Ptosis

In Station 5 you may be asked to assess a patient presenting with eyelid drooping, double vision, or limb weakness.

1. Key History-Taking Points

Timing & Character

• Onset: since when, sudden vs gradual onset, intermittent vs constant
• Progression: getting worse over time?
• Diurnal variation: worse at the end of the day (classic for myasthenia gravis)
• Laterality: one or both eyelids affected

Ocular & Bulbar Symptoms

• Double vision: is it also worse at the end of the day? (fatiguable diplopia = myasthenia)
• Speech disturbance: slurring, nasal voice, voice fading with prolonged speech
• Difficulty swallowing: dysphagia, choking, nasal regurgitation
• Facial muscle weakness

Limb Weakness & Fatiguability

• Weakness of arms or legs — is it fatiguable (worse after exercise or as day progresses)?
• Shortness of breath: myasthenic crisis may impair respiratory muscles — a medical emergency

Myasthenia-Specific: Triggers & Precipitants

• Recent infection (commonest precipitant of myasthenic crisis)
• Drugs: recent antibiotics (aminoglycosides, fluoroquinolones), beta-blockers, calcium channel blockers, penicillamine (can induce MG)
• Low potassium (medication, poor intake)

Myotonic Dystrophy Screen

• Premature frontal balding
• Cataracts (visual disturbance)
• Heart problems (palpitations, syncope — cardiomyopathy, arrhythmia, heart block)
• Lung problems, recurrent chest infections (aspiration, bronchiectasis)
• GI problems: dysphagia, constipation, diarrhoea, reflux
• Diabetes (polyuria, polydipsia)
• Excessive daytime sleepiness (hypersomnia)
• Family history of weakness — anticipation means it may be worse in children

Horner’s Syndrome Screen

• Pancoast tumour: cough, haemoptysis, chest pain, significant smoking history, weight loss, night sweats
• Anhidrosis: loss of sweating on face, arms or trunk (localises the lesion)
• Neck: any trauma or surgery to the neck, neck pain
• Headache: carotid dissection (sudden severe neck or head pain), cavernous sinus pathology

General Neurological Screen

• Sensory loss, headache, seizures, tremor, unsteadiness
• Vascular risk factors (stroke causing CN III palsy or Horner’s): hypertension, diabetes, hypercholesterolaemia, smoking, atrial fibrillation

Past Medical, Drug & Family History

• PMH: autoimmune conditions (thyroid disease, RA, SLE, diabetes), cardiovascular risk factors
• Medications: include penicillamine specifically
• Family history: autoimmune disease, muscle weakness, myotonic dystrophy

2. Key Examination Findings

Inspection

• Ptosis: unilateral vs bilateral, symmetrical vs asymmetrical, partial vs complete
• Eye position: abducted and depressed = CN III palsy (unopposed lateral rectus and superior oblique)
• Pupils:
  • Dilated, unreactive = CN III palsy (loss of parasympathetic supply) — compressive cause until proven otherwise
  • Small (miosis) with intact reflexes = Horner’s syndrome
  • Normal size = myasthenia gravis, myotonic dystrophy

Eye Movements & Fatiguability

• Test all directions; ask patient if diplopia occurs
• Specifically test CN IV: ask to look down and inwards (superior oblique)
• Specifically test CN VI: ask to look laterally (lateral rectus)
• Observe for complex ophthalmoplegia
• Fatiguability test: ask patient to sustain upward gaze for 20 seconds — ptosis worsening = myasthenia gravis
• Ice pack test: apply ice to closed eyelid for 2 minutes — improvement in ptosis suggests myasthenia gravis

Pupils & Visual Examination

• Pupil reflexes (direct and consensual)
• RAPD (relative afferent pupillary defect — Marcus Gunn test)
• Visual fields
• Visual acuity
• Fundoscopy
• Temporal artery palpation if age >50 (giant cell arteritis — a cause of CN III palsy and visual loss)

Other Cranial Nerves

• CN V (facial sensation), CN VII (facial movements), CN VIII (hearing), CN IX/X (palate movement, gag), CN XI (trapezius/SCM), CN XII (tongue)

Myasthenia-Specific Tests

• Eye closure (peek sign): ask to close eyes — inability to sustain tight closure, lids slowly part
• Lip closure
• Neck flexion and extension against resistance
• Jaw supporting sign: patient supports their jaw with hand to aid mouth closure
• Fatiguable proximal limb weakness: test elbow flexion/extension, shoulder abduction; ask to perform 10–20 repetitions (“chicken wing” arm exercises) then retest — weaker after exercise
• Speech fatiguability: ask to count to 50 — voice fades or becomes nasal
• Inspect for: midline sternotomy scar (thymectomy), Cushingoid appearance (steroid use), NG tube or gastrostomy (PEG), spirometer at bedside
• Respiratory: assess chest expansion; offer FVC measurement
• Look for associated autoimmune conditions: thyroid signs, RA hands, SLE rash, diabetic fingerprick marks

Myotonic Dystrophy-Specific Tests

• Grip myotonia: shake patient’s hand — delay before grip release; ask to rapidly open and close fist
• Percussion myotonia: tap thenar eminence with tendon hammer — thumb flexes and sustains
• Face and neck: frontal balding, myopathic facies (long, wasted face), bilateral ptosis, cataracts; palpate temporalis and masseter on clenching (wasted and weak); palpate sternocleidomastoids (wasted and weak — swan neck); goitre
• Delayed eye opening: ask to close eyes tightly then open — delayed
• Chest: gynaecomastia, apex beat, pacemaker scar, auscultate heart (murmur), auscultate lungs (bronchiectasis)
• Pulse and diabetic fingerprick marks

Horner’s Syndrome-Specific Examination

• Hands: wasting of small muscles (T1), APB power, FDI power, sensation C8–T1, clubbing, DM fingerprick marks (Pancoast)
• Neck: scars (thyroidectomy/neck surgery), carotid pulse, lymphadenopathy, goitre, tracheal deviation, carotid bruits
• Axilla: scars (apical surgery)
• Chest: auscultate lungs (apical signs of Pancoast), heart sounds

General Neurological Assessment

• Tone, power, sensation (note: sensation is normal in myasthenia and myotonic dystrophy), reflexes (reduced/absent in myotonic dystrophy), coordination

3. Specific Investigations

Bloods

• AChR antibodies: positive in 80–90% of generalised MG
• Anti-MuSK antibodies: positive in 10–20%, often positive when AChR negative
• Antistriatal muscle antibodies: positive in ~90% with thymoma
• TFTs: Graves’ disease in 5% of MG; exclude thyroid eye disease as cause of ophthalmoplegia
• FBC, CRP: screen for infection (myasthenic crisis trigger)
• CK: normal in MG; elevated in myopathies
• U&E: hypokalaemia worsens MG
• Glucose / HbA1c: diabetes (mononeuritis multiplex, myotonic dystrophy)

Diagnostic Tests for Myasthenia

• Tensilon (edrophonium) test: IV anticholinesterase — look for improvement in ptosis within 30 seconds, lasting 2–3 minutes; requires cardiac monitoring (bradycardia, heart block, asystole) and resuscitation equipment
• Ice pack test: ice applied to closed eyelid for 2 minutes — ptosis improves in MG (cooling improves neuromuscular transmission)

Neurophysiology

• Repetitive nerve stimulation: decremental response in amplitude with repeated stimulation (MG); incremental response (LEMS)
• Single-fibre EMG: increased jitter — most sensitive test for MG
• EMG (myotonic dystrophy): dive-bomber pattern — waxing and waning potentials; repetitive discharges with minor stimulation

Imaging & Respiratory Function

• CT/MRI thymus: essential in all MG — 10–15% have thymoma (10% malignant), 90% have thymic hyperplasia
• CXR: mediastinal mass (thymoma), Pancoast tumour (apical lung mass), cardiomegaly (myotonic dystrophy)
• Spirometry (FVC): monitor respiratory muscle involvement; FVC <1 L = critical
• Saturations, ABG
• For Horner’s: MRI brain and spine (central), CT thorax (preganglionic — Pancoast), MRI/A head and neck + Carotid Doppler (postganglionic — dissection, cavernous sinus)
• For CN III palsy: urgent MRI/MRA/CTA if pupil dilated, brainstem signs, other CNs involved, or acute severe headache (posterior communicating artery aneurysm)

Pharmacological Pupil Tests (Horner’s Syndrome)

• Cocaine 4%: normal pupil dilates; affected pupil does not dilate at 60 minutes (confirms Horner’s)
• Apraclonidine 0.5%: normal pupil constricts; affected pupil dilates relatively (denervation hypersensitivity — confirms Horner’s)
• Hydroxyamphetamine 1%: pupil dilates if central or preganglionic lesion; does not dilate if postganglionic lesion (localises lesion)

4. Management

Myasthenia Gravis

• Identify and treat precipitant: infection, culprit drugs, medication non-compliance, hypokalaemia
• SALT assessment and NG/PEG feeding if bulbar involvement
• Anticholinesterases: pyridostigmine (first-line symptomatic therapy)
• Immunosuppression: prednisolone (with gastro- and bone protection); steroid-sparing agents — azathioprine, mycophenolate mofetil
• Acute/crisis treatment: plasma exchange (plasmapheresis), IV immunoglobulin (IVIG)
• Thymectomy: recommended in thymoma and in generalised MG in patients under 65
• Neurology referral; monitor FVC regularly

Myotonic Dystrophy

• MDT: neurology, ophthalmology, cardiology, respiratory, gastroenterology, endocrinology, SALT, physiotherapy, OT, psychiatry, geneticist, GP
• Myotonia: phenytoin, quinine, procainamide, mexiletine
• Manage complications: pacemaker for heart block; treat diabetes and obstructive sleep apnoea
• Screen relatives (autosomal dominant; anticipation)
• Surgical: cataract removal; note anaesthesia is high risk in myotonic dystrophy

CN III Palsy

• If compressive (dilated pupil), brainstem signs, or acute severe headache: urgent MRI/MRA/CTA; neurosurgery referral for aneurysm coiling/clipping
• If pupil-sparing isolated CN III with vascular risk factors: optimise cardiovascular risk factors; no driving, climbing or heavy machinery; eye patch or prism for diplopia; review at 3 months; MRI if not recovered

Horner’s Syndrome

• Treat the underlying cause (localise lesion first — central/preganglionic/postganglionic)
• Urgent imaging if carotid dissection or Pancoast tumour suspected

Ptosis Cheat Sheet