsy refers to a group of neurological disorders characterised by seizures (>2). A seizure/ictus refers to a brief episode of signs/symptoms caused by synchronised electrical activity in the brain. Epilepsy is common, affecting 1% of the population.
What are the types of Epilepsy?
Epilepsy falls within two main categories: generalised (affecting all parts of the cerebral cortex) or partial/focal (affecting one region or lobe or hemisphere, but can spread to other regions and lead to a secondary generalised seizure).
In generalised epilepsy, there tends to be a loss of consciousness (not necessarily, such as in myoclonic seizures). Types of generalised epilepsy include:
• Tonic-clonic seizure (grand maI)- A tonic phase (sustained muscle contraction) followed by a clonic phase (random jerks and contractions).
• Absence seizure (petite mal)- patient remains ‘absent’ just staring for a few minutes.
• Myoclonic seizure - brief jerks of a muscle or muscle group.
• Clonic - a monoclonus that is regularly repeating.
• Tonic - Sustained muscle contraction, patient goes stiff causing them to fall backwards.
• Atonic - Loss of muscle tone, causing patient to drop to the floor forwards.
Partial/focal seizures can be further divided into simple partial (where consciousness is preserved), or complex partial
What are the causes of Epilepsy?
The majority of cases are idiopathic. These fall within primary epilepsy syndromes: idiopathic generalised epilepsy, temporal lobe epilepsy, or juvenile myoclonic epilepsy.
Sometimes, seizures can occur secondary to a cause, including:
• Tumour
• Infection (e.g. meningitis, encephalitis, abscess)
• Inflammation (e.g. vasculitis, rarely MS)
• Toxic/metabolic (Na imbalance, hyper/hypoglycaemia, hypocalcaemia, hypoxia, porphyria, liver failure)
• Drugs, including withdrawal from alcohol or benzodiazepines.
• Vascular, Trauma, Congenital abnormalities.
What are the clinical features of Focal Seizures?
- Frontal lobe seizure: motor convulsions. May demonstrate Jacksonian march (convulsions start from fingers or mouth, and spread). There may be post-ictal flaccid weakness. On other hand, may have sensory seizure where strong sensations are felt in one part of the body, face or limbs.
- Temporal lobe seizure: patient experiences an aura, Déjà vu, or hallucinations of smell or taste.
- TFrontal lobe complex partial seizure: loss of consciousness, with associated automatisms and rapid recovery.
What are the clinical features of Generalised Seizures?
- Tonic-clonic: Vague symptoms before attack such as irritability. Tonic phase (sustained muscle contraction) followed by a clonic phase (random jerks and contractions). Associated faecal or urinary incontinence, tongue biting. Typical post-ictal phase of altered consciousness, lethargy, confusion, headache, back pain, stiffness.
- Absence: Starts in childhood. Characterised by loss of consciousness but maintenance of posture. Child often reported as staring blankly. No post-ictal phase.
What is status epilepticus?
Status epilepticus refers to a seizure (unless stated assume a generalised tonic-clonic seizure) that lasts for more than 30 minutes
What are the complications of Epilepsy?
Fractures in tonic-clonic seizures. Hypoxia/brain damage if status epilepticus is not controlled.
How can Epilepsy be investigated?
Bloods:
• Glucose as hyperglycaemia or hypoglycaemia can cause seizures.
• FBC to look for generalised infections.
• U&Es as electrolyte imbalances, particularly Na+ imbalances or uraemia can cause seizures.
• Serum prolactin can help differentiate generalised seizures from non-epileptic seizure disorder, as seizures increase serum prolactin.
EEG (Electroencephalogram) can help classify the seizure disorder.
A head CT/MRI should be performed to look for any lesions, which could explain the seizure.
How is Epilepsy managed?
Status Epilepticus (Generalised Convulsive)”
Although defined as seizure lasting for more than 30 minutes, treatment is started after 5 minutes:
1. ABC - protect airways, breathing and circulation.
2. I.V, rectal or I.M benzodiazepine such as lorazepam (IV) or diazepam (PR).
3. If seizures reoccur or do not stop, give I.V phenytoin under ECG monitoring.
4. If this fails, give IV phenobarbital.
5. If this fails, administer general anaesthesia and ventilate the patient.
Treat the cause if possible i.e. hypoglycaemia.
General Practise:
Only start anti-convulsant therapy after >2 unprovoked seizures.
Patient education is very important. This includes avoiding triggers, and keeping a seizure diary. Recommended supervision for swimming or climbing. Driving is only permitted if not had a seizure in more than 6 months.
Surgery for refractory epilepsy?
