Pathology: Damageto olfactory nerve
Aetiology: Headinjury, tumour, sinus disease
Symptoms: Hyposmia, anosmia, altered taste
Signs: Changein taste sensation on examination
Investigations: Imaging: CT or MRI to assess for underlying cause
Treatment: Treat underlying cause
Complications: Nil
Prognosis: If secondary to braininjury then condition is permanent
Pathology: Damageto optic nerve
Aetiology: Raisedintracranial pressure, accelerated hypertension, Polythaemia rubra vera
Symptoms: Loss of vision
Signs: Changein taste sensation on examination
Investigations: Visual Fields: Loss of vision
Fundoscopy: Blurringof optic disc margins, loss of venous pulsation
Imaging: MRI to assess forunderlying cause
Treatment: Treat underlying cause
Complications: Nil
Prognosis: Dependent on cause
Pathology: Damageto oculomotor nerve
Aetiology: Medical: Diabetes, demyelination,brainstem infarct
Surgical: Compression of CNIII e.g. posteriorcommunicating artery aneurysm
Symptoms: Diplopia
Signs: Ptosis,eye held ‘down & out’ by action of unaffected lateral rectus and superioroblique.
Dilated pupil in surgical CNIII palsy due tocompression of parasympathetic fibres as they lie on the outer aspect of theoculomotor nerve nerve
Investigations: Bloods: Fasting glucose, ESR
Imaging: MRI to assess for underlying cause
Treatment: Treat underlying cause
Complications: Nil
Prognosis: Dependent on cause
TrochlearNerve Palsy (IV)
Pathology: Damageto trochlear nerve – Affecting superior oblique muscle
Aetiology: Trauma,raised intracranial pressure, congenital palsy
Symptoms: Diplopia
Signs: Eyeis held slightly elevated and is unable to look down and in
Investigations: Clinical Examination
Treatment: Medical: Prisms, Botulinum Toxin
Surgical: Correct of deficit
Complications: Nil
Prognosis: Dependent on cause
Pathology: Unknownpathogenesis affecting Trigeminal Nerve
Aetiology: Idiopathic,MS, vascular compression, tumors
Symptoms: Painfuldisabling sensory symptoms in the distribution of the trigeminal nerve
Signs: No clinical signs
Investigation: Imaging: MRI to assess for underlyingcause
Treatment: Medical: Neuropathic Analgesia: Carbamazepine,gabapentin, and lamotrigine.
Severe cases: IV phenytoin, nerve injectionwith alcohol or glycerol
Surgical: Microvascular decompression, partial rhizotomyof nerve
Complications: Depression and anxiety
Prognosis: Usually responds toneuropathic analgesia.
Spontaneous remission mayoccur
Pathology: Damageto abducens nerve – Affecting lateral rectus muscle
Aetiology: Demyelination,raised intracranial pressure, vasculitis, diabetes, trauma, brainstem
infarct,multiple sclerosis
Symptoms: Horizontal diplopia
Signs: Eye unable to abductbeyond midline
Investigations: Bloods: FBC, fasting glucose, ESR
Imaging: MRI to assess for underlying cause
Treatment: Medical: Prednisolone, anti-virals,
Surgical: Correct of deficit
Complications: Nil
Pathology: Damageto facial nerve
Aetiology: Idiopathic: Bell’s Palsy
BrainstemLesions: Strokeor tumour
Infection: Varicella Zoster (RamseyHunt Syndrome), HSV, Lyme disease, Meningitis
Systemic: Diabetes, Sarcoidosis,Guillain-Barré Syndrome
Symptoms: Unilateral facial weakness, hyperacusis
Signs: Vesicle formation inBell’s Palsy and Ramsey Hunt Syndrome
Investigations: Imaging: MRI to assess for underlying cause
Treatment: Medical:Prednisolone,eye lubrication and acyclovir
Complications: Corneal injury, nerve degeneration and weakness
Prognosis: 80% recover within 2months.
Pathology: Damageto vestibulocochlear nerve
Aetiology: Brainstem Lesions: Tumours or MultipleSclerosis
Infection: Basal meningitis
Trauma:
Drugs: Alcohol, gentamicin
Symptoms: Vertigo, Tinnitus
Signs: Sensorineuraldeafness
Investigations: Rinne and Weber Test: Assess for hearing loss
Imaging: MRI to exclude underlyingpathology
Treatment: Dependent on underlyingcause
Complications: Dependent on underlying cause
Prognosis: Dependent on underlyingcause
Pathology: Damageto cranial nerves IX,X,XI and XII – lower motor neuron lesions
Aetiology: Guillain-BarreSyndrome, Motor neuron disease, tumours
Symptoms: Difficulty with speech and swallowing
Signs: Tongue weakness,facial muscle weakness
Investigations: Clinical Examination: Assess Gag reflex and uvular deviation
Treatment: Dependent on underlyingcause
Complications: Dependent on underlying cause
Prognosis: Dependent on underlyingcause
Pathology: Damageto cranial nerves IX,X,XI and XII – upper motor neuron lesions
Symptoms: Difficulty with speech and swallowing
Signs: Tongue weakness,facial muscle weakness
Signs: Sensorineuraldeafness
Investigations: Clinical Examination: Assess Gag reflex and uvular deviation
Treatment: Dependent on underlyingcause
Complications: Dependent on underlying cause
Prognosis: Dependent on underlyingcause
Pathology: Damageto accessory nerve
Aetiology: Stroke,tumour, trauma
Symptoms: Weakness of sternocleidomastoid and trapeziusmuscles
Signs: Difficulty shruggingshoulders
Investigations: Nerve Conduction Studies: Assess for underlying pathology
Treatment: Dependent on underlyingcause
Complications: Dependent on underlying cause
Prognosis: Dependent on underlyingcause
Pathology: Damageto hypoglossal nerve
Aetiology: Upper Motor Neuron: Cerebrovasculardisease and motor neuron disease
Lower Motor Neuron: Tumour
Symptoms: Weakness of tongue muscles
Signs: Upper Motor Neuron Lesion: Stiff tongue movement
Lower Motor Neuron Lesion: Atrophy and fasciculationof tongue muscle
Investigations: Imaging: MRI to assess for underlying abnormality
EMG: If fasciculation present
Treatment: Dependent on underlyingcause
Complications: Dependent on underlying cause
Prognosis: Dependent on underlyingcause
