Extra notes Flashcards
What changes does chronic alcahol consumption cause in the CNS?
Enhances GABA mediated inhibition in the CNS (similar to benzodiazepines) and inhibits NMDA-type glutamate receptors
What changes does alcahol withdrawal cause in the CNS?
Decreased inhibitory GABA and increased NMDA glutamate transmission
Symptoms of alcohol withdrawal syndrome
>
tremor, sweating, tachycardia, anxiety at 6-12 hours seizures at 36 hours delirium tremens is at 48-72 hours
What are the initial (early) symptoms of alcohol withdrawal syndrome?
Tremor, sweating, tachycardia, anxiety at 6-12 hours
When do seizures occur in alcohol withdrawal syndrome
36 hours
When does delirium start in alcohol withdrawal syndrome
48-72 hours
When does the initial early symptoms of alcohol withdrawal syndrome start?
6-12 hours
Management of alcohol withdrawal syndrome
- first-line: long-acting benzodiazepines e.g diazepam
> Lorazepam may be preferable in patients with hepatic failure. - carbamazepine also effective in treatment of alcohol withdrawal
What benzodiazepines are used in the management of alcohol withdrawal syndrome?
Long acting benzodiazepines e.g. diazepam
Lorazepam may be preferable in patients with hepatic failure.
Brown Sequard syndrome
Rare neurological condition characterized by a lesion in the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side.
Features of right-sided Brown Sequard syndrome
Right sided (ipsilateral) proprioception/vibration loss & weakness but would cause contralateral (left-sided) loss of pain and temperature.
Features of left-sided Brown Sequard syndrome
Left sided (ipsilateral) proprioception/vibration loss & weakness but would cause contralateral (right-sided) loss of pain and temperature.
Tuberous sclerosis
A rare autosomal dominant condition that causes mainly non-cancerous (benign) tumours to develop in different parts of the body.
Tuberous sclerosis mode of inheritance
autosomal dominant
What are the cutaneous features of Tuberous sclerosis
- Depigmented ‘ash-leaf’ spots
- Shagreen patches
- Adenoma sebaceum
- subungual fibromata
- Café-au-lait spots
What are shagreen patches
Roughened patches of skin over lumbar spine
Subungual fibromata
Painless, slow-growing tumor seen in the nail apparatus. They can be spherical or oval in shape and firm or elastic in consistency.
What are the neurological features of Tuberous sclerosis
- developmental delay
- epilepsy (infantile spasms or partial)
- intellectual impairment
Retinal hamartomas
Dense white areas on retina (phakomata)
Lymphangioleiomyomatosis
Multiple lung cysts
A lung disease caused by the abnormal growth of smooth muscle cells, especially in the lungs and lymphatic system. This abnormal growth leads to the formation of holes or cysts in the lung.
Left homonymous hemianopia
Left visual field defect, i.e. Lesion of right optic tract
Right homonymous hemianopia
Right visual field defect, i.e. Lesion of Left optic tract
Homonymous superior quadrantanopia
Lesion of the Inferior optic radiations in the temporal lobe
Is a loss of vision in the same upper quadrant of visual field in both eyes
Homonymous superior quadrantanopia
Lesion of the inferior optic radiations in the temporal lobe (Meyer’s loop)
Is a loss of vision in the same lower quadrant of visual field in both eyes
Correct card
Homonymous quadrantanopia
PITS (Parietal-Inferior, Temporal-Superior)
Congruous defect of visual field: causes
Simply means complete or symmetrical visual field loss
Causes - optic radiation lesion or occipital cortex
Incongruous defects of visual field: causes
Usually optic tract lesions
Is incomplete or asymmetric visual field loss
Bitemporal hemianopia
Lesion of the optic chiasm
What causes an inferior chiasmal compression and thus bitemporal hemianopia?
Commonly a pituitary tumour
What causes a superior chiasmal compression and thus bitemporal hemianopia?
Commonly a craniopharyngioma
5-HT3 antagonists examples
Ondansetron
Granisetron
5-HT3 antagonists mechanism of action
Antiemetics used mainly in management of chemotherapy-related nausea. Act in the chemoreceptor trigger zone area of the medulla oblongata.
5-HT3 antagonists adverse effects
Constipation is common
Prolonged QT interval
Absence seizure features
> Absences last a few seconds
quick recovery
Provoked by hyperventilation or stress
Usually unaware of seizure
May occur many times a day
EEG: bilateral, symmetrical 3Hz spike and wave pattern
Global aphasia
Large lesion affecting the inferior frontal gyrus, superior temporal gyrus and the arcuate fasiculus resulting in severe expressive and receptive aphasia
May still be able to communicate using gestures
Conduction aphasia
Classically due to a stroke affecting the arcuate fasiculus - the connection between Wernicke’s and Broca’s area
Speech is fluent but repetition is poor. Aware of the errors they are making – Comprehension is normal
Wernicke’s (receptive) aphasia
Due to a lesion of the superior temporal gyrus. It is typically supplied by the inferior division of the left MCA
This area ‘forms’ the speech before ‘sending it’ to Broca’s area. Lesions result in sentences that make no sense, word substitution and neologisms but speech remains fluent - ‘word salad’
Comprehension is impaired
Broca’s aphasia
Due to a lesion of the inferior frontal gyrus. It is typically supplied by the superior division of the left MCA
Speech is non-fluent, laboured, and halting. Repetition is impaired
Comprehension is normal
Arnold-Chiari malformation
Describes the downward displacement, or herniation, of the cerebellar tonsils through the foramen magnum.
Malformations may be congenital or acquired through trauma.
Features of Arnold-Chiari malformation
> non-communicating hydrocephalus may develop as a result of obstruction of CSF outflow
headache
syrinomyelia
Ataxia causes
Cerebellar hemisphere lesions cause peripheral (‘finger-nose ataxia’)
Cerebellar vermis lesions cause gait ataxia
Ataxia telangiectasia
Autosomal recessive disorder caused by a defect in the ATM gene which encodes for DNA repair enzymes. It typically presents in early childhood with abnormal movements.
Features of Ataxia telangiectasia
> cerebellar ataxia
telangiectasia (spider angiomas)
IgA deficiency - recurrent chest infections
10% risk of developing malignancy, lymphoma or leukaemia, but also non-lymphoid tumours
Erb-Duchenne paralysis
damage to C5,6 roots
winged scapula
may be caused by a breech presentation
Klumpke’s paralysis
damage to T1
loss of intrinsic hand muscles
due to traction
Causes of brain abscess
> extension of sepsis from middle ear/ sinuses
trauma or surgery to the scalp
penetrating head injuries
embolic events from endocarditis
Investigations of brain abscess
CT scanning
Management of brain abscess
Craniotomy is performed and the abscess cavity debrided
IV antibiotics: IV 3rd-generation cephalosporin + metronidazole
Intracranial pressure management: e.g. dexamethasone
Carbamazepine mechanism of action
Binds to sodium channels increases their refractory period
Cataplexy
Sudden and transient loss of muscular tone caused by strong emotion (e.g. laughter, being frightened).
Features range from buckling knees to collapse.
Cavernous sinuses
Are paired and are situated on the body of the sphenoid bone. It runs from the superior orbital fissure to the petrous temporal bone.
The cerebral perfusion pressure (CPP)
Is defined as being the net pressure gradient causing blood flow to the brain. The CPP is tightly autoregulated to maximise cerebral perfusion.
Charcot-Marie-Tooth Disease
Charcot-Marie-Tooth Disease is the most common hereditary peripheral neuropathy.
Results in a predominantly motor loss. There is no cure, and management is focused on physical and occupational therapy.
Most common hereditary peripheral neuropathy
Charcot-Marie-Tooth Disease
Charcot-Marie-Tooth Disease features
History of frequently sprained ankles Foot drop High-arched feet (pes cavus) Hammer toes Distal muscle weakness Distal muscle atrophy Hyporeflexia Stork leg deformity
Common peroneal nerve lesion
The sciatic nerve divides into the tibial and common peroneal nerves. Injury often occurs at the neck of the fibula
Most characteristic feature is foot drop.
Complex regional pain syndrome
Umbrella term for a number of conditions such as reflex sympathetic dystrophy and causalgia. It describes a number of neurological and related symptoms which typically occur following surgery or a minor injury. CRPS is 3 times more common in women.
Types of Complex regional pain syndrome
Type I (most common): there is no demonstrable lesion to a major nerve
Type II: there is a lesion to a major nerve (causalgia)
Reflex sympathetic ?
Features of Complex regional pain syndrome
progressive, disproportionate symptoms to the original injury/surgery allodynia temperature and skin colour changes oedema and sweating motor dysfunction
Drugs causing a peripheral neuropathy
amiodarone isoniazid vincristine nitrofurantoin metronidazole
EMG characteristics for neuropathy
Increased action potential duration
Increased action potential amplitude
EMG characteristics for myopathy
Decreased action potential duration
Decreased action potential amplitude
Essential tremor
A neurological disorder that causes your hands, head, trunk, voice or legs to shake rhythmically. It is often confused with Parkinson’s disease. Essential tremor is the most common trembling disorder.
Features of Essential tremor
postural tremor: worse if arms outstretched
improved by alcohol and rest
most common cause of titubation (head tremor)
Essential tremor management
propranolol is first-line
primidone is sometimes used
Sagittal sinus thrombosis
may present with seizures and hemiplegia
parasagittal biparietal or bifrontal haemorrhagic infarctions are sometimes seen
Lateral sinus thrombosis
6th and 7th cranial nerve palsies
Lateral medullary syndrome
Also known as Wallenberg’s syndrome, occurs following occlusion of the posterior inferior cerebellar artery. Affects glossopharyngeal and vagus nerves
Features of Lateral medullary syndrome
ataxia & nystagmus
Brainstem features:
ipsilateral: dysphagia, facial numbness, cranial nerve palsy e.g. Horner’s
contralateral: limb sensory loss
Refeeding syndrome
Describes the metabolic abnormalities which occur on feeding a person following a period of starvation. The metabolic consequences include: Hypophosphataemia Hypokalaemia Hypomagnesaemia Abnormal fluid balance
Pituitary apoplexy
Sudden enlargement of a pituitary tumour (usually non-functioning macroadenoma) secondary to haemorrhage or infarction.
Features of Pituitary apoplexy
sudden onset headache similar to that seen in subarachnoid haemorrhage
vomiting
neck stiffness
visual field defects: classically bitemporal superior quadrantic defect
extraocular nerve palsies
features of pituitary insufficiency
e.g. hypotension/hyponatraemia secondary to hypoadrenalism
Pituitary apoplexy management
urgent steroid replacement due to loss of ACTH
careful fluid balance
surgery
Pituitary apoplexy investigations
MRI
Post-lumbar puncture headache
usually develops within 24-48 hours following LP but may occur up to one week later
may last several days
worsens with upright position
improves with recumbent position
Factors favouring pseudoseizures
pelvic thrusting family member with epilepsy much more common in females crying after seizure don't occur when alone gradual onset
Factors favouring true epileptic seizures over pseudoseizures
tongue biting
raised serum prolactin*
Reye’s syndrome
A severe, progressive encephalopathy affecting children that is accompanied by fatty infiltration of the liver, kidneys and pancreas. Aetiology is not fully understood although there is a known association with aspirin use and a viral cause has been postulated
Spontaneous intracranial hypotension
A very rare cause of headaches that results from a CSF leak. The leak is typically from the thoracic nerve root sleeves.
Features of Spontaneous intracranial hypotension
Strong postural relationship with the headache generally much worse when upright. Patients may, therefore, be bed-bound
Spontaneous intracranial hypotension investigations
MRI with gadolinium: typically shows pachymeningeal enhancement
Syringomyelia
Describes a collection of fluid filled cysts within the spinal cord.
Syringobulbia
Syringobulbia in which there is a fluid-filled cavity within the medulla of the brainstem. This is often an extension of the syringomyelia but in rare cases can be an isolated finding.
Causes of Syringomyelia
A Chiari malformation: strong association
trauma
tumours
idiopathic
Investigations of Syringomyelia
full spine MRI with contrast to exclude a tumour or tethered cord
a brain MRI is also needed to exclude a Chiari malformation
Features of Syringomyelia
a ‘cape-like’ (neck, shoulders and arms)
loss of sensation to temperature but the preservation of light touch, proprioception and vibration
classic examples are of patients who accidentally burn their hands without realising
this is due to the crossing spinothalamic tracts in the anterior commissure of the spinal cord being the first tracts to be affected
spastic weakness (predominantly of the lower limbs)
neuropathic pain
upgoing plantars
Wernicke’s encephalopathy
A neuropsychiatric disorder caused by thiamine deficiency which is most commonly seen in alcoholics.
