Neurology Flashcards
How do you test CNII?
To test the optic nerve;
Visual acuity (test each eye individually using the best corrected vision)
Visual fields: test all four quadrants of each eye individually ensuring hands are equidistant between examiner and examinee
Pupil: direct and consensual pupillary reflex (afferent limb), accommodation, swinging flashlight test.
Fundoscopy: optic disc oedema, optic disc pallor, venous pulsations, haemorrhages,
What sort of things do you inspect in a general neurological exam and mental status examination?
Vitals (pulse, BP, temperature) Meningismus, head injury/bruises, battles sign, raccoon eyes, tongue biting CVS: carotid bruins, heart murmurs Mental status: LOC, AVPU, GCS (out of 15) MMSE (out of 30) MoCA Frontal lobe testing for perseveration Clock drawing Orientation to time person and place
What are the causes of rapid onset of bilateral blindness?
Bilateral occipital lobe infarction, bilateral occipital lobe trauma, bilateral optic nerve damage (as with methyl alcohol poisoning), hysteria.
What are the causes of sudden blindness in one eye?
Retinal artery occlusion, retinal vein occlusion, temporal arteritis, optic neuritis, migraine, non arteritis ischeamic optic neuropathy.
What causes bilateral blindness of gradual onset?
Cateracts, acute glaucoma, macular degeneration, diabetic retinopathy (vitreous haemorrhages), bilateral optic nerve damage
What controls the parasympathetic supply to the pupils?
Parasympathetic supply to the pupils is supplied by the Edinger Westphal nucleus of the third cranial nerve. Stimulation of these fibres causes miosis (constriction of the pupil)
What supplies the sympathetic stimulation of the pupils?
Fibres from the hypothalamus go to the cilia spinal centre in the spinal cord at C8, T1, and T2 and synapse. Second order neurones exit via the anterior ramus in the thoracic trunk and synapse in the superior cervical ganglion in the neck. Third order neurones travel from here with the internal carotid artery to the eye. Stimulation of the sympathetic fibres causes myadriasis (dilation of the pupils).
What controls the efferent path of the pupillary reflexes?
Efferent motor fibres from the occulomotor nucleus travel in the wall of the cavernous sinus, alongside the trochlear, abducens and V1 CNs. All of these nerves exit together through the superior orbital fissure. The irisoconstrictor fibres terminate in the ciliary ganglion, where the post ganglionic fibres arise to enervate the iris.
What are the different functions of the occulomotor nerve?
Sympathetic supply and parasympathetic supply to the iris (sphincter papillae)
Enervates elevator palpebrae superioris (opening of the eyelid)
Controls superior rectus, inferior rectus, medial rectus, and inferior oblique
What muscle, and what cranial nerve, is responsible for elevating the eye when adducted?
Inferior oblique CN3
Check me
Whilst adducted, which CN and muscles elevate and depress the eye?
Whilst adducted, the inferior oblique (CN3) elevates the eye, and the superior oblique (CN4) depresses it.
What muscles and cranial nerve is responsible for lateral movement of the eye?
Lateral rectus (CN6)
What muscle and nerve is responsible for the medial horizontal movement of the eye?
Medial rectus (CN3)
What are the features of a third nerve lesion?
Complete potsis (with a complete lesion) Divergent strabismus (eye is 'down and out') Dilated pupil which is in reactive to light (but the consensual reaction in the opposite eye is intact) Unreactive to accommodation
What are the causes of a third nerve palsy?
Generally caused by trauma or idiopathic.
Central causes include vascular lesions in the brainstem, tumours, and rarely demyelination.
Peripheral causes include: compressive lesions (such as an aneurysm of the posterior communicating artery), tumour, basal meningitis, nasopharyngeal carcinoma or orbital lesions)
Also ischeamia, or infarction as in arteritis, diabetes mellitus, and migraine.
What are the features of a fourth nerve lesion?
Patient cannot look in and down (think walking down stairs).
Patient may walk with a head tilt.
An isolated fourth nerve palsy is rare and is usually idiopathic or related to trauma. It may occasionally occur due to lesions of the cerebral peduncles.
What are the features of a sixth nerve palsy?
Failure of the lateral movement, convergent strabismus, and Diplopia. These signs are maximal upon looking to the affected side, and the images are horizontal and parallel to each other.
What are the causes of a sixth nerve palsy?
Mono neuritis multiplex, and raised intracranial pressure.
Bilateral sixth nerve palsys are caused by trauma or wernicke’s encephalopathy
Unilateral lesions are commonly idiopathic or related to trauma. They may have a central (eg vascular lesion or tumour), or peripheral (raised ICP or diabetes mellitus) origin.
What is intern unclear opthalmaplegia?
Inter nuclear opthalmaplegia occurs when the is loss of adduction in one eye and there is nystagmus is the abducting eye, it occurs as a result of a lesion in the medial longitudinal fasiculus. This can be caused by MS or vascular disease.
What are the causes of horizontal nystagmus?
Horizontal nystagmus is caused by a vestibular lesion, or a cerebellar lesion.
What causes vertical nystagmus?
Vertical nystagmus is caused by brainstem lesions.
What can cause of loss of pain and temperature sensation of the face, but not of touch and proprioception?
This is caused by lesions of the medulla or upper spinal cord.
How do you test the trigeminal nerve?
Test the corneal reflex (note, this also tests CN7 and orbicularis occuli)
Test pain and touch.
Inspect for temporal and massater wasting
Test the massater strength
Test the jaw jerk/massater reflex
What are the symptoms of a seventh nerve palsy?
Difficulty with speaking or keeping fluids in the mouth
Facial asymmetry
Dry eyes or dry mouth (provides stimulus to the lacrimal, sublingual and submandibular glands)
Hyperacusis (paralysis of the stapedius muscle)
The seventh cranial nerve also provides taste for the anterior 2/3 s of the tongue.
How do you inspect the seventh cranial nerve?
Check for facial asymmetry,
Test for muscle power (ask patient to look up looking for muscle wrinkling, push against corrugation for strength).
Ask patient to puff out cheeks
Shut eyes tightly (check for bells phenomenon to make sure that they really are trying. Eye goes up)
Ask patient to grin.
If a lower motor neuron lesion is present check the ear and palate for vesicles of herpes zoster (Ramsay hunt syndrome)
What causes bilateral facial weakness?
Guillain barre, sarc lidos is, bilateral parotid disease, Lyme disease,or mono neuritis multiplex.
Myopathy and myasenia gravis can cause bilateral facial weakness.
How do you test CN12?
Cranial nerve twelve is the hypoglossal nerve. Check for tongue muscle bulk, fasiculations, and strength.
How do you test cranial nerve eleven?
Test cranial nerve eleven (the acessory spinal nerve) by testing trapezius and sternocleidomastd strength.
How do you test cranial nerves nine and ten?
Cranial nerves nine and ten are the glossy pharyngeal and vagus nerves.
To test these check palatal elevation, gag reflex, vocal cord function, swallowing, taste of the posterior third of the tongue.
How do you examine the eight cranial nerve?
Vestibulococlear disease
Check for tenderness of the pinna. Feel for pre and post auricular nodes. Use otoscope to inspect the ear drum.
Test hearing in each ear: finger rubbing/ whispering numbers
Rinnes test: mastoid process and external meats. Rhine positive is when air conduction is better, this is a positive test (normal or sensorineural deafness)
Webers test: put tuning fork in middle of head. A patient with conduction deafness finds the sound louder in the abnormal ear, nerve conduction deafness sound is heard in the normal ear.
Vestibular tests: hall pike manoeuvre to test for benign paroxysmal positioning vertigo.
What is the MRC muscle strength scale?
5- full power
4- submaximal power against resistance (can be 4+, 4, or 4-)
3- full range of movement against gravity without resistance
2- full range of movement with gravity removed
1- muscle flicker
0- no muscle contraction
Describe the characteristic on examination of a lower motor neuron deficit?
Muscle tone is flaccid. There are some fasiculations Reflexes are decreased Down going (flexor) Plantar reflex Weakness is present.
Describe the characteristics of an upper motor neurone lesion?
Tone is spastic. No involuntary movements. Increased reflexes Up going (extensor) reflex Weakness is present.
Describe the characteristics of an extra pyramidal motor deficit.
Muscle tone is rigid. Involuntary movements are present (eg tremor) Reflexes are normal Down going plantar reflex Absent weakness
What is the nerve root of the biceps reflex?
C5/6
What is the nerve root or the brachioradialis reflex?
C6
What is the nerve root of the triceps reflex?
C7 is the nerve root of the triceps reflex
What is the nerve root of the knee jerk reflex?
L2/L3/L4
What is the scoring system for deep tendon reflexes?
0 - absent 1 - depressed 2 - normal 3 - increased 4 - Clonus (>4 beats)
What are the two categories of sensation and how do you test for them?
Spinothalamic tract: pain and temperature
Dorsal column tract: proprioception and vibration
What is the discriminatory touch pathway?
The discriminatory touch pathway is found in the dorsal columns.
The sensory nerve detects sensory information and travels up either the fasiculus cuneatus (T6 and above) or the fasiculus gracilus (Below T6). These neurones synapse in the cuneate and gracile nucleus. The second neuron then crosses via the internal arcuate fibres and goes up the medial lemniscus. It then synapses in the VP thalamus, and connects to the sensory cortex.
Describe the spinothalamic pathway.
The spinothalamic pathway carries information regarding pain and temperature from the body.
The first order neuron synapses within 1-2 spinal levels of their entry. The second order neurones then decussate at the level of the synapse. The second order neurones the ascend up the spinothalamic tract, up the spinal lemniscus, and synapse in the VP thalamus.
Describe the cortico spinal motor pathway.
Signal starts in the upper motor neurones in the upper motor cortex. This then travels via the internal capsule, through the pyramids, and decussates at the level of the pyramidal decussation in the medulla, and continues to travel down the lateral cortico spinal tract. The upper motor neuron then synapses in the spinal cord at the level that the lower motor neuron leaves and enervates the body.
What are the diagnostic uses of a lumbar puncture?
A lumbar puncture is diagnostic for CNS infections (meningitis, encephalitis), inflammatory disorders (MS, guillame barre, vasculitis), subarachnoid heamorrhage (if CT negative), CNS neoplasm (neoplasticism meningitis)
What conditions may a lumbar puncture be therapeutic for?
A lumber puncture may be therapeutic for:
Administering anaesthesia, chemotherapy, contrast media,
or for decreasing intracranial pressure in pseudo tumour cerebri or normal pressure hydrocephalus.
What are the contraindications of a lumbar puncture?
Raised intracranial pressure (from a mass lesion) that may lead to cerebral hernia ton.
Infection of skin over the wound site
Low platelets or treatment with anticoagulation
Uncooperative patient
What’s the difference between an upper motor facial lesion and a lower motor facial lesion?
What is the difference between a facial nerve upper motor neuron lesion and a lower motor neuron lesion?
What are the opthalmalogical causes of acute vision loss?
Acute angle closure glaucoma, vitreous heamorrhage, retinal detachment, uveitis, trauma.
Endophthalmitis
What are the causes of acute loss so vision associated with the optic nerve?
Optic neuritis, anterior ischeamic optic neuropathy (arteritic and non arteritic), compression by space occupying lesions (aneurysm)
What are the vascular causes of an acute loss of vision?
TIA/amorosis fugax, central retinal artery or vein occlusion, carotid cavernous sinus fistula
What are the different causes of horner’s syndrome?
Horner’s syndrome is caused by a sympathetic defect that occurs along the path to the head, eye, and neck. Lesions can occur anywhere along the sympathetic pathway on the affected side.
1st order neuron (central): hypothalamus, medulla (lateral medulla stroke= Wallenberg syndrome), spinal tumours, MS, intracranial tumours, syringomyelia.
2nd order neuron (preganglionic): pancoast tumour, paravetebral mass, Carotid artery dissection.
3rd Order neuron (post ganglionic): cluster headache, cavernous sinus mass, trauma, carotid artery dissection
What are the common symptoms seen in vitamin B12 deficiency?
Common symptoms seen in vitamin B12 deficiency include: sob, pallor, ,acrobatic aneamia, fatigue, chest pain. Palpitations.
Confusion, or change in mental status
Decreased sense of vibration
Distal numbness and parathesia
Weakness and UMM findings, diarrhoea, and anorexia
