Neuro

Question 1

posterior cranial fossa

Answer 1

C. posterior

• skull foramen:
  
  • internal acoustic meatus; CN 7,8
  • jugular foramen; CN 9,10,11, jugular vein
  • hypoglossal canal; CN 12
  • foramen magnum; spinal roots of CN 11, brain stem, vertebral arteries

Question 2

A. CP of HIV-associated dementia

B. pathogenesis of HIV-Assoc dementia

C. What causes neuronal damage?

Answer 2

A.

• HIV infection
• medical noncompliance
• progressive cognitive decline
• CD4 counts <200 cells/mm3
• symptoms of subcortical dementia (eg attn/working memory problems, executive dysfxn, slow information processing)
  
  • HIV affects primarily the subcortical/deep gray matter structures

B. Pathogenesis

• inflammatory activation of microglial cells
• HIV-infected monocytes cross the BBB to become perivascular macrophages
• activated** macrophages and microglial cells (resident macrophages of the CNS) form groups (microglial nodules**) around small areas of necrosis and may fuse to form multinucleated giant cells.

C. neuronal damage occurs from inflammatory cytokine release by macrophages/microglial cells and the direct tociv effects of HIV-derived proteins.

Question 3

A. Define sciatica

B. what are the causes of sciatica?

Answer 3

A. nonspecific term for low back pain that radiates down the leg

B. compression of the lumbosacral nerve roots and is most commonyl caused by vertebral disc herniation or spinal foraminal stenosis (eg due to degenerative arthritis of the spine)

-innervation of the nerve rootresults in characteritic dermatomal and myotomal deicits (radiculopathy) depending on the level of involvement

Question 4

A. What is true hydrocephalus?

B. What are the {THREE} groups pertaining to the pathogenesis of hydrocephalus

Answer 4

A. a rise in the volume and pressure of CSF caused by abnormal production flow, or reabsorption of the fluid.

B.

1. Increased CSF production=rare cause of hydrocephalus. excessive CSF may be produced by choroid plexus papillomas
2. Abnormal CSF circulation=most common cause of hydrocephalus. obstructio is located in either the ventricl or arachnoid villi.
3. Disorders of CSF absorption are rare

Question 5

Abusive head trauma (AHT)-formerly known as “Shaken baby syndrome”

Answer 5

• inflicted intracranial injury due to blunt force trauma or vigorous shaking in a to-and-fro fashion
• resultant injuries are due to infants’ unique anatomic features
• infants have larger heads, enalrged subarachnoid space, higher brain water content and decreased cervical muscle tone compared to older children
  
  • these facotrs lad to increased movement of the immature brain in relation to the skull, resulting in tearing of the bridging veins and subdural hemorrhages
• AHT may occur repeatedly over weeks o months, so acute (looks lighter on CT) on chronic (on CT looks darker) subdural hemorrhages are often seen
• shaking motion also results in retinal hemorrhages due to rupture of congested retinal veins
• *posterior rib fractures are also alarming for trauma
• *inconsistent hx: rolling over is not typical before age 4 months

Question 6

Acoustic neuroma

Answer 6

• Schwann cell-derived tumor that typically arises from the vestibular portion of the vestibulocochlear nerve (CN 8)
• CP: ipsilateral sensorineural hearing loss and tinnitus due to impairment of the cochlea portion of the nerve
• damage to the vestibular component may also result in vertigo, dysequilibrium, and nystagmus
• most cases are unilateral, but bilateral are seen in pts with neurofibromatosis type 2

Question 7

ADPKD

Answer 7

• systemic disorder (though major pathological process is in the kidneys)
• intracranial berry aneurysms arise in the circle of Willis and when they rupture, they cause subarachnoid hemorrhage (SAH)
  
  • CP: severe HA (“worst HA of my life”)/thunderclap HA, neck stiffness (nuchal rigidity)-usually present or develops in the next 24 hrs as blood in the subarachnoid space acts as a meningeal irritant
• CT scan of brain without contrast=most commonly used initial imaging study for diagnosing SAH, should be done during the first 24hrs from the onset of symptoms
  
  • positive in up to 90% of patients
• If CT scan is negative a lumbar puncture needs to be performed to evaluate the CSF for the presence of xanthochromia (blood in the CSF)

Question 8

Anterior cerebral artery

Answer 8

• ACA supplies the medial portions of the 2 hemispheres (frontal and parietal lobes)
• occlusion of ACA would affect sensory and motor function of th contralateral leg and foot, while predominantly sparing the contralateral arm/face
• bilat ACA occlusion can also develop significant behavioral symptoms and urinary incontinence if frontal micturition center is affected

Question 9

Ataxia-telangiectasia

Answer 9

• autosomal recessive disorder
  
  • due to mutation of ATM gene (ataxia telangiectasia mutated) for DNA break repair
• cerebellar atrophy leads to ataxia that occurs in the first years of life
• telangiectasias=abnml dilatations of capillary vessels; superficial blanching nests of distended capillaries
• associated factors:
  
  • causes severe immunodeficiency (cell-mediated and humoral dysfunction) with repeated sinopulmonary (upper and lower airway) infections
  • increased risk of hematologic malignancies
  • risk of cancer is significantly increased because of inefficient DNA repair (DNA damage and repair is an ongoing process)
• DNA hypersensitivity to ionizing (x-ray) radiation
• another manifestation: oculocutaneous telangiectasia-usually delayed

Question 10

ATROPINE poisoning

Answer 10

• Jimson weed (Datura stramonium) poisoning/Gardener’s mydriasis-produces toxins (belladonna alkaloids) that are strong anticholinergics
• strikingly similar to atropine poisoning
• path: blockade of visceral muscarinic receptors
• CP: “ blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bon, the bowel and bladder lose their tone, and he heart runs alone.”
  
  • Heart: diminished vagal tone at the SA nodes causes relative tachy
  • Blood vessels: vasoconstriction via muscarinic receptor blockade in endothelial cells results in decreased NO synthesis
    
    • nonetheless get cutaneous flushing
  • GI: delayed gastric emptying, decreased intestinal motility, and secretion
  • Respiratory: bronchodilatation
  • GU: urinary retention via detrusor relaxation and contraction of the external urtehral sphincter
  • Secretions: decreased lacrimation (dry eyes), salivation (dry mouth) and sweating (dry and hot skin).
    
    • ATROPINE decreases ability to sweat=contributes to hyperthermia
  • Eye: mydriasis (dilated pupils) and cycloplegia (inability to focus on the near objects, blurry vision)
  • CNS: hallucinations, agitation, and delirium
• Tx: increase concentration of ACh in the synaptic cleft by a cholinesterase inhibitor=PHYSOSTIGMINE (tertiary amine, can reverse both CNS an peripheral symptoms of severe stropine toxicity)
  
  • Neostigmine and Edrophonium have a quatenary ammonium structure that limits CNS penetration

Question 11

BBB

Answer 11

• formed by tight junctions between nonfenestrated capillary endothelial cells that prevent the paracellular passage of fluids and solutes
• tight junctions (zonular occludentes-composed of transmembrane proteins (claudins and occludins) that associate with actin filaments
• only permits passage of substances form the blood to the brain via transcellular movement across the endothelial plasma membrane-limited to diffusion or carrier-mediated transport

Question 12

Chiari malformations

Answer 12

• group of congenital disorders caused by the underdevelopment of the posterior fossa
• small size of the fossa causes parts of the cerebellum and medulla to herniate through the foramen magnum
• two types:
  
  • Chiari type 1:
    
    • most common and benign
    • characterized by low-lying cerebellar tonsils that extend below the foramen magnum into the vertebral canal
    • pts present during adolescence/adulthood with paroxysmal occipital HA (due to meningeal irritation) and cerebellar dysfunction (eg dizziness, ataxia) due to compression of the cerebellar tonsils
  • Chiari type 2 (Arnold-Chiari malformation):
    
    • more severe and typically becomes evident during the neonatal period
    • characterized by: downward displacement of the cerebellum (vermis, tonsils) and medulla through the foramen magnum
    • non-communicating hydrocephalus almost always occurs due to aqueductal stenosis
    • compression of the medulla may result in dysphagia, stridor, and apnea
    • pts also often have an associated lumbar myelomeningocele which can cause lowe limb paralysis

Question 13

Cholinomimetics (cholinergic agonists)

Answer 13

• indications: non-obstructive urinary retention, paralytic ileus, glaucoma
• SE: N/V/D abdominal cramps, dyspnea (via bronchoconstriction), increased secretions (sweating, lacrimation, and salivation)
• BETHANECHOL-used to stimulate peristalsis in post-op ileus and to tx non-obstructive retention (atonic bladder)
• CARBACHOL and PILOCARPINE-used to lower intraocular pressure in glaucoma

Question 14

Clostridium tetani (Tetanus)

Answer 14

• following a puncture wound
• C. tetani causes disease by producing a potent metalloprotease exotoxin (tetanospasmin) that is deadly in nanogram quantities

1. toxin binds to receptors in the presynaptic membranes of peripheral motor neurons
2. migrate by retrograde axonal transport to central inhibitory neurons in the SC and brainstem and prevents release of the inhibitory NT glycine and GABA
3. suprresion results in increased activation of motor nerves causing muscle spasms and hyperreflexia

• CP:
  
  • difficulty opening the jaw (lockjaw or trismus)
  • fixed sardonic smile (risus sardonicus)
  • contractions of back muscles resulting in backward arching (opisthotonos)
  • very iritable
  • develop tetanic spasms in response to minor stimuli (eg loud noises)

Question 15

Comparison of frontotemporal dementia (Pick’s disease) and Alzheimer disease

Answer 15

Pick’s disease

• macroscopic exam: pronounced atrophy of frontal and temporal lobes
• onset: 50s&60s
• microscopic features:
  
  • intial neuronal loss in the frontotemporal lobes
  • Pick bodies (cytoplasmic inclusions of microtubule-associated protein tau)
• initial symptoms: personality and behavioral changes (apathy, socially inappropriate behavior)
• genetic basis: AD inheritance in 20-40%

Alzheimers

• macroscopic exam: mild-to-moderate generalized brain atrophy
• onset: 60s & 70s or older
• microscopic features:
  
  • initial neuronal loss in parietal and temporal lobes
  • neurofibrillary tangles
  • amyloid plaques
• initial symptoms: impairments involving recent memory
• genetic basis: chromosome 21 (APP gene) and Apolipoprotein E4

Question 16

Congenital toxoplasmosis

Answer 16

• transplacental infection (acquired in utero)
  
  • fetus affected only if mother is infected during first 6 months of pregnancy
  • expecting mothers should avoid cat feces to help prevent exposure
• classic triad:
  
  • hydrocephalus-due to CNS inflammation, evidenced by macrocephaly and enlargement of the ventricles
  • intracranial calcifications
  • chorioretinitis-inflammation of the choroids and the retina that can leave cotton-like white/yellow scars on the retina visisble on fundoscopy
• affected neonates also have:
  
  • hepatosplenomegaly and rash
  • mulitple neurological abnormalities (seizures, altered muscle tone and ocular movement defects)

Question 17

CTZ

Answer 17

• chemoreceptor trigger zone
• triggers the vomiting and acute nausea that results form the administration of systemic chemotherapy
• lies in the area postrema of the dorsal medulla near the fourth ventricle
• area postrema receives blood from fenestrated vessels (absent BBB), which allows it to sample chemicals circulating in the blood

Question 18

Define dysdiadochokinesia

Answer 18

feature of cerebellar ataxia and may be the result of lesions to either the cerebellar hemispheres or the frontal lobe (of the cerebrum), it can also be a combination of both

Question 19

Describe the steps for the generation adn propogation of action potentials

Answer 19

1. binding of an excitatory NT (eg glutamate) to a postsynaptic neuron causes opening of ligand-gated sodium channels
2. sodium influx and membrane depolarization
3. depolarization impulse is transmitted from the dendrites through the cell body to the axon hillock which ocntains a large number of voltage-gated sodium channels
4. once the hillock becomes sufficciently depolarized, an AP is triggered and propagates along the axon via a steady influx of sodium ions
5. whan the AP reaches the axon terminal, bvoltage gated calicum channels open and allow the influx of calicum
6. calcium is esential for the fusion and release of NT vesicles into the synpatic cleft

Question 20

Developmental milestones during toddlerhood

Answer 20

Question 21

Essential tremor

Answer 21

• the most common movement disorder
• Cp: slowly progressive, symmetric postural and/or kinetic tremor that most commonly affects the upper extremities
• often inherited in an autosomal dominant fashion (rferred to as familial tremor)
• first-line tx: nonspecific beta-adrenergic antagonist PROPRANOLOL

Question 22

ETHOSUXIMIDE

Answer 22

• Indication: absence seizures
• MOA: blocks T-type Ca channels that trigger and sustain rhythmical burst discharges in thalamic neurons

Question 23

food poisoning with Clostridium botulinum toxin

Answer 23

• CP: nicotinic blockade (diplopia and dysphagia) and muscarinic blockade (dry mouth)
• C bot=highly potent preformed neurotoxin
  
  • inhibits ACh release from presynaptic nerve terminals at the NMJ=prevention of muscular contraction
  • can be partially overcome by high-rate repetitive nerve stimulation (hence the compound muscle AP facilitation seen in the pt
• anerobic environment within a contaminated can of food allows for spore germination and organism growth
• toxin (produced by vegetative bacteria) is NOT actively secreted, ramins intracellular until autolysis causes its release into food
• toxin is readily destroyed by heat
  
  • if food not cooked properly, get 3Ds (in 12-36hr of consumption)
    
    1. diplopia
    2. dyspahgia
    3. dysphonia
• Two other forms of botulism:
  
  • wound botulism-toxin production in a wound infected with C botulinum
  • infant botulism-soncumption of C botulinum spores, classically found in contaminated honey, that then mature into vegetative toxin-producing cells
• all are medical emergencies!

Question 24

Fractures to the orbital floor

Answer 24

• commonly result from direct frontal trauma to the orbit floor (composed of zygomatic bone and maxilla)
• infraorbital nerve (continuation of maxillary nerve) runs along the orbital floor in a groove in the maxilla before exiting the skull inferior to the orbit
• damage can result in numbness and paresthesia of the upper cheek, upper lip, and upper gingiva
• also, displacement of the orbital contents through the floor may cause eophthalmos and inferior rectus muscle can also become entrapped, limiting superior gaze

Question 25

Friedreich ataxia

Answer 25

• autosomal recessive disorfer caused by mutation of the frataxin (FXN) gene
  
  • gene codes for an essential mitochondrial protein involved in the assembly of iron-sulfur enzymes
  • increased trinucleotide repeats (GAA) in the mutated gene causing decreased FXN expression which leads to less mitochondrial energy production and icnreased oxidative stress, resulting in degeneration of neural tracts and peripheral nerves
• Characteristic sites of involvement:
  
  • spinocerebellar and lateral corticospinal tract degeneration causes gait ataxia and spastic muscle weakness respectively
  • degeneration of the dorsal columns and drg causes loss of position and vibration sensation
  • kyphoscoliosis and foot abnormalities (pes cavus-high arches) are characteristic skeletal deformities
  • heart involvement includes HOCM and CHF
  • DM develops in 10% of pts

Question 26

Generalized Anxiety Disorder

Answer 26

DSM-5 criteria:

• excessive worry, anxiety (multiple issues) > or equal to 6 months
• difficult to control
• > or equal to 3 of the following symptoms:
  
  • restlessness/feeling on edge
  • fatuge
  • difficulty concentrating
  • irritability
  • muscle tension
  • sleep disturbance
• significant distress of impairment
• not due to substances, another mental disorder, or medical condition
• Tx: cognitive behavioral therapy, SSRIs or SNRIs

Question 27

Glial cells

Answer 27

• glial cells (neuroglia) are non-excitable cells of the CNS that perform a variety of supportive functions
• there are three major types:

1. Astrocytes
   
   1. origin: neuroectoderm
   2. appearance: round vesicular nuclei, small cell bodes, contain glial fibrils, comprised of glial fibrillary acidic protein (GFAP)
   3. functions:
      
      1. tissue repair
      2. structural support
      3. BBB
      4. mtabolic
   4. astrocytosis (or gliosis)-in the event of irreversible neuronal damage and neuronal death, astrocytes proliferate at the site of injury-universal response of the CNS to severe damage.
   5. after neuronal death, form closely connected firm meshwork-gliotic scar
2. Oligodendrocytes
   
   1. origin: neuroectoderm
   2. appearance: small round dark nuclei surrounded by pale halo; fewer processes than astrocytes
   3. function: production of myelin
3. Microglia
4. 1. origin: monocytes in the bone marrow
   2. appearance: small elongated nuclei; many short branching processes
   3. function: phagocytosis

Question 28

Hemispheric stroke/Hemiparesis

Answer 28

• more involvement of the arm than the leg
• occurs due to the occlusion of the MCA
  
  • MCA supplies the face and arm areas of the motor and sensory cortex, Broca’ and wernicke’s speech areas, and the frontal eye lid
  • MCA also gives rise to small, penetrating branches that perfuse the internal capsule and basal ganglia
• If the occluded MCA is in th dominant hemisphere (usually the left), aphasia may also occur
• **contrary to pop belief, L. hemisphere of the brain is most often dominant in bot R- and L-handed ppl

Question 29

Huntington disease

Answer 29

• autosomal dominant neurodegenerative disease caused by increase in the number of CAG trinucleotide repeats in the gene that codes for the huntingtin protein
• gain-of-function leads to pathological interaction with other proteins, including various TF
• transcriptional repression (silencing) is one of the mechanisms by which mutated huntingtin is thought to cause dz
• acetylation of histones weakens the DNA-hstone bond and makes DNA segments more accessible for TF and RNA polymerases, enhancing gene transcription
• in Huntington dz, abnml huntingtin causes increased histone deacetylation, silencing the genes necessary for neuronal survival

Question 30

Incidence of disease

Answer 30

number of new cases of a disease per year/total population at risk (dont include the people who already have the dz)

Question 31

ischemic-hypoxic encephalopathy

Answer 31

• profound cerebral hypoperfusion may lead to global cerebral ischemia (aka i-he)
• CP: cardiogenic shock and evidence of watershed necrosis on autopsy
• path:
  
  • profound systemic hypOtension (eg due to cardiac arrest or shock) diminishes blood supply to the entire brain causing global cerebral ischemia
  • neurons dont store glycogen so theyre highly sensitive to ischemia
  • interruption of cerebral blood supply for 5-10s=loss of consciousness (syncope)
  • 4-5 mins=permanent damage to brain tissue
  • pyramidal cells of the hippocampus and Purkinje cells of cerebellum are most vulnerable to ischemic injury and are usually affected first
  • with profounf ischemia necrosis of areas supplied by distal-most branches of the cerebral arteries, watershed infarction, can occur
• Watershed zones: located at the borders between areas perfused by the anterior, middle, and posterior cerebral arteries
• cortical watershed infarcts typically appear as bilateral wedge-shaped strips of necrosis over the cerebral convexity, parallel and adjjacent to the longitudinal cerebral fissure
• pts with severe carotid artery stenosis may develop unilateral infarcts

Question 32

Kinesin

Answer 32

• microtubule associated motor protein
• function: ANTErograde transport of intracellular vesicles and organelles toward the plus (rapidly growing) end of microtubules
• uses energy derived from ATP hydrolysis to move along the microtubule
• in neurons: carries NT-containing secretory vesicles and organelles away form the cell body and toward the nerve terminal (down xons to synpatic terminals)

Question 33

L5 radiculopathy

Answer 33

• most common form of lumbosacral radiculopathy
• due to compression of the L5 nerve root usually as a result of L5-S1 spinal foraminal stenosis (degenerative arthritis of the spine) OR L4-L5 vertebral disc herniation
• CP: back pain radiating down the leg with sensory loss over the buttocks, lateral thigh, and calf, and dorsal foot.
  
  • there may also be weakness on foot dorsiflexion, inversion, eversion, and toe extension

Question 34

LAMOTRIGINE

Answer 34

• MOA: anticonvulsant that works by blocking voltage-gated sodium channels
• Indication: treat partial and generalized seizures and is also effective for bipolar disorder
• SE:
  
  • 10% develop benign rash
  • 1%: potentially life threatening rash due to Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN)
  • pts with SJS/TEN develop flu-like symptoms (fever, malaise, myalgias) followed by extensive mucocutaneous lesions
  • histopath: lesions are characterized by (mucocutaneous) epidermal necrosis and subepidermal bullae
  • other anticonvulsant with SJS/TEN risk: carbazepines, phenobarbital, phenytoin

Question 35

Length/space constant

Answer 35

• measure of how far along an axon an electrical impulse can propogate
• a decrease in LC can result from increased charge dissipation long a nerve axon
• one of the purposes of myelin: increase the length constant and decrease the time constant–both of which improve axonal conduction speed
• demyelination impairs stimulus transmission
• *think of myelin as insulation around a rod heated at one end-the better insulated the rod, the more effective its transmission of heat

Question 36

LEVODOPA

Answer 36

• immediate precursor of dopamine (NT absent in the nigrostriatum of pts with Parkinsons)
• Dopamine cannot cross BBB, but L can
• unfortunately, L is rapidly metabolized in the peripheral tissues and only small percentages reach the brain–peripheral catabolism due to COMT
• usually administer with CARBIDOPA (a perioheral dopa decarboxylase inhibitor)
• Yay, ENTACAPONE
  
  • COMT inhibitor that increase the bioavalability of L by inhibiting peripheral methylation
  • TOLCAPONE-another COMT inhibitor, inhibits both peripheral and central methylation
  • associated with hepatotoxicty

Question 37

Liquefactive necrosis

Answer 37

• release of lysosomal enzymes from these ischemic neurons results in degradation of the tissue in the ischemic region
  
  • phagocytic cells migrate into the area and remove the necrotic tissue leaving a cavity
  • astrrocytes proliferate aroun the necrotic area with the formation of a scar (gliosis)
• complete digestion and removal of necrotic tissue with formation of cystic activity=liquefactive necrosis
• hypoxic CNS injury is often followed by liquefactive necrosis
• abscess formation due to bacterial or fungal infection is another example of this type of necrosis

Question 38

Lysosomal Storage Diseases

Answer 38

Question 39

MAC

Answer 39

• minimal alveolar concentration is a measure of potency of an inhaled anesthetic-it is an intrinsic property of the anesthetic; BUT depends on body temp and decreases with increasing pt age
• it is the concentration of the anesthetic in the alveoli that renders 50% of patients unresponsive to painful stimuli (ED50)
• potency is inversely proportional to the MAC
• the lower the MAC, the more potent the anesthetic

Question 40

Meningiomas

Answer 40

• common, slow-growing (benign) intracranial tumors that typically affect adults and tend to arise in regions of dural reflection (eg falx cerebri, tentorium cerebelli)
• CP: often asymptomatic but may present with HA, seizure, or focal neurologic deficits depending on tumor size and location
• lesions incolving the primary cortex (particularly in the nondominant hemisphere) may cause contralateral hemineglect due to impaired visuospatial processing

Question 41

Methylmalonic acidemia

Answer 41

• autosomal recessive organic acidemia resulting from complete or partial deficiency of the enzyme methylmalonyl-CoA mutase
• hypoglycemia results from overall increased metabolic rate leading to increased glucose utilization and dirct toxic inhibition of gluconeogeneisis by organic acids
  
  • presence of hypoglycemia leads to increased free fatty acid metabolism that produces ketones, resulting in further anion-gap metabolic acidosis
• organic acids also directly inhibit the urea cycle leading to hyperammonemia
• during the neonatal period metabolic derangements manifest as: hypotonia, lethargy, vomiting, and respiratory distress (tachypnea due to acidosis)
• diagnosis is confirmed by presence of: elevated urine methylmalonic acid and proprionic acid

Question 42

Migraine Headaches

Answer 42

• common in younger women
• usually unilateral with a pulsating or throbbing quality and generally last 4-72 hours
• CP: photophobia, phonophobia, and nausea
• Path: pain is due to activation of trigeminal afferents that innervate the meninges
  
  • this causes release of vasoactive neuropeptides, including substance P and calcitonin gene-related peptide which redults in neurogenic inflammation due to vasodilation and plasma protein extravasation
• Tx: triptans (serotonin 5-HT,1B/5-HT,1D agonists used as abortive therapy during an acute migraine
  
  • beta blockers, antidepressants (AMITRIPTYLINE and VENLAFAXINE) and anticonvulsants (VALPROATE and TOPIRAMATE) are commonly used for migraine prophylaxis

Question 43

Mini-mental State Examination

Answer 43

• widely used screening tool for cognitive impairment able to assess attention and concentration

1. Orientation-providing name, location, and current date
2. Comprehension-floowing multistep commands
3. concentration-reciting months of the year backwards
4. short-term memory-recalling 3 unrelated words after 5 minutes
5. long-term memory-providing details of significant life events
6. language-writing a complete sentence with noun-verb agreement
7. visual-spatial-drawing intersecting pentagons
8. executive function-drawing a clock oriented to the time requested

Question 44

Mitochondrial disorders

Answer 44

• exclusively maternal inheritance (ovum is lrge and has many copies of mtDNA)
• mitochondrial disease affect both M and F offspring with equal frequency (100%) but there are variable degrees of severity
• variability because: during mitosis, mitochondria are randomly distributed between daughter cells…some cells contain mit with mostly damaged mtDNA, some contain mostly nml mit genomes
• mix of two types of genetic material=HETEROPLASMY and is responsible for the clinical variability of mit disease
• Important mit syndromes:
  
  1. Leber hereditary optic neuropathy-leads to bilat vision loss
  2. myoclonic epilepsy with ragged-red fibers: myoclonic seizures and myopathy associated with exercise
     
     1. skeletal muscle biopsy shows irregularly shaped muscle fibers (ragged red fibers)
  3. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS)
     
     1. CP: muscle weakness, blood test: increased serum lactate levels both post-exercise and at rest

Question 45

MPTP

Answer 45

• toxic substance that induces a Parkinsonism-like syndrome by destroying dopaminergic neurons in the CNS
• SELEGILINE is an inhibitor of MAO, type B (the causative agent)
  
  • used to clinically delay the progression of Parkinson disease
  • mny neurologists favor the use of combinations of SELEGILINE, anticholinergics, and AMANTADINE until they no longer provide control of symptoms

Question 46

Multiple Sclerosis

Answer 46

• autoimmune demyelinating disease of the CNS that typically presents in young women (<50)
  
  • CP: neurologic deficits disseminated in time and space
    
    • blurry vision
    • diplopia
    • focal weakness/numbness
    • dysarthria
    • bowel/bladder dysfunction
  • common intial manifestation: optic neuritis-monocular visual loss with pain on eye movement and an afferent pupillary defect
• MRI: white matter lesions scattered throughout the brain and/or SC with a predilection for the subcortical periventricular regions
• Path: autoimmune response targeting oligodendrocytes (myelin-producing cells of the CNS)
  
  • leads to slowed nerve conduction
• can cause spasticity-related complications by MS plaque in the SC
  
  • CP: paraparesis, urge incontinence, a thoracic sensory level
• spasticity=increase in resistance to passive muscle movement or a velocity-dependent increase in tonic stretch reflexes
  
  • CP: muscle stiffness, painful muscle spasms, scissoring gait, lack of dexterity
• the loss of descending inhibitory control from the upper motor neurons results in lower motor neuron overactivity, leading to increased tone and hyperreflexia
• tx: BACLOFEN-an agonist at the GABA-B receptor, effective monotherapy for the tx of spasticity secondary to both brain and SC lesions; dcreases the excitability of spinal reflexes
  
  • TIZANIDINE is also effective and commonly used

Question 47

Myasthenia gravis

Answer 47

• tensilon test (edrophonium): improvement or resolution of weakness
• nerve stimulation studies: decremental response
• cause: circulating Ab directed against nicotinic AChR on the POST-synaptic membrane of the NMJ
  
  • autoAb binding leads to receptor degradation, producing fluctuating weakness that worsens over the course of the day and mostly affects the extraocular muscles (eg ptosis, diplopia) and bulbar muscles (fatigable chewing, dysphagia)
• most pts also have thymic abnormalities (thymoma, thymic hyperplasia)-may appear as an anterior mediastinal mass on chest imaging

Question 48

Myotonic dystrophy

Answer 48

• autosomal-dominant disorder
• caused by an increased number of trinucleotide repeats (CTG)–expansion– on myotonia-protein kinase gene
  
  • number of repeats increases with subsequent generation, causing increasingly severe disease in each generation (anticipation)
• classic symptoms: difficulty loosening one’s grip after a handshake or inability to release the doorknob
• 2nd most common inherited muscle disorder (Duchenne muscular dystrophy is the most common)
• CP:
  
  • sustained muscle contraction (myotonia)
  • weakness and atrophy
  • cataracts
  • frontal balding and gonadal atrophy

Question 49

Narcolepsy

Answer 49

• DSM-5 diagnostic criteria:
  
  • recurrent lapses into sleep or naps (minimum 3x/wk for 3 months)
  • at least 1 of the following:
    
    • cataplexy: brief loss of muscle tone precipitated by strong emotion (laughter, excitement)
    • low CSF levels of hypocretin-1
    • shortened REM sleep latency
• Associated features:
  
  • hypnagogic or hypnopompic hallucinations
  • sleep paralysis

Question 50

Neonatal Intraventricular hemorrhage (IVH)

Answer 50

• common complication of prematurity
• can lead to long-term neurodevelopmental impairment
• occurs most frequently in infants born befoe 32 wks gestation and/or birth weight <1500g and almost alway within the first 5 postnadal days
• CP: clinically silent OR present with an altered level of consciousness, hypotonia, and decreased spontaneous movements
• symptoms of catastrophic bleeding: bulging anterior fontanelle, hypOtension, decerebrate posturing, tonic-clonic seizures, irregular respirations, and coma
• in preterm infants, usually originates from the germinal matrix, a highly cellular and vascularized layer in the subventricular zone from which neurons and glial cells migrate out during brain development
  
  • matrix contains numerous thin-walled vessels lacking the glial fibers that support other bloo vessels throughout the brain, which contributes to the risk of hemorrhage
  • especially vulnerable to hemodynamic instabilit as premature infants can have impaired autoregulation of cerebral blood flow

Question 51

Neural Tube Defects

Answer 51

• due to failure of the neuropores (folds that fuse to create the neural tube)
• anterior NTD:
  
  • anecephaly (complete absence of the brain)
  • encephalocele (protrusion of neural tissue through the cranial defect)
• posterior NTD:
  
  • spina bifida occulta
  • meningocele and meningomyelocele
    
    • both present as cystic mass at the lower spine region covered with skin; a tuft of hair may be present i the area
    • meningocele: mass consists of spinal meninges that protrude through the defect in vertebral arches
    • meningomyelocele: a portion of the SC or cauda equina lies within the protruding meningeal sac
  • rachischisis
• folate supplementatio during early pregnancy decreases the incidence of NTD
• high dose folate intake is recommended for all women of childbearing age because the NT develops very early in fetal life

Question 52

Neurofibromatosis Type 1 (von Recklinghausen disease)

Answer 52

• autosomal dominant neurocutaneous disorder caused by mutations in the NF1 tumor suppressor gene
• CP: hyperpigmented macules (café-au-lait spots) over the trunk soon after birth and are at increased risk of developing CNS neoplasms (these can cause elevated intracraniel pressure and HA)
• cutaneous neurofibromas usually manifest during early adolescence as multiple, raised, fleshy tumors (<2cm) that often increase in size and number with age
  
  • benign nerve sheath neoplasms predominantly comprised of Schwann cells (embryologically derived from the neural crest)

Question 53

Neuronal reaction to injury

Answer 53

• occurs during disease or injury, the nurons display a number of characteristic changes

1. Acute neuronal injury (red neuron)
   
   1. type of injury: transient severe (irreversible) insult that leads to cell death
      
      1. transiet ischemia, hpoxia, or hypoglycemia
   2. histopath (visible in 12-24 hrs after the injury and are followed by death of the neuron):
      
      1. shrinkage of the cell body+separation from surrounding tissue
      2. pyknosis (shrunken and basophilic) of the nucleus
      3. loss of Nissl substance
      4. eosinophilic cytoplasm
2. Axonal reaction
   
   1. type of injury: loss of axon
   2. histopath:
      
      1. enlargement of the cell body
      2. eccentric nucleus
      3. enalrgement of the nucleolus
      4. dispersion of the Nissl substance
3. Neuronal atrophy
   
   1. type of injury: progressive degenrative disease
   2. histopath:
      
      1. loss of neurons and functional groups of neurons
      2. reactive gliosis

Question 54

Organophosphate Poisoning

Answer 54

• most commonly occurs in farmers and agricultural workers exposed to excessive amounts of pesticides
  
  • pesticides irreversibly inhibit cholinesterase in both muscarinic and nicotinic cholinergic synapses
  • they decrease the degradation of ACh and increase ACh concentration in the synaptic cleft, leadinf to overstimulation of the corresponding receptors
• CP=excessive cholinergic stimulation; DUMBELS-due to muscarinic activation
  
  • D=diarrhea (stimulation of smooth muscle of GI tract), diaphoresis (excessive sweating ue to stimulation of secretory glands)
  • U=uination (stimulation of smooth muscle of detrusor)
  • M=miosis (constriction of pupillary sphincter)
  • bronchospasm (increased bronchial smooth muscle tone), bronchorrhea (increased bronchial secretion), bradycardia (decreased conductance)
  • E=emesis (due to GI stimulation)
  • L=lacrimation (along with stimulation with other secretory glands)
  • S=Salivation
• increased ACh concentration in the nicotinic synapses of NMJ leads to muscle fasciculations followed by paralysis
• OPP also penetrate the BBB and cause seizures and CNS depression
• tx: ATROPINE-reverse muscarinic symptoms of OPP poisoning but does not have any effect on nicotinic receptors
  
  • pts treated with atropine are still at risk for muscle paralysis
  • PRALIDOXIME is the only medication that reverses both muscarinic and nicotinic effects of OPP by “restoring” cholinesterase from its bond with these substances
    
    • effective only if given EARLY after the exposure

Question 55

Pancoast Tumors

Answer 55

• non-small cell lung cancers (eg squamous cell carcinoma, adenocarcinoma) that arise near the superior sulcus
• pts may develop ipsilateral shoulder pain, upper limb paresthesias, and areflexic arm weakness due to involvement of the brachial plexus
• Horner’s syndrome (eg ipsilateral partial ptosis, miosis, anhydrosis) can also occur due to involvement of the cervical sympathetic ganglia

Question 56

PKU

Answer 56

• deficiency of the snzyme phenylalanine hydroxylase or its cofactor tetrahydrobiopterin causes accumulation of phenylalanine in body fluids and the CNS
• homozygous infants are nml at birth, but gradually develop severe intellectual disability and seizures if left untreated
• hypopigmentation of the skin, hair, eyes, and catecholaminergic brain nuclei is also frequently seen

Question 57

Proprionyl CoA

Answer 57

• derived from amin acids (val,ile, met, thr), odd-numbered FA, and cholesterol side chains
• congenital deficiency of propionyl CoA carboxylase, the enzyme responsible for the conversion of propionyl CoA to methylmalony CoA, leads to the development to proprionic acidemia

Question 58

Proximal median nerve injury

Answer 58

• often occurs with supracondylar humerus fractures
• CP:
  
  • sensory loss over the palmer aspect of the first 3 digits
  • impairment of thumb flexion/opposition
  • flexion of the second/third digits
  • wrist flexion/abduction

Question 59

Radial Nerve

Answer 59

• largest branch of the brachial plexus and receives fibers from C5-T1
• innervates all of the extensor muscles of the upper limb below the shoulder and provides sensory innervation to the skin of the posterior arm, forearm, and dorsal lateral hand
• tracks within the radial groove on the humerus, so is vulnerable to traumatic injury (eg penetrating stab wound) at the humeral midshaft
  
  • nerve can also be injured during its superficial course within the axilla
• pts with proximal radial neuropathy typically have weakness during wrist and finger extension (wrist drop) and variable sensory loss over the posterior arm and forearm

Question 60

Radial nerve injury

Answer 60

• can occur with repetitive pressure/trauma at the axilla (eg improperly fitted crutches or an individual sleeps with the arm over a chair)
• CP:
  
  • weakness of the forearm, hand, and fingers extensors (eg, wrist drop, absent triceps reflex)
  • sensory loss over the posterior arm and forearm, dorsolateral hand, and dorsal thumb
  • more distal lesions spare the triceps brachii

Question 61

Resting membrane potential

Answer 61

• equilibrium potentials of cellular ions reflect how they would affect the membrane potential if the membrane were completely permeable to that ion
• if resting membrane potential is negative, that means that at rest, the membrane is most permeable to an ion with a negative equilibrium potential (such as potassium or chloride, theoretically)
• if membrane were permeable to sodium instead (which has a positive equilibrium potential) then the restin gmembrane potential would be positive

Question 62

Serotonin Syndrome

Answer 62

• CP of neuromuscular excitation: hyperreflexia, clonus, myoclonus, rigidity, tremor
• CP of autonomic stimulation: hyperthermia, tachycardia, diaphoresis, V/D
• also: altered mental status (agitation and confusion)
• any drugs that increase serotoning levele, including combinations of SSRIs and MAO inhibitors and high doses of SSRIs can precipitate this syndrome
• tryptophan is a precursor for serotonin and metabolis occurs via the enzymes tryptophan hydroxylase and amino acid decarboxylase
• Tx: supportive care including airway maintenance, hydration, temperature maintenance
• pharm tx for severe cases: tx with serotonin receptor antagonists (CYPROHEPTADINE-first gen histamine antagonist with nonspecifc 5-HT1 and 5-HT2 receptor antagonistic properties

Question 63

Status epilepticus

Answer 63

• due to complex febrile seizure or infectious meningitis/encephalitis
• intitial drug of choice for tx: intravenous benzodiazepine (LORAZEPAM)
  
  • due to its efficacy and rapid onset of action
  • benzos enhance the effect of the inhibitory NT GABA at the GABA-A receptor, a ligand-gated ion channel
  • allosteric attachment of benzos to the GABA-A R causes increased INFLUX of negatively charged chloride ions in response to GABA binding
  • this leads to hyperpolarization of the postsynaptic nuron and suppression of AP firing (anticonvulsant effect)
  • it is rapid acting and better than PHENYTOIN

Question 64

Subarachnoid hemorrhage (SAH) + vasospasm

Answer 64

• SAH
  
  • CP: abrupt onset of generalized, excruciating HA [“worst HA of my life”]
    
    • also fever and nuchal rigidity
    • no focal neurological deficits
  • non-contrast CT scan: hyperdenisty witin cisterns/sulci
  • most common form:
    
    • saccular (berry) aneurysms-usually occur at the circle of Willis, with ACA=most common site
    • Berry associated with Ehlers-Danlos syndrome and ADPKD
  • arteriovenous malformations also predispose certain indivs to SAH
• in 20-30% of pts with SAH vasospasm leading to clinical symptoms occurs
• cerebral vasospasm symptoms:
  
  • altered mental status
  • focal neurological deficits
• prevention of cerebral vasospasm: CCB (specifically NIMODIPINE)

Question 65

Subthalamic nucleus

Answer 65

• important role in the modulation of basal ganglia output, it is a component of the BG
• damage (eg lacunar stroke–consequence of long-standing HTN and DM) may result in contralateral hemiballism due to reduced inhibition of the thalamus
• CP: wild, involuntary, large-amplitude, flinging movements of the proximal limbs (eg arm and/or leg) on one side of the body

Question 66

Syringomyelia

Answer 66

• Classically: disproportionate loss of pain and temp sensation (dissociated anesthesia) involving arms and hands, upper extremity weakness and hyporeflexia, lower extremity weakness and hyperreflexia, and kyphoscoliosis (abnormal curvature of the vertebral column in two planes (coronal and sagittal); combination of kyphosis and scoliosis.
• CSF-fluid cavity called a syrinx (central cystic dilation) usually forms in the cervical region of the spinal cord
• areas most commonly damaged: ventral white commissure and ventral horns
  
  • vwc:
    
    • area of decussation for the fibers of the lateral spinothalamic tract which transmits pain and temp sensation from peripheral receptors to the somatosensory cortex
    • first order neurons in the drg
    • second order neurons in the dorsal horn
    • third order neurons in VPL
    • fourth order in primary somtoensory cortex in the parietal lobe (area 312)

Question 67

Tay-Sach’s disease (LSD)

Answer 67

• autosomal recessive
• caused by deficiency in beta-hexosaminidase A, which results in accumulation of GM2 ganglioside within cel lysosomes
• common pop: Ashkenazi Jews
• nml development in first couple months, 2-6 months develop:
  
  • progressive weakness (neurodegeneration)
  • hypotonia
  • loss of motor skills
  • abnml startle reflex with acoustic stimuli
• eventually develop seizures, blindness, spasticity
• buzzword: cherry-red macular spot
• no hepatosplenomegaly
• life expectancy: 2-5 yrs

Question 68

TCAs

Answer 68

• tricyclic antidepressants (TCAs) such as imipramine, doxepin, amitriptyline, and clomipramine have stronger anticholinergic properties than heterocyclics or SSRIs
• they should be used with caution in pts with benign prostatic hyperplasia (BPH), as they may cause urinary retention
• TCAs are commonly used for the tx of painful diabetic neuropathy and are more effective for short-term pain relief than many newer generation anticonvulsants
• Tricyclic ACTION/corresponding SIDE EFFECT

1. inhibition of presynaptic NT (NE and serotonin) reuptake/tremor, insomnia
2. blockade of cardia fast sodium channels/conduction defects, arrythmias, hypotension
3. antagonism of central and peripheral muscarinic acetylcholine receptors/hyperthermia, flushin, dilated pupils, intestinal ileus, urinary retention, sinus tachycardia
4. antagonism of peripheral alpha-1 adrenergic receptors/peripheral vasodilation (orthostatic hypotension)
5. antagonism of histamine (H1) receptors/sedation

Question 69

Temporal Lobe lesions

Answer 69

• can disrupt Meyer’s loop and produce a contralateral superior quadrantanopia
• temporal lobe lesions can also produce other neurologic manifestations: aphasia (dominant hemisphere lesions), memory deficits, seizures (complex partial and tonic-clonic) and hallucinations (auditory, olfactory, and visual)

Question 70

Thiamine (vit B1) deficiency and Wernicke encephalopathy

Answer 70

• Thiamine deificiency ACUTELY leads to Weirnicke encephalopathy
  
  • neural structure most frequently affected/undergoing necrosis=mammillary body-pt of Papez circuit, a neural pathway of the limbic system that is involved in the cortical control of emotion and memory
  • pathophys: thiamine is a key coenzyme for PDH (involved in glucose metabolism)
    
    • thiamine deficiency=brain unable to properly metabolize glucose and turn it into energy
  • CP: ataxia, nystagmus, ophthalmoplegia, anterograde amnesia
  • alcoholic or malnourished pts should receive iv thiamine supplementation before iv dextrose admin because giving dextrose sans prior thiamine can lead to a Wernicke encephalopathy
• Thiamine deficiency CHRONICALLY leads to Korsakoff psychosis
  
  • CP: anterograde and retrograde amnesia, apathy, lack of insight, and confabulation

Question 71

Toxoplasmosis

Answer 71

• buzz: multiple ring-enhancing lesions in an HIV pt
• HIV CP: oral thrush (usually seen with CD4 ct<200/m3), cervical and inguinal lymphadenopathy, brain lesions
• toxic encephalitis CP:
  
  • HA, seizures
  • multiple ring-enhancing CNS lesions on MRI
• trasmitted though contaminated foods and pet cats exposure

Question 72

Vit B12 deficiency

Answer 72

• often presents with megaloblastic anemia (impaired DNA synthesis), pancytopenia, and neurologic deficits (impaired myelin synthesis)
  
  • features for anemia: exertional dyspnea, fatigue, pallor
• neuro findings: subacute combined degeneration of the dorsal columns and lateral corticospinal tract
• elevations in methymalonic acid and homocysteine levels occur due to decreased metabolism of these molecules

Question 73

Wernicke Syndrome

Answer 73

• triad:
  
  1. ophthalmoplegia
  2. ataxia
  3. confusion
• lethal in 10-20% of patients
• foci of hemorrhage and necrosis in the mamillary bodies and periaqueductal gray matter are fund on autopsy
• condition occurs due to chronic thiamine deficiency (common condition in pts with alcoholism)
  
  • thiamine deficiency results in decreased glucose utilization, especially pronounced in the CNS
• diagnosis for thiamine deficiency: increase in erythrocyte transketolase levels after thiamine infusion
• tx: thiamine supplementation with glucous infusion

Question 74

West Nile Virus (WNV)

Answer 74

• CP: febrile viral illness with a rash and neurologic manifestations, including encephalitis (confusional state), meningitis, or flaccid paralysis syndomre
• positive-sense, single-stranded RNA flavivirus transmitted by female mosquitos (Culex), most commonly in the summer
• diagnosis: if cp present along with positive CSF anti-WNV Ab
• management is supportive

Question 75

What are the embryologic derivatives of endoderm?

Answer 75

• GI tract
• liver, pancreas
• lungs
• thymus, parathyroids, thyroid follicular cells
• middle ear
• bladder and urethra

Question 76

What are the macroscopic and microscopic ischemic changes of ischemic stroke?

Answer 76

1. 12-24 hour
   
   1. micro: “red neurons” (eosinophilic cytoplasm, pyknotic nuclei, loss of Nissl substance)
2. 24-72 hr
   
   1. micro: neutrophilic infiltration
3. 3-7 days
   
   1. micro: macrophage/microglia infiltration and phagocytosis begin
4. 1-2 weeks
   
   1. micro: reactive gliosis and vascular proliferation around the necrotic area
   2. macro: liquefactive necrosis (1 wk-1 month)
5. >2 weeks
   
   1. micro: glial scar formation
   2. macro: cystic area surrounded by dense glial fibers (>1month)

Question 77

What are the embryonic derivatives of mesoderm?

Answer 77

• muscles (skeletal, cardiac, and smooth)
• connective tissue, bone, and cartilage
• serosa linings (eg peritoneum)
• cardiovascular system
• blood, lymphatic system, spleen
• internal genitalia
• kidney and ureters
• adrenal cortex

Question 78

A. What are the nurological comorbidities for Down syndrome?

B. What are the characteristic pathologic neuro changes?

Answer 78

A. intellectual disability and early-onset Alzheimer disease (AD)

B. AD changes involve accumulation of intracellular neurofibrillary tangles (composed of tau protein, a primary component of intracellular microtubules) and extracellular amyloid-beta plaques.

• in AD tau gets hyperphosphorylated, causing microtubule structures to collapse into tangles
• ABeta is an abnml fragment of amyloid precursor protein (pts with Downs have 3 copies of this gene) which is normally involved in synaptic formation and repair. amyloid fragments harden into insoluble plaques that accumulate in brain tissue and vessel walls.

Question 79

What are the steps of axonal reaction?

Answer 79

• Wallerian degeneration occurs in the segment of axon that has lost connection with the cell body-it represents the degeneration of axon and myelin distal to a point of injury
• distal segment: sweeling and irregularity are noted
• week later: axon is destroyed, fragments are digested by Schwann cells and macrophages.
• similar degenerative changes in the segment of axon the lies proximal to the injury, extends to the closest node of Ranvier

main components of azonal reaction:

• cellular edema of the cell body, it becomes swollen and ound, nucleus displaced to the periphery
• Nissl substance becomes fine, granular, and dispersed thoughtout the cytoplasm (central chromatolysis)
• changes reflect an increased synthesis of protein by the cells in order to regenrate the severed axon.

Question 80

What are the three subcategories of ectoderm and what are their embryonic derivatives?

Answer 80

1. surface ectoderm

• Rathke’s pouch (anterior pituitary)
• lens and cornea
• inner ear sensory organs
• olfactory epithelium
• nasal and oral epithelial linings
• epidermis
• salivary, sweat, and mammary glands

2. neural tube:

• brain and spinal cord
• posterior pituitary
• pineal gland
• retina

3. neural crest

• autonomic, sensory, and celiac ganglia
• Schwanna cells
• pia and arachnoid mater
• aorticopulmonary septum and endocardial cushions
• branchial arches (bones and cartilage)
• skull bones
• melanocytes
• adrenal medulla

Question 81

What is caused by the atrophy of the caudate nucleus?

Answer 81

• Huntington disease
  
  • CP:
    
    • insiious onset of chorea (involuntary, low-amplitude movements involving the distal limbs)
    • dementia
    • behavioral abnormalities

Question 82

What is the difference between brainstem lesions and SC lesions?

Answer 82

• brainstem lesions:
  
  • typically result in crossed signs (contralateral hemiparesis or sensory loss)
  • cranial nerve abnormalities
  • diplopia
  • vertigo
  • ataxia
• SC lesions:
  
  • ipsilateral spastic hemiparesis and sensory loss below the level of spina involvement

Question 83

What is the effect of damage to the left temporal hemiretina?

Answer 83

disruption of the transmission of visual information along the ipsilateral optic nerve, lateral optic chiasm, optic tract, lateral geniculate body, optic radiations, and primary visual cortex

Question 84

[FX] What is the most common cause of inherited intellectual disability?

Answer 84

A. Fragile X Syndrome-an X-linked disorder

B. Path: unstable expansion of trinucleotide repeats (CGG) in the fragile X mental retardation 1 (FMR1) gene

C. key physical findings: dysmorphic facial features (prominent forehead, jaw, chin, and protruding ears; protruding ears); macroorchidism (testicular enlargment), macrocephaly long narrow face

-become most noticeable after puberty

D. Neuropsych findings:

• developmental delay
• intellectual disability
• ADHD
• anxiety
• autism spectrum disorder

Question 85

What is the most commonly injured leg nerve?

Answer 85

• common peroneal nerve!
• blunt trauma to the laeral aspect of the leg, fibular neck fractures, and external pressure due to proonged immobility (eg hospitalization, surgery, or casting) can injure the nerve
• CP:
  
  • equinovarus (plantarflexed and inverted) posture due to paralysis of the peroneus longus and peroneus brevis muscles (mediate foot eversion)
  • paralysis of the tibialis anterior muscle (medial dorsiflexion)
  • paralysis of the extrinsic extensors of the toes
  • loss of sensation to the anterolateral leg and dorsum of the foot
  • foot drop on gait examination-compensate with “steppage gait”, affected foot will often slap to the ground with each step (“foot slap”)

Question 86

A. What is the most dreaded cause of CN 3 palsy?

B. CN3

C. CN4

D. CN6

Answer 86

• an enlarging intracranial aneurysm
• CN3
  
  • eye muscles innervated: SR, MR, IR, IO, and levator palpebrae superioris
  • oculomotor functions-adduction, depression, elevation, and external rotation
  • lesion findings:
    
    • eye deviated downward and laterally
    • diagonal diplopia
    • dilation of pupil and loss of accommodation
    • ptosis
• CN4
  
  • eye muscles innervated: SO4
  • oculomotor functions: internal rotation, depression, and abduction
  • lesion findings: eye deviated upward, vertical and torsional diplopia
• CN6
  
  • eye muscles innervated: LR6
  • oculomotor functions: AB-duction
  • lesion findings: eye deviated medially, horizontal diplopia

Question 87

A. How is the notochord formed?

B. What does the notochord do?

Answer 87

A. 2 days after gastrulation begins, some of the epiblast cells migrate cranilly through the primitive node (cephalic end of the primitve streak) to form a midline cellular cord aka the NOTOCHORD.

B.

i. it induces the overlying ectoderm to differentiate into the neuroectoderm and form the neural plate.
ii. the neural plate gives rise to the neural tube and neural crest cells, remainder of the ectoderm becomes the surface ectoderm.

Question 88

What is the relationship btween ornithine and urea?

Answer 88

• ornithin transport into mitochondria is essential for urea formation
• ornithin is need to combine with carbomyl phophate wihtin the mitochondria to form citrulline in the second step of the urea cycle
• urea cycle defects cause neurological damage primarily due to the accumulation of ammonia
• protein restriction would improve this condition

Question 89

A. What nerve roots is sciatic nerve derived from and where does compression most often occur?

B. Describe the two different regions where compression most often occurs

Answer 89

A. sciatic nerve is derived from the L4-S3 nerve roots and compression most often occurs at the level of L5 or S1

B.

1. S1 radiculopathy
   
   1. characterized by pain and sensory loss down the posterior thigh and calf to the lateral aspect of the foot
   2. pts may also have:
      
      1. weakness of thigh extension (eg due to denervation of the gluteus maximus)
      2. knee flexion (hamstring)
      3. foot plantarflexion (gastrocnemius) with an absent ankle jerk reflex
2. L5 compressions:
   
   1. pain/paresthesia radiating down the lateral thigh and calf to dorsal foot
   2. pts often have:
      
      1. weakness on foot dorsiflexion and inversion (eg due to enervation of the tibalis anterior)
      2. foot eversio (peroneus)
      3. toe extension (extensor digitorum brevis)

Question 90

What virulence factor of E coli causes neonatal meningitis?

Answer 90

K1 capsular antigen allows the bacteria to survive in the bloodstream and establish meningeal infection

Question 91

When does gastrulation occur and when is it initiated?

Answer 91

• initiated by formation of the primitive streak-a thickening of the epiblast cell layer that ppears at the caudal end of the embryo and grows crnaially
• next step: epiblast cells undergo an epithelial-to-mesenchymal transition, causing them to lose their cel-cell adhesions properties
• next step: they migrate downward though the primitive streak to form the mesoderm and endoderm layers.
• remainder of the epiblast layer forms the ectoderm

Question 92

When there is progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation what is indicated?

Answer 92

neuromuscular junction pathology (eg MG) and/or abnormally rapid diaphragmatic nuscle fatigue (eg restrictive lung or CW disease)

Question 93

Wilson’s disease

Answer 93

• aka hepatolenticular degeneration
• atrophy of the lentiform nucleus (globus pallidus and putamen-cystic degeneration)
• CP:
  
  • liver-hepatitis, cirrhosis
  • psychiatric-depression, personality changes
  • neurologic-dysarthria, movement disorder

Question 94

Hippocampal atrophy

Answer 94

• atrophy on brain MRI is HIGHLY suggestive of the diagnosis for Alzheimer’s disease
• hippo demonstrates the greatest degree of atrophy

Question 95

Arginase deficiency

Answer 95

• arginase is an enzyme of the urea cycle that produces urea and ornithine from arginine
• tx of arginase deficiency: low-protein diet devoid of arginine
  
  • OR: admin of synthetic protein made of essential AA=improve neuro abnormalities

Question 96

Urea Cycle

Answer 96

• converts ammonia (generated fro metabolism of alpha AA) to urea
• involves 5 enzymatic step (2 in mitochondrial matri and three in cytosol)
• carbomyl phosphate synthetase I (CPS)=RATE-LIMITING step in urea cycle
  
  • combines CO2, ammonia, and ATP to form carbamoyl phosphate
  • requires presence of NAG (N-acetylglutamate)=allosteric activator
• toxic effects of ammonia accumulation:
  
  • first few feedings provide protein load to infant=AA available for metab, but defect in urea cycle prevents disposal of toxic ammonia= lethargy, vomiting, seizures

Question 97

C. neoformans

Answer 97

• opportunisitic fungus that causes meningitis (or meningoencephalitis) in immunosuppressed pts
• Morphology: yeast form only; round or oval encapsulated clels with narrow-based buds
• Virulence factors: thick polysaccharide capsule
• epidemiology:
  
  • present in soil and pigeon droppings
  • opportunistic infection
  • respiratory transmission
• Infection:
  
  • primary: lung
  • most common: meningoencephalitis
  • can be disseminated
• Diagnosis:
  
  • India Ink stain of CSF
  • latex agglutination of CSF
  • Culture (Sabouraud’s agar)
  • methenamine (GMS), mucicarmine stains of tissue
• Tx: Ampho B and Flucytosine (acute meningitis)
  
  • Fluconazole for lifelong prophylaxis

Question 98

Herpes zoster

Answer 98

• clinical combo of varicella IgG Ab (Ab generally confer immunity vs. chickenpox reinfection, but NOT against herpes zoseter) and a dermatome-centered, vesicular, painful rash is strongly suggestive of herpes zoster (ie shingles)
• Herpes zoster results from REACTIVATION of latent VZV infxn (in DRG) and most frequently occurs in the elderly or immunocompromised
• primary VZV infection occus in kids and is highly contagious=chicken pox
  
  • CP: fever, malaise, pharyngitis, and a generalzied vesicular and pruritic rash
    
    • skin lesions appear as successive crops on the face, trunk, and limbs, most have crusted within 6 days of onset
  • kids who have experience chickenpox infxn are typiclaly resistant to future episodes of chickenpox, but can develop herpes zoster later in life
• Varicella vaccine recommended for:
  
  • all kids 12-18 mo
  • women of childbearing age
  • adults with sustained risk of exposure
  • household contacts of immunocompromised hosts
  • *vaccine0induced immunity appears to dissipate over time

Question 99

Myoclonic seizures due to juvenile myoclonic epilepsy (JME)

Answer 99

• a form of idiopathic generalized epilepsy that may be familial
• pts are typically otherwise health
• CP: during adolescnece w/ myoclonic seizure (brief, involuntary jerking movements) involving both upper extremities with preservation of consciousness
• symptoms: usually occur within the first hour of waking, can be provoked by sleep deprivation
  
  • affected pts can also develop generalized tonic-clonic and absence seizures
• Tx: because JME is a form of generalized epilepsy, tx should include a broad-spectrum anticonvulsant (VALPROIC ACID…also: lamotrigine, levetiracetam, topiramate)
  
  • avoid: narrow-spectrum anticonvulsants which are favored for local onset seizures and may aggravate seizures in this situation

Question 100

Epilepticus

Answer 100

• recurrent or continuous generalized tonic-clonic seizures that last for more than 30 minutes without a return to consciousness
• life-threatening conditio, with a number of systemic effect:
  
  • HTN, tachycardia, cardiac arrhythmias, lactic acidosis
• Tx should be started asap, includes:
  
  • benzodiazepines (first-line); LORAZEPAM
    
    • more rapid onset of action (a few mins)
  • PHENYTOIN given simultaneously to prevent recurrence of seizures
    
    • inhibits neuronal high-frequency firing by reducing the ability of Na channels to recover from inactivation.
    • at high freq firing rates, neuron becomes refractory to reactivation and reduces seizure activity
  • if the above two dont work, use PHENOBARBITAL
  • alternatively: midazolam, propofol, inhaled anesthetics to induce a state of general anesthesia

Question 101

Difference between: Delirium, Dementia, and Depression in the elderly

Answer 101

• Delirium
  
  • Epidemioogy: elderly pts with medical illness, neuro conditions (Parkinson dz, dementia, prior stroke)
  • Pathophys:multifactorial, realted to increased oxidative stress, neuroinflammatory mediators, and impaired NT functioning
  • CP: anxiet, agitation, delusions, and/or hallucinations
  • onset-acute
  • consciousness-impaired
  • course-fluctuating
  • prognosis-reversible
  • memory impairment-global impairment
• Dementia
  
  • onset-gradual (months to years)
  • consciousness-intact
  • course-progressive
  • prognosis-irreversible
  • memory impairment-remote memory spared
• Depression
  
  • onset-gradual (months)
  • consciousness-intact
  • course-episodic
  • prognosis-reversible
  • memory impairment-moderately impaired focus/concentration

Question 102

long thoracic nerve

Answer 102

• serratus anterior
• damage=winged scapula

Question 103

CN 10 (vagus)

Answer 103

• PS innervation to viscera of chest and foregut

Question 104

Nigrostriatal degeneration in PD

Answer 104

• reuces activity of the thalamus and its projetions to the cortex resulting in bradykinesia and rigidity
• pts with medically intractable s/s of PD may benefit from high-freq deep brain stimulation of the globus pallidus internus or subthalamic nucelus
  
  • this promotes thalamo-cortical disinhibition with improved mobility

Question 105

Wernicke aphasia

Answer 105

• receptive aphasia
  
  • CP: well-articulated, nonsensical speech paired with lack of language ocmpehension (Wernicke-Word salad)
• W’s area located in the auditory association cortex within the posterior portion of the superior temporal gyrus in the dominant temporal lobe
• MCA supplies Broca’s area (superior division) and W’s area (inferior division)

Question 106

Absence seizures

Answer 106

• mainly in kids (boys)
• CP: sudden, momentary lapses in awareness, staring, rhythmic blinking, occasional clonic jerks of arms or hands
• no postictal or recollection
• last <10 sec
• tx: Ethosuximide (or sodium valproate)
• interictal EEG: generalized 3Hz spike-wave complexes superimposed on nml background activity

Question 108

Retinal artery occlusion (RAO)

Answer 108

• important cause of acute, painless, monocular visio loss
• most common cause: thromboembolic complications of atherosclerosis in the internal carotid that then travels though the ophthalmic artery

Question 109

Clozapine Tx guidelines

Answer 109

• Ci:
  
  • tx-resistant schizophrenia
  • schizophrenia associated with suicidality
• SE:
  
  • agranulocytosis
  • seizures
  • myocarditis
  • metabolic syndrome

Question 110

Naltrexone

Answer 110

• opiod antagonist
• first line pharm tx for moderate to severe alcohol use disorder

Question 111

First-gen ANTI-histamines

Answer 111

• chlorpheniramine, diphenhydramine
• block histamine receptors, also have anti-muscarinic, anti-alpha adrenergic, and anti-serotonergic properties
• anti-cholinergic effects on the oculuar ciliary muscles impair accomodation and causes blurring of vision for close objects

Question 112

mu, kappa, delta

Answer 112

Question 113

mood stabilizers in bipolar

Answer 113

Question 114

Clinical Features of Oppositional Defiant d/o

Answer 114

Question 115

Paraneoplastic syndromes

Answer 115

• can occur due to production of hormone-like substances form tumor cells
• also can result f/m immune rxns against tumor cells that cross-react with nml cells, causing dysfxn and/or damage to healthy organs and tissues
• neuro PNS (eg PN cerebellar degeneration are an a.i. phenomenon)

Question 116

Restless leg syndrome

Answer 116

• charac: uncomfortable sensation in legs accompanied by urge to move them
• relief with movement (walking, stretching)
• worse at rest and when falling asleep
• tx: DA agonists
• causes:
  
  • idiopathic
  • iron deficinecy
  • diabetes (especially with neuropathy)
  • MS, PD
  • Dx (antidepressants, metoclopramide)

Question 117

Nigrostriatal degeneration in PD

Answer 117

• reduces activity of the thalamus and its projections to the cortex=bradykinesia and rigidity
• pt with mediclaly intractable s/s of PD ma benefit from high-freq deep brain stimulation of the GLObus PALLIDUS INTERNUS or STN (subthalamic nucleus) as it promotes thalamo-cortical disinhibition with improved motility

Question 118

CJD (Creutzfeldt-Jakob dz)

Answer 118

• sporadic or infectious
• cause rapidly progressive dementia and myoclonic jerks
• microscopic: multiple vacuoles in the gray matter (spongiform encephalopathy)…vacuoles turn into cysts
• path: linked to abnml protein (prion)
• Prions: long incubation pd, no tx, invaraibly fatal

Question 119

Hypothalamic nuclei and major fxns

Answer 119

• ventromedial: mediates satiety, destruction=hyperphagia
• lateral: mediates hunger, destruction=anorexia
• anterior: mediates heat dissipation, destruction=hyperthermia
• posterior: mediate heat conservation, destruction=hypothermia
• arcuate: secretion of DA (inhibits prolactin), GHRH and gonadotropin RH
• Paraventricular: ADH, CRH, oxytocin and thyrotropin-releasing hormone secretion
• supraoptic: secretion of ADH and oxytocin
• Suprachiasmatic: circadian rhythm regulation and pineal gland fxn

Question 120

benign glomus tumor (glomangioma)

Answer 120

• can produce very tender, small (few mm), red-blue lesion under the nail bed
• originates form modified smooht muscle cells that control the thermoregulatory fxns of dermal glomus bodies

Question 121

Nicotinic cholinergic receptors

Answer 121

• receptors of NMJ, ligand-gated ion channel receptor (ionotropic R)
• as AP progress to presynaptic terminal, voltage-gated ca channels open, allow entry of calcium into nerve cytoplasm
  
  • triggers fusion of storage vesicles with the membrane, allowing release of ACh
  • ACh diffuses across synaptic cleft, interacts with nicotinic cholinergic receptors on motor end plate
  • na and ca INFLUX, K OUTflux results in generation of an end-plate potential

Question 122

Narcolespy

Answer 122

• hypocretin-1 and 2 (orexin A and B) are neuropeptides produced in the lateral hypothalamus that fxn to promote wakefulness and inhibit REM sleep-related phenomena
• most pt with narcolepsy with cataplexy demonstrate undetectable levels of hypocretin-1 in CSF
• DSM5:
  
  • definition: recurrent lapses into sleep or napping multiple times within the same day, at east 3x weekly for 3 mo
  • at least 1 of the following:
    
    • cataplexy:
      
      • conscious, brief episodes of sudden bilat mu tone loss precipitated by laughter/joking
      • spontaneous, abnm facial mvmt sans emotional triggers
    • hypocretin-1 deficiency by CSF fluid analysis
    • REM latency less than or equal to 15min

Question 123

Langerhans cells

Answer 123

• dendritic cells found in the skin that act as professional APC
• derived from myeloid line
• possess characteristic raquet-shaped intracytoplasmic granules (Birbeck granules)

Question 124

Myasthenic or cholinergic crisis

Answer 124

• can both cause exacerbation of MG in a pt txd with cholinesterase inhibitors
• edrophonium (Tensilon) test helps differentiate these two conditions
• clinical improvement after erdophonium admin=undertxd=Myasthenic crisis!

Question 125

Neuroleptic Malignant Syndrome (NMS)

Answer 125

• life-threatening adverse rxn to anti-psychotic meds
• characterized by: diffuse muscle rigidity, hyperthermia, autonomic instability, altered sensorium
• anti-psychotic should be stopped and supportive care provided
• Dantrolene can be used to reduce muscle rigidity

Question 126

Germinomas

Answer 126

• most common pineal gland tumor
• CP: obstructive hydrocephalus and dorsal midbrain (Parinaud) syndrome
• in the suprasellar region cause endocrinopathies due to pit/hypothalamic dysfxn

Question 127

neuroblastoma

Answer 127

• mean ag eonset: 2yo
• micro: solid sheets of small cells with dark nuclei, scant cytoplasm (small blue round cells)
• CP of main tumor: retroperitoneal mass (displace kidney), HTN, anorexia, weight loss
• metastases:
  
  • invasion of epidural space (dumbbell tumor)-SC compression
  • BM: pancytopenia
  • liver: hepatosplenomegaly
  • skin: palpable nodules
  • periorbital: proptosis, periorbital ecchymoses
  • Paraneoplastic syndrome: opsoclonus, myoclonus, truncal ataxia
• biochem: increased excretion of catecholamines in urine
• prognosis: better if pt<1 yo, worse with higher number of N-myc copies

Question 128

Schwannomas

Answer 128

• histo: biphasic pattern of cellularity (Antoni A and B areas) and S-100 positive (neural crest origin)
• can arise from peripheral nerves, nerve roots, and CN (except CN2)
• acoustic neuromas are most common type of intracranial schwannoma and located at cerebellopontine angle at CN8

Question 129

epidural hematoma

Answer 129

• middle meningeal artery
• between skull and dura
• Cp: lucid interval, followed by loss of consciousness
• CT scan: biconvex hematoma

Question 130

Subdural hematoma

Answer 130

• briding cortical veins
• between dura and arachnoid
• gradual onset of HA and confusion=CP
• crescent-shaped hematoma (CT)

Question 131

Subarachnoid hemorrhage

Answer 131

• aneurysm or AV malformation of anterior and posterior communicating arteries
• between arachnoid and pia mater
• sever HA (worst HA of my life), fever, nuchal rigidity=CP
• blood in basal cisterns =CT

Question 132

Medulloblastoma

Answer 132

• 2nd most common brain neoplasm of childhood
• located in cerebellum, often at vermis
• consists of shets of small, blue cells
• like other PNET (primitive neuroectodermal tumors), poorly differentiated and hv bad prognosis

Question 133

Temporomandibular d/o (TMD)

Answer 133

• PP:can arise from problems involving temporomandibular jt, the muscles of mastication, and nerves that supply the jaw
• CP: because mandibular division of the trigeminal nerve supplies the middle ear and muscles of mastication, TMD can present with both otologic symptoms and jaw pain, HA
• mandibular nerve: largest branch of trigeminal nerve, has sensory and motor
  
  • sensation to TMJ, mandibular teeth, floor of mouth, inside cheeks, ant tongue, skin of lower face
  • motor: mu of mastication (medial, lateral pterygoid, masseter, temporalis), mu of floor of mouth, tensor veli palatini, tensor tympani

Question 134

Lambert-Eaton syndrome

Answer 134

• s/s/: weakness improves d/r the day and with exercise. weakness of proximal muscle
• assoc w/ pre-existing malignancy
• path: Ab vs. pre-synaptic calcium channels
• tensilon test (edrophonium): no clinical improvement
• nerve stimulation studies: incremental response

Question 135

Contralateral sensory loss

Answer 135

• caused by damage to:
  
  • ventral posterior nucleus (receives input from spinothalamic tract and dorsal columns)
  • ventral posterior medial nucleus (receive input from trigeminal pathway) of the thalamus
• both nuclei send somatosensory projections to the cortex via thalamocortical fibers

Question 136

Lacunar infarctions

Answer 136

• PP: small vessel occlusion due to lipohyalinosis and microatheroma formation in the penetrating vessels supplying the deep brain structures
• RF: uncontrolled HTN and DM

Question 137

Primary CNS lymphomas

Answer 137

• most frequent CNS tumor in imunosuppressed pts, especially pts with AIDS
• PP: arise from B cells, universally associated with EBV
• high-grade tumors with poor prognosis (respond poorly to chemo)

Question 138

Charcot-Bouchard aneurysm

Answer 138

• assoc: HTN
• location:
  
  • basal ganglia
  • cerebellum
  • thalamus
  • pons
• size:<1mm
• result of rupture: intracerebral hemorrhage
• s/s of rupture: progressive neuro deficits, HA may follow

Question 139

Saccular (berry) aneurysms

Answer 139

• assoc w/: ADPKD, Ehlers-Danlos syndrome, HTN
• location: circle of Willis
• size: variable, 2-25mm
• result of rupture: subarachnoid hemorrhage
• s/s/ of rupture: sudde severe HA, focal neuro deficits uncommon

Question 140

Congenital hydrocephalus

Answer 140

• causes:
  
  • congenital obstruction (aqueductal stenosis, Chiari malformation)
  • acquired obstruction (congenital infection, post-hemorrhagic)
• s/s:
  
  • macrocephaly
  • bulging fontanelle
  • poor feeding
  • developmental delay
  • spasticity and hyperreflexia (from UMN injury)
• tx: cerebral shunting (ventriculoperitoneal shunt)
• imaging: enlarged ventricles
• sans tx: spasticity due to stretching of periventricular pyramidal tracts, developmental delays, seizures

Question 141

Phenytoin

Answer 141

• anticonvulsant used in tx of grand-mal (tonic-clonic) seizures, partial seizures, status epilepticus
• MOA: inhibits abnml elctrical activity of the brain by blocking voltage-gated sodium channels in neurons
• narrow therapeutic index with several adverse effects:
  
  • mainly CNS manifestations-ataxia and nystagmus
  • L-T: gingival hyperplasia (common; reversible when phenytoin withdrawn), coarsening of facial features, hirsutism
  • interferes with metab of folic acid, amy cause megaloblastic anemia
  • induces cyp450=increase metab and dcreases blood level of many meds
  • d/r pregnancy: fetal hydantoin syndrome
• gingival hyperplasia: phenytoin causes increased expression of PDGF, when gingival macrophages are exposed to increased amt of PDGF, they stim proliferation of gingival cells and alveolar bone

Question 142

Ramelteon

Answer 142

• BZ, antihistamines, sedating anti-depressants should be avoided in tx of insomnia in elderly (due to adverse effects)
• Ramelteon, melatonin agonist, safe and effective in reducing time to sleep onset in the elderly
• few SE, minimal dosage adjustment necess

Question 144

normal pressure hydrocephalus

Answer 144

• triad (wacky, wobbly, wet):
  
  • urinary incontinence
  • ataxic gait
  • dementia
• communicating hydrocephalus that occurs due to a diminished reabsorptive capacity of the arachnoid villi
• CT scan: symmetric dilation of ventriculi

Question 145

Cavernous hemangiomas

Answer 145

• vascular malformations
• occur mostly within brain parenchyma (above cerebelar tentorium)
• INC risk of intracerebral hemorrhage and seizure
  
  • CT: irregular hyperdense/bright mass

Question 146

intrathoracic expansion of lung ca

Answer 146

• phrenic nerve irritation and palsy
  
  • C3-C5 cervical segments, innervates ipsi hemidiaphragm
• phrenic nerve irritation: dyspnea, hiccups, referred pain to the shoulder
• phrenic nerve palsy: respiratory distress, diminished breath sounds on affected side

Question 147

Narcolepsy tx

Answer 147

• agents that promote wakefulness (psychostimulants)
• Modafinil-non amphetamine stimulant=first line
  
  • effective, well-tolerated, rare drug abuse
  • MOA: enahnce dopaminergic signaling
• amphetamines=second line agents due to sympathomimetic SE:
  
  • HTN, arrythmia, psychosis, risk of dependency

Question 148

Valproate and NTD

Answer 148

• valproate increase risk of NTD: 1-3%
• valproate inhibits intestinal folic acid absorption=teratogenicity
• mood stabilizing properties and effective maintenace tx of bipolar d/o
• also first-line: Lithium

Question 149

Seroneg spondyloarthropathies

Answer 149

• ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and arthirits assoc with inflamm bowel dz
• indivs expressing HLA B27 are at increased risk

Question 150

Ankylosing spondylitis

Answer 150

• chronic inflamm d/o of sacroiliac hts and axial skeleton
• most common in: young and middle aged men
• CP: morning stiffness and low back pain
• charac: destruction of articular cartilage with resulting stiffness and fusion of axial jts
  
  • sacroiliac jts tendet to palpation, spine may have decreased range of motion
• xray of sacroiliac jt: erosions, sclerosis, narrowing, fusion of jt spaces
• spine xrays: sclerosis, ligamentous calcification, vertebral fusion (bamboo spine)

Question 151

Glioblastoma

Answer 151

• most common primary cerebral neoplam of adults
• arise from astrocytes
• located within the cerebral hemisphere and may cross the midline (butterfly glioma)
• highly malignant tumors, grossly contain areas of necrosis and hemorrhage, soft and poorly defined

Question 152

Reactive arthritis (spondyloarhropathy)

Answer 152

• preceding infection: GU infxn (chlamydia trachomatis), Enteritis (Salmonella, shigella, yersinia, campy, c. diff)
• musculoskeletal: asym oligoarthritis, enthesitis, dactylitis
• Extraarticular s/s:
  
  • ocular-conjunctivitis, ant uveitis
  • genital: urethritis, cervicitis, prostatitis
  • dermal: keratoderma blennorrhagicum, circinate balanitis
  • oral ulcers

Question 153

vertebral osteomyelitis

Answer 153

• CP: pt with new or worsening back pain, fever, and recent endocarditis or bacteremia (espec. S. aureus), OR, pt with new neuro findings and fever with or sans back pain
• MRI of spine for diagnosis

Question 154

Bone remodeling

Answer 154

• osteoBLASTS-bone forming cells
  
  • synthesize bone matrix, release alk phos in systemic circulation
• osteoCLASTS-bone-resorbing cells
  
  • tartrate-resistant acid phosphatase, urinary hydroxyproline, urinary deoxypyridinoline (most reliable of the 3) reflect clast activity

Question 155

SAME DAVE

Answer 155

sensory afferent motor efferent

dorsal afferent ventral efferent

Question 156

cryptococcal meningoencephalitis

Answer 156

• CP:
  
  • HA, fever, lethargy in 2 wks
  • s/s/ more acute/sever in HIV pts
• Diag:
  
  • lumbar puncture: low glucose, increased protein, leukocyte ct low in HIV pt
  • transparent capsule on India ink staining
  • cryptococcal Ag in CSF
  • cultured on Sabouraud agar
• Tx: initially with Ampho B and Flucytosine
  
  • longterm maintenance therapy with Fluconazole

Question 157

Acute Gouty arthritis

Answer 157

• s/s/:
  
  • usually involves first metatarsophalangeal jt or knee
  • swelling, erythema, exquisite tenderness
  • s/s dvelop rapidly over 24hrs
• diag: joint aspiration shows needle-shaped, negatively birefringent crystals
• tx: NSAIDs (Naproxen, Indomethacin) preferred if no contraindications
  
  • Colchicine used as 2nd line therapy
    
    • inhibits tubulin polymerization and microtubule formation in leukocytes
    • reduces neutrophil chemotaxis and emigration to sites inflamed by tissue deposition of monosodium urate crystals
    • GI mucosal fxn is also impaired by microtubule disruption leading to diarrhea

Question 158

Clasp-knife spasticity

Answer 158

• charac: initial resistance to passive extension followed by a sudden release of resistance
• seen with UMN lesions and results from a lack of UMN inhibition on the spinal stretch reflex arc
  
  • UMN lesions can affect any pt of the pyramidal motor system
• pts with internal capsule stroke comonly have pure motor weakness affecting the contralat arm, leg, lower face
• contralat spasticity or increased tone, hyperreflexia, and a positive Babinski sign are also present

Question 159

Tonic-clonic seizures

Answer 159

• sodium valproate=drug of choice for pts with absence and associted tonic-clonic seizures
• Ethosuximide also effective against absence seizure but doesnt suppress tonic-clonic seizures
  
  • blocks T-type Ca channels that trigger and sustain rhythmic pulsed discharges in thalamic neurons

Question 160

Innervation of the tongue

Answer 160

• motor innervation
  
  • CN12 (hypoglossal) with the exception of palatoglossus muscle which is innervated by vagus (CN10)
• general sensory:
  
  • touch, pain, pressure, temp sensation provided by:
    
    • ant 2/3 tongue-mandibular branch of trigeminal nerve (CN V3)
    • post 1/3 of tongue: glossopharyngeal nerve (CN9)
    • posterior area of tongue root: vagus nerve (CN10)
• gustatory innervation (taste buds):
  
  • ant 2/3 tongue: chorda tympani branch of facial nerve (CN7)
  • post 1/3 tongue: CN9 (glossopharyngeal)
  • post area of tongue root and taste buds of the larynx and upper esophagus: CN 10

Question 161

Diazepam

Answer 161

• long acting Benzodiazepine
• Indications:
  
  • anxiolytic-manage generalized anxiety d/o and panic attacks
  • sedative-hypnotic-S-T tx of insomnia
  • anti-convulsant: status epilepticus, first-line (along with chlordiazepoxide) for tx of seizure associated with alc withdrawal
  • muscle relaxant-stop the spasticity caused by UMN d/o (MS, strokes, SC trauma) and tetanus
• SE: sedation, impair coordination and balance, confusion, decrease memory and concentration
  
  • worse with co-admin of other CNS-depressants
  • DO NOT mix with alcohol, barbiturates, neuroleptics, 1st gen anti-histamines

Question 162

What causes Wernicke syndrome

Answer 162

chronic thiamine (vit B1) deficiency

Question 163

What are the THREE main characteristic manifestations of WErnicke syndrome

Answer 163

1. OCULOMOTOR DYSFUNCTION
   
   1. d/t damage involving CN3,6, and vesibular nuclei
   2. rapidly reversbile
   3. usually resolves almost completely with THIAMINE admin
2. ATAXIA
   
   1. d/t damage to cerebellar cortex and vestibular nuclei
   2. takes longer to resolve
   3. some pts have PERMANENT s/s
3. MENTAL STATUS CHANGE
   
   1. disorientation, apathy, DEC attn span
   2. responds well to tx
   3. BUT memory and learning abnormalities persis–> KORSAKOFF syndrome

Question 164

Korsakoff syndrome

Answer 164

• assoc w/ damage to anterior and dorsomedial thalamic nuclei
• causes: memory loss and psychological phenomenon=CONFABULATION
  
  • fill memory gap with fake story they think is true
• also causes: inability to form new memories (anterograde amnesia)
• impairment in memory and learning is usually PERMANENT

Question 165

(Adamantinomatous) craniopharyngiomas

Answer 165

• benign suprasellar tumors in children
• cords/nests of palisading squamous epithelium with internal areas of lamellar WET KERTAIN under ight microscopy

Question 166

Ependymomas

Answer 166

• present as paraventricular tumors (floor of the fourth ventricle)
• characteristic: perivascular rosettes under light microscopy

Question 167

Schwannomas

Answer 167

• mostly benign tumors that commonly arise from the vestibular branch of CN8 at the cerebellopontine angle
• light microscopy: spindle cells with palisading nuclei arranged around VEROCAY BODIES composed of eosinophilic cores (Antoni A pattern)

Question 168

diabetic mononeurotherapy

Answer 168

• often involves CN3
• caused by predominantly central iscehmia
  
  • affects the somatic nerve fibers
  • spares peripheral parasympathetic fibers
• s/s:
  
  • ptosis
  • “down and out” gaze
  • normal light and accomodation reflexes

Question 169

NT and DZ-NE

Answer 169

• INC in anxiety
• DEC in depression
• synthesized in locus ceruleus (pons)–stress and panic

Question 170

NT and DZ-DA

Answer 170

• INC in Huntinton dz
• DEC in:
  
  • Parkinson dz
  • depression
• locations of synthesis:
  
  • ventral tegmentum
  • (substantia nigra) SN pars compacta (MB) midbrain

Question 171

NT and DZ-5-HT

Answer 171

• DEC in anxiety
• DEC in depression
• syn in: raphe nuclei (pons, medulla, midbrain)

Question 172

NT and DZ-ACh

Answer 172

• INC in Parkinson dz
• DEC in:
  
  • Alzheimer dz
  • Huntington dz
• syn in: basal nucleus of Meynert

Question 173

NT and DZ-GABA

Answer 173

• DEC in:
  
  • anxiety
  • Huntington dz
• syn in: nucleus accumbens
  
  • reward ctr, pleasure, addiction, fear

Question 174

anterior cranial fossa

Answer 174

A. Anterior

skull foramen:

cribiform plate; transversing structures: CN 1 olfactory bundles

Question 175

middle cranial fossa

Answer 175

B. Middle

skull foramen:

optic canal; transversing structures: CN 2, ophthalmic artery, central retinal vein

superior orbital fissure; CN 3,4,5.1,6, ophthalmic vein, sympathetic fibers

foramen rotundum; CN 5.2 (maxillary)

foramen ovale; CN 5.3 (mandibular)

foramen spinosum; middle meningeal artery and vein

Question 176

define hydrocephalus ex vacuo

Answer 176

C. In diseases associated with cerebral atrophy (Alzheimer, Pick dz) ventricular enlargement occurs seondar to atrophy od the brain–there is compensatory ventricular expansion=hydrocephalus ex vacuo

there is CT image similar to true BUT CSF pressure is NOT increased

Question 177

drug-induced parkinsonism

Answer 177

• type of EPS (extra pyramidal symptom) caused by meds that block D2 receptors
• management: DEC or discontinue offending med and tx with anticholinergi anti-parkinsonian meds

Question 178

what common SE of SSRIs may lead to nonadherence

Answer 178

sexual dysfunction

Question 179

stimulant intoxication

Answer 179

• CP: paranod ideation
• must be differentiated form primary psychiatric d/o
• physical signs:
  
  • tachycardia
  • HTN
  • hyperthermia
  • diaphoresis
  • mydriasis