Leg weakness Flashcards
What are the causes of weak legs?
unilateral foot drop: DM, common peroneal nerve palsy, stroke, prolapsed disc, MS. Weak legs with no sensory loss: MND, polio, parasagittal meningioma. Chronic spastic paraparesis: MS, cord tumour (astrocytoma, haemangioblastoma, ependymoma), cord metastases, MND, syringomyelia, subacute combined degeneration of the cord, hereditary spastic paraparesis, taboparesis, histiocytosis X, parasites (eg schistosomiasis). Chronic flaccid paraparesis: peipheral neuropathy, myopathy (rare, arms also involved). Absent knee jerks and extensor plantars: combined cervical and lumbar disc disease, conus medullaris lesions, MAST (MND or myeloradiculitis, Friedraich’s ataxia, subacute combined degeneration of the cord(vit B12 deficiency), taboparesis
What are the 5 questions important to ask to aid diagnosis?
Was onset sudden? Are legs flaccid or spastic? Is there sensory loss? Is there loss of sphincter controls? Any signs of infection eg extradural abscess?
What are the symptoms/signs of spinal cord compression?
symptoms: spinal or root pain may precede leg weakness and sensory loss, arm weakness often less severe, bladder spinchter involvment (late - manifests as hesistancy, frequency and later as painless retention). Signs: look for motor, reflex and sensory level, normal findings above it, LMN at level and UMN below the level (but tone and reflexes usually absent in acute)
What are the causes of cord compression?
secondary malignancy in spine is commonest. Also: infection (epidural abscess), cervical disc polapse, haematoma (warfarin), intrinsic cord tumour, atlanto-axial subluxation, myeloma.
What is the differential diagnosis of spinal cord compression?
transverse myelitis, MS, carcinomatous meningitis, cord vasculitis (PAN, syphilis), spinal artery thrombosis, trauma, dissecting aneurysm, Guillain-Barre
What is the treatment for spinal cord compression?
if malignancy - dexamethasone IV 4mg/6h, radiotherapy or chemotherapy +/- decompressive laminectomy
What is the difference between lesions high up the spinal cord and those lower down?
cauda equina and conus medullaris: leg weakness is flaccid and reflexic. Higher lesions: legs are spastic and hyperreflexic
What are the signs of conus medullaris lesions?
mixed UMN and LMN leg weakness, early urinary retention and constipation, back pain, sacral sensory disturbance, erectile dysfunction
What are the signs of cauda equina lesions?
back pain and radicular pain down the legs, asymmetrical, atrophic, areflexic paralysis of the legs, sensory loss in a root distribution, decreased sphincter tone
