Medicine 4 Flashcards by Akash Srinivasan

What is internuclear ophthalmoplegia and what is it caused by?

Caused by damage to the medial longitudinal fasciculus which is responsible for allowing communication between the ipsilateral CN3 (adduction) and contralateral CN6 (abduction).
This leads to failure of adduction of the ipsilateral eye. Nystagmus in the abducting eye may be noted.

It is most commonly caused by multiple sclerosis (and stroke in older patients)

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What is the difference between bulbar and pseudobulbar palsy?

Bulbar: lower motor neurone palsy of CN 9 to 12.
Pseudobulbar: upper motor neurone palsy affecting CN 5, 7, 9-12.

Both cause dysphagia and dysarthria but pseudobulbar palsy will also cause lack of facial expression, difficulty chewing and emotional lability.

NOTE: key difference is that bulbar palsy causes LMN signs (e.g. tongue fasciculations) whereas pseudobulbar causes UMN signs (e.g. exaggerated gag reflex)

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What are the different types of motor neuron disease?

Amyotrophic lateral sclerosis (50%) - UMN and LMN signs
Primary lateral sclerosis - mainly UMN signs (spastic leg weakness and pseudobulbar palsy)
Progressive bulbar palsy - only affects CN 9-12
Progressive muscular atrophy - LMN signs only, affects distal to proximal (best prognosis)

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List some lower motor neurone signs.

Muscle wasting
Fasciculations
Hypotonia
Hyporeflexia

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List some causes of LMN signs.

DISTAL: Charcot-Marie-Tooth disease, paraneoplastic, lead poisoning, GBS, botulism
PROXIMAL: muscular dystrophy, myositis, Cushing’s, thyrotoxicosis, diabetic amyotrophy, alcohol
UNILATERAL: polio, mononeuropathy

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List some causes of peripheral sensory neuropathy.

Diabetes mellitus 
Alcohol abuse 
B12 deficiency 
Chronic renal failure 
Hypocalcaemia 
Vasculitis 
Drugs (e.g. isoniazid)

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What features of diabetic neuropathy can be seen in the lower limbs?

Distal sensory loss (gloves and stockings)
Bilateral loss of ankle jerk (due to sensory neuropathy)
Mononeuritis multiplex (foot drop)

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List some manifestations of autonomic neuropathy in diabetes mellitus.

Postural hypotension 
Gastroparesis 
Diarrhoea 
Urinary retention 
Erectile dysfunction

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List the main features of Charcot-Marie-Tooth disease.

Pes cavus 
Symmetrical distal muscle wasting (claw hand, champagne bottle led) 
Thickened nerves 
High stepping gait 
Weak foot and toe dorsiflexion
Absent ankle jerk 
Variable loss of sensation

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List some differentials for bilateral ptosis.

Myasthenia gravis
Myotonic dystrophy
Congenital
Senile 
Bilateral Horner's (RARE)

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Describe the typical presentation of Guillain-Barre syndrome.

Symmetrical ascending flaccid paralysis and sensory disturbance (paraesthesia)
Can cause autonomic neuropathy (labile BP)

NOTE: Miller-Fisher variant is characterised by ophthalmoplegia, ataxia and areflexia

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Which muscles are weak in a facial nerve palsy?

Fronatlis (raising eyebrows)
Orbicularis oculi (scrunching eyes) 
Orbicularis oris (smiling)

NOTE: UMN lesion spares frontalis and orbicularis oculi - if UMN then it may be due to a stroke so do other neuro exams

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List some causes of facial nerve palsy.

Idiopathic (Bell's palsy) - 75%
Vascular (stroke)
Multiple sclerosis 
Space-occupying lesion 
Vestibular schwannoma 
Meningioma
Ramsay-Hunt syndrome 
Parotid tumour 
Sarcoidosis 
Lyme disease

NOTE: patients may complain of hyperacusis due to paralysis of stapedius and aguesia (loss of taste)

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What causes Ramsay-Hunt syndrome?

Reactivation of VZV in the geniculate ganglion of CN7

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List some causes of Horner’s syndrome.

Multiple sclerosis
Pancoast tumour
Trauma (central line, carotid endarterectomy)
Cavernous sinus thrombosis

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What are the main features of oculomotor nerve palsy?

Ptosis (LPS)
Eye points down and out (unopposed superior oblique and lateral rectus)
Dilated pupils
May have ophthalmoplegia and diplopia

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List some causes of third nerve palsy.

MEDICAL: mononeuritis (DM), MS, midbrain infarction, migraine
SURGICAL: raised ICP (transtentorial herniation), cavernous sinus thrombosis, posterior communicating artery aneurysm

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What is a Holmes-Adie pupil?

Dilated pupil with no response to light and sluggish response to accommodation
Benign condition, more common in females

Also known as myotonic pupil and usually presents with sudden-onset blurred vision. Aetiology unknown.

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What are Argyll-Robertson pupils?

Small, irregular pupils
Accommodation intact
Reaction to light is lost
Atrophied and depigmented iris

Causes include neurosyphilis and DM (lesion in pretectal lesion)

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What is an RAPD (Marcus Gunn pupil)?

Minor constriction to direct light

Dilatation when moving light to abnormal light (due to defect in the afferent pathway)

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List some causes of RAPD.

Optic neuritis (MS)
Ischaemic optic/renal disease (central retinal artery occlusion)
Severe glaucoma
Direct optic nerve damage (trauma, tumour)
Retinal detachment (diagnosed with ultrasound B scan)
Severe macular degeneration
Retinal infection (CMV, herpes)

List some features of optic atrophy.

Reduced visual acuity 
Reduced colour vision 
Central scotoma 
Pale optic disc 
RAPD

Outline the visual pathway.

Retina
Optic nerve 
Optic chiasm (nasal fibres decussate)
Optic tract 
Lateral geniculate nucleus of thalamus 
Optic radiation (superior field = temporal; inferior field = parietal)
Visual cortex

A lesion at what point in the visual pathway causes homonymous hemianopia?

Contralateral defect beyond the optic chiasm (retrochiasmatic)
A larger defect suggests a larger lesion or it’s closer to the chiasm

NOTE: examine for ipsilateral hemiparesis and cerebellar signs

Which visual defect might you see in a middle cerebral artery stroke?

Homonymous hemianopia NOTE: MCA supplies the optic radiation in the temporal and parietal lobes

Which visual defect might you see in a posterior cerebral artery stroke?

Homonymous hemianopia with macular sparing (branch of MCA supplies the visual cortex) NOTE: patients will not have hemiparesis but may have cerebellar signs

List some causes of monocular blindness.

``` Eye problem (e.g. cornea, vitreous, retina) Optic nerve (optic neuropathy) ```

List some causes of bitemporal hemianopia.

Pituitary tumours | Craniopharyngioma (benign suprasellar tumour from Rathke's pouch)

What could cause a negative Rinne's test?

Negative = BC > AC True: conductive deafness False: complete sensorineural hearing loss

How is Weber's test interpreted?

SNHL: lateralises to normal ear Conductive: lateralises to abnormal ear

List some causes of conductive hearing loss.

``` Canal obstruction (wax, foreign body) Tympanic membrane perforation: trauma, infection Ossicle defects: otosclerosis, infection, fluid in middle ear ```

List some causes of sensorineural hearing loss.

``` Presbyacusis Drugs (gentamicin, vancomycin) Infection (meningitis, measles) Tumour (vestibular schwannoma) Alport syndrome (SNHL + haematuria) ```

Describe how dysphasia can be tested.

Nominal dysphasia: name three objects Receptive dysphasia: three-stage command Conductive dysphasia: repeat a sentence

What is the difference between dysarthria and dysphasia?

Dysarthria: impaired articulation of sound Dysphasia: impairment of language

List some causes of dysarthria.

Mouth lesions Pseudobulbar palsy Bulbar palsy Cerebellar lesion

Describe the different types of dysphasia.

Expressive: Broca's area damage (inferior frontal gyrus) - non-fluent speech but comprehension intact Receptive: Wernicke's area damage (superior temporal gyrus) - fluent but meaningless speech, comprehension impaired Conductive: arcuate fasciculus damage - comprehension intact, unable to repeat words/phrases

Which areas of skin tend to be affected by plaque psoriasis?

``` Extensors Behind the ears Scalp Umbilicus Sites of trauma (Koebner phenomenon) Auspitz sign (pinpoint bleeding at site of scraping) ``` DDx: fungal infection, lichen planus, Bowen's disease, dermatitis

List some different subtypes of psoriasis.

``` Plaque Guttate (drop lesions after Strep infection) Pustular (generalised or palmo-plantar) Erythrodermic Flexural ```

What are the five patterns of psoriatic arthritis?

``` Symmetrical polyarthritis Asymmetrical oligoarthritis DIP involvement Arthritis mutilans Psoriatic spondylopathy ```

List some complications of neurofibromatosis.

Epilepsy Sarcomatous change Scoliosis Learning difficulty

List some causes of cafe au lait spots.

NF1 Noonan syndrome McCune Albright syndrome (cafe au lait spots, polyostotic fibrous dysplasia and endocrinopathy (precocious puberty))

What are the main features of Peutz-Jeghers syndrome?

Autosomal dominant mutation of STK11 gene on chromosome 19 Leads to multiple mucocutaneous macules (on lips and oral mucosa) and GI hamartomatous polyps (can bleed/intussusception) They have an increased risk of colorectal cancer

List some causes of erythema multiforme.

Infection (HSV, mycoplasma, other (TB, histoplasmosis, Yersinia) Drugs (sulphonamides, NSAIDs, allopurinol) Severe form is called Stevens-Johnson syndrome (with mucosal ulceration and liver failure) DDx: tinea, discoid eczema

List some causes of erythema nodosum.

Systemic: sarcoidosis, IBD, Behcet's disease Infection: streptococcal, TB Drugs: sulphonamides, OCP NOTE: the pain begins before the skin changes

List some extra-articular features of rheumatoid arthritis.

Eyes: episcleritis, keratoconjunctivitis sicca Heart: pericarditis Lungs: pulmonary fibrosis Abdomen: splenomegaly (Felty) Urine: amyloidosis from chronic inflammation Skeletal: atlanto-axial subluxation Skin: rheumatoid nodules

Which surgical procedures might patients with rheumatoid arthritis undergo?

Carpal tunnel decompression Tendon repairs and transfers Ulna stylectomy Arthroplasty

What are the main side-effects of methotrexate?

Bone marrow suppression Hepatotoxicity Pulmonary fibrosis

What is Jaccoud arthropathy ?

Chronic non-erosive reversible joint disorder occurring due to repeated bouts of arthritis commonly associated with SLE Mimics rheumatoid arthritis but is caused by tendon contractures which are reducible on extension

Describe the pattern of symptoms seen in ankylosing spondylitis.

Back pain that is worst in the morning and improves with exercise NOTE: check for extra-articular manifestations as well (e.g. aortic regurgitation, ankylosing spondylitis, Achilles tendinitis, apical fibrosis, amyloidosis)

List some risk factors for gout.

``` Obesity Hypertension Drugs (thiazides, cytotoxic) Lymphoproliferative disorder Chronic renal failure Alcoholism Diet - purine rich foods ```