Aetiology of Nerve palsies Flashcards
what might interupt neural supply
Interruption of blood supply
Intracranial vascular abnormality
Space occupying lesion
Ophthalmoplegic migraine
Trauma
Changes in intracranial pressure
Diseases (e.g diabetes, multiple sclerosis)
Inflammatory conditions (e.g meningitis)
Infections
AIDS
what is the prognosis for neurological palsies
Recovery more likely:
When treatment of underlying cause successful (Park et al, 2008)
Regression:
Notably in tumours
Spontaneous remission
what can interrupt the blood supply to the nerve
Ischaemic attacks (small vascular accidents – due to blockage or bleed)
Isolated palsies in the elderly frequently due to these
Recovery rate - high (e.g 90% of 3rd n palsy by 6/12, Akagi et al, 2008)
Generally stated risk factors:
Diabetes
Arteriosclerosis
Hypertension
What are the different types of vascular accidents
Stroke – blood supply to a part of the brain is cut off
Ischaemic Stroke - decreased blood supply caused by a blockage (most strokes)
Haemorrhagic Stroke – bleeding in or around the brain (more rare)
Transient Ischaemic Attack (TIA) - Acute vascular disturbance where the disability lasts less than 24 hours
Infarction - Development of an area of localised tissue death (necrosis) as a result of lack of oxygen (anoxia) caused by an interruption in blood supply e.g. occlusion of an artery.
Thrombosis - Aggregation of platelets, fibrin, clotting factors and cellular elements of blood which become attached to the interior wall of a vein or artery
what are risk factors for the development of 6th nerve palsies and third nerve palsies
Patel et al (2005) 6th nerve palsies
Confirmed diabetes as a risk factor – 6 fold increase for diabetes, 8 fold increase for diabetes and hypertension
Hypertension alone – no increase
Jacobson et al (1994) Ocular motor nerve palsies
Diabetes - 5.75 increase
Left ventricular hypertrophy – 5.5 increase NOT hypertension alone
describe the progression in ishacemic palsies
Pain and sudden diplopia typical initial symptoms in ischaemic or compressive disorders
11/16 patients examined within 1 week of onset showed progression (3 to 23 days)
No group differences found, but non-progressive recovered quicker (mean 7.2 weeks c/w mean 11.2 weeks)
Mechanism: ?intraneural compression and further microvascular ischaemia from oedema after initial insult(Jacobson et al, 1995)
how is cocaine linked to oculmotor abnormalities
Cocaine abuse should be considered in the differential diagnosis for oculomotor abnormalities especially in the young.
(Nemeth et al, 1993)
Also consider in cases with Myasthenia – may precipitate or exacerbate symptoms
How is giant cell temporal arteritis linked to the development of nerve palsies
Inflammatory disease of blood vessels
Affects artery walls, predominantly extracranial vessels - particularly superficial temporal arteries
6% - 70% irreversible visual loss
Occult giant cell arteritis - where there are no systemic symptoms (ocular only)
Median age of onset: 75 years. Rare under 50 years
what is the erythrocyte sedimentation rate in giant cell arteritis
Normal: 0-30 mm/hr
Age difference - lower in the young
96% of GCA patients had ESR>50mm/h – hallmark of GCA
(Martinez-Taboada et al, 2000)
what are the systemic signs and symptoms of gca
Jaw claudication
Headache
Weight loss
Malaise
Anorexia
Scalp tenderness
Abnormal temporal artery(tender, nodular, or nonpulsating temporal artery)
Myalgia
Fever
Anaemia
Neck pain
what are the ocular findings found in giant cell arteritis
symptoms
Amaurosis fugax (painless, transient, monocular or binoc visual loss)
Visual loss
Diplopia
Eye pain
Ocular ischaemic lesions
Anterior ischaemic optic neuropathy (lack of blood supply to ON)
Central retinal vein occlusion
Cilioretinal artery occlusion
Posterior ischaemic optic neuropathy (lack of blood supply to retrobulbar ON)
what are examples of intracranial vascular abnoramlities
Aneurysms
Arteriovenous malformations
Fistulas
what are aneuyrsms
Persistent localised dilations of a blood vessel wall which may result from a developmental defect or be acquired from:e.g. acquired degenerative change, infection, inflammation, trauma
Symptoms occur from pressure, bleeding or rupture
are aneurysms symptomatic
90% asymptomatic until rupture
10% present with mass effect
Interval warning to rupture - 1 day to 4 months (median 14 days) (Barrow and Reisner, 1996)
Rupture: 12% die before receiving medical attention
what are ruptured anyerusms
Patients describe as ‘the worst headache of their life’
Medical emergency – aim is to repair the artery and stop bleeding with immediate surgery
Any patient presenting with diplopia & terrible headache needs to be seen as a medical emergency
Aneurysms make leak before they rupture
what ocular involvement occurs in anyerusms
Internal carotid and posterior communicating artery 3rd nerve palsy
Intracranial portion of internal carotid Compression anterior visual pathway
Cavernous sinus3rd and 6th nerve Isolated 6th nerve palsy (frequently with ipsilateral Horner syndrome)
what are arteriovenous malformations
Congenital, anomalous communications between arterial & venous circulations
Blood is shunted from arteries to veins without an intervening capillary bed
Usually become symptomatic during 2nd & 3rd decades of life
Presence of objective bruit valuable diagnostic sign
Headache - often misdiagnosed as migraine
Signs and symptoms occur due to compression, haemorrhage, ischaemia or vascular steal
what are carotid carvenous fistulas
Abnormal connection between carotid artery and cavernous sinus
Classified as:
Traumatic or spontaneous
Velocity of flow: High or low
Direct or dural
Internal carotid or external carotid
what are the two types of carotid carvenous venous fistulas
high flow direct and low flow dural (indirect)
high flow
Often after head injury
Pulsating exophthalmos
Conjunctival chemosis
Cranial Bruit
Diplopia in 60-70%
low flow
Minor signs and symptoms
Onset of redness one or both eyes
Mild proptosis, minimal eyelid swelling, conjunctival chemosis
May or may not be cranial bruit
Diplopia - most often 6th nerve palsy
20-30% result in visual loss
what are the characteristics of carvenous sinus syndrome
3rd, 4th 6th nerve palsy, alone or in combination (usually ipsilateral)
Oculosympathetic paralysis
Proptosis
Ophthalmic and maxillary division of 5th nerve may be affected
Periorbital or hemicranial pain
Trigeminal neuralgia
what is the aetiology of carvenous sinus syndrome
Trauma
Vascular (CC fistula, aneurysm, thrombosis)
Tumour (e.g cavernous sinus meningioma)
what are types of space occupying lesion
Aneurysms
Subdural haematoma
Tumours (Neoplasms)
what nerves are affected by what type of tumours
4th and sixth nerves most commonly affected
3rd nerve affected in pituitary tumours
Generally suspected where palsy is progressive or does not recover….. but
what is a skull base tumour and how is it related to nerve palsies
Skull base tumourcan be any type of tumor that forms in the skull base, which is the bottom of the head and the body ridge in the back of the eyes.
what is a opthalmoplegic migraine
Rare condition – sometimes called intracranial neuralgia
Unilateral headache
Followed by 3rd nerve palsy - partial or complete, pupil often affected
6th nerve may be affected and a suggested cause of recurrent 6th nerve palsy in children - in absence of any pathology
how is trauma related to nerve palsies
4th nerve particularly susceptible to closed head trauma
6th nerve may be affected if downward displacement of brain stem
3rd nerve least frequently affected by trauma, frontal blow to accelerating head
Shaken baby syndrome – isolated or bilateral palsies may occur
what is idiopathic intracranial hypertension
Occurs rarely in children
In adults higher incidence in females and in the obese
Main signs and symptoms include:
Headache
Nausea and vomiting
Papilloedema (swelling of optic disc)
Pulsatile tinnitus
6th nerve palsy commonest – 3rd & 4th also reported
Unilateral or bilateral
(NB Also concomitant strabismus or decompensation has been reported)
Can respond to Diamox or gain relief following lumbar puncture
when do you get intracranial hypotension
Following dural puncture (e.g diagnostic lumbar puncture; accidentally during epidual anaesthesia)
Headache (and nausea), worse when upright, may occur after puncture
Extraocular muscle palsy is a rare complication
6th nerve palsy commonest – 3rd & 4th also reported
Unilateral or bilateral
Onset 1 – 3 days after puncture
(Nishio et al, 2004)
how is diabetes related to nerve palsies
3rd nerve or 6th nerve most frequently affected
Pupil generally spared
?CauseInterruption of blood supplyInflammation of nerveFocal demyelination
why is pupil involvement in a third nerve palsy significant
Rule: when aneurysm compresses 3rd nerve, the iris sphincter will be impaired
Do not apply rule where palsy is incomplete
Great caution in the under 50 year age group unless glaring vasculopathic risk factors
how does abberent regeneration occur in third nerve palsie
Features occur six weeks or more after
onset. Include (alone or in combination):
Retraction of upper lid on down gaze
Elevation of upper lid on adduction
Constriction of the pupil on elevation, depression or adduction
Adduction on attempted elevation (and occasionally on depression)
Tends to occur where trauma or space occupying lesion is cause
what is herpes zoster opthalmicus
Virus affects dorsal root ganglia - trigemminal ganglia affected - unilateral painful rash
Muscle palsies may be ipsilateral, contralateral or bilateral, and may affect one or more nerves
Can affect any age, but more common in elderly or immuno-compromised
Treated with anti-viral therapy (e.g acyclovir)
what is demyleination
Multiple SclerosisDemyelination of nerve sheathSuspected in young adults with isolated nerve palsy(most common age for presentation 20 – 40 years; but can be younger or older)
May have other symptoms or history of previous episode
what are other inflammatory conditions
Meningitis
Encephalitis
Poliomyelitis
Tertiary syphilis (late stage)
Tolosa-Hunt syndrome
what is tosola hunt syndrome
Non-specific granulomatous inflammation
in anterior part cavernous sinus / SOF area
Possible involvement 3rd, 4th, 6th nerves with severe constant pain
Visual loss if ON involved
Proptosis
Sluggish Pupil
Diagnosis: CT scan, ESR may be raised
Treatment: Systemic steroids (e.g prednisolone)
what other diseases are involved in the aetiology of neurological palsies
Systemic lupus erythematosus (SLE)
Immunological disorder affecting connective tissue and nervous system
Nerve palsy may be due to vaso-occlusion of small vessels
No cure, pain relief used, if severe immunosuppressives
Sarcoidosis
Granulomatous disease
Isolated or multiple nerve palsies reported, may be accompanied by pain
No cure, but treated with steroids
what is Gillian barre syndrome
Acute inflammatory demyelinating polyradiculoneuropathy – Aetiology not fully understood. May occur after viral infection.
Slightly more common in males than females, can affect any age but most common 20-50 yrs age
Sudden, acute motor paresis peaking within 4 weaks
Ocular involvement to varying extent: ophthlmoplegia, fixed dilated pupils, optic neuritis, facial nerve palsy
Treatment: Intravenous immunoglobulin treatment, steroids, plasma exchange (treatment removes antibodies from blood)
what is miller fisher syndrome
Possibly a variant of Guillan-Barre
May occur after upper respiratory tract infection
Ophthalmoplegia – usually symmetrical (divergence paralysis, impaired smooth pursuit have also been reported)
Ataxia
Hyporeflexia or areflexia
Diagnosis: Increased protein in CSF from lumbar puncture.
Management: As for Guillan-Barre. Good prognosis.
what infections can cause nerve palsies
Gradenigo’s Syndrome
Infection of middle ear leading to petrositis and affecting 6th nerve as it crosses petrous part of temporal bone
Ipsilateral pain of trigeminal nerve distribution
Constant ottorhea
how is aids related to the cranial nerves
Complications may involve cranial nerves:
Infections Parasitic e.g toxoplasmosis Fungal e.g cryptococcosis
Neoplasms
Vascular (high risk of infarct or haemorrhage)
what are the causes of multiple cranial nerve palsies
Neoplasms
TraumaLess common:
Cavernous Sinus Lesions, Aneurysms, Herpes Zoster, Meningitis, Encephalitis, Tolosa-Hunt, Miller Fisher.
what are the causes of congenital neurogenic palsies
Congenital conditions
Hydrocephalus
Cerebral palsy
Inherited SO palsy
Intoxications from mother
Lead poisoning, drugs, alcohol
Birth trauma
