Neuro II - First Aid Flashcards
A 33 year old male presents with left-sided hearing loss. Symptoms began shortly after going to the shooting range for the first time, he didn’t have ear plugs. What results would you expect to see from the Rinne and Weber tests?
He’s got conductive hearing loss from a popped ear drum. The Rinne test will be abnormal, with left-sided bone hearing better than left-sided air hearing. The Weber test will cause the sound to localize to the left ear.
A 27 year old female presents with right-sided hearing loss and vertigo. You think she had a viral infection that caused these symptoms. What results would you expect to see from the Rinne and Weber tests?
She likely has vestibular labrynthitis. This causes sensorineural hearing loss. Her Rinne test will be normal, with right-sided air hearing better than right-sided bone hearing. Her Weber test will cause localization of the sound to her good ear, the left side.
A 79 year old man presents with bilateral hearing loss. You determine that this is a result of aging. What region of the cochlear duct is most likely causing hearing loss in this patient?
The part of the basilar membrane that vibrates most with high frequency sounds is the base (closest to the oval and round windows). This region becomes stiff and vibrates less with age, causing hearing loss of high-frequency sounds first.
A patient presents to the clinic complaining of difficulty standing, he keeps falling to his left. He says that he feels like the left side of his body is completely uncoordinated and he overshoots grabbing things with his left hand. Where in the cerebellum does he likely have a lesion?
The left lateral cerebellar hemisphere is responsible for receiving right cortical input. Input is received through the middle cerebellar peduncle. The cerebellum then relays feedback via the dentate nuclei to the right cortex. Deficits in this system will cause problems with modulation and coordination of motor movements because the cortex and cerebellum are no longer in communication. Lesions could be anywhere along this tract. Note that input is received from the contralateral cerebral cortex and output sent to the same contralateral cortex.
A patient presents to the clinic with difficulty standing upright and maintaining his gaze in a single direction. Where in the cerebellum might this patient have a lesion?
Vestibulocerebellum. This region of the cerebellum receives direct input from the vestibular nerves. It is responsible for suppressing the vestibuloccular reflex and allowing eyes to stay fixed on an object while the head is rotating. Additionally, the medial region of the cerebellum is responsible for balance and truncal coordination, which is why the patient can’t stand upright.
What would happen if you had a genetic mutation that eliminated connections between granule cells and Purkinje cells in cerebellar gray matter?
Mossy afferent fibers enter the cerebellum and some synapse directly on the deep nuclei (dentate, emboliform, globose, fastigial), exciting them. Some continue to synapse on the granule cells to excite them. Granule cells then excite Purkinje cells, which in turn inhibit the deep nuclei. Normally this excitation and inhibition of the deep nuclei allows us to fine tune movements. Without the inhibitory Purkinje cell action, movements would be uncoordinated.
What is the sole cerebellar input that provides climbing fibers?
Inferior olive. These are thought to inhibit incorrect movements because they synapse directly on the Purkinje cells and thus cause rapid inhibition.
A patient presents with right-sided proprioceptive deficits. MRI reveals a lesion that prohibits proprioceptive fibers from entering the cerebellum. Where is the likely location of the lesion?
Inferior cerebellar peduncle, this is the location of ipsilateral proprioceptive cerebellar input.
A patient presents to the clinic complaining of rapid onset eye problems. On forward gaze the patient’s eyes deviate to the left. Physical exam reveals inability to produce voluntary horizontal saccades to the patient’s right side. When the patient’s gaze is directed to the left, nystagmus is greatest. Where does he most likely have a lesion?
The left frontal eye field (FEF) or the right paramedian pontine reticular formation (PPRF). When you decide to voluntarily look RIGHT, the LEFT FEF initiates the command. The command then travels to the RIGHT PPRF. The PPRF transmits the signal to the RIGHT CN VI nucleus causing contraction of the right lateral rectus. The signal from the CN VI nucleus also travels to the LEFT CN III nucleus via the MLF, causing the LEFT medial rectus to contract.
If a patient presents with a frontal eye field lesion, will the eyes deviate towards or away from the side of the lesion? What if the lesion was in the paramedian pontine reticular formation?
FEF: eyes deviate toward the side of the lesion on forward gaze. PPRF: eyes deviate away from the side of the lesion on forward gaze.
A patient presents with an inability to look up over the past few days. MRI reveals a pineal gland tumor. What is causing her to present this way?
The pinealoma can compress the superior colliculi of the midbrain, which is the conjugate vertical gaze center.
Your grandma has a stroke that diminishes the activity of every single cranial nerve except for one. What portion of her brain was affected by the stroke?
Probably the thalamus. CN I is the only cranial nerve without thalamic relay to the cortex.
A patient comes to see you for a routine eye exam. You report that conjugate gaze was normal in all cardinal directions and that pupils were equal, round, reactive to light and accommodation. What parts of your report tell us that cranial nerve III is fully in tact?
1) Cardinal directions tell us the SR, IR, MR & IO are all functioning. 2) Equally reactive to light and accommodation tells us that the pathway from retinal ganglion cells -> Edinger-Westphal nucleus -> parasympathetic fibers that innervate the sphincter pupillae and ciliary muscles are in tact on both sides. 3) The fact that the patient’s eyes are open tells us CN III innervation of levator palpebrae is unaffected.
A patient presents to the ED with a stroke. Imaging reveals infarction of areas in the midbrain. What cranial nerves may be affected?
III and IV nuclei are located in the tegmentum of the midbrain
A patient presents to the ED with a stroke. Imaging reveals infarction of areas in the pons. What cranial nerves may be affected?
V, VI, VII and VIII nuclei are located in the tegmentum of the pons.
A patient presents to the ED with a stroke. Imaging reveals infarction of areas in the medulla. What cranial nerves may be affected?
IX, X and XII nuclei are located in the tegmentum of the medulla.
After a terrible motorcycle accident, you rush to the scene with your pen light. Pupils are equal and reactive to light, however, the patient only closes the right eye when you touch his left cornea. What cranial nerve is affected in this patient?
CN VII on the left, after the facial motor nucleus. The afferent limb of the corneal reflex is V1. V1 travels up to the spinal Vth nucleus where it synapses. The spinal Vth nucleus then activates bilateral facial motor nuclei to fire the palpebral part of the orbicularis oculi.
Afferent and efferent pathways in the jaw jerk reflex
Afferent = V3 muscle spindle fiber from masseter. Efferent = V3 motor neuron to masseter
A patient comes to see you after hitting his head on the diving board. When you shine your light into this left pupil, it stays dilated and the right pupil constricts. What cranial nerve is likely affected?
Left CN III. When you shine the light in the left eye, the retinal ganglion cells transmit the signal up CN II. CN II sends some fibers to the pretectal nucleus. The pretectal nucleus sends fibers to the Edinger-Westphal nucleus. The Edinger-Westphal nucleus sends out parasympathetic fibers that synapse in the ciliary ganglion. The ciliary ganglion sends out fibers that cause the sphincter pupillae to fire.
A patient comes to the ED suffering from a terrible bout of impetigo on his face. You send him home with some topical antibiotics. Two days later he returns complaining of double vision and decreased sensation on his upper lip and nose. Physical exam reveals absence of corneal reflex when the right eye is touched and complete paralysis of the right extra-ocular muscles (opthalmoplegia). What is causing his symptoms?
Veins of the face drain through the cavernous sinus. His impetigo infection spread into the cavernous sinus and caused thrombosis of the veins in there, compressing extra ocular CNs III, IV and VI and sensory CNs V1, V2.
Is the right or left trigeminal nerve lesioned in this patient?
Right. The weak pterygoid muscles are overcome by the normal pterygoid muscles on his left side, causing the jaw to deviate toward the side of the lesion.
A patient presents to your clinic looking like this. What cranial nerve is affected and where is the lesion?
Note that his forehead is flattened out, this indicates a CN VII LMN lesion because the forehead has bilateral UMN input and would maintain tonicity if an UMN were lesioned.
A patient presents to the clinic complaining of a dry right eye because he cannot close it. He also says that food has lost some taste. Physical exam reveals a drooping left corner of the mouth. What are possible etiologies of this condition?
This patient is presenting with symptoms of facial nucleus damage. When idiopathic, this is called Bell’s Palsy. It can also be a complication of AIDS, Lyme, HSV, HZV, Sarcoidosis, Tumors or Diabetes.
You take a big bite of your wife’s ice cream cone while she isn’t looking. When she notices she tells you to open your mouth so she can see if you are the culprit. What muscles did you use to bite and what ones do you use to expose yourself as the culprit?
Bite muscles: Masseter, Medial Pterygoid and Temporalis. Open muscle: Lateral pterygoid. “Lateral Lowers the jaw, all the rest bite”
You are sitting in church and have to hold to hymn book a few feet in front of your face so you can read the words. How is what you have different from the 80 year old lady who has the same symptoms sitting next to you.
You have hyperopia, which is characterized by an eye too short, causing the image to be focused behind the retina. She has presbyopia, characterized by decreased accommodation due to sclerosis and decreased elasticity of the lens. Both of these are fixed with a convergent lens.
You need to sit in the front of your classes to be able to see what is on the powerpoint. What type of lens do you need to correct your vision?
Divergent lens. You have myopia, characterized by an eye too long which causes the image to be focused in front of the retina.
Your optometrist tells you that you have an astigmatism. What type of lens do you need to correct your vision?
Cylindrical lens. An astigmatism is characterized by abnormal curvature of the cornea that results in different focal power in different axis that creates multiple focal points.
A 16 year old girl presents to the clinic with the eye condition shown below. She also complains of bilateral joint pain in the knees, ankles, wrist and small joints of the hands and toes. What other systemic inflammatory disorders may present with this eye condition?
She has uveitis from juvenile idiopathic arthritis. Rheumatoid arthritis, sarcoid, TB and HLA-B27 associated conditions may present with uveitis.
A 52 year old man with AIDS presents to the clinic with increasing blindness. His fundoscopic exam is shown below. What are possible viral etiologies of this condition?
He has viral retinitis, CMV being the most common cause of blindness in patients with AIDS due to immunosuppression. Blindness happens as a result of retinal necrosis and scarring. HSV and HZV can also cause retinitis.
A 77 year old woman presents with acute, painless vision loss in her left eye. Fundoscopic exam is shown below. What is your diagnosis?
Central retinal artery occlusion, characterized by retinal whitening and a cherry red spot.
A 37 year old man presents with increasing intraocular pressure. What regions of his eye may be dysfunctional and causing increased aqueous humor?
Anything along the aqueous humor pathway: it is secreted by the ciliary processes into the posterior chamber, then enters the anterior chamber via the pupil, then percolates through trabecular meshwork and exits via the canal of Schlemm.
A 27 year old female presents with blurry vision in her right eye. Two months ago she experienced onset of facial weakness that got better. Labs reveal oligoclonal bands in her CSF. What cells are being destroyed in her CNS?
Oligodendrocytes are destroyed in patients with MS.
A 34 year old man presents to the clinic with rapid onset weakness of all extremities. He had an upper respiratory infection a couple of days ago. What cells are being destroyed in this patient?
Schwann cells are destroyed in patients with Guillain-Barre.
A 19 year old male presents complaining that the FBI is following him everywhere because he is going to take over the country. What regions of this patient’s brain may be over synthesizing dopamine?
In schizophrenia, too much dopamine may be due to overactivity of the ventral tegmentum and substantia nigra pars compacta.
A 22 year old new mother comes to see you 3 months after her child’s birth because she is feeling anxious and depressed. What region of her brain may have decreased activity?
In anxiety and depression, 5-HT is decreased, which is synthesized in the raphe nucleus. In an
A 91 year old man is brought to you by his son complaining of personality changes, loss of memory and inability to follow directions. What region of this patients brain may show degeneration?
ACh is decreased in Alzheimers. ACh is synthesized in the Basal nucleus of Meynert.
A 55 year old man is brought to the clinic because of increased angry outbursts lately. You notice a slow, snake like tremor in his hands. What regions of this patient’s brain may have decreased activity?
ACh and GABA are decreased in Huntington’s. ACh is synthesized in the basal nucleus of Meynert. GABA is synthesized in the nucleus accumbens.
Regions of the brain that can be affected by metabolites in the blood?
OVLT: osmotic. Neurohypophysis: ADH release. Area postrema: makes you vomit.
What are the functions of the hypothalamus?
“TAN HATS”: Thirst, Anterior pituitary regulation, Neurohypophysis, Hunger, Autonomic, Temperature, Sex.
Inputs to the hypothalamus
Area postrema responds to emetics. OVLT sensed changes in osmolarity.
A patient is involved in a car accident that traumatically damages his brain. Shortly thereafter he develops diabetes insipid us. What region of his brain was damaged?
Supraoptic nucleus of the hypothalamus. This is the nucleus responsible for synthesis of ADH, which will be released by the posterior pituitary.
A 32 year old woman starts to nest in her house the night before she gives birth to her child. What region of her brain is causing her to do this?
The paraventricular nucleus of the hypothalamus is responsible for synthesizing oxytocin, which will be released by the posterior pituitary.
A 17 year old female presents to the clinic with anorexia. What region of her brain could be responsible for her anorexia?
Lateral area of the hypothalamus. This region is responsible for hunger stimulation.
An 18 year old boy presents with obesity. Labs reveal increased leptin in the blood, indicating resistance to leptin. What region of his brain is causing him to eat all the time?
Ventromedial are of the hypothalamus. This region is responsible for satiety and lesions in this region causing leptin resistance increasing eating behaviors. Normally leptin stimulates the area and makes you satiated.
What structures of the brain are responsible for the 5 F’s: feeding, fleeing, fighting, feeling and sex?
Limbic system: amygdala, hippocampus, fornix, mammillary bodies and cingulate gyrus.
How does giving a patient pramipexole improve symptoms of Parkinson’s disease?
Pramipexole is a D2 agonist. Activating the D2 receptors inhibits the indirect nigrostriatal pathway, resulting in an overall increase in thalamic activation. This in turn increases cortical stimulation and helps with Parkinsonian symptoms.
A 66 year old woman presents with a resting tremor, rigidity, expressionless face and postural instability. A few years later the patient passes away. Autopsy of her brain is shown below. What would you expect to see on histological analysis of this tissue?
Note the depigmented substantia nigra characteristic of Parkinson’s. You would find Lewy bodies composed of alpha-synuclein
A 44 year old man comes to the neurology clinic complaining of depression, aggression, dementia, slow writhing movements of the fingers (athetosis) and uncontrollable jerky movements (chorea). His father had a similar condition and died at the age of 51. What is causing the symptoms seen in this patient?
Anticipated CAG repeats caused Huntington’s disease to present earlier in this patient than in his father. The repeats cause NMDA receptor binding, glutamate toxicity and atrophy of the striatum (caudate + putamen). Atrophy of the striatum results in loss of ACh and GABA neurotransmitters and patients will present with chorea, depression, aggression and dementia.
A patient comes to the ED confused. Labs reveal hyponatremia. You quickly correct Na+ levels and shortly thereafter the patient develops locked-in syndrome. What happened?
Central pontine myelinolysis. This is caused by massive axonal demyelination in the pontine white matter tracts, affecting motor, ARAS and cranial nerve tracts.
A 71 year old man comes to the ED with symptoms of stroke. His angiogram is shown below. What symptoms will this patient most likely present with?
This patient has a basilar artery occlusion largely affecting the anterior inferior cerebellar artery (AICA). This can cause infarction of the lateral pons’ cranial nerve nuclei, vestibular nuclei (vomiting, vertigo & nystagmus), facial nucleus (facial paralysis, decreased taste, decreased lacrimation, salivation, decreased corneal reflex), spinal trigeminal nucleus (decreased pain and temperature sensation to ipsilateral side of face), cochlear nuclei (ipsilateral hearing loss), sympathetic fibers (ipsilateral Horner’s syndrome) and the cerebellum (ataxia, dysmetria).
A 71 year old man comes to the ED with symptoms of stroke. His CT is shown below. What symptoms will this patient most likely present with?
Note the infarct of the posterior cerebellum, this patient will present with ataxia & dysmetria. This occurs with occlusion of the posterior inferior cerebellar artery (PICA). Occlusion of this artery also causes infarction of the lateral medulla which includes the vestibular nuclei (vomiting, vertigo & nystagmus), lateral spinothalamic tract (contralateral decreased pain and temperature sensation to limbs), spinal trigeminal nucleus (ipsilateral loss of pain and temperature sensation to face), nucleus ambiguus (dysphagia, hoarseness & decreased gag reflex), sympathetic fibers (ipsilateral Horner’s syndrome)
A 71 year old man presents to the ED with symptoms of stroke. His CT is shown below. What symptoms will this patient most likely present with?
This patient has an infarct in the occipital lobe and probably had a posterior cerebral artery occlusion. This would present with contralateral hemianopia.
A 71 year old man presents with rapidly deteriorating neurological symptoms. CT angiogram is shown below. What are most likely his symptoms?
This patient has a saccular aneurism of the anterior communicating cerebral artery. This vessel lies on top of the optic chiasm. Consequently, aneurism most often results in visual field defects.
A 71 year old man presents with rapidly deteriorating neurological symptoms. His angiogram is shown below. What are most likely his symptoms?
He has an aneurism of the posterior communicating artery. This most often causes cranial nerve palsy at CN III. Clinically the patient will present with ptosis, pupil dilation and the eye pointed down and outward.
What extra ocular muscles are you testing in patients as they look in each direction?
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Lesions in what part of the optic tract will cause the visual defect seen below?
Meyer’s loop (headed to the temporal lobe). This can happen in a MCA infarct affecting the right temporal lobe.
Lesions in what part of the optic tract will cause the visual defect seen below?
Dorsal optic radiation (headed to the parietal lobe). This can happen in a MCA infarct affecting the left parietal lobe.
What causes the nystagmus in the eye looking laterally when patients have internuclear opthalmoplegia?
Overfiring of CN VI because CN III is not being activated due to MLF lesion.
