UWorld_2.11

Question 1

Botulism mechanism of infection

Answer 1

• main kinds: food-borne, wound, infant (honey)
• food-borne:
  
  • spores grow intracellularly
  • autolysis ==> release of neurotoxin into food (NOT actively secreted)
    
    • toxin can be destroyed by heating, but if food is not cooked well, toxin will exert its effects
  • neurotoxin ==> blocking of ACh release from nerve terminals @ NMJ ==> flaccid paralysis

Question 2

Clinical presenation of botulism

Answer 2

• “three ‘Ds’”:
• diplopia
• dysphagia
• dysphonia

Question 3

Characteristics of Digeorge Syndrome

Answer 3

• CATCH-22
• Cardiac abnormality (especially tetralogy of Fallot)
• Abnormal facies
• Thymic aplasia ==> T-cell dysfxn
• Cleft palate
• Hypocalcemia/Hypoparathyroidism
• 22q11.2 deletion

Question 4

Characteristics of tuberous sclerosis

Answer 4

• AD
• cutaneous angiofibromas (adenoma sebaceum)
• seizures
• mental disability
• pathology
  
  • CNS hamartomas and benign neoplasma
  • renal/visceral cysts
  • cardiac rhabdomyomas

Question 5

Characteristisc of Marfan syndrome

Answer 5

• AD
• Mutation @ FBN1 gene @ chromosome 15 ==> connective tissue glycoprotein defect
• associated sx:
  
  • tall stature
  • cystic medial necrosis ==> aortic dissection
  • lens dislocation
  • narrow face

Question 6

Major fxns of stomach

Answer 6

1. Protein digestin
   
   1. parietal cells ==> HCl
   2. chief cells ==> pepsinogen
   3. pepsinogen ==> pepsin ==> degrades proteins
2. IF secretion ==> absorption of vitamin B₁₂
3. Gastric resevoir = slow emptying into small bowel

Question 7

Tx/recommendations after total gastrectomy

Answer 7

• parental B₁₂
• to avoid dumping syndrome (colicky ab pain, nausea, diarrhea)
  
  • small meals
  • low dietary intake of simple sugars

Question 8

Identify: A-H

Answer 8

• A = Corpus Callosum
• B = Lateral Ventricle
• C = Caudate
• D = Internal capsule
• E = Putamen
• F = Globus Pallidus
• G = Amygdaloid nuclei
• H = Internal Capsule

Question 9

Cystic degeneration of putamen ==> dx?

Answer 9

Wilson’s disease

Question 10

Presentation of GVHD

Answer 10

• most common afer allogeneic bone marrow transplant or organs rich in lymphocytes (e.g. liver) or transfusion of non-irradiated blood
• T cells @ donor tissue recognize host MHC antigens and attack
  
  • both CD4+ and CD8+ cells
• skin, liver, and GI tract are generally most affected
• Sx/Labs
  
  • w/in one week of transplant
  • liver damage ==> jaundice + elevated LFTs (ALT, AST, alk phos, bilirubin)
  • GI damage ==> diarrhea, intestinal bleeding, ab cramping, ileus
  • [severe cases] ==> skin desquamation

Question 11

Meckel diverticulum characteristics

Answer 11

• blind pouch connected to ileum <== incomplete obliteration of onphalomesenteric duct (connects midgut lumen and yolk sac cavity in fetal life)
• ectopy ==> gastric, pancreatic and other types of cells/mucosa that may be found at meckel diverticulum
• presentation
  
  • commonly ==> painless melana
  • may become infected/inflamed ==> ~appendicitis presentation

Question 12

Ectopy definition

Answer 12

• microscopically and functionally normal cells/tissue found in an abnormal location due to embryonic maldevelopment

Question 13

Valsalva maneuver impact on venous return/heart murmurs

Answer 13

• ==> decreased venous return
• mitral valve prolapse & hypertrophic cardiomypathy ==> more audible
• aortic stenosis ==> less audible

Question 14

Common heart murmur in CHF

Answer 14

• S3 = “ventricular gallop” <== blood rushing into partially filled ventricle or into a stiff ventricle
• best heard w/bell of stethoscope @ apex in L lateral decubitus position + patient completely exhales (==> heart closer to chest wall)

Question 15

Characteristics of duodenal lining

Answer 15

• villi covered by simple columnar epithelium w/brush border
  
  • goblet cells ==> mucous secretion
  • APUD = amine precursor uptake and decarboxylation cells
• @ lamina propria = crypts of lieberkuhn ==> deliver secretion to intervillar spacese
• submucosa is deep to muscular mucosae
  
  • Brummer’s glands ==> alkaline mucous

Question 16

Characteristics of jejunal villi

Answer 16

• more goblet cells vs. duodenal villi
• crypts of Lieberkuhn persist; open into intervillar space
• heavy lymphocytic infiltrate of lamina propria is common

Question 17

Characteristics of ileum

Answer 17

• ileum is similar to jejunum
• Peyer’s patches = lymphatic nodules ==> adjacent to villi/crypts