7.5 Raised Intracranial Pressure, Brain Tumours, Cranial Nerve Lesions & Spinal Cord Disorders
Key Takeaways
Bell's palsy is a lower motor neurone facial palsy that involves the forehead; prednisolone started within 72 hours improves recovery, and eye protection prevents corneal damage.
A painful third nerve palsy with a dilated pupil suggests compression by a posterior communicating artery aneurysm and needs urgent CT angiography.
NICE NG12 advises considering an urgent direct-access MRI brain (within 2 weeks) for adults with progressive, subacute loss of central neurological function.
Idiopathic intracranial hypertension typically affects young women with obesity, causing headache and papilloedema with normal brain imaging and a raised opening pressure.
Motor neurone disease causes mixed upper and lower motor neurone signs with no sensory loss; riluzole and non-invasive ventilation prolong survival.
Raised Intracranial Pressure, Brain Tumours, Cranial Nerve Lesions & Spinal Cord Disorders
Raised Intracranial Pressure (ICP)
The skull is a rigid box, so a mass, oedema, blood or blocked CSF flow raises pressure once compensation fails (the Monro-Kellie doctrine).
- Features: headache worse on lying down, coughing and in the morning; vomiting; papilloedema; falling GCS; sixth nerve palsy (a "false localising" sign).
- Herniation: an expanding supratentorial mass causes uncal herniation with an ipsilateral fixed dilated pupil (third nerve compression) and contralateral weakness. Cushing's response (rising blood pressure with widening pulse pressure, bradycardia and irregular breathing) is a late, pre-terminal sign.
- Immediate management: ABCDE, head up at 30 degrees, avoid neck ties that obstruct venous return, treat seizures, and keep PaCO2 low-normal (about 4.5–5.0 kPa). Osmotherapy (mannitol or hypertonic saline) buys time before neurosurgery. Dexamethasone reduces vasogenic oedema around tumours but is not used in traumatic brain injury.
- Lumbar puncture is contraindicated when raised ICP from a mass lesion is suspected, until imaging excludes it.
Idiopathic Intracranial Hypertension (IIH)
Typically a young woman with obesity, with daily headache, transient visual obscurations, pulsatile tinnitus and bilateral papilloedema. MRI (with venography to exclude venous sinus thrombosis) is normal, and lumbar puncture shows a raised opening pressure with normal CSF. Associations include tetracyclines, retinoids and recent weight gain. Management: weight loss, acetazolamide, regular visual field monitoring; urgent surgery (CSF shunting, venous stenting or optic nerve sheath fenestration) if vision is threatened.
Brain Tumours
- Adults: metastases are the most common intracranial tumours (from lung, breast, melanoma, kidney and colon). The commonest malignant primary is glioblastoma; meningiomas are usually benign extra-axial tumours with a dural tail; vestibular schwannoma causes unilateral sensorineural hearing loss and tinnitus (bilateral tumours suggest neurofibromatosis type 2); pituitary adenomas cause visual field and hormonal problems.
- Children: most tumours are in the posterior fossa (pilocytic astrocytoma, medulloblastoma), presenting with headache, vomiting and ataxia.
- Presentation: progressive focal deficit, new seizures in adulthood, personality change, or raised ICP features.
Referral (NICE NG12):
- Adults: consider an urgent direct-access MRI brain (CT if MRI is contraindicated) within 2 weeks for progressive, subacute loss of central neurological function.
- Children and young people: consider a very urgent referral (within 48 hours) for newly abnormal cerebellar or other central neurological function.
New seizures also have driving implications (the patient must stop driving and notify the DVLA).
Cranial Nerve Lesions
| Lesion | Features | Key Points |
|---|---|---|
| Third nerve palsy | Ptosis, eye "down and out", diplopia | Pupil involved (dilated) + pain = compression, for example a posterior communicating artery aneurysm (urgent CT angiography). Pupil-sparing palsy is usually microvascular (diabetes, hypertension). |
| Fourth nerve palsy | Vertical diplopia, worse looking down (stairs, reading); head tilt away | Often trauma or congenital |
| Sixth nerve palsy | Failure of abduction, horizontal diplopia | Microvascular, or a false localising sign of raised ICP |
| Bell's palsy (seventh) | Sudden unilateral lower motor neurone facial weakness including the forehead; may have altered taste, hyperacusis, ear pain | See below |
| Upper motor neurone facial weakness | Forehead spared (bilateral cortical supply) | Think stroke; follow the stroke pathway |
| Trigeminal neuralgia | Brief electric-shock pains in V2 or V3, triggered by touch, eating or wind | Carbamazepine first-line; refer if atypical (sensory loss, age under 40, bilateral) |
Bell's Palsy
- Prednisolone within 72 hours of onset (for example 50 mg daily for 10 days, or 60 mg daily for 5 days then reducing).
- Eye care: lubricating drops by day, ointment and taping at night if the eye cannot close.
- Refer if there is no improvement after 3 weeks, other neurological signs, or features suggesting another cause (parotid mass, ear infection, cholesteatoma).
- Ramsay Hunt syndrome (varicella zoster): facial palsy with vesicles in the ear canal and ear pain; treat with an antiviral plus prednisolone and refer to ENT.
Horner's Syndrome
Partial ptosis, miosis and (depending on the level) anhidrosis on the affected side, from interruption of the sympathetic chain. Causes include Pancoast tumour, carotid artery dissection (a painful Horner's with neck pain needs urgent imaging), lateral medullary stroke, syringomyelia and neck surgery.
Spinal Cord Disorders
Cord lesions cause upper motor neurone signs below the level (spasticity, brisk reflexes, extensor plantars), a sensory level and bladder or bowel dysfunction. Acute cord compression from tumour, abscess, haematoma or disc needs emergency MRI (see sections 11.3 and 13.4).
| Syndrome | Cause | Pattern |
|---|---|---|
| Brown-Séquard (hemisection) | Penetrating trauma, tumour | Ipsilateral weakness and loss of vibration and proprioception; contralateral loss of pain and temperature |
| Anterior cord syndrome | Anterior spinal artery infarction (aortic surgery) | Weakness and loss of pain and temperature below the level; vibration and proprioception preserved |
| Central cord syndrome | Neck hyperextension in older people with spondylosis | Arms weaker than legs |
| Subacute combined degeneration | Vitamin B12 deficiency | Dorsal column loss (sensory ataxia, positive Romberg) with upper motor neurone weakness; replace B12 before folate |
| Syringomyelia | Fluid cavity in the cord (Chiari malformation) | "Cape-like" loss of pain and temperature with preserved light touch; wasting of hand muscles |
| Degenerative cervical myelopathy | Spondylosis compressing the cervical cord | Clumsy hands, gait unsteadiness, Hoffmann's sign; MRI and spinal surgical referral |
Motor Neurone Disease (MND)
Progressive degeneration of upper and lower motor neurones, usually after age 50.
- Features: a mixture of upper motor neurone (spasticity, brisk reflexes) and lower motor neurone signs (wasting, fasciculations), bulbar weakness (dysarthria, dysphagia), and weight loss. Sensation, eye movements and sphincters are spared.
- Types: amyotrophic lateral sclerosis (most common), progressive bulbar palsy, progressive muscular atrophy and primary lateral sclerosis; some patients develop frontotemporal dementia.
- Diagnosis: clinical with EMG (widespread denervation); exclude cervical myelopathy and multifocal motor neuropathy.
- Management: multidisciplinary care, riluzole (modest survival benefit), non-invasive ventilation for respiratory muscle weakness (improves survival and quality of life), gastrostomy for dysphagia and weight loss, and early advance care planning.
A 34-year-old woman wakes with weakness of the right side of her face. She cannot wrinkle her right forehead or close her right eye fully. Symptoms started 24 hours ago. Ear examination is normal and there are no other neurological signs. What is the most appropriate management?
Prednisolone with eye lubricants and night-time taping
Reassurance only, as most cases recover fully
Urgent CT head and assessment for thrombolysis as a stroke
Oral aciclovir 800 mg five times daily alone for 7 days
A 52-year-old man has a sudden severe headache and drooping of his left eyelid. The left eye is deviated down and out and the left pupil is dilated and unreactive. What is the most important next investigation?
Elective outpatient MRI of the orbits
Serum acetylcholine receptor antibody testing
HbA1c and 24-hour ambulatory blood pressure monitoring
Urgent CT angiography of the cerebral arteries
A 63-year-old man has 6 months of progressive weakness of his hands and legs, difficulty swallowing and weight loss. He has wasting and fasciculation of the hand muscles with brisk reflexes and extensor plantars. Sensation and eye movements are normal. What is the most likely diagnosis?
Myasthenia gravis
Guillain-Barré syndrome
Motor neurone disease
Multiple sclerosis
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