5/23 UWorld

Question 1

Which is more worrisome and why: unilateral facial paralysis sparing the forehead or unilateral facial paralysis involving the forehead?

Answer 1

• Upper motor neuron lesion - more severe, could mean stroke
  
  • Destruction of motor cortex or connection between motor cortex and facial nucleus
  • Contralateral paralysis of lower facial muscles (sparing of forehead)
• Lower motor neuron lesion - Bell’s Palsy
  
  • Destruction of facial nucleus or facial nerve
  • Ipsilateral paralysis of upper and lower muscles of face
• Explanation:
  
  • Facial motor nucleus receives motor fibers for the lower face from the opposite motor cortex and motor fivers for the upper face from both moto cortices
  • So if a lesion occurs in the L motor cortex facial region, there is still sufficient innervation for R upper face from R motor cortex
  • But since L motor cortex is the only innervation of R lower face, there will be paralysis of R lower face

Question 2

What are the 4 midline structures and associated lesion presentations in the brainstem

Answer 2

Motor pathway - contralateral weakness

Medial lemniscus - contralateral proprioception/vibration deficit

Medial longitidinal fasciculus - ipsilateral internuclear ophthalmoplegia

Motor nuclues and nerve - ipsilateral CN motor loss (3, 4, 6, 12)

Question 3

What are the 4 lateral structures and associated lesion presentations of the brainstem?

Answer 3

Spinocerebellar - ipsilateral ataxia

Spinothalamic - contralateral pain and temp

Sensory V - ipsilateral pain and temp of the face

Sympathetic - ipsilateral Horner’s

Question 4

What are the layers that you go through during a spinal tap?

Answer 4

Skin - superficial fascia - supraspinous ligament - interspinous ligament - ligamentum flavum - epidural space - dura mater - subdural space - arachnoid membrane - subarachnoid space (this is where CSF is)

Question 5

Diseases associated with berry aneurysm

Answer 5

Ehlers-Danlos syndrome

Autosomal dominant polycystic kidney disease

Question 6

Describe the presentation of normal pressure hydrocephalus

Answer 6

• Ventricular dilation with normal ICP
• Occurs in the elderly
• Triad - “Wet, wacky, wobbly”
  
  • Urinary incontinence = wet
  • Dementia = wacky
  • Ataxia = wobbly
    
    • Magnetic gait – feet appear stuck on floor

Question 7

Describe cluster HA (duration, location, features, associated sx, treatment)

Answer 7

15 min – 3 hours

Repetitive (often occur daily at the same time)

Unilateral, non-throbbing heading

Excruciating pain, usually perioribital

Associated with lacrimation, rhinorrhea, and Horner syndrome (ptosis and miosis, not anhidrosis)

Treatment: 100% O2, sumatriptan

Question 8

Describe tension HA (duration, location, features, associated sx, treatment)

Answer 8

Usually 4 – 6 hours

Bilateral headache with constant, steady pain

Usually in frontal or occipital lobe

No throbbing, no photophobia, no phonophobia, no aura

Treatment: NSAIDs, Acetaminophen

Question 9

Describe migraine HA (duration, location, features, associated sx, treatment)

Answer 9

Usually 4 – 72 hours

Unilateral pulsing, throbbing headache

Associated with nausea, photophobia, phonophobia, and aura

Treatment: Triptans

Question 10

Describe the MOA of Triptans

Answer 10

• Mechanism of action:
  
  • Selective agonists of 5HT-1B and 5HT-1D receptors located on meningeal vessels, trigeminal nerve, and brainstem
  • Activation of these receptors on vessels causes vasoconstriction of cerebral and meningeal vessels (this will attenuate inflammation and decrease the stretch at pain receptors)
  • Activation of receptors directly on trigeminal nerve will prevent the release of vasoactive peptides, thus preventing vasodilation in the first place
  • Activation of receptor in brainstem can inhibit pain pathways

Question 11

Tumors associated with von Hippel-Lindau disease

Answer 11

Renal cell carcinoma (bilateral)

Hemangioblastoma

Pheochromocytoma

Question 12

What is the tumor marker for tumors of astrocytes (glioblastoma multiforme and pilocytic astrocytoma)

Answer 12

GFAP +

Question 13

Describe the blood supply of the brainstem (medial and lateral of midbrain, pons, and medulla)

Answer 13

• Midbrain:
  
  • Medial - posterior cerebral
  • Lateral - posterior cerebral
• Pons:
  
  • Medial - Basilar
  • Lateral - Anterior inferior cerebellar artery (AICA)
• Medullar:
  
  • Medial - anterior spinal (ASA)
  • Lateral - Posterior inferior cerebellar artery (PICA)

Question 14

What is the mechanism of Hepcidin sequestering iron

Answer 14

• Hepcidin influences body iron storage through its interaction with ferroportin, a transmembrane protein responsible for transferring intracellular iron to the circulation
• Upon binding Hepcidin, ferroportin is internalized and degraded, decreased intestinal iron absorption and inhibiting the release of iron by macrophages

Question 15

Complications of Hereditary spherocytosis

Answer 15

Aplastic crisis

Pigmented gallstones - due to increased bilirubin from lysed RBCs

Question 16

Classic presentation of AML

Answer 16

Bleeding in the setting of DIC (characterized by decreased fibrinogen)

Question 17

Which coagulation factor has the shortes half-life

Answer 17

Factor VII

Question 18

Mechanism of Desmopressin treatment in bleeding disorders

Answer 18

Increases release of Factor VIII (treats Hemophilia A) and vWF (treats von Willebrand disease)

Question 19

Enzyme deficient in acute intermittent porphyria

Answer 19

• Deficiency of Porphobilinogen (PBG) deaminase
  
  • THINK: Acute intermittent = guys hollering “damn” (deam-inase) intermittently at A CUTE pretty big girl (PBG) walking by

Question 20

Presentation and treatment of acute intermittent porphyria

Answer 20

• Symptoms – 5 P’s
  
  • Painful abdomen, Port wine colored urine (due to increase PGB), Polyneuropathy, Psychological disturbances, Precipitated by drugs (CYP450 inducers), alcohol, and starvation
• Treatment
  
  • Glucose + heme = inhibition of ALA synthase

Question 21

MOA of Flutamid

Answer 21

Testosterone receptor inhibitor

Inhibits androgen receptor-binding

Used to treat prostate cancer (testosterone-dependent)

Question 22

Name of GP2b3a antagonist drugs

Answer 22

Abciximab

Eptifibatide

Tirofiban

Question 23

What causes autosplenectomy in sickle cell patients?

Answer 23

Vaso-occlusion

Question 24

Why might you see macrocytic anemia is sickle cell patients

Answer 24

• Hemolytic anemia leads to increased erythrocyte turnover and increased folic acid requirement
  
  • So patients are prone to developing relative folic acid deficiency

Question 25

What lymphoma has t(14;18) and what gene abnormality will it cause

Answer 25

Follicular lymphoma * t(14;18) = heavy chain Ig (14) and BCL-2 (18) * Overexpression of BCL-2 = decreased apoptosis * Recall that BCL2 stabilizes mitochondrial membranes, preventing leakage of cytochrome C, and thus preventing apoptosis * Follicle is where B-cells are produced, so lack of apoptosis = malignant B-cell proliferation

Question 26

In what brain bleed do you get a lucid interval

Answer 26

Epidural hematoma Rupture of middle meningial artery

Question 27

Flow of info through the cerebellum

Answer 27

* Inputs (mossy and climbing fibers) - cerebellar cortex - axons of purkinje fibers (always inhibitory signal) - deep nuclei of cerebellum - output targets (usually superior cerebellar peduncle - contralateral ventral lateral nucleus of thalamus)

Question 28

* Functional units of cerebellum and their corresponding deep nuclei

Answer 28

* Vestibulocerebellum * Vermis + flocculonodular (most medial) * = Fastigial deep nucleus * Spinocerebellum * Vermis + paravermis * = Interposed (Emboliform + Globose) deep nucleus * Cerebrocerebellum * Lateral hemisphere * = Dentate deep nucleus REMEMBER: * Lateral to medial = Don’t Eat Greasy Foods * Dentate * Emboliform * Emboliform + Globose = Interposed * Globose * Fastigial

Question 29

What is the presentation and cause of hemiballismus

Answer 29

Sudden, wild flailing of half of body (1 arm +/- ipsilateral leg) Seen in lesion of contralateral subthalamic nucleus

Question 30

Define athetosis and it's cause

Answer 30

Slow, writhing movements, especially seen in the fingers Due to lesion of basal ganglia (Huntington's)

Question 31

Define chorea and its cause

Answer 31

Sudden, jerky, purposeless movements Seen in lesion of basal ganglia (e.g. Huntington's)

Question 32

Define dystonia

Answer 32

Sustained, involuntary muscle contractions Due to Writer’s cramp, blepharospasm, torticollis

Question 33

Define akathisia and its cause

Answer 33

* Dancing in place (voluntary) / Restlessness * Compulsion to move * Seen with neuroleptic use or in Parkinson’s

Question 34

Define asterixis and its cause

Answer 34

* Extension of wrists causes “flapping” motion * Associated with hepatic encephalopathy, Wilson disease, and other metabolic derangements

Question 35

Identify the location of the following in the spinal cord: Dorsal column Spinothalamic tract Corticospinal tract (lateral and anterior)

Answer 35

Question 36

What part of the spinal cord is damaged in Werdnig-Hoffman disease

Answer 36

Anterior motor horn - LMN deficit with SYMMETRIC weakness (vs. poliomyelitis which is LMN deficit with ASYMMETRIC weakness)

Question 37

What part of the spinal cord is affected/presentation of complete occlusion of the anterior spinal artery

Answer 37

* Damage to everything except dorsal column * Spinothalamic damage = loss of bilateral pain and temperature below the lesion * Corticospinal damage = UMN below the lesion * Anterior horn damage = LMN deficit at the level of the lesion

Question 38

What part of the spinal cord is damaged/presentation of ALS

Answer 38

* Aka Lou Gehrig disease * Damage to anterior motor horn and lateral corticospinal tract * Presents with both UMN and LMN deficits * Lack of sensory impairment distinguishes from syringomyelia * Caused by defect in superoxide dismutase (O2- to H2O2)

Question 39

What part of the spinal cord is damaged/presentation of Tabes dorsalis

Answer 39

Due to tertiary syphilis Damage to dorsal column Impaired propriocepton Absence of DTRs and (+) Romberg Argyll Robertson pupils (accommodation but no reaction to light)

Question 40

Findings in Brown-Sequard syndrome

Answer 40

Ipsilateral UMN signs below level of lesion (corticospinal tract damage) Ipsilateral loss of tactile, vibration, proprioception sense below level of lesion (dorsal column) Contralateral pain and temp loss 2-3 segments below level of lesion (spinothalamic tract) 2-3 segments below because remember info travelled up 2-3 segments via Lissaur’s tract Ipsilateral pain and temp loss at level of lesion Ipsilateral LMN signs at level of lesion

Question 41

What is the Charcot triad and what disease is it for?

Answer 41

* Multiple sclerosis * Charcot triad of symptoms - SIN: * Scanning speech * Intention tremor, Incontinence, Internuclear ophthalmoplegia * Nystagmus

Question 42

Describe MRI and lumbar puncture of MS

Answer 42

* MRI (gold standard) * Periventricular plaques (areas of oligodendrocyte loss secondary to demyelination and reactive gliosis) * Lumbar puncture * Increased protein * Oligoclonal IgG bands

Question 43

\Describe cause/presentation of Friedrich ataxia

Answer 43

* Autosomal recessive trinucleotide repeat disorder - GAA * Frataxin gene of chromosome 9 * Leads to impairment in mitochondrial function * Degeneration of cerebellum and spinal cord * Ataxia, muscle weakness, loss of vibratory sense and proprioception, diabetes mellitus, hypertrophic cardiomyopathy * Presents in childood with kyphoscoliosis * THINK: Friedreich is fratastic (frataxin): he’s your favorite frat brother, always staggering and falling but has a sweet, big heart