Nervous System, Opthamology, Psychiatry Flashcards
What type of receptors are mu opioid receptors and what types of second messenger pathways do they activate?
G-protein linked receptors; activate and regulate many 2nd messenger pathways- one involves K+ conductance: upon binding to mu receptors, morphine causes G-protein coupled activation of K+ channels to increase K+ efflux from the cell. This causes hyperpolarization of the post synaptic neurons and termination of pain transmission. Other pathways induce inhibition of adenlyl cyclase, calcium conductance, and inhibition of NT release.
In the neuromuscular junction, Ach release from presynaptic terminal vesicles depends on the inflow of what ion?
Inflow of extracellular calcium into the presynaptic terminal; this occurs following neuronal depolarization and opening of voltage gated Ca2+ channels.
What type of receptors are found on postsynaptic skeletal muscle end plates?
Ligand gated sodium and potassium ion channels.
What microscopic changes are seen in brain tissue 12-48 hours post ischemic injury?
Red neurons- eosinophilic cytoplasm, pyknotic nuclei, loss of Nissl substance
When does liquefactive necrosis of brain tissue appear macroscopically after injury?
1-2 weeks after injury.
What is a pyknotic nucleus?
A small and deeply basophilic nucleus.
What embryological process gone wrong is responsible for neural tube defects?
Failure of fusion of the neural tube during the fourth week of fetal development. This occurs in the region of the neuropores, at the cranial or caudal end of the neural tube. This leads to a persistent communication between the spinal canal and amniotic cavity.
Amniotic fluid of a fetus with a neural tube defect will show what diagnostic markers?
a-fetoprotein and Acetylcholinesterase. AFP will also be elevated in maternal serum.
What are two anterior neural tube defects?
Encephalocele, anencephaly.
What are three posterior neural tube defects?
Spina bifida occulta, meningiocele, meningomyelocele. Posterior NTDs are more common than anterior NTDs
What is encephalocele?
Herniation of the brain tissue through a cranial defect.
What is anencephaly?
Total absence of the brain and calvarium.
To what drug class does Thiopental belong?
Short acting, IV barbiturate anesthetic
What is Thiopental used for?
Induction of anesthesia due to its rapid onset
How is mutated huntingtin protein thought to cause Huntington’s disease?
Transcriptional repression (silencing) due to histone deacetylation
What is the result of histone acetylation?
Weakening of the DNA histone bond that makes DNA segments more accessible for transcription factors and RNA polymerases enhancing gene transcription.
An isolated right nasal hemianopia is caused by a lesion in what location?
Right peri-chiasmal lesion.
What is a possible cause of an isolated right nasal hemianopia?
Calcification or aneurysm of the internal carotid artery impinging on uncrossed lateral retinal fibers.
What may cause monocular scotoma?
Macular degeneration, optic neuritis.
What type of lesion may cause left homonymous superior quadrantanopia?
Right temporal lobe- meyers loop region
What type of lesion may cause left homononymous inferior quadrantanopia?
Right parietal lobe (dorsal optic radiation)
What type of lesion would cause left homonymous hemianopia with macular sparing?
Lesion to the right primary visual cortex (occipital lobe)
What structures does the posterior cerebral artery supply?
Thalamus, medial temporal lobe, splenium of the corpus callosum, parahippocampal gyrus, fusiform gyrus, occipital lobe. It also supplies CN III and IV
What is the most common finding of PCA infarction?
Contralateral hemianopia often with macular sparing. Contralateral paresthesias and numbness affecting the face, trunk, and limbs occur if the lateral thalamus is also affected.
How do you distinguish between schizoaffective disorder and bipolar disorder/ major depression with psychotic features?
Temporal relationship of psychotic symptoms to mood symptoms- in bipolar disorder and major depression with psychotic features, psychotic sx occur exclusively during manic or depressive episodes. When the patient’s mood is euthymic, there are no psychotic sx.
Describe the positional relationship between the caudate, globus pallidus and putamen.
Head of the caudate lies in the inferolateral wall of the anterior horn of the lateral ventricle. It is separated from the globus pallidus and putamen by the internal capsule.
What is the site called where the frontal, parietal, temporal, and sphenoid bones meet in the skull?
Pterion
Why is the pterion relevant?
Skull is thin here and the middle meningeal artery courses within the skull deep to this point- fractures to this region can cause an epidural.
The middle meningeal is a branch of what artery?
The maxillary artery (which is a branch of the external carotid).
Korsakoff syndrome is associated with damage to what regions of the brain?
Anterior and dorsomedial thalamic nuclei.
What nervous system defects are associated with Vitamin E deficiency?
Degeneration of the spinocerebellar tracts, dorsal column of the spinal cord, and peripheral nerves.
Vitamin E deficiency closely resembles what genetic condition?
Freiderich ataxia- degeneration of the spinocerebellar tracts, dorsal column of the spinal cord, and peripheral nerves; ataxia, dysarthria, loss of position and vibration sensation.
Poliomyelitis causes damage to what region of the spinal cord?
Anterior horn cells.
What is myotonia?
Abnormally slow relaxation of muscles.
What are classic symptoms of myotonic muscular dystrophy?
Difficulty loosening one’s grip after a handshake, inability to release the doorknob. Cataracts, frontal balding, gonadal atrophy. Type 1 muscle fibers are more affected; NO fibrofatty replacement.
Describe the inheritance of myotonic dystrophy.
Autosomal dominant trinucleotide expansion of CTG in the gene coding for myotonia protein kinase. Anticipation occurs.
What is the mechanism of action of cocaine?
Indirect sympathomimetic- Prevents the reuptake of monoamines (NE, D, 5-HT) resulting in sympathetic stimulation and CNS activation.
What drugs are used to treat generalized anxiety disorder?
Benzodiazapines and antidepressants.
On light microscopy, what is seen in temporal arteritis?
Granulomas in the media of the arteries consisting of mononuclear infiltrates and multinucleated giant cells. These changes are segmental.
What condition occurs in more than half of patients with temporal arteritis?
Polymyalgia rheumatica
What is polymyalgia rheumetica?
Neck, torso, shoulder, pelvic girdle pain and morning stiffness. Fatigue, fever, weight loss may also occur.
What causes central pontine myelinolysis?
Rapid correction of chronic hyponatremia
What are the manifestations of central pontine myelinolysis?
Spastic quadriplegia and pseudobulbar palsy.(CN Ix, X, and XI are demyelinated)
What is pseudobulbar palsy?
Head and neck muscle weakness, dysphagia, dysarthria
Deficiencies in what vitamins are common in patients with cystic fibrosis?
Fat soluble (A, D, E, K)
What are the most common clinical manifestations of vitamin E deficiency?
Neuromuscular disease (skeletal myopathy, spinocerebellar ataxia, pigmented retinopathy) and hemolytic anemia (increased susceptibility of neuronal and erythrocyte membranes to oxidative stress). Involvement of the dorsal column of the spinal cord causes loss of proprioception and vibratory sense; spinocerebellar involvement causes ataxia.
What is one of the principle functions of vitamin E?
Protection of fatty acids from oxidation; deficiency disposes cell membranes with high fatty acid content to oxidative injury.
Cholinomimetics are indicated in what three conditions?
Paralytic ileus, urinary retention, glaucoma.
What is Lamotrigine used to treat and what is its principle side effect?
Anticonvulsant for partial seizures; may cause life threatening skin rash.
What two genetic conditions are associated with berry (saccular) aneurysms?
ADPKD, Ehlers-Danlos syndrome.
In SAH, where does blood accumulate?
Between the arachnoid and pia mater
What does LP reveal in a patient with SAH?
Gross blood or xanthochromia (yellow discolouration of CSF)
What are Charcot-Bouchard aneurysms?
Small aneurysms that occur in patients with long standing hypertension. They are found in the arterioles that supply the basal ganglia, internal capsule, and deep white matter. They can cause intercerebral hemorrhage, but not SAH.
What is DRESS syndrome?
Drug reaction with eosinophilia and systemic symptoms that typically occurs 2-8 weeks after exposure to high risk drugs such as anticonvulsants, allopurinol, sulfonamides, and antibiotics.
What are the symptoms of DRESS syndrome?
Fever, generalized lymphadenopathy, facial edema, diffuse skin rash, eosinophilia, organ dysfunction.
What lab values are associated with DRESS syndrome?
eosinophilia, atypical lymphocytosis, elevated ALTs.
What is mixed cryoglobulinemia?
Small to medium vasculitis caused by circulating immunoglobin-complement complexes that precipitate on refrigeration. It is typically associated with chronic inflammatory states and may present with systemic findings- fatigue, arthralgias, myalgias, and palpaple purpura in the lower extremities.
What deposits stain congo red and are seen with apple-green birefringence under polarized light?
Amyloids.
Where does amyloid angiopathy occur?
Deposits in the media and adventitia of cerebral vessels that cause thickening of the basal membrane, stenosis of the vessel lumen, and fragmentation of the elastic lamina.
What composes senile plaques?
Parenchymal, extracellular deposits of amyloid. These are seen in many elderly people and are not pathologic.
What types of effects can tricyclic anti-depressants have on the cardiac conduction system?
Quinidine like effects- can cause QRS and QT prolongation and cardiac dysrhythmias. These effects are due to inhibition of fast sodium channels
What is the most effective intervention for TCA overdose?
Hypertonic Sodium Bicarbonate- it can correct QRS prolongation, reverse hypotension, and treat ventricular dysrhythmias.
Where is the body’s satiety center?
The ventromedial nucleus of the hypothalamus.
What symptoms are noted with bilateral lesions to the ventromedial nuclei?
Hyperphagia, obesity, rage/ savage behaviour.
What is the most common cause of lesions to the ventromedial nuclei?
Tumor- namely craniopharyngioma.
What is synaptophysin?
A transmembrane glycoprotein found in the presynaptic vesicles of neurons, neuroectodermal, and neuroendocrine cells.
Immunoreactivity of a CNS tumor for synaptophysin indicates a tumor of what origin?
Neuronal origin
Where are primary brain tumors most commonly located in adults and in children?
Adults- supratentorial; children- infratenrotial
What brain tumors stain positive for GFAP?
Gliomas- astrocytomas, oligodendrogliomas, ependymomas, peripheral neural sheath tumors.
Which benzodiazapines are short acting and typically used before bedtime?
Triazolam and alprazolam.
Name four intermediate to long acting benzodiazepines.
Lorazepam, flurazepam, diazepam, chlordiazepoxide
Name the three types of glial cells.
Astrocytes, oligodendrocytes, microglia.
From what tissue type are astroctyes derived?
Neuroectoderm
From what tissue type are oligodendrocytes derived?
Neuroectoderm
From what tissue type are microglia derived?
Monocytes in the bone marrow
What are the functions of astrocytes?
Repair, structural support, BBB support, metabolic.
What is the function of oligodendrocytes?
Production of myelin.
What compensates for volume loss that occurs after neuronal cell death?
A glial scar.
What is the thalamic syndrome?
Total sensory loss on the contralateral side of the body. There are no motor deficits and proprioception is often profoundly affected and may lead to difficulty ambulating and falls.
Damage to what nuclei cause complete contralateral sensory loss?
The thalamic VPL and VPM nuclei.
What are lacunar infarctions?
Small cavities located within the basal ganglia, posterior limb of the internal capsule, pons, and cerebellum. They are caused by occlusion of the small penetrating arteries that supply these structures.
What are the primary mechanistic causes of lacunar infarcts?
Lipohyalinosis and microatheromas
What is lipohyalinosis?
A destructive vessel lesion characterized by loss of normal arterial architecture, mural foam cells, and in acute cases, evidence of fibrinoid vessel wall necrosis.
What causes microatheromas?
Accumulation of lipid laden macrophages within the intimal layer of a vessel.
Damage to what area causes hemiballism?
Contralateral subthalamic nucleus (most commonly from a lacunar stroke).
What is hemiballism?
wild, flinging movements of the extremities on one side of the body.
The subthalamic nucleus is part of what region?
Basal ganglia. It is ventral to the thalamus and superior to the internal capsule.
What is kinesin?
A microtubule associated motor protein whose function is anterograde transport of intracellular vesicles and organelles towards the growing end of microtubules down axons to synaptic terminals. It is powered by ATP.
What is seen on light microscopy of peripheral nerves in a patient with Guillain Barré?
Segmental demyelination and endoneural inflammatory infiltrate.
What is the function of cranial nerve VII?
Motor output to the facial muscles, parasympathetic innervation to the lacrimal, submandibular, and sublingual salivary glands, special afferent fibers for taste from the anterior 2/3 of the tongue, somatic afferents from the pinna and external auditory canal.
What findings are specific to Bell’s palsy?
Sudden onset of unilateral facial paralysis. Specific findings include impaired eye closure, eyebrow sagging, inability to smile and frown, disappearance of the nasolabial fold, and the mouth being drawn to the non-affected side. Patients may also have decreased tearing, hyperacusis, and/or loss of taste sensation over the anterior two thirds of the tongue.
Why is atropine administered prior to bronchoscopy?
To decrease respiratory mucous secretions and promote bronchodilation.
What symptoms are associated with atropine toxicity?
Dry and flushed skin, hyperthermia, mydriasis, cycloplegia, bronchodilation, tachycardia, constipation, urinary retention.
What is the mechanism of action of physostigmine?
Acetylcholinesterase inhibitor both peripherally and centrally (it is a tertiary amine so is capable of crossing the BBB).
Which acetylcholinesterase agents have quaternary ammonium structures and this can’t penetrate the CNS?
Neostigmine and edrophonium.
What is the mechanism of Buspirone?
Selective 5HT1A receptor agonist that has no hypnotic, sedative, or euphoric effects. Dependence does not occur and there is minimal potential for abuse.
What clinical findings are associated with tabes dorsalis due to Treponema pallidum (syphilis) infection?
Sensory ataxia (may cause wide based gait), lancinating pains, neurogenic urinary incontinence, Argyll robertson pupils.
What is tabes dorsalis?
A late form of neurosyphilis that usually manifests 5-20 years after primary infection.
What are Argyll Robertson pupils?
Small, irregularly shaped pupils that fail to constrict in response to light but constrict normally in response to accommodation. They are thought to be caused by spirochetes invading and damaging the midbrain tectum.
What tracts of the spinal cord are affected by Tabes dorsalis?
Dorsal columns and dorsal roots of the spinal cord, resulting in loss of position and vibration sense and severe lancinating pains. Peripheral reflexes may also be absent.
What are the primary symptoms of cryptococcal infection in HIV patients?
Subacute meningitis- fever, malaise, headache.
What are the primary symptoms of Herpesvirus type 1 encephalitis?
Encephalitis where the temporal lobe is primarily affected- symptoms include fever, headache, confusion, personality changes.
What causes progressive multifocal leukoencephalopathy?
Reactivation of the JC virus (polyomavirus). Symptoms include progressive dementia, motor deficits, and visual impairment.
What is subacute sclerosing panencephalitis?
Rare complication of measles occuring years after infection. It is caused by continuous replicating viral particles which cause a persistent, nonproductive infection that evades host immune mechanisms. Accumulation of viral nucleocapsids within neurons and oligodendrocytes results in formation of intranuclear inclusions and inflammation, demyelination, and gliosis in several cerebral areas.
What type of virus is measles?
Enveloped, single-stranded RNA virus that is a member of the paramyxovirus family. Its genome codes for hemagglutin and matrix protein.
What is seen in the CSF of patients with subacute sclerosing panencephalitis?
Oligoclonal bands (antibodies) of measles virus.
What is progressive supranuclear palsy?
A form of parkinsonism resulting from neurodegeneration of the midbrain and frontal subcortical white matter. It presents with rapidly progressive gait dysfunction and falls, executive function loss, vertical gaze palsy. Biopsy usually shows deposits of abnormal p-tau.
What are the diagnostic criteria for bullemia nervosa?
Recurrent binge eating with compensatory behaviours to prevent weight gain. These behaviours must occur at least twice a week for at least 3 months. Compensatory responses are typically purging or nonpurging (excessive excercise, dieting, fasting).
What distinguishes binge purge anorexia from binge purge bulemia?
Anorexia entails low body weight (<85% of ideal or BMI of 17.5) and amenorrhea.
How does hydrocephalus in early infancy present?
With macrocephaly, irritability, poor feeding, muscle hypertonicity, hyperreflexia. Hypertonity and hyperreflexia result from upper motor damage caused by stretching of the periventricular pyramidal tracts.
What nerve innervates the posterior part of the external auditory canal? What innervates the remainder of the canal?
The small auricular branch of the vagus nerve. Mandibular division of the trigeminal nerve (auriculotemporal branch) innervates the rest. The inner surface of the tympanic membrane is innervated by the CN IX tympanic branch.
Name five medications that may cause seizures.
Bupropion, clozapine (at high doses), isoniazid, ciprofloxacin, imipenem (antibiotic).
Describe the symptoms of lithium toxicity.
Neuromuscular excitability, irregular coarse tremors, fascicular twitching, agitation, ataxia, delirium. Hemodialysis is the most effective way to reduce blood levels of Li.
What can lead to lithium toxicity?
Renal injury toxins and drugs that alter GFR as it is almost exclusively excreted by the kidneys.
Name four classes of drugs that lead to increased lithium levels.
Thiazide diuretics, ACE-Is, NSAIDs, nondihydropyridine Ca2+ channel blockers (verapamil, diltiazem).
What is clasp knife spasticity?
Initial resistance to passive extension followed by a sudden release of resistance. It is seen in UMN lesions.
What symptoms are associated with internal capsule stroke?
Pure motor weakness affecting the contralateral arm, leg, and lower face. Contralateral spasticity or increased tone, hyperreflexia, and a positive Babinski sign are also present.
What is the function of the insula?
The insular cortex is involved in integrating body states with emotions (limbic system), ANS control, and conscious experience of visceral sensations.
What is the function of the putamen?
Part of the basal ganglia; plays a role in the initation of movement. Lesions in this area can cause contralateral tremor, bradykinesia, and rigidity.
What symptoms result from damage to the external and internal segments of the globus pallidus?
Part of the basal ganglia/ extrapyramidal motor system. Damage to the external segment results in decreased motion/ movement; damage to the internal segment results in excessive motion/ movement
UMN lesions can affect what regions?
Any part of the pyramidal motor nervous system including the corticospinal tracts of the spinal cord, the medulla, pons and midbrain, the internal capsule, and the precentral gyrus (primary motor cortex).
Prolactinomas are derived from what embryologic layer?
Surface ectoderm.
Ectoderm gives rise to what three layers?
Surface ectoderm, neural tube, and neural crest.
Blotchy red muscle fibers on Gomori trichrome stain are characteristic of what condition?
Mitochondrial myopathies- “Red ragged fiber diseases”
Name the three most common mitochondrial myopathies.
Myoclonic epilepsy with red ragged fibers (MERRF), Leber optic neuropathy (blindness), mitochondrial encephalopathy with stroke like episodes and lactic acidosis (MELAS).
From what embryologic layers are neurofibromas derived?
Tumors of schwann cells derived from the neural crest.
Describe the two most important mechanisms of the development of diabetic neuropathy.
- Non-enzymatic glycosylation of proteins leads to increased thickness, hyalinization, and narrowing of the arterial walls. These changes cause diabetic mucroangiopathy of endoneural arterioles; ischemic damage follows.
- Intracellular hyperglycemia occurs in peripheral nerves- accumulating glucose is converted into sorbitol and fructose by aldose reductase. Sorbitol increases cell osmolarity and facilitates water influx into the cell. This causes osmotic damage to axons and schwann cells.
Name five effects of volatile anesthetics.
Increased cerebral blood flow, myocardial depression, hypotension, respiratory depression, decreased renal function.
What is the most common cause of acute and painless monocular vision loss?
Central retinal artery occlusion (CRAO).
What fundoscopic findings are characteristic of central retinal artery occlusion?
Pale retina with cherry red macula.
Describe the blood supply to the macula and to the retine.
Macula is supplied by the choroid artery; the remainder of the retina is supplied by the central retinal artery.
From where is the central retinal artery derived?
The opthalmic artery which is a branch of the internal carotid.
What symptoms are associated with diabetic retinopathy?
Blurry vision, poor night vision, floaters, decreased peripheral vision. Fundoscopy reveals aneurysms, cotton wool exudates, dot and blot retinal hemorrhages and new retinal vessel formation.
What target organs are innervated by alpha-1 receptors?
Peripheral vasculature, bladder, eye.
What target organs are innervated by beta-2 receptors?
Peripheral vasculature (skeletal muscle), bronchi, uterus.
Alpha 1 stimulation of the eye causes contraction of what muscle?
The ocular pupillary dilator muscle.
What should not be taken if a patient is prescribed levodopa?
B6 (or most over the counter vitamins that have B6) B6 increases peripheral metabolism of levodopa and less drug enters the CNS.
What is a common physiologic change associated with Cimetidine?
Gynecomastia.
What is ‘reaction formation’?
A behaviour pattern in which a person does the opposite of what he/she feels or desires. Ex- when a person uses excessive behaviour to cover up how he/she really feels because that feeling may be perceived as unacceptable.
What is ‘projection’?
Transplantation of ones unacceptable impulses or behaviours onto another person or situation.
What is the difference between ‘repression’ and ‘suppression’?
Suppression is voluntary withholding of unpleasant thoughts, repression is relatively unconscious.
What is ‘displacement’?
The transfer of an impulse or desire toward a safer and less distressful object.
Lateral horns of the spinal cord are present in what spinal segments?
T1-L2 (sympathetic preganglionic neurons).
What regions does the dorsal column system contain?
Gracile fasciculus, cuneate fasciculus.
What symptoms result from demyelination of the axons within the dorsal columns of the spinal cord?
Lancinating pains, paresthesias, loss of vibratory and position sensation. Sensory ataxia also prevails in the dark.
Brain atrophy in advanced alzheimer’s disease is associated with what regions?
Temporoparietal lobes and hippocampus. The greatest degeneration occurs in the hippocampus and hippocampal atrophy on MRI is highly suggestive of AD.
What four histologic changes are characteristic of active (acute) MS plaques?
Demyelination with relative preservation of axons, accumulation of lipid-laden macrophages (containing products of myelin breakdown), astrocytosis (injury proliferation response), infiltration by lymphocytes and mononuclear cells.
What are the early and late manifestations of oculomotor nerve compression by an aneurysm?
Early: dilated pupil and loss of acomodation; Late: ptosis and opthalmoplegia.
What are the clinical symptoms of diabetic opthalmoplegia?
Down and out position with normal sized reactive pupil and ptosis.
What ocular motor never is most commonly involved in diabetic opthalmoplegia?
CN III- mononeuropathy will present with acute onset diplopia. It is caused predominately by central ischemia.
Describe the pathway of aqueous humor production and transport in the eye.
It is produced by epithelial cells of the ciliary body and excreted into the posterior eye chamber and transferred through the pupil into the anterior eye chamber. The anterior chamber angle contains a trabecular meshwork through which the aqueous humor diffuses into Schlemm’s canal (scleral venous sinus). Schlemm’s canal drains into the episcleral and conjunctival veins.
What is glaucoma and how does it develop?
Chronic eye disease characterized by increased IOP. It develops due to diminished outflow or increased secretion of aqueous humor.
When does narrow angle glaucoma occur?
When the anterior chamber narrows obstructing the trabecular meshwork. It is often precipitated by anticholinergic medications and manifests with an acute attack of headache and eye pain.
What types of drugs are used to treat glaucoma?
Drugs to decrease production of aqueous humor or to increase its outflow- non selective beta blockers like Timolol work by diminishing secretion of aqueous humor by the ciliary epithelium. Acetazolamide is a carbonic anhydrase inhibitor that decreases aqueous humor secretion by the ciliary epithelium; PG F2a and cholinomimetics (pilocarpine, carbachol) decrease IOP by increasing outflow.
When is clozapine used to treat schitzophrenia?
In treatment resistant patients for both positive psychotic symptoms (delusions and hallucinations) and negative symptoms of social withdrawal, anhedonia, blunted affect, and poor initiative.
What is the mechanism of action of clozapine and how does it differ from other traditional antipsychotics?
Clozapine acts on D4 receptors; traditional drugs act on D2 receptors.
What side effects are avoided with Clozapine?
Dopaminergic side effects- pseudoparkinsonism, tardive dyskinesia, hyperprolactinemia.
What is the greatest side effect associated with clozapine?
Life threatening agranulocytosis. WBC monitoring during treatment is required. Another important side effect is seizures.
Where is Wernicke’s area?
Posterior portion of the superior temporal gyrus in the dominant temporal lobe. It is supplied by the MCA (as is the superior division of Broca’s area)
Name four conditions that carpal tunnel syndrome is associated with.
Hypothyroidism, DM, RA, dialysis associated amyloidosis.
What cranial nerve is associated with the first branchial arch?
CN V
What bones are associated with the first branchial arch?
Maxilla, zygoma, mandible, vomer, palatine, incus, and malleus.
Muscles of mastication, the anterior belly of the digastric, the mylohyoid, the tensor tympani, and the tensor veli palatini are derived from what tissue?
Mesoderm.
What atypical antipsychotic is most likely to cause extrapyramidal symptoms and which is least likely?
Most likely- Risperidone; least likely- Clozapine.
When does acute dystonia manifest after treatment with antipsychotics?
Between four hours and four days after receiving medication
What is treatment for acute dystonia?
Antihistamines or anticholinergics.
What is akathisia and when can it occur after treatment with antipsychotics?
Subjective feeling of restlessness that compels patients to move around; it can occur at any time during treatment.
What symptoms are associated with neuroleptic malignant syndrome?
Delirium, fever, muscle rigidity, autonomic instability.
What is the typical viral pattern of CSF composition?
Lymphocytic pleocytosis, normal glucose, elevated protein. A few RBCs may also be present due to hemorrhagic destruction of the temporal lobes.
What condition most commonly causes retinitis in HIV positive patients with a CD4+ count less than 50?
CMV retinitis- caused by hematogenous spread of CMV to the eye.
What is the most common complication of CMV retinitis?
Retinal detachment.
What is used to treat CMV retinitis?
Ganciclovir.
Name three locations of possible brain herniation due to compression.
Falx cerebri, tentorium cerebelli, foramen magnum
What is transtentorial (uncal) herniation?
Medial temporal lobe (uncus) herniates through the gap between the crus cerebri and tentorium
What is subfalcine herniation?
Cingulate gyrus herniation under the falx cerebri. It may potentially compress the anterior cerebral artery.
What is tonsillar herniation?
Cerebellar tonsils displace through foramen magnum and compress medulla.
Transtentorial herniation may cause compression of which of the following structures?
Ipsilateral CN III, ipsilateral PCA, compression of contralateral cerebral peduncle against tentorium
What symptoms are caused by damage to CN III?
A fixed and dilated pupil followed by paralysis of the occulomotor muscles which leads to ptosis and a down and out position of the ipsilateral eye
What visual symptoms are associated with compression to the posterior cerebral artery?
Contralateral homonymous hemianopsia with macular sparing.
Compression of the cerebral peduncle against the tentorium causes what symptoms?
Contralateral hemiparesis.
What is typically the first sign of uncal herniation?
A fixed and dilated pupil on the side of the lesion. Ipsilateral paralysis of oculomotor muscles, contralateral or ipsilateral hemiparesis, and contralateral homonymous hemianopsia with macular sparing may also occur.
What is cataplexy?
Brief loss of muscle tone precipitated by strong emotion.
What CSF levels are low in patients with narcolepsy?
Hypocretin-1
What effects does narcolepsy have on latency to REM sleep?
Shorter latency to REM sleep
What type of drug is primidone?
An antiepileptic that is metabolized to phenobarbital and phenylethylmalonamide (PEMA). It has anti-seizure effects also.
What drug characteristically causes elevated phenobarbital levels?
Primidone- it is metabolized to phenobarbital
What are the somatic motor functions of CN IX?
Innervation of stylopharyngeus muscle.
What are the parasympathetic functions of CN IX?
Innervation of the inferior salivatory nucleus
What nerve innervates parotid gland secretion?
CN V
What are the general sensory functions of CN IX?
Inner surface of tympanic membrane, eustacian tube, posterior 1/3 of tongue, tonsillar region, upper pharynx (affects portion of the gag reflex), carotid body, carotid sinus.
What clinical features result from a lesion to the glossopharyngeal nerve?
Loss of gag reflex, loss of sensation to upper pharynx, posterior tongue, tonsils, and middle ear cavity; loss of taste sensation on posterior 1/3 of tongue.
What nerve innervates taste sensation for the anterior two thirds of the tongue?
Chorda tympani branch of the facial nerve (CN VII).
A calcified cystic mass seen on MRI is likely what type of tumor?
Cragiopharyngioma.
What structure shares a common origin with a craniopharyngioma?
Pituitary gland.
Describe the appearance of craniopharyngiomas on light microscopy.
Cysts lined by stratified squamous epithelium. Keratin pearls may be seen. They are usually filled with a yellow, viscous fluid rich in cholesterol crystals.
From where are craniopharyngiomas derived?
Remnants of Rathke’s pouch.
What is Rathke’s pouch?
Envagination of the ectoderm that lines the fetal oral cavity..
