Neurology
Seán Keenan
2022
,Cranial Nerves
Cranial Nerve Functions and Signs
Nerve Name Type Functions Clinical Findings
CNI Olfactory Sensory - Smell - Loss of Smell
CNII Optic Sensory - Sight - Loss of Sight
- Eye movements (MR/LR/SR/IO) - Ptosis
CNIII Oculomotor Motor - Pupil constriction/accomodation - Down and out eye
- Eye lid - Dilated, fixed pupil
- Defective, downward gaze
CNIV Trochlear Morot - Eye movements (SO)
- Progresses to vertical diplopia
- Loss of corneal reflex(afferent)
- Facial sensation
CNV Trigeminal Noth - Loss of facial sensation
- Mastication
- Paralysis of mastication muscles/ jaw deviation
- Defective abduction
CNVI Abducens Motor - Eye Movement (LR)
- Progresses to horizontal diplopia
- Facial movement - Flaccid paralysis of upper + lower face
CNVII Facial Both - Taste (anterior 2/3 of tongue) - Loss of corneal reflex (efferent)
- Lacrimation and Salivation - Loss of taste / hyperacusis
- Hearing loss
- Hearing
CNVIII Vestibulocochlear Sensory - Vertigo
- Balance
- Nystagmus
- Taste (posterior 1/3 of tongue)
- Hypersensitive carotid sinus reflex
CNIX Glossopharyngeal Both - Swallowing and Salivation
- Loss of gag reflex (afferent)
- Mediates carotid body/sinus input
- Phonation
- Uvula deviates away from site of lesion
CNX Vagus Both - Swallowing
- Loss of gag reflex (efferent)
- Innervates viscera
- Head movement
CNXI Accessory Motor - Weakness turing head (contralateral side)
- Shoulder movement
CNXII Hypoglossal Motor - Tongue movement - Tongue deviates to side of lesion
,Headaches
Description
Tension headaches are the most common type of headache and also the mildest forms. Cluster headaches are more
disabling but also treatable. More sinister causes include where headaches are secondary to another cause such as
space-occupying lesions, meningitis or subarachnoid haemorrhage. Good Hx is therefore key in distinguishing.
Headaches
Sudden Onset Headache Character
- Red Flag: Novel severe acute headache is concerning - Tension: Tight banding pain squeezing head
- SAH: Thunderclap; Often occipital; Stiff neck; ↓GCS - Sinus: Pain behind brow or cheek
- Meningitis: Fever; Stiff neck; Purpuric rash - TMJ: Pain at temples in front of ears
- NB: If recurrent meningitis consider Mollaret’s (HSV) - Cluster: Excruciating pain behind eye
- Encephalitis: Fever; Seizures; ↓ GCS - Neck: Pain at top ± Back of head
Gradual Onset Headache - Migraine: Pain, N&V and visual disturbances
- Venous sinus thrombosis: Papilloedema; Gradual - Acute Glaucoma: Eye pain ± ↓ Vision
- Sinusitis: Sinus pain; Post-nasal drip; Bending ↑ pain - GCA: Pulseless temporal artery
- Tropical: Flu-like illness; Typhus; Malaria Drug history
- ↓ICP: CSF leak; Worse on standing; Fluids relieves - Overuse: Opioids/Triptans ≥15 d/month
Precipitating Factors - NB: Resolves 2 months post-cessation
- Trauma : Arrange head CT if ↓ GCS or chronic - Stop: Withdraw analgesics
- Specific Triggers: E.g. food, sex, medications - Treat: Treat rebound headache with NSAIDs
, Tension Headaches
Description Investigations
- Sex: Commoner in women - Head CT / MRI: If unusual or complicated
- Chronicity: Defined as chronic if >15 d / month Management
Presentation - Acute: Aspirin; Paracetamol; NSAID
- Features: Dull Ache; Tight band on forehead - NB: Opiates are ineffective
- Referred: Tender on scalp, neck, and shoulder m. - Preventative: Low dose amitriptyline; Acupuncture
Causes
- Multi: Stress; Dehydration; Squinting
Cluster Headaches
Description Investigations
- Incidence: 1:500; FHX ↑ risk by 5-18x - Head MRI / CT: If complicated
- Sex: 3x more common in men Management
- Lifestyle: Commoner in smokers - Acute Management
Presentation o 1L: 100 % O2 for ~15 mins (80 % respond)
- Pain: Occurs 1-2x a day; Lasts 15 mins to 2 hours o ≥18 YO: SC 6 mg Sumatriptan (75 % respond)
- Character: Intense stabbing pain around eye o 12-17 YO: Nasal 5 mg Zolmitriptan
- Clusters: Typically last 4-12 wks; Often nocturnal o NB: Triptans CI in CAD (↑ vasospasms)
- Associated: Eyelid swelling; Miosis; Ptosis - Preventatives
Causes o 1L: 360 mg Verapamil
- Alcohol: Strongest associated factor o Other: Tapered prednisolone; Lithium
Trigeminal Neuralgia
Presentation Causes
- Sex: Commoner amongst men - Triggers: Contact with trigger points (see below)
- Age: >50 YO; If <40 YO red flag - 2o: Compressed CNV; Tumour; Shingles; MS; Chiari
- Ethnicity: Asian females Management
Presentation - 1L: Carbamazepine
- Character: Paroxysmal, intense, stabbing pain - Other: Gabapentin
- NB: Occurs in the trigeminal nerve distribution - Surgery: Resection may be required
- Red-F: Sensory change; HL; Optic neuritis; FHx MS
Tension Headache: Amitriptyline Trigeminal Neuralgia: Carbamazepine
Cluster Headache: Verapamil Migraine: Propranolol; Topiramate
Seán Keenan
2022
,Cranial Nerves
Cranial Nerve Functions and Signs
Nerve Name Type Functions Clinical Findings
CNI Olfactory Sensory - Smell - Loss of Smell
CNII Optic Sensory - Sight - Loss of Sight
- Eye movements (MR/LR/SR/IO) - Ptosis
CNIII Oculomotor Motor - Pupil constriction/accomodation - Down and out eye
- Eye lid - Dilated, fixed pupil
- Defective, downward gaze
CNIV Trochlear Morot - Eye movements (SO)
- Progresses to vertical diplopia
- Loss of corneal reflex(afferent)
- Facial sensation
CNV Trigeminal Noth - Loss of facial sensation
- Mastication
- Paralysis of mastication muscles/ jaw deviation
- Defective abduction
CNVI Abducens Motor - Eye Movement (LR)
- Progresses to horizontal diplopia
- Facial movement - Flaccid paralysis of upper + lower face
CNVII Facial Both - Taste (anterior 2/3 of tongue) - Loss of corneal reflex (efferent)
- Lacrimation and Salivation - Loss of taste / hyperacusis
- Hearing loss
- Hearing
CNVIII Vestibulocochlear Sensory - Vertigo
- Balance
- Nystagmus
- Taste (posterior 1/3 of tongue)
- Hypersensitive carotid sinus reflex
CNIX Glossopharyngeal Both - Swallowing and Salivation
- Loss of gag reflex (afferent)
- Mediates carotid body/sinus input
- Phonation
- Uvula deviates away from site of lesion
CNX Vagus Both - Swallowing
- Loss of gag reflex (efferent)
- Innervates viscera
- Head movement
CNXI Accessory Motor - Weakness turing head (contralateral side)
- Shoulder movement
CNXII Hypoglossal Motor - Tongue movement - Tongue deviates to side of lesion
,Headaches
Description
Tension headaches are the most common type of headache and also the mildest forms. Cluster headaches are more
disabling but also treatable. More sinister causes include where headaches are secondary to another cause such as
space-occupying lesions, meningitis or subarachnoid haemorrhage. Good Hx is therefore key in distinguishing.
Headaches
Sudden Onset Headache Character
- Red Flag: Novel severe acute headache is concerning - Tension: Tight banding pain squeezing head
- SAH: Thunderclap; Often occipital; Stiff neck; ↓GCS - Sinus: Pain behind brow or cheek
- Meningitis: Fever; Stiff neck; Purpuric rash - TMJ: Pain at temples in front of ears
- NB: If recurrent meningitis consider Mollaret’s (HSV) - Cluster: Excruciating pain behind eye
- Encephalitis: Fever; Seizures; ↓ GCS - Neck: Pain at top ± Back of head
Gradual Onset Headache - Migraine: Pain, N&V and visual disturbances
- Venous sinus thrombosis: Papilloedema; Gradual - Acute Glaucoma: Eye pain ± ↓ Vision
- Sinusitis: Sinus pain; Post-nasal drip; Bending ↑ pain - GCA: Pulseless temporal artery
- Tropical: Flu-like illness; Typhus; Malaria Drug history
- ↓ICP: CSF leak; Worse on standing; Fluids relieves - Overuse: Opioids/Triptans ≥15 d/month
Precipitating Factors - NB: Resolves 2 months post-cessation
- Trauma : Arrange head CT if ↓ GCS or chronic - Stop: Withdraw analgesics
- Specific Triggers: E.g. food, sex, medications - Treat: Treat rebound headache with NSAIDs
, Tension Headaches
Description Investigations
- Sex: Commoner in women - Head CT / MRI: If unusual or complicated
- Chronicity: Defined as chronic if >15 d / month Management
Presentation - Acute: Aspirin; Paracetamol; NSAID
- Features: Dull Ache; Tight band on forehead - NB: Opiates are ineffective
- Referred: Tender on scalp, neck, and shoulder m. - Preventative: Low dose amitriptyline; Acupuncture
Causes
- Multi: Stress; Dehydration; Squinting
Cluster Headaches
Description Investigations
- Incidence: 1:500; FHX ↑ risk by 5-18x - Head MRI / CT: If complicated
- Sex: 3x more common in men Management
- Lifestyle: Commoner in smokers - Acute Management
Presentation o 1L: 100 % O2 for ~15 mins (80 % respond)
- Pain: Occurs 1-2x a day; Lasts 15 mins to 2 hours o ≥18 YO: SC 6 mg Sumatriptan (75 % respond)
- Character: Intense stabbing pain around eye o 12-17 YO: Nasal 5 mg Zolmitriptan
- Clusters: Typically last 4-12 wks; Often nocturnal o NB: Triptans CI in CAD (↑ vasospasms)
- Associated: Eyelid swelling; Miosis; Ptosis - Preventatives
Causes o 1L: 360 mg Verapamil
- Alcohol: Strongest associated factor o Other: Tapered prednisolone; Lithium
Trigeminal Neuralgia
Presentation Causes
- Sex: Commoner amongst men - Triggers: Contact with trigger points (see below)
- Age: >50 YO; If <40 YO red flag - 2o: Compressed CNV; Tumour; Shingles; MS; Chiari
- Ethnicity: Asian females Management
Presentation - 1L: Carbamazepine
- Character: Paroxysmal, intense, stabbing pain - Other: Gabapentin
- NB: Occurs in the trigeminal nerve distribution - Surgery: Resection may be required
- Red-F: Sensory change; HL; Optic neuritis; FHx MS
Tension Headache: Amitriptyline Trigeminal Neuralgia: Carbamazepine
Cluster Headache: Verapamil Migraine: Propranolol; Topiramate
