Neurology Flashcards
Clinical features in secondary headaches - space-occupying lesion
- Worse when lying down or coughing
- Morgning vomiting
- Headache cause night-time waking
- Change in mood, personality, or educational performance
- Visual field defects
- Cranial nerve abnormalities causing diplopia, new-onset squint or facial palsy
- Abnormal gait
- Torticollis (tilting of the head)
- Growth failure
- Papilledema
Definition of ac epileptic seizure
- Due to excessive and hyper synchronous electrical activity
Definition of convulsions
A seizure with motor components; stiff (tonic), massive jerk (myoclonic), jerking (clonic), trembling (vibratory), thrashing about (hyper motor)
Definition of acute symptomatic epileptic seizures
- Seizure provoked by an acute brain injury, e.g. from ischemia, cerebral contusion, or cortical inflammation. Do not constitute an epilepsy.
Characteristics of a febrile seizure
- In children between age 6 months - 6 years
- 10% risk if first-degree relative
- Seizure usually occur real in a viral infection when tmp is raising rapidly
- Usually generalized tonic-clonic seizures
Most common cause of transient loss of consciousness?
Syncope –> due to transient impairment of brain oxygen delivery
Causes of paroxysmal disorders (‘Funny turns’)
- ‘Blue breath-holding’ spells - toddlers hold breath when upset, expiratory apnea
- Reflex asystolic syncope - due to cardiac systole from vagal inhibition. Triggered by pain or discomfort from head trauma, cold food, fright or fever.
- Syncope
- Migraine
- Benign paroxysmal vertigo
Most common cause of epilepsy
- Genetic (i.e. “idiopathic”) - complex inheritance
Definition of generalized seizures
- Discharge arises from both hemispheres
- Loss of consciousness if >3 seconds duration
- No warning
- Symmetrical seizures
- Bilaterally synchronous seizure discharge on EEG
Defintion of focal seizure
- Seizure aries from one or part of one hemisphere
- May be heralded by an aura which reflects the site of origin
- May or may not be associated with change in consciousness or evolve to generalized tonic-clonic seizure
Jacksonian march
A frontal seizure that is clonic, the travel proximally.
Characteristics of a temporal lobe seizure
- Auditory or sensory (smell or taste) phenomena
- Lip-smacking, plucking at one’s clothing, walking in a non-purposeful manner
Characteristics of occipital seizures
- Stereotyped visual hallucinations
Characteristics of parietal lobe seizures
- Contralateral altered sensation (dysaesthesias)
- Distorted body image
Causes of seizures
- Epilepsi
* Genetic (70-80%) = “idiopathic”
* Structural, metabolic - cerebral malformation, HIE, IVH, cerebral tumor, neurodegenerative disorders - Acute symptomatic seizures
* Stroke, intracranial infection
* Hypoglycemia, hypocalcemia, hypomagnesemia
* Poisons/toxins - Febrile seizures
- Non-epileptic seizures
* Convulsive syncope
* Sudden rise in ICP
* Sleep disorders
* Functional/medically unexplained
Absence seizure
- Transient loss of consciousness
- Abrupt onset and termination
- Flickering of the eyelids, minor alteration in muscle tone.
- Can often be precipitated by hyperventilation
Types of generalized epileptic seizures
- Absence
- Myoclonic
- Tonic
- Tonic-clonic
- Atonic
Myoclonic seizure
- Brief, often repetitive, jerking movements of the limbs, neck or trunk.
- Physiology: Hiccups (myoclonus of diaphragm), passing though stage II sleep
Tonic seizure
- Generalized increased muscle tone
Tonic-clonic seizure
- Rhythmical contraction of muscle groups following the tonic phase
- Tonic phase - children may fall
- Do not breath - cyanosed
- Clonic phase - jerking of the limbs. Irregular breathing, cyanosis persist, saliva accumulate in mouth
- Biting of tongue, incontinence of urine.
- Seizure last from few second to minutes - then unconsciousness or deep sleep for up to several hours.
Atonic seizure
- Combined with a myoclonic jerk - then transient loss of muscle tone causing a sudden fall to the floor or drop of the head.
Characteristics of frontal lobe seizure
- Motor phenomena
What is the drug used in rescue therapy of >5min seizure
Buccal midazolam
Infantile spasms (West syndrome)
- Age: 3-12 months
- Violent flexor spams of head, trunk and limbs –> the extension of arms
- Multiple bursts of 20-30, each last 1-2 s.
- Most have underlying neurologic cause
- Treatment: Vigabatrin and/or corticosteroids
Lennox-Gastatut syndrome
- Age: 1-3 years
- Multiple seizure types - atonic, atypical absences and tonic seizures in sleep
- Poor prognosis
Childhood absence epilepsy
- Age: 4-12 years
- Momentary, unresponsive stare with motor arrest
- May twitch eyelid, hand, or mouth minimally
- Sudden onset, last <30 s.
- No recall of seizure, realizes that they have missed something
Which drug should be avoided in absence and myoclonic seizures?
Carbamazepine
Definition of status epilepticus
Seizure lasting 30 minutes or repeated seizures for 30 minutes without recovery of consciousness
Features of a neuromuscular disorder
- Key feature: weakness
- Hypotonia (floppiness)
- Delayed motor milestones
- Unsteady/abnormal gait
- Fatiguability
- Muscle cramps
Gowers’ sign
- Suggestive of proximal muscle weakness
- Child need to turn prone to rose to a standing from supine position
- ‘Climb up’ the legs with the hands
- Associated with Duchenne muscular dystrophy
Disorders of the anterior horn cell
Signs of denervation: weakness, loss of reflexes, fasciculation, wasting
- Spinal muscular atrophy
- Poliomyelitis
Disorders of the peripheral nerve
- Hereditary motor sensory neuropathies
- Guillain-Barré
- Bell palsy
Disorders of neuromuscular transmission
- Myasthenia gravis
Muscle disorders
- Muscle dystrophies (Duchenne, Becker, Congenital)
- Inflammatory myopathies (Benign acute myositis, Polymyositis)
- Myotonic disorders (Dystrophia myotonica)
- Metabolic myopathies
- Congenital myopathies
Genetics of Spinal muscular atrophy
- Autosomal recessive
- Mutation in SMA1 gene
Pathophys. of Spinal muscular atrophy
Degeneration of the anterior horn cells
- Leading to progressive weakness and wasting of skeletal muscles
Types of Spinal muscular atrophy
SMA1. Severe infantile (Werdnig-Hoffman disease) - most common
SMA2. late infancy, slower progression
SMA3. chronic juvenile
Cause of Guillain-Barré syndrome
- 2-3 weeks after an URT infection or campylobacter gastroenteritis
- Antibodies against protein components of myelin
Clinical features of Guillain-Barré syndrome
- Ascending, progressive symmetrical weakness over a few days to 2 weeks
- Loss of tendon reflexes
- Loss of autonomic involvement –> tachycardia, bradycardia and other arrhythmias, hypertension, orthostatic hypotension, urinary retention, ileus, loss of sweating
- Bilateral facial weakness (easily missed in children)
- Difficulty with chewing and swallowing
- Risk of aspiration
Bell palsy is paresis of which nerve?
Lower motor neuron of the VIIth cranial nerve
Causes of Bell palsy
Etiology is unknown
Associated with post-infection - Herpes simplex, Lyme disease
Clinical features of myasthenia gravis
- Presentations usually after 10 years of age
- Ophthalmoplegia
- Ptosis
- Loss of facial expression
- Difficulty chewing
- Generalized, especially proximal, weakness
How to diagnose myasthenia gravis?
- Observe improvement following administration of I.V. Edrophonium over a few minutes
or - oral Pyridostigmine or Neostigmine over days
- 60-80% have positive actetylcholine receptor antibodies
Treatment of myasthenia gravis
- Choline esterase inhibitors - Pyridostigmine or Neostigmine
- Immunosuppressive therapy
- Prednisolone, Azathioprine, Mycophenolate mofetils, Monoclonal Ab
- Thymectomy
- Plasmapheresis
Genetics of Duchenne muscular dystrophy
- X-linked recessive
- Deletion of the gene for dystrophin (connects cytoskeleton of a muscle fibre to the surrounding extracellular matrix)
What are the causes of dystrophin deficiency?
- Influx of calcium ions
- Breakdown of the calcium calmodulin complex
- An excess of free radicals –> leading to myofibre necrosis
Clinical features of Duchenne muscular dystrophy
- Waddling gait
- Language delay
- Gower’s sign - need to turn prone to rise
- Pseudohypertrophy of the calves
- Life expectancy - late twenties from respiratory failure or cardiomyopathy
