Other OSCE bits Flashcards
Causes of absent red reflex (fundal reflex) - Adults and Children
- Adults: cataracts, vitreous haemorrhage, and retinal detachment
- Children: congenital cataracts, retinal detachment, vitreous haemorrhage and retinoblastoma
Describe the Snellen chart measurement and how the numbers work - eg. 6/6 (20/20), 6/20 etc. and 6/12 (-2) + what you do if the pt has poor vision
- Visual acuity is recorded as chart distance (numerator) [either 6m or 20ft] over the number as the denominator (which is the distance a ‘normal’ person would be able to see the letter at)
- eg. 6/20 —> pt can see the letters at 6m away the same as normal can see 20m away from chart
- 6/60 = top line
- If they can read the line but get two letters wrong for example it would be 6/12 (-2)
- if the pt gets more than 2 letters wrong then the previous line should be recorded as their acuity
- Poor vision: 6m, then 3m, then 1m, then counting fingers (CF), then hand movements (HM), then perception of light (PL)
Explain these visual field defects
- Bitemporal hemianopia
- Homonymous hemianopia
- Scotoma
- Monocular vision loss
Pathophysiology of RAPD / the pupillary reflex
Cover test - which direction will the eye move relating to the type of strabismus (squint)
Causes of anosmia
- Mucous blockage —> preventing odours from reaching the olfactory nerve receptors
- Head trauma —> can result in shearing of the olfactory nerve fibres
- Congenital anosmia
- Parkinson’s —> anosmia is an early feature
- COVID-19
Actions of extraocular muscles
- Superior rectus: Primary – elevation
- Inferior rectus: Primary – depression
- Medial rectus: Adduction of eyeball
- Lateral rectus: Abduction of eyeball
- Superior oblique: Depresses, abducts and medially rotates
- Inferior oblique: Elevates, abducts and laterally rotates
Trigeminal nerve branches + what does each supply?
- Ophthalmic (V1) —> forehead, upper eyelids, and eyes
- Maxillary (V2) —> middle of face (including cheeks, nose, lower eyelids, upper lip/teeth, and gums)
- Mandibular (V3) —> lower face (including jaws, lower lip/teeth, and gums) + has a motor branch that enables chewing, biting, and swallowing
Facial nerve branches
TZBMC
Facial nerve movements, what muscle is tested in each?
- Raised eyebrows
- Eyes closed
- Blow cheeks out
- Smile (show teeth)
- Purse lips (whistle)
- Raised eyebrows - frontalis
- Closed eyes - orbicular oculi
- Blown out cheeks - orbicularis oris
- Smiling - levator anguli oris and zygomaticus major
- Pursed lips (whistle) - orbicularis oris and buccinator
Causes of sensorineural hearing loss and conductive hearing loss
When testing CN XII (hypoglossal), which side does the tongue deviate in a left-sided lesion?
hypoglossal nerve palsy causes atrophy of the ipsilateral half of tongue and deviation to side of lesion
After completing a cranial nerve examination, what further tests would you do?
- Full neurological examination including the upper and lower limbs
- Neuroimaging (eg. MRI head) —> if concerns about space-occupying lesions or demyelination
- Formal hearing assessment (including pure tone audiometry) —> if there are concerns about vestibulocochlear nerve function
What do you look for on general inspection in a neurological examination (upper/lower limb examination)
In an upper limb neuro examination, what does a +ve pronator drift indicate? + what muscles are involved to cause this?
- +ve if forearm pronates - indicates a contralateral pyramidal tract lesion
- Pronation occurs because, in the context of an UMN lesion, the supinator muscles of the forearm are typically weaker than the pronator muscles.
What scale is used to assess muscle power + details
Power is graded 0 to 5 using the MRC muscle power scale
For each movement - myotome + nerve + muscles involved
- Shoulder abduction
- Shoulder adduction
- Elbow flexion
- Elbow extension
- Wrist extension
- Wrist flexion
- Finger extension
- Finger abduction
- Thumb abduction
- Shoulder abduction (C5 - axillary nerve) - deltoid (primary) and other shoulder abductors
- Shoulder adduction (C6/C7 - thoracodorsal nerve) - teres major, latissimus dorsi, and pectoralis major
- Elbow flexion (C5/C6 - musculocutaneous and radial nerve) - biceps brachii, coracobrachialis, and brachialis
- Elbow extension (C7 - radial nerve) - triceps brachii
- Wrist flexion (C6/C7 - median and ulnar nerve) - flexors of the wrist
- Wrist extension (C6 - radial nerve) - extensors of the wrist
- Finger extension (C7 - radial nerve) - extensor digitorum
- Finger abduction (T1 - ulnar nerve) - First dorsal interosseous (FDI), Abductor digiti minimi (ADM)
- Thumb abduction (T1 - median nerve) - abductor pollicis brevis
For each reflex - nerve root tested + name of tendon
- Biceps reflex
- Supinator
- Triceps reflex
- Biceps reflex (C5/C6) - biceps brachii tendon (medial aspect of antecubital fossa)
- Supinator (C5/C6) - brachioradialis tendon (posterolateral aspect of wrist)
- Triceps reflex (C7) - triceps tendon (superior to olecranon process of the ulna)
What type of reflexes are seen in UMN lesions and LMN lesions? (ie. hyperreflexia or hyporeflexia)
- Hyperreflexia - UMN lesions (eg. stroke, spinal cord injury)
- Hyporeflexia - LMN lesions (eg. brachial plexus pathology or other peripheral nerve injuries)
Testing upper limb dermatomes - where would you touch for each of the dermatomes?
C5:the lateral aspect of the lower edge of the deltoid muscle (known as the “regimental badge”).
C6:the palmar side of the thumb.
C7:the palmar side of the middle finger.
C8:the palmar side of the little finger.
T1:the medial aspect antecubital fossa, proximal to the medial epicondyle of the humerus.
When assessing dermatomes, what tracts/columns are being assessed in:
- light touch
- pin-prick
- vibration sense
- Light touch (dorsal columns and spinothalamic tracts)
- Pin prick (spinothalamic tract)
- Vibration sensation (dorsal columns)
When assessing coordination, what would patients with cerebellar pathology exhibit on:
- finger-to-nose test
- dysdiadochokinesia
Finger-to-nose:
- Dysmetria (over/undershooting the target)
- Intention tremor
Dysdiadochokinesia:
- may struggle to carry out task (movements slow and irregular)
After completing an upper or lower limb neuro examination, what further assessments/investigations would you like to do?
- Full neurological examination (including cranial nerves, lower/upper limbs, and cerebellar assessment)
- Neuroimaging (eg. MRI spine and head)
Name some gait abnormalities
Clues:
- cerbellar pathology
- Parkinson’s
- peripheral neuropathy
- proximal myopathy
- stroke
- hereditary spastic paraplegia
- normal pressure hydrocephalus
- Apraxia gait (magnetic gait) - normal pressure hydrocephalus
Romberg’s test is based on the premise that a patient requires at least two of the following three senses to maintain balance whilst standing:
- Proprioception:the awareness of one’s body position in space.
- Vestibular function:the ability to know one’s head position in space.
- Vision:the ability to see one’s position in space.
What does Romberg’s test assess?
- Used to assess for loss of proprioception or vestibular function (sensory ataxia)
- ie. screens for non-cerebellar causes of balance issues
Romberg’s test:
- causes of proprioceptive dysfunction
- causes of vestibular dysfunction
- Causes of proprioceptive dysfunction - Ehlers-Danlos syndrome, B12 deficiency, Parkinson’s, and aging (presbypropria)
- Causes of vestibular dysfunction - * vestibular neuronitis, Ménière’s disease*
.
Spasticity and rigidity - which one is velocity-dependent (ie. the faster you move the limb, the worse it is)?
Spasticity - associated with pyramidal tract lesions (eg. stroke)
For each movement - myotome + nerve + muscles involved
- Hip flexion
- Hip extension
- Knee flexion
- Knee extension
- Ankle dorsiflexion
- Ankle plantar-flexion
- Big toe extension
- Hip flexion (L1/L2 - femoral nerve) - iliopsoas
- Hip extension (L5/S1/S2 - inferior gluteal nerve) - gluteus maximus
- Knee flexion (S1 - sciatic nerve) - hamstrings
- Knee extension (L3/L4 - femoral nerve) - quadriceps
- Ankle dorsiflexion (L4/L5 - deep peroneal nerve) - tibialis anterior
- Ankle plantar-flexion (S1/S2 - tibial nerve) - gastrocnemius, soleus
- Big toe extension (L5 - deep peroneal nerve) - extensor hallucis longus
For each reflex - nerve root tested + name of tendon
- Knee jerk
- Ankle jerk
- Plantar reflex (Babinski) - no tendon - but what is an abnormal/Babinski sign?
- Knee jerk (L3/L4) - patellar tendon
- Ankle jerk (S1) - Achilles tendon
- Plantar reflex/Babinski (L5, S1) - extension of big toe and spread of the other toes –> suggests UMN lesion
Lower limb dermatomes and where you would touch to test sensation for each of the following:
- L1
- L2
- L3
- L4
- L5
- S1
- L1:inguinal region and the very top of the medial thigh
- L2:middle and lateral aspect of the anterior thigh
- L3:medial aspect of the knee
- L4:medial aspect of the lower leg and ankle
- L5:dorsum and medial aspect of the big toe
- S1:dorsumand lateral aspect of the little toe
Upper limb dermatomes and where you would touch to test sensation for each of the following:
- C4
- C5
- C6
- C7
- C8
- T1
- C4: just above shoulder
- C5:the lateral aspect of the lower edge of the deltoid muscle (known as the “regimental badge”).
- C6:the palmar side of the thumb.
- C7:the palmar side of the middle finger.
- C8:the palmar side of the little finger.
- T1:the medial aspect antecubital fossa, proximal to the medial epicondyle of the humerus.
Does joint proprioception involve the spinothalamic tracts or the dorsal columns?
Dorsal columns
Plexuses and what they innervate:
- Cervical plexus
- Brachial plexus
- Lumbosacral plexus
- Cervical plexus (C1-C4) - innervates diaphragm, shoulders, and neck
- Brachial plexus (C5-T1) - innervates upper limbs
- Lumbosacral plexus (L2-S4) - innervates lower extremities
Headache red flags
- Raised ICP signs - nausea/vomiting/Valsalva manouvre/focal neuro signs
- Meningism - fever/neck stiffness/rash
- Sudden + severe - SAH
- GCA - temporal tenderness/hard on palpation…
- Trauma - bleed?
- Hx of cancer - metastases
What side would the uvula deviate if there is a left side vagus nerve lesion + which muscles are involved?
- Uvula deviates towards unaffected side - affected side’s muscles are paralysed/weak, therefore functioning muscles on contralateral side pull uvula towards them
- due to paralysis of the palatopharyngeal muscles
Using a typical appearance of a stroke (eg. arm flexed, leg extended/circumduction gait), describe the pyramidal pattern of weakness
(think of typical stroke pt who has flexed arm and circumduction gait)
- Upper body - weakness predominantly affects extensors, leading to a flexor posture (e.g. flexed elbow/wrist/fingers)
- Lower body - weakness predominantly affects flexors, leading to an extensor posture (e.g. extended knee and plantarflexed foot)
GCS score - what is lowest/highest/requires intubation?
- 3= lowest = completely unresponsive
- 15 =highest = fully alert
- ≤ 8 —> intubation
What is the corpus callosum?
- bundle of nerve fibers that connects the right and left sides of the brain
- (largest white matter structure in the brain - think MS affects myelin)
- responsible for allowing the two hemispheres to communicate with each other
Key symptoms of bacterial meningitis + key sign for meningococcal meningitis
- Symptoms - headache, fever, neck stiffness, and photophobia
- Sign: petechial rash (non-blanching)
Investigations for suspected bacterial meningitis + diagnostic test
- CSF (gram stain, culture)
- Blood cultures - to guide antibiotics
- Diagnosis: gram stain + CSF culture / bacterial PCR
Risk factors for TB meningitis
- exposed to pulmonary TB
- areas of high prevalence / homelessness / immunosuppression
Main cause of fungal meningitis (rare)
untreated HIV infection (very immunosuppressed)
Causes of Guillian Barre
- CMV (cytomegalovirus)
- EBV
- campylobacter jejuni
Peripheral pattern of weakness (LMN lesions) - Give differential for each short hx
- fatigable weakness, affects extraocular/bulbar muscles first, improves with rest, associated with thymoma
- proximal weakness, improves with repeated use, associated with small cell lung cancer
- descending paralysis, dilated pupils, respiratory involvement
- Myasthenia gravis
- Lambert-Eaton myasthenic syndrome (LEMS)
- Botulism
Peripheral pattern of weakness (LMN lesions) - Give differential for each short hx
- inflammatory myopathies, painful proximal weakness, heliotrope rash in dermatomyositis
- progressive weakness, Gower’s sign (children)
- Polymyositis / Dermatomyositis
- Muscular dystrophies
- Duchenne - more severe, progresses faster, occurs < 5yrs old
- Becker - symptoms appear in teens/early adulthood
Peripheral pattern of weakness (LMN lesions) - Give differential for each short hx
- ascending paralysis, areflexia, post-infectious
- glove-and-stocking sensory loss, distal weakness, diabetic pt
- progressive distal weakness, pes cavus, foot drop
- subacute combined degeneration – sensory ataxia, UMN + LMN signs
- Guillain-Barré Syndrome (GBS)
- Diabetic polyneuropathy
- Charcot-Marie-Tooth disease
- B12 deficiency
Peripheral pattern of weakness (LMN lesions) - Give differential for each short hx
- sciatica, weakness in affected myotome, pain radiating along a nerve root
- saddle anaesthesia, bowel/bladder dysfunction – urgent referral!
- Cervical or lumbar radiculopathy
- Cauda equina syndrome
Central pattern of weakness (UMN lesions) - Give differential for each short hx
- sudden-onset focal neurological deficit, unilateral weakness, speech disturbance, visual field defect, sensory loss, hx of TIA / atrial fibrillation
- sudden-onset and severe headache, nausea/vomiting/seziures, reduced GCS, hx of hypertension / anticoagulation use
- Ischaemic stroke (MCA, ACA, PCA syndromes)
- Haemorrhagic stroke (intracerebral haemorrhage, SAH)
Central pattern of weakness (UMN lesions) - Give differential for each short hx
- optic neuritis, sensory symptoms, UMN signs, Lhermitte’s sign
Internuclear ophthalmoplegia
- Multiple Sclerosis (MS)
Central pattern of weakness (UMN lesions) - Give differential for each short hx
- Bilateral symptoms below lvl of lesion
(Bilateral paralysis + pain/temp loss, Preserved proprioception/vibration (dorsal columns spared))
- Spinal cord lesion
(Anterior cord syndrome)
Central pattern of weakness (UMN lesions) - Give differential for each short hx
- progressive asymmetric weakness, fasciculations, no sensory loss (mixed LMN + UMN signs)
- MND - Amyotrophic lateral sclerosis (ALS)
- bulbar onset = worse prognosis
.
Give a differential for each of the movement disorder hx
- resting tremor, rigidity, bradykinesia, postural instability, Parkinsonian gait
- chorea, personality change, dementia
- bilateral action tremor, improves with alcohol
- Parkinson’s disease
- Huntington’s disease
- Essential tremor
Cerebellum symptoms - DANISH
- Dysdiadochokinesia
- Ataxia (gait and posture)
- Nystagmus - vertical nystagmus
- Intention tremor
- Slurred, staccato speech
- Hypotonia/heel-shin test
“Blackouts” - differentials
- Seizure (epileptic)
- Syncope (cardiogenic)
- Hypoglycaemic episode
What are some causes of cerebellar problems?
(need to add more?)
- Excessive alcohol hx
- Toxins - mercury, lead
- Genetic predisposition - ie. cells of the cerebellar just degenerate faster than other cells in the body
- Hereditary ataxia (Friedrich’s)
- Stroke affecting the cerebellar
Peripheral neuropathy differentials
- Alcohol
- Diabetes
- Hypothyroid
- Vitamin deficiencies (B12/folate, B1/thiamine)
- Infection –> GBS
Spot diagnosis (3 findings + causes)
3rd nerve palsy
- left eye is in a ‘down and out’ position due unopposed action of SO and LR
- there is also a ptosis due to loss of innervation to levator palpebrae superiors
- and mydriasis due to loss of parasympathetic innervation to sphincter pupillae
.
- Causes: compression from tumour, PCOM aneurysm, trauma, infection
Spot diagnosis + causes
Trochlear nerve palsy
- only innervates SO - results in vertical diplopia when looking inferiorly due to loss of pulling the eye downwards
- pts may try and compensate by tucking their chin in and tilting head forwards
.
- Causes: vascular disease (diabetes), aneurysm
Spot diagnosis + causes
Abducens nerve palsy
- only innervates LR - results in unopposed adduction of eye, leading to a convergent squint
- pt will have horizontal diplopia
.
- Causes: tumour, MS, injury
Primary causes of headaches VS Secondary causes of headaches
