5/18 UWorld

Question 1

What is the presentation of multiple sclerosis

Answer 1

• Charcot triad of symptoms - SIN:
  
  • Scanning speech
  • Intention tremor, Incontinence, Internuclear ophthalmoplegia
  • Nystagmus
• Hemiparesis, hemisensory symptoms

Question 2

MRI findings in multiple sclerosis

Answer 2

Periventricular plaques (areas of oligodendrocyte loss and reactive gliosis)

Question 3

Describe the mechanism behind glucagon as a treatment for beta blocker toxicity

Answer 3

Glucagon acts on G-protein coupled receptors, increasing intracellular cAMP, and thus increasing release of intracellular calcium during muscle contraction

This increases heart rate and cardiac contractility

Question 4

What are the 2 types of epithelium in Meckel diverticulum

Answer 4

Gastric and pancreatic

Question 5

What are the branches of the celiac trunk

Answer 5

• Common hepatic artery
  
  • Gastroduodenal artery
    
    • R gastroepiploic - greater curvature of stomach (anastomoses with L gastroepiploic)
    • Anterior superior pancreaticoduodenal à head of pancreas, proximal duodenum
  • Right gastric artery - lesser curvature of stomach (anastomoses with L gastric a.)
  • Proper hepatic artery
• Splenic artery - spleen
  
  • Left gastroepiploic artery - greater curvature of stomach
• Left gastric artery - lesser curvature of stomach

Question 6

What are the actions of angiotensin II

Answer 6

• (1) Acts on the zona glomerulosa cells of the adrenal cortex to stimulate synthesis of aldosterone
  
  • Aldosterone acts on principal cells of renal distal tubule and collecting duct to increase Na+ reabsorption and increase K+ and H+ excretion
• (2) Stimulates Na+/H+ exchange in the renal proximal tubule
  
  • Leading to increased reabsorption of Na+ and HCO3-
• (3) Acts on the hypothalamus
  
  • Increases thirst and water intake
  • Increases release of ADH
• (4) Acts directly on arterioles to cause vasoconstriction
  
  • Leads to an increase in TPR à increased BP
• (5) Constricts efferent arteriole of the glomerulus
  
  • Increases filtration fraction to preserve renal function (GFR) in low volume states

Question 7

How does Hepatitis D use Hepatitis B in order to cause infection

Answer 7

• Hepatitis D antigen must be coated with Hepatitis B surface antigen (HBsAg) in order to penetrate the hepatocyte to cause infection and multiply

Question 8

Cause of gastric varices within the fundus

Answer 8

Portal HTN

Splenic vein thrombosis (often due to pancreatitis, pancreatic cancer, or abdominal tumors - splenic vein runs posterior to pancreas)

Question 9

Describe the relationship between Creatinine and GFR

Answer 9

• When GFR is normal, relatively large decreases in GFR result in only small increases in serum creatinine
  
  • A person’s serum Cr can be essentially normal even after 50% loss of kidney function
• Cr levels begin to rise significantly as the GFR declines to <60%
  
  • As the GFR continues to decline, the slope of the Cr curve steepens

Question 10

What is the formula for filtration fraction?

Answer 10

FF = RPF/GFR

Question 11

Describe the adenoma-to-carcinoma sequence of colorectal cancer

Answer 11

• Normal colon
  
  • APC (adenomatous polyposis coli) gene mutation
• Colon at risk for polyps
  
  • KRAS mutation
• Development of polyps/adenoma
  
  • p53 mutation (loss of tumor suppressor) + increased expression of COX
• Progression to carcinoma

Question 12

Describe Displacement vs. Projection

Answer 12

• Displacement
  
  • Transferring avoided feeling or ideas to a neutral person
  • E.g. Father yells at child because his boss yelled at him
• Projection
  
  • Attributing unacceptable internal impulses to an external source
  • E.g. Accusing wife of cheating because of your desire to cheat

Question 13

Describe Isolation (psych)

Answer 13

• Separating feelings from ideas and events
• E.g. Describing murder in detail without an emotional response

Question 14

What is reaction formation

Answer 14

• Unconsciously replacing warded-off feelings by emphasis on its opposite
• E.g. Really sexual person become a monk

Question 15

Describe sublimation (psych)

Answer 15

• Consciously replacing an unacceptable wish with a similar but acceptable course of action
• E.g. Redirection of aggression towards father into sports

Question 16

What drugs can be used for nocturnal enuresis?

Answer 16

• Imipramine:
  
  • TCA
  • Decreases Non-REM N3
  • Short-term treatment
• Desmopressin
  
  • Decreases urination
• Indomethacin:
  
  • Decreases renal blood flow, thus decreasing urine formation

Question 17

What is the cavernous sinus and what does it contain?

Answer 17

• Collection of venous sinuses on either side of pituitary
• Contains CNs III, IV, V1, VI, and occasionally V2, + internal carotid
• Cavernous sinus syndrome:
  
  • Can be due to pituitary tumor, infection
  • Presentation:
    
    • Ophthalmoplegia (CN II, IV, VI)
    • Decreased corneal sensation (CN V1)
    • Horner syndrome
    • Decreased maxillary sensation (CN V)

Question 18

Describe each stage of the sleep cycle

Answer 18

• Sleep stages:
  
  • To remember EEG waves THINK: BATS Dream Big
• Awake (eyes open)
  
  • Beta waves
• Awake (eyes closed)
  
  • Alpha waves
  • Meditating
• Non-REM N1
  
  • Theta waves
  • Light sleep
• Non-REM N2
  
  • Sleep spindles and K complexes
  • Bruxism (teeth grinding)
• Non-REM N3
  
  • Delta waves (lowest frequency)
  • Deepest sleep
  • Sleep-walking, night terrors, bed wetting
• REM sleep
  
  • Beta waves
  • Loss of motor tone
  • Dreaming

Question 19

Describe embryology of brain formation

Answer 19

• (1) Prosencephalon
  
  • Telencephalon
    
    • Cerebral hemisphere
    • Lateral ventricles
  • Diencephalon
    
    • Thalamus, hypothalamu
    • 3rd ventricle
• (2) Mesencephalon
  
  • Midbrain
    
    • Aqueduct
• (3) Rhombencephalon
  
  • Metencephalon
    
    • Pons, cerebellum
    • Upper 4th ventricle
  • Myelencephalon
    
    • Medulla
    • Lower 4th ventricle

Question 20

Supraoptic nucleus of the hypothalamus

Answer 20

Produces ADH to be stored in posterior pituitary

THINK: Eyeball cup filled with water

Question 21

Paraventricular nucleus of the hypothalamus

Answer 21

Produces oxytocin to be stored in posterior pituitary

THINK: near valleys filled with love and happiness

Question 22

Pre-optic area of hypothalamus

Answer 22

• Secretes GnRH -> stimulates release of LH and FSH
• THINK: Before you even see (pre-optic), the person for who they really are you start secreting sex hormones

Question 23

Dorsomedial nucleus of the hypothalamus

Answer 23

• Stimulates GI
• Stimulation = savage behavior and obesity
• THINK: green monster on your back making you angry and eating out of jealousy

Question 24

Arcuate nucleus of the hypothalamus

Answer 24

• Releases dopamine and GHRH
• Regulates hunger and satiety
• THINK: a smile is an arc so the arcuate nucleus gives you a dopey smile

Question 25

What are the 3 vagal nuclei and their functions?

Answer 25

* Nucleus Solitarius * Visceral sensory information à taste, baroreceptors, gut distension * Nucleus Ambiguous * Motor innervation of pharynx, larynx, upper esophagus (e.g. swallowing, palate elevation) * Dorsal motor nucleus * Sends autonomic fibers to heart, lungs, upper GI

Question 28

What tumors show Rosenthal fibers?

Answer 28

Pilocytic astrocytoma * Rosenthal fibers – eosinophilic corkscrew fibers * THINK: Children’s Christmas tree star is on top of a spiral thing with tall Chris Rossman (Rosenthal) putting up the star

Question 29

What tumors show Homer Wright rosettes?

Answer 29

Medulloblastoma * Homer Wright rosettes (small blue cells wrap around pink areas of neuritic processes) * THINK: Homer Simpson has the brain of a child with an actual problem of brain cells (child tumor of neurons)

Question 30

What tumors show perivascular pseudorosettes

Answer 30

Ependymoma

Question 31

What tumor shows pseudopalisading (bordering central area of necrosis)

Answer 31

* Glioblastoma multiforme * Pseudopalisading – tumor surrounding central necrosis * THINK: looks like a firework (central area of nothing with surrounding); firework = star (astrocyte tumor of adults)

Question 32

What is the enzyme that catalyzes the formation of ribose sugars in the HMP shunt

Answer 32

Transketolase

Question 33

What is the predominant inflammatory cell in gout

Answer 33

Neutrophils

Question 34

Treatment for pyruvate dehydrogenase deficiency

Answer 34

Ketogenic diet (high fat, low carb diet with moderate levels of protein) This forces the production of ketone bodies to fuel the body in place of glucose, so less pyruvate is generated via glycolysis Lysine and leucine are exclusively ketogenic aminao acids and cannot be metabolized to pyruvate

Question 35

Describe the defect and effect of conduction aphasia

Answer 35

Conduction aphasia - damage to arcuate fasciculus (connection between Broca's and Wernicke's area) Broca's and Wernicke's are intact (speech and comprehension are intact), but no connection between what you hear and what you say (repitition is impaired)

Question 36

Describe the defect and effect of global aphasia

Answer 36

Global aphasia - Broca and Wernicke area affected Influent speech and impaired comprehension

Question 37

Lesion to what part of the brain gives you expressive dysprosody?

Answer 37

Non-dominant Broca's area

Question 38

Effect of lesion to the dominant parietal cortex

Answer 38

Gerstmann syndrome agraphia (inability to write), acalculia (inability to calculate), finger agnosia (inability to distinguish fingers), left-right disorientation

Question 39

What are the 3 C's to remember about toxicity of TCA's?

Answer 39

Cardiac, coma (anti-H1), convulsions (anti-GABA)

Question 40

Describe the mental/psychological changes in delirium vs. dementia

Answer 40

Delirium - Disorganized thoughts, delusions, hallucinations, sleep disturbance Dementia - Cognitive decline, with minimal psychotic symptoms

Question 41

Compare Parkinson's to Lewy body dementia

Answer 41

* Lewy body:Early onset dementia + Lewy bodies * Vs. Parkinson’s which has late onset dementia + Lewy bodies * Lewy bodies within the cortex (aggregates of a-synuclein) * Vs. Parkinson’s which affects the substantia nigra * Characterized by dementia and visual hallucinations, followed by Parkinsonian features

Question 42

Presentation of Creutzfeldt Jacob disease

Answer 42

Rapidly progressive dementia + ataxia + startle myoclonus

Question 43

Cause of and presentation of homocystinuria

Answer 43

* Causes: * o Cystathionine synthase deficiency * o Decreased affinity of cystathionine synthase for B6 * o Methionine synthase deficiency * Presentation: * o Homocysteine in urine * o Marfanoid habitus * o Ocular changes (downward and inward lens subluxation – vs. Marfan which is upward) * o CV effects * Homocysteine is prothrombotic, which may lead to premature acute coronary syndrome * o Kyphosis * o Intellectual disability

Question 44

Deficiency and presentation of Phenylketonuria

Answer 44

* Due to: * Deficiency in phenylalanine hydroxylase, or * Deficiency in tetrahydrobiopterin cofactor (BH4) * BH4 is also a cofactor used for serotonin synthesis * Tyrosine becomes an essential amino acid * Presentation: * Intellectual disability * Growth retardation * Seizures * Fair skin - inability to make melanin * Eczema * Must body odo