Neurology

Clinical Assessment

Introduction

It is so important to take a detailed skilled history and an accurate timeline of problems as they have arisen. Neurological diagnosis is 90% historical supplemented with signs and imaging and other tests. In some scenarios such as TIA or a seizure the history may well be all the evidence that there is to go on. Take your time over it. Be forensic in your questioning almost like a witness statement after a serious crime. What happened. Get witness testimony either from available family or contact neighbours or friends (with the patient's permission).

The core questions

  • where is the lesion - use the history, clinical signs and knowledge of functional neuroanatomy
  • What is the lesion - the speed of onset, resolution, periodicity helps, age of person, risk factor presence of absence
  • How do I treat it

Symptoms and sign timings and Periodicity

  • Instant or over few seconds
    • Vascular e.g. SAH, TIA, Stroke (Negative neurology)
    • Electrical - seizure (Positive neurology)
  • Hours to Days- Inflammation
    • Demyelinating plaque with MS, ADEM, Transverse myelitis
    • Infection e.g. Viral Encephalitis, Meningitis
  • Weeks to Months
    • Motor neurone disease
    • Malignant neoplasm - Aggressive primary brain tumour or Metastatic disease
    • Creutzfeldt Jacob disease
    • Subacute combined degeneration
  • Months to Years
    • Alzheimer's disease
    • Parkinson's disease and other degenerative diseases
    • Slow growing Primary brain tumour e.g. meningioma
  • The duration of Symptoms and periodicity helps too
    • Resolution to normal within minutes with later recurrences: Epilepsy, TIA
    • Worst at onset and then slowly improves with time over days/weeks : Stroke, Multiple sclerosis, Inflammatory
    • Diurnal - Myasthenia gravis weakness worsens with day, Headache of space occupying lesion gets better to recur on waking next morning, Episodes lasting days followed by resolution and then further episodes, Remitting relapsing MS

Neurological examination

Introduction

The approach varies greatly be it in the outpatient clinic, the acute assessment unit or the HDU or ITU. The neurological exam has to be matched and appropriate to answer the questions that are asked either by the clinical case or by the examiner. In the clinical case these are typically - where is the lesion, what is the cause and how do I treat it ? You therefore need to have learned the basic building blocks of the neurological exam and be able to improvise as needed. Talking sense about findings is also important. You will not win points for suggesting that a bilateral leg weakness is a stroke as your first differential. Having a basic understanding of neurological pathways and some basic anatomy will go a long way to success. It is therefore important to be able to extract as much neurological information that one can be it from a confused patient, a comatose patient or a very compliant and helpful patient. The neurological exam is often too large and time consuming to do even for most fastidious neurologists who focus instead on the questions mentioned and extract exactly the examinations that will answer these questions they wish to answer. In exams you might be asked to do small snippets of an exam or be asked to address a single question.

Break it up into its constituent parts.

  • Higher functions
  • Motor
  • Sensory
  • Visual
  • Cerebellar
  • Cranial nerves
  • Peripheral nerves

Higher level

  • The approach is general initial observational Dress - clean, unkempt, soiled, unshaven
  • Mannerism - anxious, tics, labile emotions, bewildered, mania, depression, restless
  • Behaviour - inappropriate e.g. violence, urinating/defaecating inappropriately

The Comatose patient - Glasgow coma scale

This was initially produced by neurosurgeons in Glasgow in the early 1970s before CT scanning was invented in order to pick those patients who needed urgent neurosurgical intervention. It has survived the test of time thanks to its usefulness and provides a useful framework to think about patients with suspected intracranial pathology and coma. Changes are important as well as absolute values and can suggest urgent action or referral needed. Do not just give a number but be able to describe the scores themselves. Even the dead get 3 points. Stroke patients with aphasia loose 5 points automatically but otherwise maybe awake, even mobile but non verbally communicable.
  • Eye Opening
    • Spontaneous 4
    • To speech 3
    • To pain 2
    • no response 1
  • Best Motor Response
    • To Verbal Command obeys 6
    • To Painful Stimulus
    • localises pain 5
    • flexion-withdrawal 4
    • flexion-abnormal 3
    • extension 2
    • no response 1
  • Best Verbal Response
    • oriented and converses 5
    • disoriented and converses 4
    • inappropriate words 3
    • incomprehensible sounds 2
    • no response 1

Confusion

  • This is where one should start if one is presented a patient where there is a problem with memory or confusion is suspected.
  • Try if the patient is rousable with a GCS > 12. Remember that many misinterpret the dysphasic patient with the delirious patient.
  • As you work your way through the MTS you will soon get an idea if the issue is language or cognition.
  • Start with a few questions on patient's name, age and date of birth, what time it is, day, month and year.
  • A basic "abbreviated" MTS is fine generally. It may seem superfluous when clerking an 80 year old in for heart failure but if they are confused several nights later one can compare to see if it is new or that was the admission baseline. Delirium is a bad prognostic indicator.
  • Mini mental state
    • What is your age? (1 point)
    • What is the time to the nearest hour? (1 point)
    • Give the patient an address, and ask him or her to repeat it at the end of the test. (1 point) e.g. 42 West Street
    • What is the year? (1 point)
    • What is the name of the hospital or number of the residence where the patient is situated? (1 point)
    • Can the patient recognise two persons (the doctor, nurse, home help, etc.)? (1 point)
    • What is your date of birth? (day and month sufficient) (1 point)
    • In what year did World War 1 begin? (1 point) (other dates can be used, with a preference for dates some time in the past.)
    • Name the present monarch/dictator/prime minister/president. (1 point) (Alternatively, the question "When did you come to [this country]? " has been suggested)
    • Count backwards from 20 down to 1. (1 point)
  • A more reproducible way is to use the MMSE

High Functions

Speech

Introduction

  • Language is mainly produced by the dominant cortex which is the left side in right handers and the right side in 50% of left handers.
  • Various parts of the left cortex are involved and these are termed

Anatomy of speech

  • Broca's area - inferior frontal lobe below the motor strip
  • Wernicke's area - posterior temporal lobe and neighbouring parietal lobe
  • Arcuate fasciculus which connects the two

Pathway

  • Sound arrives into Heschl's gyrus (primary auditory cortex) of the superior temporal lobe
  • Sounds processed in Wernicke's area - posterior temporal lobe and neighbouring parietal lobe and decoded into words.
  • Connected closely to limbic system for emotion and frontal lobe for semantics (meaning).
  • Brocas's area in the frontal lobe and close to premotor and motor cortex for mouth and larynx/pharynx generates speech
  • Arcuate fasciculus which connects the two
  • Physiology is incompletely understood but enough to do basic examination

Types of Dysphasia

  • Aphasia - no speech produced when there is damage to a large area of left frontal/temporal/parietal usually a MCA infarction
  • Expressive dysphasia - reduced words, hesitant, non fluent non grammatical speech. Understands simple verbal commands (do not give visual clues) e.g. touch your nose, touch your right ear with your left hand. Communication by writing also usually affected. Damage to Brocas's area just below the motor strip in the frontal lobe. Associated right hemiparesis.
  • Receptive dysphasia - comprehension is affected but can produce some normal speech. Impaired naming. Impaired reading/writing. Damage to Wernicke's area. May have associated hemianopia.
  • Conduction dysphasia - cannot repeat words or phrases. As them to repeat "no ifs ands or buts" Involves arcuate fasciculus between speech areas or a large area of damage
  • Commonest causes are stroke (ischaemic and haemorrhage) and space occupying lesions affecting the grey matter.
  • Language deficits such as aphasia may be the predominant feature in some dementias - primary progressive aphasia

Dyslexia and Dysgraphia

  • Inability to read and communicate by writing. Usually a dominant parietal lobe deficit
  • Usually accompanies a language deficit. Those with dysphasia usually have matching dyslexia and dysgraphia too

Dysarthria and dysphonia

  • Problems with articulation of speech and volume
  • Ask patient to say "British constitution", "west register street"
  • Problems with the movement of the mouth, palate, tongue such that speech is slurred and incoherent
  • Multiple causes and only a small subset are neurological
  • Not a "higher function" but usually just a motor/sensory issue

Causes

Non - neurological

  • Disease of the oropharynx and palate e.g. poor dentition, poor fitting dentures
  • Cleft palate, oral cancers, infections, bone disease, joint disease
  • Laryngeal disease - infections, cancers etc
  • Functional/Hysterical - sometimes seen - whispering speech. Exclude organic causes first.

Neurological

  • Cerebellar Scanning type speech - cerebellar disease, drugs such as alcohol, excess phenytoin etc
  • Motor weakness due to stroke or SOL affecting anywhere from motor cortex where conscious oropharyngeal movements are organised to the cranial nerve nuclei. Can be due to anterior or posterior circulation strokes as well as SOL.
  • Bulbar palsy - Nasal speech. fasciculating tongue, decreased jaw jerk. Seen with polio, MND, neuropathies
  • Pseudobulbar palsy - High pitched Donald duck speech, Increased jaw jerk, stiff spastic tongue. Seen with Bilateral stroke disease, MND
  • Neuropathies affecting lower cranial nerves e.g. polio, GBS
  • Myasthenia gravis can cause dysarthria and dysphonia

Other Higher level "cortical" functions

Apraxia

  • Inability to do a specific skilled task despite normal cognition, no ataxia, normal vision, motor and sensory function
  • Dressing apraxia - patient puts trousers on over head
  • Comb your hair - unable to do so, Button up shirt.
  • Functionally important as they can have implications on a patients ability to self care
  • Ideomotor apraxis due to a dominant parietal injury. Cannot perform complex tasks.

Agnosia

  • Inability to recognise objects e.g. a 1 pound coin or a key in the hand

Anosognosia

  • Patient does not comprehend that they have a neurological deficit. Seen with right cortical/parietal lesions most commonly strokes.
  • Despite a marked left hemiparesis patient will try to get out of chair to walk - leads to falls/injury.
  • Can lead to patients convincing unwary doctors they are fine and be discharged from A&E despite being unable to walk and actually should have been considered for thrombolysis.

Extinction

  • When stimuli presented bilaterally either visually or sensorial e.g. touch only one side is appreciated
  • Suggests a contralateral parietal lobe deficit

Assessment of Motor Function

Upper limb motor

Paralysis is a very useful and hard sign of neurological disease. One must immediately ask where the lesion is. Generally this will mean looking at the pattern of weakness as mentioned below, whether the weakness is Upper motor neurone or lower using tone and reflexes and plantar, the speed of onset of symptoms and accompanying sensory symptoms

Inspection

  • Always initially start looking for wasting, scars and fasciculations.
  • Feel muscle bulk and look for wasting. If marked quads wasting could measure thigh circumference.
  • Check symmetry of findings. Palpate muscles - are they tender ?

Pronator drift

  • Ask patient to hold arms out straight ahead horizontally with palms up and close eyes
  • If the affected side slowly pronates and elbow flexes and drifts down is a subtle sign of an UMN lesion on that side

Tone

  • Assess upper limb tone in the wrist and elbow. Get the patient to relax and distract with irregular movements.
  • Different types of altered tone associated with disease
    • Spasticity
      • Increased tone seen with pyramidal weakness classically is variable with velocity and distance joint moved.
      • High tone often gives way and has been called "clasp knife"
      • Best seen in forearm supination in upper limb and knee flexion in lower limb.
    • Extrapyramidal disease
      • Gives a more constant increase in tone through all movements and is called "lead pipe" rigidity.
      • Seen classically with parkinson's disease
      • If there is a superimposed tremor the increased tone may be called "coghwheel"
    • Gegenhaltan
      • An erratic increase in tone in those with frontal lobe dysfunction also called "paratonia"

Power - Upper limb

  • Shoulder abduction before 90 degrees is supraspinatus muscle and suprascapular nerve and C5 root
  • Shoulder abduction beyond 90 degrees is deltoid supplied by axillary nerve C5
  • Shoulder adduction is by multiple muscles/nerves and generally C7 root and adds little
  • Shoulder external rotation is by infraspinatus and suprascapular nerve and C5 root
  • Shoulder internal rotation is subscapularis muscle and subscapular nerve and C5 root
  • Elbow flexion biceps muscle and Musculocutaenous nerve and C6 and some C5 roots
  • Elbow flexion half pronated (holding a cup) is radial nerve supply to brachioradialis and is most C6 and some C5
  • Elbow extension is by triceps supplied by radial nerve and C7 root
  • Wrist flexion flexor carpi radialis (Median) Flexor carpi ulnaris (ulnar) and C7/8 roots
  • Wrist extension extensor carpi radialis longus and external carpi and ulnaris radial nerve/posterior interosseous C7
  • Finger flexion : Median and Ulnar nerves to Long and short flexors
  • Finger extension: extensor digitorum Posterior interosseous nerve (radial) C7
  • Finger abduction: Ulnar nerve (dorsal interossei) T1 (DAB)
  • Finger adduction: Ulnar nerve (palmar interossei) T1 (PAD)
  • Thumb opposition: Opponens pollicis Median nerve T1
  • Thumb flexion : Flexor pollicis brevis Median nerve T1
  • Thumb adduction: Adductor pollicis T1

Individual nerves - Motor

  • Median nerve: Opponens pollicis Abduction and opposition of thumb and thumb flexion and T1 nerve root
  • Ulnar nerve: Flexion of ring and little finger (medial two lumbricals) and adduction and abduction of fingers (dorsal interossei) and thumb adduction T1
  • Radial nerve: "Wrist drop" Wrist extension by long and short extensors C8

Reflexes - Tests the integrity of the normal reflex arc and the effect of higher centres on it

  • Biceps C5(6)
  • Supinator C(5)6
  • Triceps C6/7
  • Hoffman reflex is hyperreflexia - flick DIP of the index finger and thumb adducts
  • Record as -,+,++,+++

Coordination

  • Finger-Nose - test for coordination
    • Touch tip of nose and then my finger, eyes open. Examiner should move finger around as a moving target
    • Ask patient to touch nose with eyes closed to assess proprioceptive deficit as a cause of ataxia
  • Rapid movements
    • Touch left palm with right palm and then supinate right hand to touch left palm with dorsum of right hand. Alternative quickly and then switch sides
    • Difficulty called dysdiadochokinesia and is a sign of cerebellar disease

Interpretation

  • Increased suggests a loss of inhibition from higher pathways with an Upper motor lesion
  • Be able to draw a reflex arc with afferent and efferent pathways
  • Absence suggests a lower motor neurone lesion e.g. neuropathy such as Guillain Barre syndrome

Absent reflexes

  • Peripheral Neuropathy e.g. GBS
  • Disease of the neuromuscular junction
  • Myopathy

Lower limb

Inspection

  • look for deformity, scars, wasting, fasciculations, pick up leg asking first to check if it is not painful and
  • look at heel for ulcers and sole of feet for ulcers which might suggest a sensory neuropathy

Tone

  • Assess tone by first rolling the leg and then a sudden lift up at the knee and see if the ankle comes off the bed. Could suggest increased tone.
  • Get a feel for tone at ankle and knee and don't forget to test for clonus either now or after having demonstrated increased reflexes

Power - lower limb

  • Hip flexion Femoral nerve Iliopsoas "Pull knee up" L1/2 roots
  • Hip extension Gluteus maximus Inferior gluteal nerve "Force thigh down onto bed" L5/S1 roots
  • Knee flexion L5/S1 hamstrings Sciatic nerve "bend knee"
  • Knee extension L3/4 Femoral nerve quadriceps "straighten knee"
  • Ankle plantar flexion S1 sciatic gastrocnemius" push foot down"
  • Ankle dorsiflexion L4/5 Sciatic via common peroneal nerve. Tibialis anterior "pull foot up"
  • Toe flexion; S1/2 "Curl down toes" sciatic small muscles of foot
  • Toe extension L5 S1 Sciatic nerve toe extensors "curl toes up"

Reflexes

  • Knee : L3/L4
  • Ankle : S1/S2
  • Babinski - rub pen along lateral border and toes should curl
  • If reflexes are increased look for clonus at the ankle and patella
  • If reflexes are not found then try using reinforcement

Coordination

  • Heel shin test
    • Same as finger nose in many ways but using feet
    • Run right heel along left shin and lift off and place on left patella and run it down again. Alternate sides.
    • Can even ask patient to touch examiners finger with large toe
    • Ask patient to place one heel on alternate patella with eyes closed
  • Heel-toe gait
    • An under-utilised tests of motor dysfunction - formerly a test of acute alcohol intoxication a well known depressant of cerebellar function
    • Patient walks with heel to toe. Look for ataxia. A useful tests of neurological impairment

Interpretation

  • Patterns of weakness to recognise(once weakness is found use tone and reflexes to determine if UMN or LMN)
  • Pyramidal e.g. stroke : Upper limb extensors weaker than flexors, lower limb flexors weaker than extensors
  • Proximal weakness: Unable to raised arms above head, get out of chair - suggests a myopathic weakness or Myasthenia or Guillan Barre syndrome
  • Fatiguable weakness : Myasthenia gravis
  • Distal symmetrical weakness: Peripheral neuropathy or Inclusion body myositis
  • Hemiparesis Face/arm/leg : suggests contralateral intracranial pathology
  • Hemiparesis Arm and Leg: Contralateral intracranial pathology or cervical cord pathology
  • Weakness both legs - suggests cord or cauda equina damage
  • Hemiparesis and contralateral cranial nerve signs suggests brainstem lesion e.g. right IIIrd nerve and C/L hemiparesis

Radiculopathy

  • C5 - radial side of forearm and reduced biceps reflex and power
  • C6 - deficit in thumb and first finger and decreased bicep and bracioradialis
  • C7 - deficit in middle and ring finger and reduced triceps jerk
  • C8 - Deficit in little finger and reflexes are normal
  • T1 - T12 - pain in distribution but no weakness. Can cause chest wall pain. Mistaken as cardiac pain.
  • L2 - sensory deficit lateral and anterior thigh weak psoas and quadriceps. Reflexes normal
  • L3 - sensory deficit lower medial thigh weak psoas and quadriceps. Reduced knee jerk
  • L4 - sensory deficit medial lower leg. Decreased knee jerk
  • L5 - Lateral lower leg. Weak. No reflex abnormality
  • S1 - lateral foot and with weak gastrocnemius. Reduced ankle jerk

Cerebellar disease

Hemispheric signs

  • Dysarthria - Monotonous scanning or even staccato speech
  • Broad based unsteady speech
  • Past pointing - finger nose test
  • Hypotonia and Pendular reflexes
  • Truncal and limb Ataxia - walking toe to heel
  • Nystagmus worst to affected side

Causes

  • Stroke (haemorrhage or infarct)
  • Tumour - primary, metastases, paraneoplastic
  • Drug toxicity especially common antiepilepsy drugs, alcohol
  • Degeneration
  • Multiple sclerosis

Cerebellar Vermis (midline signs)

  • Impaired truncal and walking balance
  • Poor heel toe walking impossible
  • Wide based gait
  • Acute and chronic alcoholism or a tumour on the vermis is main cause

Sensation

Introduction

  • Sensation passes into the cord through the posterior root. It is carried initially either through the dorsal columns or spinothalamic tracts.
  • Conscious sensation is appreciated at the level of the sensory cortex.
  • Generally the minimum for cutaneous sensation is pinprick and light touch (cotton wool) over the nerve dermatomes comparing right and left
  • Suspected dissociated sensory loss requires testing for temperature as well as proprioception
  • You do need to have an idea of dermatomes but do this by remembering a few landmarks

Proprioception

Simple Testing

  • Tests the dorsal columns which also carry some vibration and touch sensation. Dorsal columns remain on same side of the sensory loss of the cord and only cross over in the medulla at the foramen magnum
  • Choose distal joint and move proximal. Hold joint by side and isolate joints above and below so that only one is moved. Ask patient to describe orientation of the digit or toe or foot. With eyes closed get patient to touch nose.

Romberg test

  • Patient stands with feet together. Push to chest to see if patient can maintain stance. If unable to then this is instability which could be for a variety of reasons
  • Repeat with eyes closed and see and if this makes a marked difference then suggests that visual input vital to maintain posture and there is a problem with dorsal column function carrying proprioception information

Vibration

  • Use a 128 Hz tuning fork and apply to distal bony points e.g. bony part of big toe, medial malleolus, patella
  • See if a vibrating can be distinguished from a non vibrating fork

Temperature

  • Assesses spinothalamic tracts which cross over to other side of cord very quickly after entering
  • Usually the coolness of the tuning fork is used and see if the patient can perceive it

Fine touch

  • Use a cotton wool in each of the dermatomal areas or any area of decreased sensation working to that with normal sensation. Tests Dorsal columns

Pinprick

  • Use disposable pins. Move from areas with sensory loss to normal. Spinothalamic

Patterns of Sensory loss

  • Sensory loss - over one side of body face/arm and leg is seen with contralateral intracranial pathology
  • Symmetrical cape like loss of pain and temperature over shoulders and hands suggests syringomyelia
  • Loss of proprioception suggests B12 involvement with SACD or Tabes dorsalis
  • Glove and Stocking loss suggests peripheral neuropathy
  • Sensory loss below a certain area symmetrically suggests spinal cord disease
  • Reduced perianal sensation suggests cauda equina damage

Perineal Examination

  • Becomes important when there is concern that lower sacral nerves have been affected usually by a suspected cauda equina lesion
  • Ask about urinary incontinence or overflow or retention and erectile dysfunction
  • Do a rectal exam and ask patient to squeeze on your finger looking for signs of weakness

Neurophthalmology

Introduction

Retinal anatomy/physiology should be known

  • Cones centrally do colour
  • Rods peripherally do visibility in poor light
  • Optic nerve enters eye on the nasal side
  • Most cones are concentrated at the macula

Know

  • The optic pathways must be known well and you must be able to draw them
  • Role of the brainstem in controlling eye movements
  • Anatomy of III/IV/VI nuclei and their interconnections

General Examination

  • Ptosis
    • Partial ptosis:Horner's syndrome, Congenital, Age related, Myasthenia gravis, Myotonic dystrophy, Myopathy
    • Full ptosis : IIIrd nerve lesion
  • Lid retraction
    • Grave's disease causing thyrotoxicosis
  • Proptosis
    • Grave's Thyroid eye disease
    • Retroorbital tumour - optic nerve glioma, dermoid, haemangioma
    • Carotid-cavernous fistula
    • Orbital inflammation
    • Orbital cellulitis
  • Enophthalmos
    • Horner's syndrome

Pupils

Normal response

  • Light reflex
    • With patient staring into distance shine a bright light into the eye.
    • This requires a functioning eye and optic pathway and optic radiations.
    • Fibres go to the midbrain. Here they synapse with Edinger Westphall nucleus and parasympathetic pupilloconstrictor fibres go via the IIIrd never to cause bilateral pupillary constriction.
    • Impaired with Argyll Robertson pupil.
    • Ensure you can test for a Relative afferent pupillary defect (RAPD)

    Accommodation

    • Look into distance and then focus on finger 10 cm away. Should constrict and adduct
    • Arises in the frontal lobes and travels efferently through the same pathways as for light.

Look for

  • Miosis : Opiates, Senile miosis, Horner's syndrome
  • Mydriasis : Cocaine, Adrenaline, Anticholinergics, IIIrd nerve lesion
  • Argyll robertson pupils: Miosed irregular pupils which accommodates but no light reaction seen with neurosyphils and diabetes and midbrain tumours
  • Holmes-Adie pupil - unilateral semidilated pupils which constricts slowly to light or accommodation. Parasympathetic lesion. Seen in young woman with reduced deep tendon reflexes.

Acuity

  • Should be done in each eye in turn. Either a snellen chart or some other reproducible assessment e.g. Small newsprint at 30 cm. Patient is allowed to wear normal reading glasses and if these are not present a pinhole should be used. If one cannot see even large headline newsprint at 30 cms then try finger counting. If cannot see that then try hand waving or do they have any light perception at all.
  • Snellen chart : Read chart at 6m. Record at which distance from the chart they should be legible and record as 6/60 (what is normally seen at 60m is the smallest thing that can be read at 6m)
  • Hand held chart at 30 cm and record smallest print size N.5 , N.6 etc

    Causes of reduced VA (start from front of eye)

    • Corneal ulcer or oedema or other disease
    • Cataract
    • Vitreous haemorrhage
    • Retinal haemorrhage or infarction
    • Optic neuropathy
      • Demyelination
      • Ischaemic
      • Compression
    • Pathology to optic radiations
    • Occipital lobe disease
  • Milder forms of optic nerve damage may present with
    • A central scotoma
    • Decreased VA
    • Decreased colour perception
    • Relative afferent pupil defect
  • Optic neuritis - inflamed nerve with visual loss, eye pain, altered colour vision, swollen disc - Multiple sclerosis, Idiopathic
  • Optic atrophy - pale disc due to loss fo axons due to nerve damage. See table for causes. Affected have reduced acuity and reduced colour vision.
  • Relative afferent pupil defect - Torch is swung from eye to eye, Normal Eye constricts to light and then dilates when light removed. Other eye does the same as shared pathways. However good eye continues to dilate when light shone in bad eye. Marcus Gunn pupil

Visual fields

  • Most commonly used to look for hemianopia related to stroke or space occupying lesion. Remember light from the left of the midline is dealt with by the contralateral optic radiations and occipital cortex.
  • Gross field defects - sitting opposite. Ask patient to look directly at you. Move fingers into upper lateral quadrants and wiggle fingers at a time and see if patient can point to the moving finger. Then move both together presenting a bilateral stimulus. Do the same for lower lateral quadrants. Useful in acute stroke patients for screening for gross defects in those who are not able to do a more formal detailed exam. If there is no field loss but when movement is not appreciated when stimuli presented both sides this is visual inattention rather than hemianopia.
  • Confrontation - sitting opposite again get patient to remove glasses and to look directly at you. Cover opposing eyes - patient may be able to cover own. Use a white hat pin or simply using fingers and bring it in at 45 degree angles from each quadrant and test when the patient sees it. Look for the classical defects. A white pin is used as the peripheral rods are more receptive to monochromatic colours. Always start with the pin beyond the field of vision.
  • Macular sparing - important to document. If the pins is moved horizontally from hemianopia to the good side is it seen before the midline or not. If so then the macula is spared. This will be a less severe visual loss. Important in stroke.
  • Central vision : As this is mainly cones then a coloured red pins is used. Repeat the confrontation method. If there is a defect then try and map it out and see if it in one or both eyes.

Defects

  • Tunnel vision
    • Chronic papilloedema or glaucoma
  • Blind eye
    • Reduced VA in one eye.
    • See table for causes of monocular blindness
    • Usually due to an eye or optic nerve problem.
  • Bitemporal hemianopia
    • Both temporal fields are affected
    • Suggests a chiasmal lesion though true BTH is rare
    • Pituitary tumours, Craniopharyngiomas
  • Homonymous hemianopia
    • Defect lies behind the chiasma and may involve the optic radiations as they pass through parietal or temporal lobes to the occipital lobe
  • Homonymous quadrantonopia
    • Damage to Temporal lobe radiations causes superior quadrantonopia
    • Damage to Parietal lobe radiations causes an inferior quadrantonopia
  • Macular sparing
    • Damage to Occipital cortex may have sparing of the region for macula vision.
    • Seen with posterior circulation infarcts where the MCA sends a branch that supplies the crucial macular region.
  • Scotomas
    • Retinal disease or optic nerve : MS, Ischaemic or toxic optic neuropathy
    • retinal haemorrhage or infarction
  • Altitudinal defects
    • Where in one eye there is a deficit in the horizontal plane often due to a vascular lesion usually involving the upper or lower half of vision

Fundoscopy

  • Dark lesions
    • Retinitis pigmentosa
    • Laser burns
    • Melanoma
  • Macula
    • Cherry red with central retinal artery occlusion
  • Haemorrhages
    • Dot - microaneurysms
    • Blot - deep retinal bleeds from microaneurysms
    • Flame - superficial retinal bleeds
    • Subhyaloid - superficial (seen with SAH)
  • Yellowish lesions
    • Hard exudates - diabetes and HTN
    • Cotton wool spots - retinal infarcts, Diabetes, HIV, SLE
  • Optic disc (papilla)
    • Normally venous pulsations
    • Papilloedema (Visual acuity not affected until late)
      • Raised ICP (can be a late sign)
      • CO2 narcosis
      • Malignant hypertension
    • Papillitis (early acuity loss, colour vision, field defects)
      • MS, Idiopathic
    • Optic atrophy (acuity loss, field defects, colour vision impaired)
      • MS, Traumatic damage to ON, Neurosyphilis
      • Tobacco, Alcohol, Ethambutol,
      • Chronic Papilloedema
    • Deep cup
      • Chronic glaucoma

Eye movements***

  • Often the abnormality is very obvious from initial inspection. For more subtle or unclear situations test pursuit and saccadic eye movements.
  • Place a left hand on the patients forehead so they do not move their head. Ask them to follow an object held in your right hand.
  • Pursuit movements can be tested by simply getting the patient to follow your finger in the classic H pattern looking for any weakness. Note where diplopia is maximal. Close each eye on turn to see which one loses the outer false image. This is the weak eye.
  • Saccadic movements - place both hands at North west and south east and ask patient to flick quickly from one to another. Then South east to north west. Any disparity in vertical and horizontal speed of eye movements can be seen. With INO there is a marked horizontal slowness compared with vertical.
  • Convergence by moving finger towards bridge of pt's nose.
  • Test accommodation by patient looking into distance, then a finger 10cm from nose.
  • Shine light in from the side to gauge pupil's light reaction.
  • Assess both direct and consensual responses.
  • Assess afferent pupillary defect by moving light in arc from pupil to pupil.

Oculomotor nerve

Oculomotor (III) controls all the muscles except Lateral rectus and Superior oblique. The nerve originates in the midbrain and passes forwards and leaves midbrain anteriorly and passes close to the PCA on its way to the eye. A IIIrd nerve palsy will have several findings

  • Complete ptosis (in picture books the eye lid is taped up)
  • Pupil looks "down and out"
  • Pupil is dilated (except diabetes)

Causes

  • Posterior communicating artery aneurysm - may only come to attention when aneurysm leaks with a thunderclap headache
  • Diabetes (normal pupil)
  • Vasculitis
  • Midbrain pathology + Corticospinal tracts
  • Cavernous sinus disease
  • Head trauma

Trochlear Nerve

Trochlear nerve (IV) arise in the midbrain and controls superior oblique which pulls the eye down and in. Patient has difficulty descending stairs. Diplopia maximal on down and inward gaze.

Causes e.g. Head injury, Diabetes

Abducens Nerve

The abducens (VI) nerve arises in the pons and supplies only the lateral rectus for abducting the eye and so diplopia maximal in this direction. It has a long intracranial course and can therefore be vulnerable to trauma.

  • Idiopathic - unknown cause and resolves
  • Congenital
  • Pontine infarction or haemorrhage
  • Cavernous sinus disease
  • Malignancy
  • Middle ear infection
  • MS
  • Raised ICP - "false localising sign" as pathology on one side e.g. right SOL can cause a left VI nerve

Oculomotor and Trochlear palsy

This is rare but you might be asked how to distinguish. Ask the patient to Look down if the IV is inactive the eye intorts

Internuclear Ophthalmoplegia

  • Internuclear ophthalmoplegia (INO) is damage in the pathways (Medial longitudinal fasciculus) between the cranial nerve nuclei for III and VI which coordinate horizontal conjugate gaze.
    • Hold both fingers up on either side of the patient and ask them to flick quickly between each. There is failure of adduction of one eye and the abducting eye experiences nystagmus. The movement is possible when not done as a conjugate gaze.
    • Classically due to MS but also seen in pontine infarcts and diabetes

Vertical Gaze palsies

  • Vertical gaze palsies are rare but affect the IIIrd nerve and connections
    • Parinaud's syndrome - midbrain lesion. Lid retraction and poorly reactive pupils
    • Hydrocephalus
    • Pinealoma

Nystagmus

Introduction

  • Defined as abnormal involuntary, rapid, and repetitive movements of the eye

Aetiology

  • Usually originates from retinal disease, labyrinthine disease or brainstem/cerebellar disease
  • Nystagmus is named by its fast phase if it is jerky
  • It may not have a faster phase and be equal and so Pendular
  • Nystagmus is common and normal at extremes of gaze so avoid extremes

Examination

  • 1st degree - present only with deviation to one side
  • 2nd degree - present only with deviation to one side and midline
  • 3rd degree - present only with deviation all directions of gaze

Interpretation

  • Downbeat nystagmus suggests a lesion at the foramen magnum and cervicomedullary junction. Fast phase is down
  • Peripheral - e.g. Damage to labyrinth/vestibular nerve
  • Central (CNS) Nystagmus - Slow phase to right, fast phase to left. May be tinnitus and hearing loss, Vertigo and nystagmus settle together. Meniere's, vestibular neuronitis, vascular disease. Vertigo uncommon
  • Damage right cerebellum / brainstem connections - Fast phase to Right, slow phase to left, MS, Stroke, Malignancy, Wernicke's, Alcohol, Drugs

Cranial nerves

CN I: Olfactory

  • Test each nostril in turn with orange peel or essence bottles of coffee, vanilla, peppermint. Do not use smelling salts.
  • Affected in some localised and systemic diseases

Causes of loss of sense of smell

  • Sinusitis/Rhinitis
  • Meningioma
  • frontal tumour,
  • An early sign in Parkinson's disease and perhaps some dementias

CN II: Optic nerve

- see section on eye exam
  • Visual acuity
  • Visual fields
  • Pupil size
  • Pupil response to light
  • Pupil response to accommodation
  • Ophthalmoscopy

CN III, IV, VI: Oculomotor, Trochlear, Abducens - see eye section

CN V: Trigeminal

Basics

  • Mixed sensory (face, gums, teeth, cornea, sinuses) and motor nerve (mastication muscles)
  • Largest of the cranial nerves. Several brainstem nuclei.

Examination

  • Corneal reflex: patient looks up and away as you touch cornea with a wisp of cotton wool.
  • Look for afferent blink (VII) reflex in both eyes, ask if could feel it.
  • Facial sensation: sterile sharp item on forehead, cheek, jaw. Occiput and angle of jaw are supplied by C2.
  • Repeat with dull object. Ask to report sharp or dull.
  • If abnormal, then temperature [heated/ water-cooled tuning fork], light touch [cotton].
  • Motor: pt opens mouth, clenches teeth (pterygoids).
  • Palpate temporal, masseter muscles as they clench.
  • Test jaw jerk: Finger on tip of jaw. Grip patellar hammer halfway up shaft and tap finger lightly. Usually nothing happens, or just a slight closure. If increased closure, think UMNL, especially pseudobulbar palsy.

Lesions seen with brainstem vascular disease, posterior fossa tumours, herpes simplex and zoster infections, MS can cause neuralgia, Trigeminal neuralgia dealt with later on

    CN VII: Facial

    Basics

    • Nucleus lies in the pons

    Examination

    • Inspect facial droop or asymmetry. Subtle weaknesses may not be apparent until tested. Loss of nasolabial fold on affected side. Unable to close eye.
    • Facial expression muscles: pt looks up and wrinkles forehead. Examine wrinkling loss.
    • Feel muscle strength by pushing down on each side [UMN preserved because of bilateral innervation].
    • Pt shuts eyes tightly: Try to open, compare each side.
    • Pt grins, ask patient to whistle, puff cheeks. Ask to close mouth and try to move lips apart.
    • Corneal Blink reflex already done. See CN V

    Causes

    • LMN - Bells palsy, parotid tumour, Herpes Zoster (Ramsay Hunt syndrome with vesicles in outer ear)
    • UMN - Stroke, SOL

      CN VIII: Vestibulocochlear

      Basics

      • Hearing, Balance
      • Nucleus in the Pons

      Examination

      • Rub one hand's fingers with noise on one side, other hand noiselessly. Ask pt. which ear they hear you rubbing. Repeat with louder intensity, watching for abnormality.
      • Weber's test: Lateralisation. 512/ 1024 Hz [256 if deaf] vibrating fork on top of patients head/ forehead. "Where do you hear sound coming from?" Normal reply is midline.
      • Rinne's test: Air vs. Bone Conduction
      • 512/ 1024 Hz [256 if deaf] vibrating fork on mastoid behind ear. Ask when stop hearing it.
      • When stop hearing it, move to the patients ear so can hear it.
      • Normal: air conduction [ear] better than bone conduction [mastoid].
      • If indicated, look at external auditory canals, eardrums.

      CN IX, X: Glossopharyngeal, Vagus

      Basics

      • Both Lie in the medulla

      Examination

      • Voice: hoarse or nasal. Patient. swallows, coughs (bovine cough: recurrent laryngeal).
      • Examine palate for uvular displacement. (unilateral lesion: uvula drawn to normal side).
      • Pt says "Ah": symmetrical soft palate movement.
      • Gag reflex [sensory IX, motor X]: Stimulate back of throat each side. Normal to gag each time.

      CN XI: Accessory

      Basics

      • Lies in the medulla

      Examination

      • From behind, examine for trapezius atrophy, asymmetry.
      • Pt. shrugs shoulders (trapezius).
      • Pt. turns head against resistance: watch, palpate SCM on opposite side.

      CN XII: Hypoglossal

      Basics

      • Nucleus lies in the medulla

      Examination

      • Listen to articulation.
      • Inspect tongue in mouth for wasting, fasciculations.
      • Protrude tongue: unilateral deviates to affected side.