Hersenen Flashcards
Most common cause of radial nerve palsy
entrapment at spiral groove
‘Saturday night palsy’
presenting symptoms of radial nerve palsy
- Wrist and finger drop
- Usually painless
- Motor weakness – mainly the extensors (wrist/finger extension)
Numbness over first dorsal interosseous muscle
Most common cause of ulnar nerve palsy
Entrapment at ulnar groove (medial epicondyle of humerus)
NB: Cyclists may end up with a problem due to excessive compression on the wrist
presenting symptoms of ulnar nerve palsy
May be history of trauma at elbow
• Sensory disturbance and weakness “weak grip”
• Usually painless
• Motor weakness - finger abduction/wrist flexion
Most common cause of median nerve palsy
entrapment within carpal tunnel at wrist
• Pregnancy
• hyperthyroisism
presenting symptoms of median nerve palsy
History of intermittent nocturnal PAIN, numbness and tingling – often relieved by shaking hand
Patient may complain of “weak grip”
Positive Tinel’s sign/Phalen’s test (Wrist Flexion Test)
Motor weakness
Most common cause of Anterior Interosseous Branch (median nerve) palsy
Trauma to forearm
presenting symptoms of Anterior Interosseous Branch (median nerve) palsy
unable to make ok sign
weak grip
history of trauma to forearm
no sensory changes
Most common cause of femoral nerve palsy
haemorrhage / trauma
May be iatrogenic (femoral lines)
presenting symptoms of femoral nerve palsy
Not normally painful
Weakness of Quadriceps = knee extension
Weakness of Hip flexion/hip abduction
Numbness in medial shin
Most common cause of common peroneal nerve palsy
entrapment at fibular head
Most common mononeuropathy in the lower limb
common peroneal nerve
presenting symptoms of common peroneal nerve palsy
May be history of trauma, surgery or external compression (crossing of legs)
Acute onset foot drop + sensory disturbance
Usually painless
Motor weakness
NB: Foot drop is a common sign in neurology, but when it comes from Common peroneal nerve, ankle reflexes will be intact and foot inversion is still possible
Mononeuritis multiplex
painful, asymmetrical sensory and motor peripheral neuropathy
involves isolated damage to at least 2 separate nerves
causes tend to be systemic (DM, vasculitis, CT diseases, lymphoma, infection - Hep C/HIV)
Multiple nerves in random areas of the body can be affected.
What does breathlessness on lying flat indicate?
Weakness of the diaphragm
Worse on lying flat because the abdominal viscera exert pressure
Functions of the peripheral nervous system
sensory input to CNS
motor output to muscles
innervation of viscera
Causes of length-dependent axonal neuropathy
diabetes
alcohol
Folate / B12 / thiamine /B6 deficiency RA, SLE, vasculitis Renal failure, hypothyroidism Drugs Infectious: HIV, hepatitis B & C
Guillain-Barré syndrome
Acute inflammatory demyelinating neuropathy
Progressive (ascending) weakness. Affects proximal muscles. +/- respiratory / bulbar / autonomic involvement
Flaccid, quadraparesis with areflexia
History of recent infection (campylobacter/EBV/CMV). Trigger infection causes formation of antibodies which attack the myelin sheath
Demyelination will cause conduction block
Myasthenia gravis
Autoimmune disorder: antibodies to nicotinic acteylcholine receptor at post-synaptic NMJ
May be associated with thymic hyperplasia or thymoma
Affects young women in 20’s and older men in 70’s
Fatiguable weakness of ocular, bulbar, neck, respiratory and/or limb muscles
Antibodies to AChR present in 85% of cases
commonest type of peripheral neuropathy
Length-dependent axonal neuropathy
Which condition presents with ascending flaccid tetraparesis?
Guillain-Barré syndrome
Which condition is characterised by formation of antibodies against post-synaptic acetylcholine receptor?
Myasthenia gravis
Primary headache vs Secondary headache
Primary headache = headache and its associated features is the disorder (no underlying cause)
• E.g. Migraine, tension-type headache, cluster headache
Secondary headache = secondary to underlying cause
• E.g. Subarachnoid haemorrhage, SOL, meningitis, temporal arteritis, high/low ICP, drug-induced
‘Red Flag’ features suggesting secondary headache
= SNOOPT
Systemic symptoms
Neurological signs or symptoms (focal/non-focal)
Older age at onset (>50)
Onset is acute (under 5 minutes) = thunderclap
Previous headache history is different / absent
Triggered headache (valsalva or posture)
Assess cranial nerves and fundoscopy
Aura
Recurrent reversible focal neurological symptom (eg. visual, sensory, motor)
Develops over 5-20 mins and lasts <60 mins
Visual aura is most common (eg. scotoma, flashing lights, fortification spectrum)
Sensory aura often starts in hand and migrates up arm
Migraine presentation
Headache: • commonly throbbing or pulsatile • Moderate – severe intensity • Gradual onset, duration 4 –72hrs • Unilateral in 60%, can radiate • Aggravated by routine physical activity
Associated symptoms • Nausea and vomiting • Photophobia • Phonophobia • Osmophobia • Mood disturbance • Diarrhoea
Medication overuse headache
headache 15+ days per month associated with frequent
use of acute relief medications
Management of migraine
- Avoid triggers
- Reduce caffeine / alcohol intake
- regular meals and sleep patterns
Acute management
• Simple analgesia (Paracetamol, Aspirin, NSAIDs)
• Triptans (eg. Sumatriptan)
• +/- antiemetic (eg. domperidone, metoclopramide)
Prophylaxis
• Beta-blockers (Propanolol)
• Tricyclic antidepressants (Amitriptyline, Nortriptline)
• Anti-epilepsy drugs (Sodium Valproate)
Thunderclap headache
abrupt-onset of severe headache which reaches maximal intensity <5 mins (and lasts >1 hr)
“worst headache of life”
“like being hit over the head”
considered as SAH until proven otherwise
Other causes: • Intracerebral haemorrhage • Arterial dissection (vertebral or carotid) • Cerebral venous sinus thrombosis • Bacterial meningitis
Investigation of thunderclap headache
Aim to identify SAH
Bloods ECG CT brain LP - Performed after 12 hours to look for xanthochromia Intracranial pressure
xanthochromia
yellow discoloration indicating the presence of bilirubin in the cerebrospinal fluid
Raised pressure headaches: features
Worse on lying flat, improved on sitting / standing up
Worse in the morning
Persistent nausea / vomiting
Worse on valsalva (eg. coughing, laughing, straining)
Worse with physical exertion
Transient visual obscurations with change in posture
Raised pressure headaches: examination findings
Optic disc swelling – papilloedema
Impaired visual acuity / colour vision
Restricted visual fields / enlarged blind spot
III nerve palsy
VI nerve palsy (false localizing sign)
Focal neurological signs
Causes of raised ICP
Mass effect - tumour, oedema, haematoma, abscess
Increased venous pressure - cerebral venous sinus thrombosis, obstruction of jugular venous system
Obstruction to CSF flow / absorption - hydrocephalus, meningitis
Low CSF pressure headache features
Headache worse on sitting / standing up and relieved by lying down
Loss of CSF volume causes traction on meninges, cerebral / cerebellar veins and CN V, IX and X
Causes of Low CSF pressure
Post-lumbar puncture
Spontaneous intracranial hypotension due to dural tear
Stroke
Rapidly developing clinical signs of focal (or global) disturbance of cerebral function, lasting more
than 24 hours or leading to death, with no apparent cause other than that of vascular origin.
objective evidence of focal ischaemic injury in a defined vascular distribution
Anything <24 hours is classified as a TIA
Stroke pathophysiology
Always due to a blood clot somewhere, e.g. heart/venous system
Blood clot ascends to the brain through the blood vessels
Blood flow is stopped, and brain becomes starved of oxygen
Neurons are depolarized
Early symptoms -> loss of function. If blood flow is restored at this point, the damage is reversible
Brain tissue dies causing areas of infarction. This is irreversible damage
Acute signs/symptoms of stroke
Unilateral weakness: leg/ face & arm/ hemiparesis. body parts affected indicate the location of the lesion due to the differential relative representation on the
motor/somatosensory cortices
Dysphasia
Visual disturbance: e.g. right homonymous heminopia
Acute light-headedness (past-pointing, nystagmus)
A stroke can cause expressive or receptive aphasia. Which artery is most likely the blocked one? And which side of the body will likely show motor signs of stroke?
Left MCA
Broca’s/Wernicke’s are located in the left hemisphere in the majority of people.
Right side of the body will be affected (left motor cortex controls the right side of the body)
Definition of ischaemic stroke
An episode of neurological dysfunction caused by focal cerebral, spinal, or retinal infarction.
Causes of ischaemic stroke
Cardiac embolism – e.g. AF, heart failure
Total Anterior Circulation Syndrome (TACS)
Hemiparesis + Higher cortical dysfunction + hemianopia
Usually proximal MCA or ICA occlusion
Remember: 3H’s
Partial Anterior Circulation Syndrome (PACS)
o Isolated higher cortical dysfunction OR
o Any 2 of hemiparesis, higher cortical dysfunction, hemianopia
Usually branch MCA occlusion
Remember: Partial, therefore only part (2/3Hs)
Posterior Circulation Syndrome (POCS)
Isolated hemianopia OR Brainstem syndrome
Can include perforating arteries, PCA or cerebellar arteries
Lacunar Syndrome (LACS)
Pure motor stroke OR pure sensory stroke OR sensorimotor stroke OR ataxic hemiparesis OR clumsy hand-dysarthria
Small vessel disease (deep perforating vasculopathy)
Definition of intracerebral haemorrhage
A focal collection of blood within the brain parenchyma or ventricular system that is not caused by trauma.
Patient presents with new onset expressive dysphasia which he woke up with. What kind of stroke is this?
PACS
Patient presents with sudden onset speech disturbance and left-sided weakness 1 hour ago.
O/E: left hemiparesis, left sided hemianopia, left sided neglect
What kind of stroke is this?
TACS
Patient presents with sudden onset right sided weakness 5 hours ago.
O/E: hypoasthaesia right face, arm, leg. No movement against gravity in right arm and leg.
What kind of stroke is this?
LACS
Patient presents with left sided neck pain since skiing 2/7 ago. Sudden onset vertigo and ataxia yesterday.
O/E: nystagmus, right ptosis, small pupil on right, hypoasthaesia right face, arm, leg, hoarse, right upper limb ataxia
POCS
Treatment approach: Ischaemic stroke
IV thrombolysis +/- thrombectomy. Aspirin
Thrombolysis must be within 4.5 hours of onset
Thrombectomy within 6-8 hours. For large vessel disease only
Stroke unit care -> coordinated care, short/long term therapy, prevent aspiration
Hemicranectomy
Treatment approach: Haemorrhagic stroke
Intracerebral bleed requires aggressive control of blood pressure
Stroke unit care -> coordinated care, short/long term therapy, prevent aspiration
Neurosurgical evaluation
GCS: Eye Opening
4 - Spontaneous
3 - to verbal command
2 - to pain
1 – none
N.B. cannot be assessed if eyes are swollen
GCS: Verbal Response
5–oriented (T/P/P) 4–confused 3–inappropriate 2–incomprehensible sounds 1–none
NB. Append “T” to score if patient is intubate
GCS: Motor
6 - Obeys commands 5 - Localizes pain 4 - Normal Flexion 3 - Abnormal flexion – looks robotic, slow and unnatural (decorticate) 2 - Extension (decerebrate) 1 – None
Coma according to GCS
Coma = inability to:
o Obey commands
o Speak
o Open eyes to pain
Classification of head injury using GCS
Minor = 14-15 Moderate = 9-13 Severe = <8
Significance:
consistent strong association between motor score and 6-month Glasgow Outcome Scale (GOS)
GCS and 14-day mortality is ~linear
GCS and 6-month poor outcome is ~linear
Most common cause of SAH
trauma
NB: with spontaneous SAH 80-85% are caused by aneurysms.
o 15-20% non-aneurysmal
Tumours
Arteriovenous malformations
Anticoagulant therapy
Aneurysmal SAH - Predisposing factors
Smoking Female sex Hypertension Positive family history ADPCK, Ehlers Danlos, coarctation of the aorta
SAH History
Sudden onset (thunderclap) headache LOC Seizures Visual disturbance speech and limb disturbance Sentinel headache in 30%
Clinical examination findings with SAH
Photophobia Meningism - Nuchal rigidity (irritation of the dura) can present with CHF/pulmonary oedema Subhyaloid hemorrhages Vitreous haemorrhages Speech and limb disturbance
WFNS grading of SAH
Grade I - GCS 15 Grade II - GCS 13-14 without deficit Grade III - GCS 13-14 with deficit Grade IV - GCS 7-12 Grade V - GCS 3-6
Higher grade = more severe and worse prognosis
Investigation- SAH
CT confirms diagnosis and identifies complications
LP: xanthochromia - bilirubin (Takes 6-8 hours post SAH to produce)
If unclear, perform invasive imaging (CTA/DSA)
NB: there may be nonspecific ECG changes and slightly elevated troponin
complications of SAH
1) Rehaemorrhage - most common in first 72h
2) Hydrocephalus - due to obstruction of CSF flow
3) Delayed ischaemia - d3-10, due to vasospasm. Give nimodipine
4) Hyponatraemia
5) Cardiopulmonary complications - catecholamine release can lead to myocardial injury (“Stunned Myocardium”)
6) Seizure
7) DVT
SAH management
Conservative:
- analgesia
- fluid resuscitation
- nimodipine to prevent Ca dumping and protect against delayed ischaemia
- Anti-embolic stockings due to DVT risk
Surgical
- clipping
- Endovascular stents
Seizure
Episode of neuronal hyperactivity causing symptoms and signs (can be localized or can spread)
Epilepsy
A syndrome – spectrum of diseases
Characterized by a tendency to have unprovoked seizures
At least two unprovoked episodes of seizure (i.e. it’s not epilepsy if they have seizures following head injury)