Session 12: Integration Flashcards
Consider localisation of the lesion from history (examples)
Brain – left and right hemispheres: higher mental function, motor – pattern weakness, cortical sensation – pattern, vision
Brainstem: cranial nerves
Cerebellum:
Spinal Cord: pattern weakness, sensory level and pattern, bladder dysfunction, Brown Sequard, Syringomyelia
Nerve roots: myotomes, dermatomes
Plexuses: complex motor and sensory distributions
Peripheral nerves: glove and stocking, individual nerve palsies
Neuromuscular junction: ptosis, diplopia, bulbar dysfunction, limb weakness, fatiguability, no sensory loss
Muscle: proximal weakness, no sensory loss
Use Surgical Sieve to consider aetiology (Congenital; Acquired – vascular, degenerative, trauma, tumour, infection, inflammation, autoimmune, metabolic, toxic and idiopathic).
How would you carry out a neurological history?
Observation during history
- Gait (Parkinsonism, high steppage (foot drop), stomping (lack of sensation), circumduction (hemiparesis after stroke)
- Speech: articulation, quality, content
- Involuntary movements: tremor, tics, chores, orofacial dyskinaesias
Appropriate language: pins and needles – not paraesthesia
In conditions affecting levels of consciousness or intellect, a third party (relative or friend) might be essential to obtain an accurate picture.
Presenting Complaint
History of presenting complaint
- Distribution of symptoms
- Set the scene
- Precipitating factors
- Mode of onset: sudden (vascular until proven otherwise), gradual
- Progression: worsening, improvement, intermittent
- Systematic neurological enquiry
- Headaches
- Loss of consciousness
- Fits
- Problems with speech or swallowing
- Double vision or other problems with vision
- Muscle weakness
- Sensory loss
- Clumsiness
- Bladder problems
- Mental or cognitive difficulties
Supplementary information: PMH, drugs history, alcohol and smoking, family history, social history (work and recreation – e.g. exposed to certain metals, social circumstances) e.g. tardive dyskinesia has a delayed onset (riding of lower facial muscles) – can present 20 years after acute treatment of antipsychotic drugs, migraine tend to run in families.
Clarification on Terminology
Gradual
Blackout: loss of consciousness or loss of vision
Dizziness
- Vertigo: spinning
- Presyncope: light headed or faint
- Unsteadiness in the legs
- Anxiety
Weakness
- Loss of strength or power
- Difficulty using the limb
- Numbness
- Fatigue
- General lack of energy
Numbness: lack of sensation or abnormal sensation
Blurred vision: reduced visual acuity, double vision, moving visual field (can occur in paraneoplastic syndromes)
What could cause a temporary loss of consciousness?
Seizure
Syncope
- Reflex
- Vasovagal
- Situational (cough, micturition)
- Postural hypotension
- Cardiac
Non epileptic attack disorder (NEAD)
Hypoglycaemia
Other (AAA, PE, aortic dissection)
What are the red flag symptoms for cardiac syncope?
History of heart disease
- Ventricular arrhythmia
- Congestive cardiac failure
History of abnormal ECG
Age over 45
No prodrome
What are the discriminating features of temporary loss of consciousness?
Eye witness account
Situation and three phases of the event – pre-, intra-, post-
Stereotypy (common in epilepsy)
Serious injury
Prolonged post ictal confusion
Aura indicates partial onset
Precipitating events
Compare the features of a fit and faint
Fit:
- Warning: >50% have some aura, usually hard to describe like déjà vu or a smell
- Onset: sudden, any position
- Feature: eyes open, rigidity, falls backwards, convulses
- Recovery: confused, headache, sleepy, focal deficit (“Todd’s Palsy – focal weakness in a part of the body after a seizure)
- Other features: tongue bite, loss of bladder control
Faint
- Warning: felt faint, lightheaded, blurred/darkened vision
- Onset: only occurs sitting or standing, avoidable by change in posture
- Features: only occurs standing or sitting, eyes closed, limp, falls forwards, minor twitching only (if unable to fall flat)
- Recovery: pale, washed out, sweating, cold and clammy
- Other features: loss of bladder control rare
What are different types of headaches?
Primary: tension type headache, migraine, cluster headache + others
Secondary: vascular, infective, neoplasia, drugs, inflammation, ICP, trauma, metabolic, toxins
Acute: meningitis, encephalitis, other infections, subarachnoid haemorrhage, post-coital, thunder clap, migraine, cluster, acute angle closure glaucoma
Chronic: temporal arteritis, migraine, analgesic abuse, tension, Paget’s Disease, RICP (including benign intracranial hypertension)
Red flags: thunder headache, neck stiffness, rash, photophobia, focal neurology, nausea/vomiting, characteristics of RICP headache (present on waking, worse if lying, exacerbated by valsava/bending/cough, papilloedema), fever, recent onset or change in character
What are the features of a migraine?
Migraine:
Prodrome (hours-days)
Aura (immediately before headache)
Postdrome
Pain: throbbing, pulsating,
Photo/phonophobia: typical
Location pain: deep stabbing pain temple or eye, usually unilateral, can change sides
Severity pain: moderate-severe
Duration: 4-24 hours
Triggers: stress or relief of stress, sleep too much/little, foods, alcohol, odours, motion
Aura/prodrome: scintillating scotoma, pins and needles, weakness, vertigo
Nausea and vomiting: common
What are the features of a tension headache?
Pain: dull, pressure, tight band around head
Photo/phonophobia: rare
Location pain: generalised, usually bilateral, may be more intense scalp, forehead, temples, neck
Severity pain: mild-moderate
Duration: can remain several days, fluctuates
Triggers: stress
Aura/prodrome: no
Nausea and vomiting: rare
What are the symptoms of a cluster headache?
Severe (some patients suicidal)
Short lived (< 60 minutes)
Unilateral around eye
Nasal congestion/rhinorrhoea/ptosis/conjunctival infection
Episodic – daily for weeks
What are the different types of vertigo? How would you discriminate vertigo?
Vertigo: peripheral versus central
Presyncope
Loss of balance
- Parkinson’s Disease
- Peripheral neuropathies (loss proprioception)
- Anxiety
- Other: anaemia, hypoglycaemia
Commonest causes of peripheral vertigo: Benign Paroxysmal Positional Vertigo, Vestibular Neuronitis, Meniere’s Disease
Commonest causes of central vertigo: migraine, cerebellar disease, disorders in brainstem (cerebellar connections), drugs
Discriminating Vertigo
- Temporal pattern of symptoms
- Hearing loss
- Tinnitus
- Fullness in the ear
- Nausea
- Vomiting
- Headache
- Precipitating events
What is BPPV?
Benign Paroxysmal Positional Vertigo
Abrupt onset
Short lived (10-15 seconds) vertigo
Precipitated by head movement: turning over in bed, looking up, bending down
Onset delayed by a few seconds
Risk factors: vestibular neuronitis, head injury, age
How would you investigate weakness?
Localisation: UMN, LMN, mixed U and LMN, NMJ, muscle
Mode of onset, distribution, duration, appearance of muscle (wasting, twitching, increased bulk).
Progression
- Short term e.g. fatigability
- Long term progression or improvement
- Intermittent
Other neurological involvement:
- Sensory loss or tingling (weakness without sensory involvement: motor neurons, NMJ, muscle)
- Dysphagia
- Bladder dysfunction
- Dysarthria
- Visual disturbance
- Vertigo
Pain
FH, DH and exposure to toxins, Systemic Disease
Consider the distribution of weakness
Proximal versus distal: proximal weakness characteristic of muscle disease
Hemiparesis
Paraparesis
Quadraparesis
Upper limbs affected early: central cord e.g. syringomyelia
Bulbar weakness: this combination is very characteristic of myasthenia gravis – DON”T miss it
Ptosis and eye movements
Peripheral nerve palsies: wrist drop, foot drop, ulnar hand
Respiratory muscle weakness: high cervical, NMJ, Guillain-Barre Syndrome, phrenic nerves, muscle disease
Describe Myasthenia Gravis
Example presentation: this a middle aged man with a 5 week history of progressive, but fluctuating and fatiguable symptoms including dysarthria, dysphagia, ptosis and diplopia.
The condition is characterized by fatigable weakness of periocular, facial, neck, bulbar (hence bulbar palsies), and proximal muscles (i.e. it worsens with exercise and usually gets worse as the day goes on – diurnal).
The defect is at the NMJ: autoantibodies to the acetylcholine receptor prevent the depolarization of post-synaptic muscle fibres (prevent the entry of Ca2+ into the postsynaptic cell and subsequent muscle depolarisation). The more activity there is, the more receptors become blocked hence the fatigability. This fatigue can be overcome temporarily by the use of acetylcholinesterase inhibitors, which is the basis of the diagnostic Tensilon test.
Both immunological and genetic factors appear to be important in its pathogenesis.
The condition is associated with lymphoid hyperplasia and tumours of the thymus. Weakness may respond to surgical thymic removal, especially in young patients with a short history. Otherwise, treatment is with immunosuppression and with anti-cholinesterases (pyridostigmine or neostigmine).
Describe Syringomyelia
spinothalamic tract lesion
In syringomyelia the central canal becomes enlarged forming a cavity that compresses adjacent nerve fibres.
The spinothalamic tracts can be selectively damaged; second-order neurones subserving temperature and pain may be damaged as they decussate in the ventral white commissure (close to the central canal) causing loss of pain, crude touch and temperature sensation in the upper limbs (‘cape’ distribution or ‘suspended’ sensory loss) with preserved light touch and proprioception sensation (i.e. dissociated sensory loss. Anterior motor horn cells are similarly vulnerable – weakness and wasting of hands. Corticospinal tracts may also be affected – mono/paraparesiss.
If the fluid-filled tract extends to the brainstem (syringobulbia), dysarthria, dysphagia, tongue wasting, ataxia and nystagmus may occur.
Describe Meningitis
Meningitis is the inflammation of the leptomeninges (pia mater and arachnoid mater, not dura mater). It can onset acutely or chronically and can be caused by a bacterial or viral origin, with or without septicaemia (so non-blanching rash may not be there if infection is not yet systemic).
The meninges become completely destroyed by the pathogen and the resultant acute inflammatory response (pus, infiltrate of inflammatory cells, exudate due to increased vascular permeability), meaning that prompt diagnosis and treatment is required (patient could die within 12 hours).
Patients will present with a headache, neck stiffness and a fever, yet can also present with photophobia, vomiting and rigors. The main causative organisms vary between age group:
- Neonates: mainly E Coli, L. Monocytogenes and S. Agalactiae
- 2-5 years: H. Influenzae Type B (HiB)
- 5-30 years: N. Meningitides (types)
- Over 30 years: S. Pneumoniae
- Various in immunocompromised individuals
The condition is treated by empirical antibiotics until confirmation of pathogen.
Describe Encephalitis
Encephalitis is an infection of the neural parenchyma (mainly the grey matter, due to presence of the neuronal cell bodies) which is normally viral in cause.
The patient will present with headache, fever, confusion, drowsiness or fatigue, as well as developing to cause seizures or tremors.
The pathogen causes the entire brain to swell as a result of the lymphocytic inflammatory reaction, causing a neuronal cell death due to inclusion bodies in cells (brain becomes swollen and red => RICP => death).
Perivascular cuffing: regions of lymphocyte aggregations in Virchow-Robin space (the perivascular spaces formed when large vessels take the pia mater with when they dive deep into the brain. The pia mater is reflected from the surface of the brain onto the surface of blood vessels in the subarachnoid space. AKA the immunological spaces between the arteries and veins and pia mater that can be expanded by leukocytes).
The main causative organisms are HSV, CMV or HIV yet can also be caused by toxoplasmosis or polio. Different organisms tend to affect different parts of the brain.
- Temporal lobe: Herpes virus (can lead to epilepsy)
- Spinal cord motor neurones: polio
- Brainstem: rabies
- NB: cytomegalovirus has an owl’s eye appearance
Describe Prion Disease
Prion diseases are the result of mutated prion proteins (PrP).
Prion proteins are normal constituents of and function at neuronal synapses; any mutation to the PrPs that occurs, as a result of sporadic mutations (new mutations), familial PrPs (genetic abnormalities) or ingested PrPs (ingesting abnormal PrP => make abnormal PrP, common way of getting Prion disease), will produce PrPs which interact with normal PrPs, allowing them to undergo post-translational conformational changes.
The conformational changes occurring cause aggregation of the PrPs. PrPs aggregate, are extremely stable and build up => cause neuronal death (lack of synapses, aggregates instead) and “holes” in the grey matter.
Prion diseases produce spongiform encephalopathies and can be seen in scrapie in sheep, BSE in cows, nvCJD (new Varient Creutzfeld-Jacob disease, related to BSE ingestion) and Kuru (in tribes of New Guinea).
NB: prions are technically not infections! (Cannot be cultured, technically not alive etc)
Extra: nvJCD can cause rapid onset of dementia symptoms
Describe Subfalcine herniation
Subfalcine herniation: this herniation occurs following a mass, producing the herniation the same side as the mass. It results in the cingulate gyrus (normally lateral to falx cerebri) being pushed under the free edge of the falx cerebri, leading to ischaemia in the medial parts of the parietal and frontal lobes, and to the corpus callosum due to resultant compression of the anterior cerebral artery, leading to infarction.
Describe Tentorial Herniation
Tentorial herniation: the uncus/medial part of parahippocampal gyrus herniates through the tentorial notch (through the crura of the tentorium), normally from large brain tumours or intracranial haemorrhage. The result is damage to the CN III (on the same side), compression of the cerebral peduncles and occlusion to the posterior cerebral and superior cerebellar arteries (producing additional cerebellar signs).
Commonly fatal due to secondary haemorrhage into the brainstem, called duret haemorrhage. The blood affects the midbrain and pons which may stimulate the Cushings reflex.
Common mode of death in those with large brain tumours and intracranial haemorrhage (causes => rapid and sudden ICP)
