OSCE DDX Flashcards
DDx for spastic parapearesis with dorsal column sigsn
- cervical myelopathy
- friedreich’s ataxia
- multiplse sclerosis
- taboparesis
- subacute combined degenration of the cord
key features in cervical myelopathy
fasciculations and segmental wasting and weakness, usually corresponding to C5-C7
absence and Inversion (extension to the lower segments) of bicep and supinator reflexes + dorsal column signs
triceps is brisk
sensory loss to all mdoalities in the c5-c7 dermatomes
MYELOPATHY HAND SIGN or FINGER escape sign - sensitive indicator of pyramidal weakness in uppet limbs (deficient adduction and/or extension of the medial 2-3 fingers. can also be seen in ulnar nerve palsy - sensory testing helps differentiate it.
in lower limbs there is spastic paraparesis and dorsal column signs
DDx for spastic paraparesis
- Cord compression - look for sensory level
- Multiple sclerosis - dorsal column and cerebellar and eye signs
- Trauma - sensory level, scars, deformity
- MND - no sensory signs. Fasciculations, bulbar involvements, wasting of small muscles of hand
- Syringomyelkia - dissociated loss of sensation (preserved dorsal columns), LMN in uopper limbs, Horner’s
- Anterior spinal artery occlusion - preserved dorsal column sensation, AF?
- SCDSC - dorsal column loss, absent ankle jerks but babinski positive, anaemia, jaundice, glossitis
- friedreich’s ataxia - dorsal column signs, pes cavus, cerebellar signs
- cervical myelopathy
- Parasagittal tumour (eg meningioma) - Hx of headaches, papiloedema
- Hereditaqry spastic paraparesis - no sensory, upper limbs normal
Tunnel vision ddx
glaucoma, retinal damage or papilloedema. ‘Tubular’ vision is often functional.
Enlarged blind spot ddx
papiloedema
Unilateral field loss: ddx
blindness in one eye caused by devastating damage to the eye, its blood supply, or optic nerve
Central scotoma:ddx
a hole in the visual field (macular degeneration, vascular lesion or, if bilateral, toxins). If bilateral, may indicate a very small defect in the corresponding area of the occipital cortex (multiple sclerosis).
Bitemporal hemianopia: ddx
the nasal half of both retinas and, therefore, the temporal half of each visual field is lost (damage to the centre of the optic chiasm such as pituitary tumour, craniopharyngioma, suprasellar meningioma).
Homonymous hemianopia: ddx
ay be ‘left’ or ‘right’. Commonly seen in stroke patients. The right or left side of vision in both eyes is lost (e.g. the nasal field in the right eye and the temporal field in the left eye). If the central part of vision (corresponding to the macula) is spared, the lesion is likely in the optic radiation, without macula sparring, the lesion is in the optic tract.
Homonymous quadrantanopia:
corresponding quarters of the vision is lost in each eye (e.g. the upper temporal field in the right and the upper nasal field in the left).
* Upper quadrantanopias (4) suggest a lesion in the temporal lobe. * Lower quadrantanopias (5) suggest a lesion in the parietal lobe.
Optic disc swelling appearance and ddx
Appearance
* The optic disc is raised, swollen, and enlarged. * The disc often appears darker in colour. * The margins of the disc are blurred and become indistinct from the adjacent retina. * Retinal vessels can be seen arching down from the raised disc towards the peripheral retina. * In severe cases retinal haemorrhage may be seen around the disc.
The nervous system The term papilloedema is often, incorrectly, used to describe optic disc swelling. ‘Papilloedema’ is swelling of the optic disc due to raised intracranial pressure.
Causes
* Space occupying lesions including intracranial malignancy, subdural haematoma, and cerebral abscess. * Subarachnoid haemorrhage (commonly associated with vitreous haemorrhage). * Chronic meningitis. * Idiopathic intracranial hypertension (IIH). * Malignant hypertension. * Ischaemic optic neuropathy.
optic atrophy appearance and causes
Appearance
Pale optic disc due to loss of nerve fibres in the optic nerve head.
Cause
* Ischaemic optic neuropathy. * Optic neuritis. * Trauma. * Optic nerve compression.
features of MND
- UMN and LMN pattern of weakness.
- Fasciculations almost always present.
- Reflexes normal or ↑ until later in the disease.
- Plantar response is up-going.
- External ocular muscles almost never involved.
- No sensory disturbance (distinguishing the presentation from a polyneuropathy).
features of migraine
- Unilateral—rarely crosses the midline*.
- Throbbing/pounding headache.
- Associated with photophobia, nausea, vomiting, and neck stiffness.
- May have preceding aura.
features of raised intracranial pressure
- Generalized headache, worse when lying down, straining, coughing, on exertion or in the morning.
- Headache may wake the patient in the early hours.
- May be associated with drowsiness, vomiting, and focal neurology.
