Neurology Flashcards
What are the types of seizures?
Seizures 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, the patient goes stiff causing them to fall backwards.
- Atonic - Loss of muscle tone, causing the patient to drop to the floor forwards.
Partial/focal seizures can be further divided into simple partial (where consciousness is preserved) or complex partial (where there is an alteration of consciousness).
What are the causes of Epilepsy?
The majority of cases are idiopathic. These fall within primary epilepsy syndromes: idiopathic generalised epilepsy, temporal lobe epilepsy, 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 a post-ictal flaccid weakness. On the 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.
- Frontal 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. The 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 by greater than twice baseline.
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?
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. Important to
Only starting anti-convulsant therapy after >2 unprovoked seizures. Start treatment a with single anti-epileptic drug (AED), at the lowest possible dose. There are numerous anti-convulsant agents, but the SANAD trial suggests:
- Lamotrigine or carbamazepineas first line treatment for focal seizures
- Sodium valproate should be used for generalised seizures (supported by 2017 Cochrane review).
Other commonly used agents include phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin, ethosuximide (absence).
Other treatments:
- Epilepsy surgery is often explored in medically refractory patientswith localisation-related epilepsywho have proven symptomatic or cryptogenic focal-onset epilepsy.
- Neurostimulation devices - devices such as deep brain stimulation (DBS), vagus nerve stimulation, and responsive neurostimulation (RNS) may be used.
What is the definition and epidemiology of Encephalitis
Encephalitis is defined as inflammation of the brain parenchyma associated with neurological dysfunction. It is not very common, only 2500 cases in a year in the UK. High-risk groups include neonates (<1y) and elderly (>65y).
What is the aetiology of encephalitis?
Viruses are the main cause of encephalitis, with herpesvirus the most common group of viruses.
Immune-mediated encephalitis can be the cause of a third of cases, with antibodiesusually against NMDA receptors.
However, a cause is only found in half of cases.
What are the clinical features of Encephalitis?
Patients present with fever in infective causes, as well as a rash. The rash may be a vesicular eruption if caused by enteroviruses, HSV or VZV. A maculopapular rash is indicative of EBV (after treatment with ampicillin), measles, HHV-6 and other viruses. Lots of other rashes for different causes.
Altered mental state is a key manifestation of the disease, which can range from mild somnolescence (sleepiness), hemiparesis, ataxia to coma. These can be focal neurological deficits such as aphasia, hemianopia, brisk tendon reflexes, Babinski sign.
Seizures are also common. Generalised tonic-clonic seizures, partial complex seizures and focal seizures with secondary generalisation are very frequently seen at some point in the clinical course.
Patients also tend to have other symptoms caused by a viral infection, such as cough or gastrointestinal disturbances.
Meningism (photophobia, headache, neck stiffness) can develop, resulting in meningoencephalitis.
Describe the diagnosis of encephalitis
Bloods:
- FBC often shows elevated WBC
- U&Es may show hyponatraemia in some causes.
- LFTs may be elevated in certain causes.
- Blood cultures may detect and confirm systemic bacterial infections
CSF sample should be taken and analysed. Depending on aetiology, there may have elevated white cell count, normal/elevated protein, normal/low glucose, or normal/elevated RBCs. PCR can identify viruses.
Throat swab or nasopharyngeal aspirate to detect respiratory viruses.
MRI of the brain is the imaging study of choice or may need CT brain.
EEG should be done in all patients with persistent altered mental status or seizures.
What is the management of encephalitis?
All cases of encephalitis should be admitted and fully evaluated. Some patients with milder symptoms and signs can be managed in a regular nursing unit. All other patients, and in particular those with complications should be managed in an ICU, preferably a neuro-intensive care unit. Supportive management for all patients may include:
- Endotracheal intubation and mechanical ventilation
- Circulatory and electrolyte support
- Prevention and management of secondary bacterial infections
- DVT prophylaxis
Viral aetiologies
In most cases, the aetiology is suspected to be viral, and so the patient should be started on acyclovir until the cause is determined. As most cases are secondary to HSV this has strong evidence.
In immunocompromised patients, ganciclovir and Foscarnetare added to cover CMV, and continued until ruled out.
Non-viral aetiologies
Patients with suspected autoimmune encephalitis should be treated aggressively initially with intravenous corticosteroids (methylprednisolone sodium succinate), immune globulin, or plasma exchange. Cases with persistent altered mental status should be treated with rituximab and/or cyclophosphamide.
Confirmed bacterial encephalitis should be treated with appropriate antibiotics.
Describe the management of elevated intracranial pressure
In patients with elevated ICP, management with corticosteroids and mannitol should be considered. Initial measures are:
- Elevation of the head of the bed to 30° to 45°
- Avoiding compression of the jugular veins
- Hyperventilation to a PaCO2 of around 30. Subsequently, hyperosmolar therapy with mannitol boluses or hypertonic saline can be used to decrease ICP.
- Shunting or surgical decompression (by craniectomy) is indicated in some cases where medical management (corticosteroids, mannitol) has failed to control elevated ICP, and for impending uncal herniation.
What are the types of childhood epilepsy syndromes?
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Infantile Spasms (West Syndrome): Age of onset 3-12 months; Violent flexor spasms of the head, trunk and arms followed by extension of arms (salaam attacks) lasting 1-2s, often in bursts of 20-30.
- Most have underlying neurological cause.
- Most will lose skills and develop learning disability and continuing epilepsy.
- Childhood absence epilepsy: Age of onset 4-12 years; Good prognosis, 80% remission in adolescence, the remainder develop juvenile absence epilepsy and juvenile myoclonic epilepsy.
- Benign Rolandic epilepsy (Benign epilepsy with centro-temporal spikes): Age of onset 4-10 years; Tonic-clonic seizures in sleep, or simple focal seizures with abnormal feelings in the tongue and distortion of the face. 15% of all childhood epilepsies, remits in adolesence.
- Juvenile absence epilepsy: Age of onset 10-20 years; Absences, and generalised tonic-clonic seizures, often with photosensitivity. Learning is impaired. Lifelong treatment.
- Juvenile myoclonic epilepsy: Age of onset 10-20 years; Myoclonic seizures, generalised tonic-clonic seizures, typically shortly after waking. For example throwing drinks of cereal in the morning due to myoclonus. Lifelong treatment.
What is the definition and epidemiology of Guillian-Barrè?
Guillain-Barre Syndrome (GBS) is a type of acute post-infectious polyneuropathy characterised by symmetric and ascending flaccid paralysis. In affected patients, cross‑reactive autoantibodies attack the host’s own axonal antigens, resulting in inflammatory and demyelinating polyneuropathy.
It is quite rare, affecting up to 2 per 100,000.
What is the aetiology of Guillian-Barrè syndrome?
About ⅔ of GBS patients experience symptoms of an upper respiratory or gastrointestinal tract infection 1–4 weeks prior to the onset of GBS.
- Campylobacter enteritis is the most common disease associated with GBS.
- Cytomegalovirus is the most common virus associated with GBS
What are the clinical features of Guillian-Barre syndrome?
Initial symptoms include back and limb pain, esp. paraesthesias affecting distal extremities.
Advanced symptoms include:
- Ascending flaccid paralysis: Bilateral flaccid paralysis spreads from the lower to the upper limbs in a“stocking‑glove” distribution.
- Cranial nerve involvement: frequently bilateral facial nerve involvement (facial diplegia). Facial weakness and speech problems occur in 50% of patients.
- Landry paralysis: involvement of the respiratory muscles. Weakness can cause respiratory distress requiring ventilation.
As with lower motor neurone signs, there is reduced or absent muscle reflexes.
Neuropathic pain develops in about ⅔ of patients
What are the subtypes of Guillain-barre syndrome?
Describe the investigation results of Guillain-Barre syndrome
- The cerebrospinal fluid analysis shows albuminocytologic dissociation: elevated protein levels and normal cell counts in cerebrospinal fluid (CSF); CSF cell counts higher than 50 cells per μl CSF indicate that GBS is unlikely!
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Serological screening:
- To identify potential pathogens (e.g., Campylobacter jejuni)
- Detection of antibodies directed against gangliosides (e.g., anti‑GM1 antibodies)
- EMGs: reduced nerve conduction velocity due to demyelination : increased F‑wave latency
Describe the management and prognosis of Guillian-Barrè syndrome
Supportive management:
- Monitor cardiac and respiratory function: in some cases, intensive care unit (ICU) treatment and intubation may be indicated
- DVT prophylaxis
High dose of intravenous immunoglobulins or plasmapheresis (equivalent outcome in adults, but the only choice recommended in children)
Although GBS is considered an autoimmune disease, glucocorticoids are not recommended for treatment. They have not shown to hasten recovery or affect the long-term outcome.
Prognosis
Spontaneous recovery - sometimes full, occasionally incomplete - is usual. Up to 70% of patients with GBS have a good prognosis: Disease progression peaks 2–4 weeks after the onset of symptoms.
Define Horner’s syndrome
This is a rare condition that results from disruption of the sympathetic nerves supplying the eye. There is the triad of:
- Partial ptosis (upper-lid drooping)
- Moderate miosis (pupillary constriction)
- Hemifacial anhidrosis (absence of sweating).
What is the aetiology of Horner’s syndrome?
Horner’s syndrome disruption of the sympathetic arc supplying the eye, and can be due to disease processes at multiple levels. At the level of the:
- Brainstem/spinal chord: tumour (ganglioma), infarction,
- T1 root: brachial plexus lesion, neurofibromatosis
- Cervical sympathetic chain: Pancoast tumour (lung apex)
- Internal carotid artery: dissection or occlusion
Can also be caused by migraine or cluster headaches, as well as rarer causes such as MS.
NEUROANATOMY REMINDER:
Sympathetic innervation to the eye consists of a 3-neuron arc. First order sympathetic fibres originate in the hypothalamus and descend through the brainstem to level C8-T2 of the spinal cord, where they synapse on preganglionic sympathetic fibres.
Second order fibres leave the cord at level T1 and ascend the sympathetic chain over the apex of the lung to synapse in the superior cervical ganglion at the level of the bifurcation of the common carotid artery (C3-C4).
Third order (postganglionic) fibres pass alongside the internal carotid artery, sending branches to the blood vesselsand sweat glands of the face. They then pass via the cavernous sinus to enter the eye via the superior orbital fissure. They pass via the long ciliary nerves to supply the dilator pupillae and levator palpebrae.
What are the clinical features of Horner’s syndrome?
Patients may report the inability to open eye fully on the affected side (ptosis). Other two of the classical triad is miosis and anhidrosis.
If there is facial flushing this points to a pregnaglionic lesion, whereas orbital pain/headache points to a postganglionic lesion.
There may be other symptoms depending on the underlying cause such as head/neck pain if associated with carotid artery dissection.
What is the aetiology of Meningitis?
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Bacterial:
- Neonates: Group B Streptococci, E. coli, Listeria monocytogenes
- Children: Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae
- Adults: Neisseria meningitidis, Streptococcus pneumoniae, Tuberculosis.
- Elderly: Streptococcus pneumoniae and Listeria monocytogenes
- Viral: Enteroviruses, mumps, HSV, VZV, HIV.
- Fungal: Cryptococcus (with HIV)
- Others: Aseptic meningitis (not due to infection).
What are the clinical features of Meningitis?
- Patients present with a severe headache, photophobia (hours to days onset), neck stiffness (absent in some patients) or back ache and fever and vomiting.
- Patients are also often irritable, drowsy and confused. They can also present with psychiatric distrubance.
- Focal neurological signs complicate meningitis in 15%
Seizures are a presenting feature in 30% of patients.
A careful history should reveal risk factors such as recent travel, or exposure to rodents or ticks.
On examination there are signs of:
- Infection: fever, tachycardia, hypotension, and non-blanching petechial skin rash (indicative of Neisseria meningitidis).
- Meningism: photophobia, neck stiffness, positive Kernig’s sign (patient supine with hip flexed at 90o, knee cannot be fully extended) and Brudzinski’s sign (Passive flexion of neck causes flexion of both legs and thighs).
What are the potential complications of Meningitis?
- Septicaemia
- Shock
- DIC
- Renal failure
- Fits
- Peripheral gangrene
- Cerebral oedema
- Cranial nerve lesions, cerebral venous thrombus, hydrocephalus.
What are the investigations for Meningitis?
A CT scan is necessary in certain patients before a lumbar puncture. This is to exclude causes that would lead to increased cranial pressure (which would lead to herniation during CSF removal). If the patient has recent neurological deficit, new-onset seizures, papilledema, abnormal level of consciousness, or is immunocompromised, perform a head CT before CSF removal.
A lumbar puncture should otherwise be the first test, to analyse the CSF for microscopy, culture and sensitivity testing.
- In bacterial meningitis, the CSF will appear cloudy, and have ↑neutrophils, ↑protein and ↓glucose.
- Whereas in viral meningitis, there will be ↑lymphocytes and ↑protein but normal glucose.
Measure opening pressure: opening pressure is often raised (>20cm CSF) in meningitis.
In patients where LP is delayed, two sets of blood cultures should be sent off.
PCR can be used to amplify bacterial DNA and diagnose bacterial meningitis over viral meningitis.
What are the features of an anterior circulation stroke?
- Anterior cerebral artery syndrome is often due to embolic stroke and presents with contralateral leg weakness (motor cortex) and confusion (frontal lobe).
- Middle cerebral artery (MCA): contralateral facial weakness and hemiparesis usually of arms (motor cortex), hemi-sensory loss (loss of feeling in contralateral face and arm) (somatosensory cortex). Receptive and/or expressive dysphasia. Dyslexia, dysgraphia, dyscalculia.
What are the features of a lacunar stroke?
- Internal capsule or pons: Pure sensory and/or motor deficit.
- Thalamus: Loss of consciousness, hemisensory deficit.
- Basal ganglia: Hemichorea, parkinsonism.
What are the features of a posterior circulation stroke?
- Posterior cerebral: Contralateral homonymous hemianopia
- Anterior inferior cerebellar artery: Vertigo, ipsilateral ataxia, ipsilateral deafness, ipsilateral facial weakness.
- Posterior inferior cerebellar artery: Vertigo, ipsilateral ataxia, ipsilateral Horner’s syndrome, hemifacial loss, dysarthria and contralateral spinothalamic sensory loss.
- Basilar artery: combination of cranial nerve pathology and impaired consciousness.
What are the disease modifying drugs that are used in the management of Multiple Sclerosis?
