HINTS FOR THE NEUROLOGY STATION
•Ensure that you pay close attention to the lead-in statement, as this will guide your examination. Once you have decided on a system, be efficient with your time for this.
•Neurology cases lend themselves to being spot diagnoses (e.g. myotonic dystrophy, Parkinson’ s disease [PD], old polio and myasthenia gravis). Therefore, be alert from the moment you walk into the room.
•Looking around the bed is very relevant in neurology (e.g. calipers, walking aids, devices for measuring forced vital capacity [FVC]).
•If you spot an obvious deformity (claw hand, wrist drop, Charcot’ s joint), be sure to direct your examination towards this.
•When commenting on power, use the Medical Research Council (MRC) scale to grade it.
•Neurology is often thought of as being a particularly difficult station, but if you work on the premise that you are trying to find the site of the lesion (e.g. cerebrum, cerebellum, brainstem, spinal cord, anterior horn, peripheral nerve or muscle) and then consider the differential diagnosis, you will demonstrate to the examiners that you are organised and pragmatic.
•Have set routines for examining the cranial nerves and the peripheral nervous system (upper limb and lower limb), but be prepared to adapt your examination (e.g. you may be asked to examine just cranial nerves III– VII). Neurology particularly lends itself to this type of adjustment.
•You will earn yourself extra marks if you look for the underlying pathology; e.g. blood glucose pinprick marks, granuloma annulare and cataracts in a case of peripheral neuropathy indicate that diabetes is the underlying cause.
•If you are unable to elicit reflexes, you must demonstrate that you have attempted to elicit them with reinforcement.
•When assessing sensation, be sure to check for normal sensation on the chest first. Compare normal sensation with the peripheral sensation (i.e. ask if the sensation is different to the sensation on the chest, not merely ‘ Can you feel it?’ ).
•It is important to decide early whether to assess sensation in a dermatomal or a peripheral (‘ glove and stocking’ ) pattern. This is not always possible. Therefore, start in a dermatomal distribution and move on to test glove and stocking pattern if peripherally confluent.
•Although the patients may have been examined many times and will be well versed in the routines, you must give clear instructions about what you want them to do (remember that they’ re not allowed to help you).
•At the end of the examination, ask to examine other relevant neurological areas (including fundoscopy).
•If you believe that the diagnosis is related to vascular disease, then also mention that you would like to examine the cardiovascular system for risk factors.
Please examine this patient who has had problems with his balance, and recurrent falls over the past 6 months.
FINDINGS
•General: Action tremor
•Neurological: Ataxic gait, truncal ataxia, hypotonia, pendular reflexes, dysmetria, dysdiadochokinesis, nystagmus, slurred speech, heel– shin ataxia
•Extras:
•Features of multiple sclerosis (MS) (spastic paraparesis, sensory disturbance, internuclear ophthalmoplegia [INO])
•Stigmata of chronic liver disease
•Friedreich’ s ataxia (young patient, wheelchair/walking aids, pes cavus, kyphoscoliosis, absent ankle jerks with upgoing plantars)
PRESENTATION
This man has cerebellar dysfunction. He has an ataxic gait with nystagmus and dysarthria. He also has multiple stigmata of liver disease. The most likely cause is excess alcohol consumption.
CAUSES OF CEREBELLAR SYNDROME
•Multiple sclerosis
•Alcoholic cerebellar degeneration
•Posterior fossa space-occupying lesion
•Brainstem vascular lesion
•Inherited ataxias (e.g. Friedreich’ s) (note that the history would be longer than 6 months)
•Paraneoplastic syndromes
•Drugs (phenytoin)
INVESTIGATIONS
•Dependent on the presumed cause of cerebellar signs
•If multiple sclerosis is suspected,
•Cranial and spinal imaging (magnetic resonance imaging [MRI])
•Lumbar puncture (LP) (oligoclonal bands and protein in cerebrospinal fluid [CSF])
•Visual-evoked potentials
•Dependent on the cause of cerebellar syndrome
QUESTIONS
1.How would you identify the site of a cerebellar lesion from clinical findings?
•The cerebellum is divided into a midline vermis and two cerebellar hemispheres.
•Disease of the vermis leads to truncal ataxia and ataxic gait.
•Disease of a hemisphere causes ipsilateral dysmetria, dysdiadochokinesis, an intention tremor and fast-beat nystagmus towards the lesion.
•Multiple sclerosis (demyelination) can cause a global deficit.
2.What is Friedreich’ s ataxia?
•Autosomal recessive disorder; a trinucleotide repeat on chromosome 9.
•Degeneration of the spinocerebellar tract resulting in cerebellar signs.
•Corticospinal tract damage and peripheral nerve degeneration lead to absent ankle jerks with extensor plantars.
•Pes cavus, scoliosis and diabetes are common features. Other features include cardiomyopathy, cataracts and sensorineural deafness.
•Think of this in a younger patient.
KEY POINTS
•Prepare a speci?c examination for the cerebellar syndrome.
•Split the examination into two parts. First, ensure that you have demonstrated that the patient has cerebellar signs. Second, ensure that you have demonstrated that you have looked for specific underlying causes.
This patient has developed weakness. Please examine their upper limbs.
FINDINGS
•General: Walking aids, percutaneous endoscopic gastrostomy (PEG) tube, wasting/ oedema on affected side, upper limbs held in flexion, lower limbs held in extension
•Peripheral: Bruising (on warfarin), amiodarone facies, irregularly irregular pulse
•Increased tone
•Reduced power (use MRC grade for power)
•Hyperreflexia and extensor plantars
•Decreased sensation
•Hemianopia
•Extras:
•Observe for upper motor neurone (UMN) facial nerve lesion.
•Note any dysphasia/dysarthria.
•Neglect/visual or sensory inattention.
•Mention that you would like to perform a full cardiovascular examination.
PRESENTATION
This patient has a right-sided upper motor neurone lesion affecting arm, leg and face. The likely cause is a stroke, but I would include space-occupying lesion and demyelination in my differential diagnosis. I would like to examine his cardiovascular system, including blood pressure readings, in order to look for a predisposing cause. He mobilises with a frame.
•Comment on the side of stroke and the areas involved.
•Comment on any obvious underlying predisposing factors.
•Comment on functional status.
INVESTIGATIONS FOR STROKE
•Neuroimaging (computerised tomography [CT]/MRI)
•Blood pressure
•Fasting glucose/cholesterol
•Electrocardiogram (ECG)/24-hour tape
•Echocardiogram
•Carotid artery Doppler
MANAGEMENT OF STROKE
•Thrombolysis (provided meets criteria).
•High-dose aspirin for 2 weeks, followed by clopidogrel for secondary prevention.
•Use a tool such as the NIH Stroke Scale to assess patient functionality at onset of stroke and at regular intervals after onset.
•Speech and language assessment.
•Management of predisposing factors and secondary prevention.
•Rehabilitation (occupational therapist [OT] and physiotherapy).
•Psychological and nutritional support.
•Measure progress with tools, e.g. Modified Rankin Score to assess prognosis.
1.What extra investigations are merited in young patients with a proven stroke?
•Thrombophilia screen
•Homocystine levels (postulated to promote atherosclerosis leading to stroke)
•Bubble echo (looking for a patent foramen ovale)
2.Do you know of any alternative anticoagulants to warfarin in patients who may have suffered a thrombotic stroke and have atrial fibrillation?
•Factor 10A inhibitors, e.g. apixaban and rivoroxaban.
•Dabigitran is a direct thrombin inhibitor (Factor IIa).
3.What is ‘ lateral medullary syndrome’ ?
•This is also known as Wallenberg’ s syndrome; it is caused by a brainstem stroke in the territory of the vertebral or posterior inferior cerebellar artery.
•Clinical features include
•Ipsilateral signs: Horner’ s syndrome, nystagmus, facial sensory impairment, ataxia and diplopia
•Contralateral signs: Pain and temperature loss over opposite arm and trunk (spinothalamic tract)
4.Discuss the advantages and disadvantages of novel anticoagulant therapies versus warfarin.
•Advantages
•Rapid onset of action – no need for bridging therapy.
•Fewer interactions with other medications/foods.
•Provided patients are compliant, they are always in the therapeutic window (unlike warfarin).
•No need for repeated blood tests to monitor the international normalised ratio (INR).
•Disadvantages
•Not safe in renal failure – dose dependent on estimated glomerular filtration rate (eGFR). Consult the British National Formulary (BNF) before prescribing.
KEY POINTS
•Establish the diagnosis and the cerebral area(s) affected.
•Mention to examiners that you would like to examine the cardiovascular system (for risk factors).
•Look for evidence of disability caused by the hemiparesis and comment on this.
REFERENCE
National Institute for Health and Care Excellence. (2010) Guidance QS2. Stroke in adults. Available from https://www.nice.org.uk/guidance/qs2/resources/stroke-in-adults-58292707525. Accessed 24 August 2016.
This patient, who is undergoing preoperative evaluation for elective surgery, is noted to have bilateral ptosis. Please examine their face and proceed.
FINDINGS
•General: ‘ Myopathic facies’ , wasting of sternocleidomastoid muscle group, speech (nasal or dysarthric), pinprick marks on fingertips from blood glucose testing
•Face: Bilateral ptosis, wasting of facial muscles with hollowing of temporal fossae and cheeks, frontal baldness, smooth forehead, cataracts
•Hands: Generalised weakness and wasting of upper limbs
•Key points: The candidate must be able to demonstrate myotonia.
•Grip myotonia:
•Ask the patient to quickly clench their fist as tightly as possible and then immediately release. This will demonstrate a slow release instead of rapid finger extension.
•This can also be demonstrated by shaking the patient’ s hand, which will demonstrate slow release of grip.
•Percussion myotonia: This can be demonstrated by using a tendon hammer to tap the thenar eminence, which will display a muscle twitch, followed by a slow relaxation of the muscle group.
PRESENTATION
On examination, this patient has evidence of myotonic dystrophy. This is demonstrated by the myopathic facies: elongated face, wasting of temporal muscles, frontal balding and bilateral ptosis. I have demonstrated evidence of myotonia, as there was slow release of grip after shaking his hand and percussion myotonia on tapping the thenar eminence.
•Comment on any evidence of complications (see below).
DIAGNOSIS
•Electromyography (EMG)
•Muscle biopsy
•Genetic analysis: Expansion of cytosine– thymine– guanine (CTG) triple repeat on long arm of chromosome 19
MANAGEMENT
•Reduction of myotonia using drugs such as phenytoin, mexiletine and carbamazepine (these drugs are sodium channel blockers; they reduce myotonia but may increase weakness)
•Identification and treatment of associated complications (see below)
•Genetic counselling
•Avoidance of general anaesthesia where possible
1.List some complications associated with myotonic dystrophy.
•Cardiac
•Dilated cardiomyopathy, cardiac arrhythmias
•Respiratory
•Risk of aspiration due to muscle weakness; may require noninvasive ventilation due to myotonia affecting respiratory muscles
•Gastrointestinal
•Dysphagia, delayed gastric emptying
•Endocrine
•Increased risk of diabetes, thyroid dysfunction
•Reproductive
•Testicular atrophy, infertility
•Other
•Cataracts
2.What is the genetic basis of this condition?
•Autosomal dominant
•Trinucleotide-repeat disorder showing genetic anticipation (expansion of an unstable CTG trinucleotide repeat in the myotonic protein kinase gene)
•Affects a gene located on chromosome 19
3.What problems are associated with general anaesthesia?
•Sedatives and neuromuscular blocking drugs may lead to cardiorespiratory complications and delayed recovery from anaesthesia.
•Depolarising neuromuscular blocking agents should be avoided, e.g. suxamethonium (can lead to induced myotonia).
4.What changes would be detected on EMG in myotonic dystrophy?
•Electromyography shows the electrical potential generated by muscles when they are neurologically or electrically activated.
•Myotonic dystrophy produces high-frequency activity that varies, producing a whining sound on the loudspeaker (‘ dive-bomber’ ).
5.Describe what is meant by anticipation ?
•Anticipation is a phenomenon whereby as a genetic disorder is passed on to the next generation, the symptoms of the genetic disorder become more apparent at an earlier age with each generation.
KEY POINTS
•Try to identify myotonic dystrophy early from the characteristic facial changes.
•Be sure to examine for specific signs of myotonia (grip and percussion).
•Look for evidence of extraneurological complications.
Please examine this patient’ s eyes, as they have been complaining of double vision.
Note: The term ocular palsy refers specifically to the loss of function of an ocular muscle due to pathology in the nerve supplying it. We have also considered other causes of diplopia in this section.
FINDINGS
•General: Walking aids, eye patch, ptosis
•Neurological:
•Third (oculomotor) nerve palsy: Complete ptosis, eye looks down and out, pupil may be dilated and unreactive dependent on the cause
•Fourth (trochlear) nerve palsy: Causes weakness of downward movement of eye, causing vertical diplopia (rare)
•Sixth (abducens) nerve palsy: Inability to abduct affected eye
•Complex ophthalmoplegia: A combination/no specific nerve involvement
•INO: Impaired adduction, unilaterally or bilaterally
•Extras:
•Stigmata of diabetes mellitus
•Myasthenia gravis: Bilateral ptosis, fatiguability, thymectomy scar
•Graves’ disease: Proptosis, neck lump/scar
•Multiple sclerosis: Spastic paraparesis, cerebellar signs, walking aids/wheelchair
•Mitochondrial diseases: Hearing aid, proximal myopathy, ataxia, pacemaker (cardiomyopathy)
•Miller– Fisher syndrome: Peripheral neuropathy, ataxia, areflexia
PRESENTATION
This patient has a complex external ophthalmoplegia, as evidenced by diplopia in directions of gaze that are not attributable to a single nerve lesion. The likely cause is myasthenia gravis, as this patient also has bilateral ptosis, demonstrable fatiguability and a midline thoracotomy scar which would be consistent with a prior thymectomy.
•Where possible, try to work out which nerve is the culprit, though bear in mind that the patient may have a complex ophthalmoplegia.
INVESTIGATIONS
•Neuroimaging if a nerve lesion is suspected. MRI is most helpful, as it is important to obtain good views of the brainstem and posterior fossa.
•Investigations for causes of mononeuritis multiplex (see the section on mononeuropathy).
•Investigations for myasthenia gravis and thyroid disease in a complex ophthalmoplegia.
•Dependent on the underlying cause
QUESTIONS
1.What are the causes of an oculomotor nerve palsy?
•‘ Surgical’ : These causes generally affect the pupil.
•Posterior communicating artery aneurysm
•Space-occupying lesion in midbrain/sphenoid wing/near cavernous sinus
•Haemorrhage
•‘ Medical’ : These causes often do not affect the pupil.
•Causes of mononeuritis multiplex
•Demyelination
•Infarction
2.What are the causes of an abducens nerve palsy?
•Causes of mononeuritis multiplex.
•Vascular lesion.
•Malignancy.
•Demyelination.
•Infection (Lyme disease, syphilis).
•Raised intracranial pressure (‘ false localising’ sign).
•Wernicke’ s encephalopathy can cause a bilateral abducens nerve palsy.
3.What are the causes of a complex ophthalmoplegia?
•Nerve lesions: Demyelination, mononeuritis multiplex
•Neuromuscular junction: Myasthenia gravis
•Muscle: Graves’ disease
•Mitochondrial disease
4.What are the causes of an internuclear ophthalmoplegia?
•Multiple sclerosis
•Vascular disease
KEY POINTS
•Attempt to work out if the ocular palsy is due to a speci?c nerve lesion. If this is not possible, consider a complex ophthalmoplegia.
•The pupil may give some idea towards aetiology in an oculomotor palsy.
Please examine this patient’ s gait and proceed. They have presented with unsteadiness.
FINDINGS
•General: Patients can be in the ‘ off’ medication state (poverty of facial expression, slowness of movement, reduced blinking, etc., are clues prior to examination) or in the ‘ on’ medication state (excessive choreodystonic movements due to levodopa-induced dyskinesia).
•Neurological:
•Resting tremor (4– 6 Hz), rigidity (can be cog-wheeling in presence of rest tremor), bradykinesia (progressive decrement of amplitude of repetitive movements such as finger tapping).
•Gait: Ignition failure, short stride length, festination, freezing.
•Soft and monotonous speech.
•Micrographia.
•Rigidity can be demonstrated with concurrent activity (synkinesis – waving the right arm when assessing for the left). Distraction can bring out rest tremor – arm tremor is sometimes only revealed when testing gait or asking the patient to do a cognitive task like serial seven subtraction.
•Extras:
•Advanced therapies: Infusion pumps – apomorphine (subcutaneous) or duodopa (via percutaneous endoscopic jejunostomy [PEJ]), deep brain stimulation (implantable pulse generator or chest or abdominal wall – resembles cardiac pacemaker).
•Full assessment should also include mood, cognition (nonmotor symptoms) and functional status.
•Demonstrate that you are aware of Parkinson-plus syndromes by assessing eye movements and cerebellar signs.
PRESENTATION
This patient has evidence of Parkinson’ s disease. There is a resting tremor, as well as rigidity and bradykinesia. I note an apomorphine infusion being administered via a pump.
•This is a common presentation at the neurology station and should be recognisable from the classic triad of parkinsonism: bradykinesia, rigidity and a resting tremor.
•Be sure to discuss the functional status of the patient and consider causes other than just Parkinson’ s disease.
•Red flags for Parkinson-plus syndromes include symmetrical onset, early falls (patient in a wheelchair), lack of levodopa responses, supranuclear gaze palsy (limited downgaze) and cerebellar signs.
•Parkinson’ s disease.
•Drugs (neuroleptics).
•Parkinson-plus syndromes: Progressive supranuclear palsy (Steele– Richardson– Olszewski syndrome), multisystem atrophy (Shy– Drager syndrome).
•Stroke or space-occupying lesion affecting the basal ganglia.
•Postencephalitis.
•Wilson’ s disease.
•Other disorders resembling parkinsonism include dementia (including normal-pressure hydrocephalus) and tremulous conditions like benign essential tremor (action rather than rest tremor, i.e. postural and kinetic tremor).
INVESTIGATIONS
•Parkinson’ s disease is generally a clinical diagnosis.
•Supportive evidence may be provided by a therapeutic trial of levodopa or an apomorphine challenge.
•Cerebral imaging may be appropriate where other diagnoses require exclusion.
•A dopamine transporter (DaT) scan can be used to support a diagnosis of Parkinson’ s disease or to rule out drug-induced parkinsonism (but cannot distinguish idiopathic PD from PD-plus syndromes).
MANAGEMENT
•Multidisciplinary team (MDT) approach
•Specialist, physiotherapist, OT, specialist nurse, speech and language therapist (SALT)
•Levodopa formulations
•Other medications
•Dopamine agonists, e.g. rotigotine patch, ropinirole, pramipexole
•Anticholinergics: Trihexyphenidyl (for tremor)
•Selegiline, rasagiline (monoamine oxidase B [MAOB] inhibitors)
•Tolcapone (rarely used due to hepatic side effects), entacapone, opicapone (new) (catechol-o-methyltransferase [COMT] inhibitors)
•Apomorphine (dopamine agonist)
•Complications
•Assess disability and cognition regularly; treat depression
•Surgery
•For example, deep brain stimulation of subthalamic nucleus or internal segment of globus pallidus may be considered for those with motor fluctuations or levodopa-induced dyskinesia.
1.What are the characteristic features of Parkinson’ s disease?
•The triad of parkinsonism (bradykinesia, rigidity, resting tremor).
•In Parkinson’ s disease, these features begin asymmetrically and generally affect the upper limbs first. There is fluctuation in severity, with the patient being better some days than others.
•Autonomic dysfunction, loss of postural reflexes and balance and changes in higher mental functioning are also common later in the illness.
2.What drugs other than L-dopa are used in the management of Parkinson’ s disease?
•Dopamine agonists (e.g. ropinirole): May be used as first-line therapy, especially in younger patients (due to the decreased risk of dyskinesias), or as an add-on to levodopa.
•Anticholinergics (e.g. trihexyphenidyl): Useful for tremor.
•Monoamine oxidase B inhibitors (selegiline): May be helpful with motor symptoms.
•COMT inhibitors (entacapone): Help to decrease immobility by shortening the ‘ off ’ time associated with L-dopa.
•Apomorphine: A parenteral dopamine agonist that can be helpful with ‘ on– off’ effects. It may be given via a syringe driver.
3.What is the pathology underlying Parkinson’ s disease?
•Degeneration of the substantia nigra dopaminergic neurones in the basal ganglia. The hallmark is the presence of Lewy bodies.
4.Describe the potential problems patients need to be counselled about before commencing dopamine agonists.
•Impulse control disorders
•Hyperreligiosity
•Gambling
•Hypersexuality
•Compulsive eating
KEY POINTS
•Have a speci?c examination prepared for Parkinson’ s disease.
•Look for the triad of parkinsonism early, and then search for extra features.
REFERENCE
Benabid AL, et al. (2009) Deep brain stimulation of the subthalamic nucleus for the treatment of Parkinson’ s disease. Lancet Neurol 8(1): 67– 81.
Please examine this patient who has painful legs.
FINDINGS
•General: Walking aids, diabetic shoes, prostheses, insulin pen
•Neurological:
•‘ Glove and stocking’ sensation loss
•All sensory modalities should be tested (use a 128 Hz tuning fork to assess vibration sense, as dorsal columns are usually affected first)
•Wasting, weakness, areflexia
•Extras:
•Finger-prick testing, cataracts, ulcers, Charcot’ s joints, callus (diabetes mellitus)
•Clawing of the toes, pes cavus (Charcot– Marie– Tooth disease)
•Amiodarone facies
•Anaemia (B12 deficiency)
•Evidence of alcohol abuse
•Evidence of arthritis and rashes (vasculitis)
PRESENTATION
This patient has a predominantly sensory peripheral neuropathy, as evidenced by lack of sensation bilaterally to midcalf for all modalities. There is no evidence of any ulceration or callus formation. The most likely underlying cause is diabetes mellitus, as evidenced by finger pulp pricks from capillary blood glucose testing.
•It is important to first ensure that the patient has a peripheral neuropathy rather than a mononeuropathy or mononeuritis multiplex.
•This is a common Practical Assessment of Clinical Examination Skills (PACES) case, and looking for a cause is crucial. Try to decide if the neuropathy is predominantly motor or sensory, as this should help to elucidate the aetiology.
CAUSES OF NEUROPATHY
•Predominantly sensory neuropathy
•Diabetes mellitus
•Alcohol
•Drugs
•Vitamin deficiencies (B1, B12)
•Uraemia
•Predominantly motor
•Guillain– Barré syndrome
•Malignancy
•Charcot– Marie– Tooth disease
•Porphyria
•Lead poisoning
•Other causes include paraneoplastic syndromes, paraproteinaemia, vasculitis and infections (human immunodeficiency virus [HIV], Lyme disease).
•Some cases are idiopathic.
INVESTIGATIONS
•Full drug and alcohol history
•Blood tests: Full blood count (FBC) (including mean cell volume [MCV]), urea and electrolytes (U&Es), liver function tests (LFTs) (including gamma-glutamyl transpeptidase [GGT]), vitamin B12 and folate, glucose, thyroid function tests (TFTs), autoimmune screen and immunoglobulins, hepatitis screen, HIV screen, Lyme serology, syphilis serology
•Urine: Dip for glucose and protein, Bence– Jones protein
•Imaging: Chest X-ray (CXR)
•LP and CSF study: Protein and CSF virology
•Nerve conduction studies
MANAGEMENT
•Dependent on the aetiology; remove any precipitants and treat the cause.
QUESTIONS
1.What is an autonomic neuropathy?
•A neuropathy of the autonomic nervous system.
•May present alone or in conjunction with a motor or sensory neuropathy. The most common cause is diabetes.
•May present with postural hypotension, impotence, urinary retention, diarrhoea/constipation and a Horner’ s syndrome.
2.What is Charcot– Marie– Tooth disease?
•A hereditary, sensory and motor neuropathy. Also known as peroneal muscular atrophy.
•Usually starts at puberty with foot drop and weak legs.
•The peroneal muscles are the first to atrophy, with upper limb signs appearing at a later stage.
•There is muscle wasting, pes cavus and a bilateral foot drop (high-stepping gait). Reflexes are often absent. Sensory loss is variable.
•The most common form is inherited in an autosomal dominant manner.
3.Which drugs can cause a peripheral neuropathy?
•Amiodarone
•Gold
•Isoniazid
•Metronidazole
•Phenytoin
4.What is tabes dorsalis? Describe the gait associated with this.
•Tabes dorsalis is a demyelinating condition affecting primarily the nerves in the dorsal/posterior columns of the spinal cord. These nerves normally help maintain proprioception, vibration and discriminative touch. The gait is ‘ high stepping’ due to a lack of proprioception.
KEY POINTS
•Establish the diagnosis early to allow a cause to be found.
•Be sure to present a list of possible aetiologies to the examiner, taking into account whether the neuropathy is predominantly motor or sensory.
•The most likely causes in PACES include diabetes and Charcot– Marie– Tooth disease.
Please examine this patient who has paraesthesiae in his left hand.
FINDINGS
CARPAL TUNNEL SYNDROME
•Wasting of the thenar eminence.
•Weakness of LOAF (lumbricals, opponens pollicis, abductor pollicis brevis, flexor pollicis brevis).
•Sensory loss over the lateral 3½ digits.
•Maximal wrist flexion for 1 minute may elicit symptoms (Phalen’ s test).
•Tapping over the nerve at the wrist induces tingling (Tinel’ s test).
•Look for a scar from carpal tunnel release surgery and evidence of diabetes, hypothyroidism, acromegaly and rheumatoid arthritis.
SPECIFIC NERVE PALSIES
ULNAR NERVE PALSY
•Wasting of the hypothenar eminence (thenar eminence spared), claw hand, guttering on the dorsal aspect of the hand.
•Look for wasting of the medial aspect of the forearm (note low/high lesions, hand less clawed in high lesion).
•Weakness of abduction and adduction (test for Froment’ s sign) of the fingers and adduction of the thumb.
•Sensory loss over the medial 1½ digits.
•Look for scars (fracture dislocation) and osteoarthrosis at the elbow.
•Wrist drop, weakness of wrist extension; if the wrist is passively extended, intrinsic muscles of the hand should be intact.
•Impaired grip strength.
•Sensory loss over the first dorsal interosseous.
•Look for scars at the elbow (fracture/dislocation), and note if the patient uses crutches.
COMMON PERONEAL NERVE PALSY
•Foot drop on inspection (leading to a high-stepping gait).
•Weakness of dorsiflexion and eversion of the foot.
•All reflexes will be intact.
•Sensory loss over the lateral dorsum of the foot.
•Look for evidence of compression around the fibular neck.
PRESENTATION
This patient has wasting of the thenar eminence in the left hand, indicating a median nerve lesion. This is supported by weakness of opposition of the thumb. There is sensory loss over the lateral 3½ digits with sparing of the palm. Tinel’ s test is positive. There is a scar over the anterior wrist. The patient also has a symmetrical arthritis affecting the hands with a swan neck deformity of two digits, but no evident skin or nail changes. The likely diagnosis is carpal tunnel syndrome of the left wrist on a background of rheumatoid arthritis.
•Functionality is crucial and should always be tested and commented on. Try to find a cause for the lesion.
•In all mononeuropathies, it is important to look for causes of mononeuritis multiplex.
INVESTIGATIONS
•Single nerve lesions are often a clinical diagnosis. Neurophysiology can be used to confirm the diagnosis and to assess severity.
MANAGEMENT
•Splints and physiotherapy can be helpful. Surgery is sometimes used, especially in carpal tunnel syndrome where surgical decompression of the flexor retinaculum is a simple and definitive treatment.
QUESTIONS
1.What is the differential diagnosis of a foot drop?
•Common peroneal nerve palsy, peripheral neuropathy (especially Charcot– Marie– Tooth disease), sciatic nerve palsy, L4/5 radiculopathy (prolapsed lumbar disc) and lumbosacral plexopathy
2.What are the causes of mononeuritis multiplex?
•Wegener’ s granulomatosis.
•Amyloidosis.
•Rheumatoid arthritis.
•Diabetes mellitus.
•Sarcoidosis.
•Polyarteritis nodosa.
•Leprosy.
•Carcinomatosis.
•Note that WARDS PLC is a useful way of remembering this list.
3.What are the causes of wasting of the small (intrinsic) muscles of the hand?
•Resembles an ulnar nerve lesion, but with thenar wasting and weakness also
•Causes include
•Anterior horn cells disease, e.g. poliomyelitis
•Radiculopathy, e.g. trauma, prolapsed disc
•Plexopathy, e.g. brachial plexus injury, Pancoast’ s tumour, cervical rib
•Peripheral nerve lesions
•Muscle, e.g. disuse atrophy
KEY POINTS
•Initially look for any evident wasting or deformity.
•Examine all motor and sensory areas supplied by the nerve to localise the lesion.
•Search for a possible cause.
Please examine this patient who presents with weakness.
FINDINGS
•Amyotrophic lateral sclerosis (ALS)
•Suspect when UMNs and lower motor neurones (LMNs) occur concurrently in a limb with weakness.
•Degree of weakness depends on the number of muscles affected and distribution of motor neurone loss.
•Reflexes usually exaggerated (UMN signs) in the presence of muscle wasting and fasciculation (LMN signs).
•Sensation is unaffected throughout.
•Involvement of lower cranial nerves causes a pseudobulbar palsy.
•Progressive muscular atrophy (PMA)
•Flaccid weakness, as only LMNs affected
•Fasciculations and wasting
•Plantars down going
•Primary lateral sclerosis (PLS)
•UMN signs only
•Usually begins in lower limbs (spastic gait)
•Exaggerated reflexes
•Progressive bulbar palsy
•Only lower cranial nerves affected (IX, X, XII).
•‘ Donald Duck’ /nasal speech.
•Weakness of palatal muscles results in swallowing difficulties.
PRESENTATION
The most likely diagnosis is motor neurone disease (MND). There is generalised wasting and fasciculation. Tone is increased with generalised weakness. Reflexes are brisk/ reduced/absent. Leg reflexes are brisk and ankle clonus is present. There are bilateral extensor plantar responses.
INVESTIGATIONS
•Diagnosis is mainly clinical, based on a high index of suspicion from the collection of signs and symptoms.
•EMG
•Abnormally slowed conduction due to reduction in the number of viable motor axons/anterior horn cells to activate the muscle(s) involved
•Nerve conduction studies
•Normal sensory nerve conduction and abnormal motor nerve conduction
•Reduced muscle action potentials
•Repetitive stimulation: Decremental response with slow repetitive stimulation
•MRI
•To exclude other causes for the symptoms, e.g. cervical myelopathy/spondylosis or cord compression
MANAGEMENT
•Supportive measures
•Physiotherapy, occupational therapy, speech therapy.
•Swallowing and nutritional support (nasogastric [NG]/PEG feeding).
•Respiratory support: Noninvasive positive-pressure ventilation (NIPPV), tracheostomy and invasive ventilation.
•Advanced care planning is an important part of the patient’ s treatment.
•Specific therapy
•Riluzole: A glutamate inhibitor that acts by inhibiting voltage-gated sodium channels
•Increases survival compared with placebo by roughly 3 months; no significant effect on muscle strength or neurological function seen
1.What are the disease variants of MND?
•Amyotrophic lateral sclerosis
•Approximately 50% of cases; combined UMN and LMN signs; mostly sporadic (90%– 95%)
•Familial form: Copper/zinc superoxide dismutase (SOD-1) gene mutation on chromosome 21
•Primary lateral sclerosis
•Rare; affects upper motor neurones only; has the best prognosis but can later progress to ALS
•Progressive muscular atrophy
•Approximately 25% of cases; affects anterior horn cells only – therefore signs in distal muscle groups
•Progressive bulbar palsy
•Approximately 25% of cases; worst prognosis; affects suprabulbar nuclei and lower cranial nerves, resulting in speech and swallowing difficulties (increased risk of aspiration)
2.What is the prognosis for patients with MND?
•No known cure; usually fatal within 3– 5 years of diagnosis. Cause of death is usually aspiration pneumonia and/or ventilatory failure.
3.What is the differential diagnosis for MND?
•Degenerative: Cervical cord compression, cervical spondylosis
•Inflammatory/traumatic/inherited: Syringomyelia, spinal muscular atrophy
•Infectious: Polio, syphilis
•Malignant/paraneoplastic
4.What are the other causes of absent ankle jerks and extensor plantar responses?
•Hereditary cerebellar ataxias: Friedreich’ s ataxia, spinocerebellar ataxia
•Syphilitic taboparesis
•Subacute combined degeneration of the cord
•Conus medullaris pathology
•Combined pathologies, e.g. peripheral neuropathy from any cause in a patient with cervical spondylosis
Note that question 4 is a ‘ classic’ PACES question and should be committed to memory.
KEY POINTS
•Note any external features that may indicate the diagnosis (fasciculations, NIPPV machine).
•Note the patient’ s speech.
•It is crucial to check the plantar response.
National Institute for Health and Care Excellence. (2001) TA20. Guidance on the use of riluzole (Rilutek) for the treatment of motor neurone disease. Available from https://www.nice.org.uk/guidance/ta20/resources/guidance-on-the-use-of-riluzole-rilutek-for-the-treatment-of-motor-neurone-disease-2294449469125. Accessed 24 August 2016.
Please examine the legs of this patient who has progressive difficulty in walking.
FINDINGS
•General: Walking sticks, wheelchair, catheter, ataxic gait, dysarthria, mood (depressed/elated)
•Eyes: Internuclear ophthalmoplegia, optic neuritis, central scotoma, loss of colour vision, relative afferent pupillary defect (RAPD), nystagmus
•Neurological: Spastic paraparesis, cerebellar signs
PRESENTATION
This patient has an ataxic gait. Examination of her lower limbs shows increased tone and brisk reflexes. Further examination shows that the patient also has evidence of bilateral internuclear ophthalmoplegia. Putting these findings together, this patient is likely to have a diagnosis of multiple sclerosis.
•Comment on the patient’ s functionality by looking for general findings, e.g. walking aids, the presence of a catheter and the patient’ s general affect.
INVESTIGATIONS
•CSF analysis
•Immunoglobulin (Ig) G oligoclonal bands on electrophoresis
•Visual-evoked potentials
•Delayed response
•MRI
•Highlighting areas of demyelination
MANAGEMENT
•Multidisciplinary approach/patient education/MS support group information
•Acute relapse
•IV methylprednisolone: This may help to reduce the duration and severity of the relapse but will not alter the course of the disease.
•Interferon beta-1a
•Interferon beta-1b
•Glatiramer acetate
•Azathioprine
•Natalizumab (for highly active relapsing– remitting disease)
•Symptomatic treatment
•Spasticity: Physiotherapy, baclofen, tizanidine
•Urinary dysfunction: Oxybutynin, catheterisation
•Constipation: Laxatives, enemas
•Pain: Amitriptyline, carbamazepine, gabapentin
•Fatigue: Amantadine
•Depression: Support groups, selective serotonin reuptake inhibitors (SSRIs)
QUESTIONS
1.What is multiple sclerosis?
•Multiple sclerosis is a chronic inflammatory autoimmune disease of the central nervous system. The diagnosis depends on demonstrating at least two demyelinating lesions in the brain or spinal cord on MRI, separated in time and space.
2.What are Lhermitte’ s sign and Uhthoff ’ s phenomenon?
•Lhermitte’ s sign: Flexion of the neck causing an ‘ electric shock’ – like sensation in the trunk and limbs; this occurs in cervical spondylosis as well as MS.
•Uhthoff ’ s phenomenon: An increase in the severity of symptoms (mainly visual), commonly precipitated by an increase in temperature or by exercise.
3.How is multiple sclerosis classified?
•Relapsing– remitting
•Affects approximately 85% of MS sufferers
•Secondary progressive
•Follows a period of relapsing– remitting MS
•Primary progressive
•15% of cases; progressive deterioration from the start
•The classification of MS becomes important when considering the role of disease-modifying antirheumatoid drugs (DMARDs). Currently, these drugs can help reduce the severity and frequency of relapses in relapsing– remitting MS and secondary progressive MS.
KEY POINTS
•A combination of spastic paraparesis and cerebellar signs is likely evidence of multiple sclerosis.
•Always comment on the patient’ s functional status.
National Institute for Health and Care Excellence. (2014) Guidance CG186. Multiple sclerosis in adults: Management. Available from https://www.nice.org.uk/guidance/cg186/resources/multiple-sclerosis-management-of-multiple-sclerosis-in-primary-and-secondary-care-35109816059077. Accessed 24 August 2016.
Please examine this patient’ s legs neurologically, as they are finding it difficult to walk.
FINDINGS
•General: Walking aids, scissoring gait
•Neurological: Increased tone, clonus, decreased power, hyperreflexia, extensor plantars and sensory loss. Signs may be present only below a particular spinal level.
•Other: Evidence of cerebellar syndrome
•Cachexia and other evidence of malignancy
PRESENTATION
On examination, this patient has signs suggestive of a spastic paraparesis. This is evidenced by hypertonia, hyperreflexia and decreased power throughout the lower limbs. There is tenderness over the T12 vertebra with a sensory level present, making spinal cord compression a likely cause.
•It is important to exclude acute spinal cord compression, so tell the examiners you would ask about bladder and bowel symptoms, and would offer to perform a pulmonary regurgitation (PR) examination.
•Always check gait and assess the functional status of the patient.
CAUSES OF A SPASTIC PARAPARESIS
•Compression
•Tumour, osteoarthritis, trauma/fracture, central disc prolapse
•Transverse myelitis
•Multiple sclerosis (cerebellar signs), inflammatory and vascular disorders
•Degenerative
•Hereditary spastic paraparesis, motor neurone disease (absence of sensory signs/ combination of UMN and LMN signs), Friedreich’ s ataxia (cerebellar signs)
•Infective
•HIV myelopathy
•Others
•Cerebral palsy, subacute combined degeneration of the cord
•MRI of the spine is the gold standard imaging test.
•Other investigations include FBC, vitamin B12/folate levels, erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP), syphilis serology, CSF protein and oligoclonal bands, myeloma screen and tumour markers.
MANAGEMENT
•The most urgent treatment is needed for spinal cord compression:
•If malignancy is the cause, give dexamethasone. This is followed by radiotherapy or surgery.
•Surgery is the mainstay of treatment for other causes.
•Further management of this presentation depends on the underlying cause, although an MDT approach focusing on neurorehabilitation may be helpful.
QUESTIONS
1.What malignancies are most likely to cause spinal cord compression?
•The most likely cause is metastasis from lung, breast or prostate cancer. Kidney and thyroid primaries also commonly metastasise to bone.
•Multiple myeloma should be considered a cause of cord compression.
•Intrinsic spinal malignancy is rare.
2.What is transverse myelitis?
•Inflammation of the spinal cord, characterised by axonal demyelination. Generally, the inflammation is across the thickness of the cord.
•Symptoms come on over a period of hours to weeks.
•The most common cause is multiple sclerosis. Viral and other infections can be implicated. Often, no cause is found.
•Steroids and plasma exchange may be helpful in management, although more crucial is neurorehabilitation.
3.What is the pathology in hereditary spastic paraparesis?
•Axonal degeneration that is maximal in the terminal portions of the longest descending and ascending tracts, including the crossed and uncrossed corticospinal tracts to the legs and fasiculus gracilis. Neuronal call bodies of degenerating fibres are preserved, and there is no evidence of primary dymelination.
KEY POINTS
•When ?nding a spastic paraparesis, it is important to look for a spinal level.
•Be sure to assess gait and examine the spine locally.
•Excluding acute cord compression is essential.
Please examine this patient who has recently developed a visual disturbance and, as a result, finds that they are bumping into things.
•Sit at the same height as the patient. Ask the patient to cover each eye in turn.
•Assess both nasal and temporal fields and all four quadrants. Look carefully at where the field of vision starts/finishes and which areas of the field are lost, i.e. nasal/temporal, superior/inferior.
•Use the information collected to establish which pattern of visual field defect the patient has.
•Be sure you are familiar with the visual pathway anatomy to enable you to ascertain the site of the lesion, as the nature of the visual field defect is determined by the site of the lesion along the visual pathway.
PRESENTATION
This patient presents with a history of bumping into objects and visual impairment. They have visual loss affecting the same half of the visual field in each eye. This is known as a homonymous hemianopia.
CLASSIFICATION OF VISUAL FIELD DEFECTS
•Classification of defects depends on whether one or both eyes are affected, which half of the visual field is affected, i.e. temporal, nasal or both (heteronymous or homonymous hemianopia), and the extent of field affected in each eye relative to the other (congruity).
•Optic nerve lesions: Result in partial or complete visual loss on the side of the lesion.
•Optic chiasm lesions: Result in both temporal fields being lost.
•Optic radiation lesions: Result in homonymous field defects that depend on the location of the lesion in the temporal or parietal lobe.
•Temporal lobe lesions lead to superior homonymous quadrantanopias.
•Parietal lobe lesions lead to inferior homonymous quadrantanopias.
•The further back towards the visual cortex the defect, the greater the degree of congruity (i.e. both eyes affected to the same degree).
•Visual cortex or optic radiation lesions result in a homonymous hemianopia.
QUESTIONS
1.What are the causes of a homonymous hemianopia?
•Vascular: Stroke
•Trauma
•Tumour
•Infection: Encephalitis
•Demyelination: MS
2.What are the causes of an optic nerve lesion?
•Trauma
•Inflammatory: Demyelination, optic neuritis
•Compression: Raised intraocular or intracranial pressure
•Vascular: Acute optic artery ischaemia
•Metabolic: B12 deficiency, diabetes, alcohol excess
•Inherited conditions, e.g. Leber’ s optic neuropathy
3.What are the common causes of a bitemporal hemianopia?
•Usually occur as a result of a lesion of the optic chiasm
•Pituitary fossa tumour
•Craniopharyngioma
•Suprasellar meningioma
KEY POINTS
•Remember to assess both temporal and nasal visual ?elds for both eyes.
•Be familiar with visual pathways so the site of the lesion can be identi?ed.
•Neurology is a difficult station, particularly if you don’ t look well practiced. You must practise your examination technique until you really are slick and confident performing the examination.
•As ever, particular emphasis should be paid to observation. In neurology, many diagnoses can be made from the end of the bed (Parkinson’ s/myasthenia gravis/myotonic dystrophy). When this is the case, don’ t relax. You still need to demonstrate all the signs to the examiner.
•Looking around the bed is just as important in neurology as any other station (e.g. look for forced expiratory volume in first second [FEV1] monitors in myasthenia gravis).
•Don’ t panic if you don’ t know the diagnosis; work out where the lesion is and use a pathological sieve to create a differential list.
•Be aware of how to demonstrate specific signs for specific syndromes (e.g. myotonia in myotonic dystrophy). Your examiners will be impressed if you look confident and rehearsed while doing this.
•Go into the station prepared to do a range of examinations. You may have to examine the arms, the legs, the eyes or the cranial nerves or conduct a special examination.
•Don’ t forget to reinforce the reflexes if you think that they are absent.
•Don’ t forget to check sensation on the chest prior to commencing limb examination, so that comparison can be made. But , remember to check that it feel’ s normal on the chest wall and not just whether the patient can feel you touching.
•Asking the patient to walk so that you can assess their gait is a key skill in neurology. Be aware of the different types of gait and the different syndromes that each gait may indicate.
•When presenting your case, first tell the examiners the syndrome or the likely site of the lesion, followed by the likely cause.