Mononeuropathies Flashcards
What is the most common cause of radial nerve palsy?
Entrapment at the spinal groove known as ‘Saturday night palsy’
Describe the presentation of radial nerve palsy
Wrist and finger drop
Usually painless
Weak wrist and finger extension
Weak elbow flexion in mid-pronation
Which muscles are weakened by a radial nerve palsy?
Extensor carpi radialis longus
Extensor diggitorum communis
Brachioradialis
What is the most common cause of ulnar nerve palsy?
Entrapment of the ulnar groove (medial epicondyle of humerus)
Ulnar nerve palsy is usually painful. T/F?
False - it is usually painless
Describe the presentation fo ulnar nerve palsy
Weak index finger abduction, wrist flexion and thumb adduction
Sensory disturbance
Which muscles are weakened by ulnar nerve palsy?
Dorsal interosseous
Abductor digits minimis
Flexor carpi ulnaris
Adductor pollicus
What is the most common cause of median nerve palsy?
Entrapment within the carpal tunnel at the wrist
Describe the presentation of median nerve palsy
Intermittent nocturnal pain
Numbness and tingling, often relieved by shaking of the hand
Weak grip
Positive tinels or phalen’s test
What is the most common cause of median nerve II anterior interosseous branch palsy?
Trauma to the forearm
Describe the presentation of median nerve II anterior interosseous branch palsy?
History. of forearm pain
Patient may complain of ‘weak grip’ of keys
What is the most common cause of femoral nerve palsy?
Haemorrhage
Trauma
Describe the presentation of femoral nerve palsy?
Weak knee extension, hip flexion and numbness in medial shin
What is the most common cause of peroneal nerve palsy?
Entrapment of the fibular head
Describe the presentation of common peroneal nerve palsy?
History of trauma, surgery or external compression
Acute onset of foot drop and sensory disturbance
Painless
What are the common causes of mono neuritis multiplex?
Diabetes Vasculitis - polyarteritis nodosa Rheumatological - RA, lupus, sjogre's syndrome Infective - hep c, HIV Sarcoidosis Lymphoma
What signs/symptoms occur in large myelinated sensory fibre neuropathy?
Sensory ataxia
Loss of vibration sense
Possible: numbness and tingling
What signs/symptoms occur in large myelinated memory fibre neuropathy?
Weakness
Muscle atrophy
What signs/symptoms occur in small thinly myelinated or unmyelinated sensory fibre neuropathy?
Impaired pin prick response / temperature sensation
Painful burning, numbness and tingling
What signs/symptoms occur in autonomic neuropathy?
Postural hypotension
Erectile dysfunction
GI disturbance
Abnormal sweating
Describe the presentation of length dependent axonal neuropathy?
Occurs in patients >50 years
Diffuse involvement of peripheral nerves which is symmetrical and slowly progressive with no significant sensory ataxia
What are the possible causes of length dependent axonal neuropathy>
Diabetes Alcohol Folate/B12/thiamine/B6 deficiency RA, lupus, vasculitis, Renal failure, hypothyroidism Drugs HIV, hep B/C Charcot Marie tooth Myeloma Paraneoplastic Critical illness
Guillain Barre syndrome occurs post-infection. Which infections can commonly result in GBS?
Campylobacter
CMV
EBV
Describe the presentation of Guillain barre syndrome?
Progressive ascending weakness over a period fo days
Flaccidity
Quadraparesis
Areflexia
Possible respiratory, bulbar, autonomic involvement
How is Guillain barre syndrome treated?
IV immunoglobulin or aphaeresis
What is the chronic form of Guillain barre syndrome?
CIDP
What are the possible symptoms of muscle disorders?
Proximal limb weakness - difficulty raising arms above head, arising from a seated position
Facial weakness - characteristic myopathic faces, drooling
Eyes - ptosis, ophthalmoplegia
Bulbar - dysarthria, dysphagia
Neck and spine - head drop, scoliosis
Respiratory - breathlessness
Myocardial - exercise intolerance, palpitations
What are the possible causes of muscle disease?
Muscular dystrophies Metabolic muscle disorders (glycogen storage diseases, defects of fatty acid metabolism) Mitochondrial disorders Myotonic dystropies Inflammatory muscle disorders Neuromuscular junction disorders
Describe the pathogenesis of myasthenia gravis?
Autoimmune disorder in which antibodies bind to and block the ACH receptor at the post synaptic neuromuscular junction
What other conditions is myasthenia gravis associated with?
Autoimmune disorders
Thymus hyperplasia
Thymoma
What age groups are typically affected by myasthenia gravis?
Women in their 20s
Older men in their 70s
What are the symptoms of myasthenia gravis?
Fatiguable weakness of ocular, bulbar, neck, respiratory and/or limb muscles
How is myasthenia gravis managed?
Pyridostigmine (anti-ACH esterase)
Immunosuppressive therapies such as steroids, IV immunoglobulins
