Nir Hus Absite review q3 4


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Slides with topics that are covered and were tested in the recent Absite exams.
Nir Hus MD., PhD.

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Nir Hus Absite review q3 4

  1. 1. Absite topics 7-12Nir Hus Nir Hus
  2. 2. Q7: Timing of the first prophylactic antibiotic dose  The first prophylactic antibiotic dose should provide a sufficient antibiotic serum level throughout the surgery to combat organisms most likely to cause a site infection.  The first dose be timed to occur within 60 minutes before the surgical incision is made.  If a fluoroquinolone or vancomycin is chosen for prophylaxis, the first dose should be administered within 120 minutes of the start of surgery. Nir Hus
  3. 3. Timing of the first prophylactic antibiotic dose  For most surgeries, the use of prophylactic antibiotics should end within 24 hours after surgery.  Cefazolin or cefuroxime are suggested for cardiothoracic surgery, with the recommendtion of extension of prophylactic antibiotics up to 72 hours to avoid deep sternal infections. Nir Hus
  4. 4. Surgery Prophylaxis CommentsCardiothoracic Cefazolin or cefuroxime; if beta 72-hour duration lactam allergy, vancomycin or advocated by some, but clindamycin 24 hours is likely to be adequate Vascular Cefazolin or cefuroxime; if beta lactam allergy, vancomycin with or without gentamicin, or clindamycin Colon Oral: neomycin, with Combination of oral and erythromycin base or parenteral prophylaxis metronidazole may decrease infection ratesAdapted with permission from Bratzler DW, Houck PM. Antimicrobial prophylaxis forsurgery: an advisory statement from the National Surgical Infection Prevention Project.Clin Infect Dis 2004,38:1707. Nir Hus
  5. 5. Timing of the first prophylactic antibiotic dose  Adaptedwith permission from Bratzler DW, Houck PM. Antimicrobial prophylaxis for surgery: an advisory statement from the National Surgical Infection Prevention Project. Clin Infect Dis 2004,38:1707. Nir Hus
  6. 6. Q8: Incarcerated Groin Hernia  Incidence of incarceration ~10% among inguinal hernias.  Cannot be reduced into the abdominal cavity.  Strangulated hernias have incarcerated contents with vascular compromise.  Frequently, intense pain is caused by ischemia of the incarcerated segment. Nir Hus
  7. 7. Q8: Incarcerated Groin Hernia  Incarcerated inguinal hernias present with abdominal distention, pain, nausea, and vomiting due to intestinal obstruction.  Plain abdominal X-rays may verify intestinal obstruction in cases of incarceration. Nir Hus
  8. 8. Q9: Short Bowel Syndrome  Pathophysiology:  Dehydration  Electrolyte derangements  Acidic diarrhea  Steatorrhea  Malnutririon  Weight loss Nir Hus
  9. 9. Q9: Short Bowel Syndrome  Etiology for extensive resection:   Congenital anomalies leading to short bowel syndrom include –   Intestinal atresia   Midgut volvulus w/ intestinal necrosis   Necrotizing enterocolitis.   In Middle-aged adults –   IBS   Trauma   In the elderly-   Mesenteric ischemia   Strangulated hernia   Extensive resection due to malignancy. Nir Hus
  10. 10. Q9: Short Bowel Syndrome  Resection resulting in less than 120cm of intact bowel leads to SBS.  Resection of up to 50% of small bowel is tolerated.  Resection of up to 70% is tolerated if terminal ileum and cecum are preserved.  Infants may tolerate upto 85% of small bowel resection. Nir Hus
  11. 11. Q9: Short Bowel Syndrome  Loss of the ileocecal valve results in rapid emptying of enteral contents into the colon and reflux of colonic bacterial flora into small bowel.  The entire jejunum can be resected without serious adverse nutritional sequela. Nir Hus
  12. 12. Q9: Short Bowel Syndrome  Adaptation:  Cellularhyperplasia and bowel hypertrophy occur over a 2- to 3-year period, increasing the absorptive surface area.  Fat absorption is most likely permanently impaired. Nir Hus
  13. 13. Q10: Malabsorption & Malnutrition  Gastric hypersecretion  Cholelithiasis  Hyperoxaluria & Nephrolithiasis  Diarrhea & Steatorrhea  Intestinal Microflora Nir Hus
  14. 14. Q10: Malabsorption & Malnutrition  Gastric hypersecretion – in early postop period. Increased acid load may injure distal bowel mucosa  hypermotility & impaired absorption.  Cholelithiasis – altered bilirubin metabolism after ileal resection  increased risk of pigmented gallstones stones that is 2nd to a decreased bile salt pool. TPN also may lead to increased risk of cholelithiasis. Nir Hus
  15. 15. Q10: Malabsorption & Malnutrition  Hyperoxaluria & Nephrolithiasis –  Excessive fatty acids within the colonic lumen bind intraluminal calcium.  Unbound oxalate that normally is made insoluble by Ca-binding and is excreted in feces is thus, readily absorbed.  This results in hyperoxaluria and calcium oxalate urinary stone formation. Nir Hus
  16. 16. Q10: Malabsorption & Malnutrition  Diarrhea & Steatorrhea –  Caused by rapid intestinal transit.  Presence of hyperosmolar enteric contents.  Disruption of enterohepatic bile acid circulation.  Fat absorption is most severly impaired by ileal resection. Nir Hus
  17. 17. Q10: Malabsorption & Malnutrition  Intestinal Microflora –  Loss of ileocecal valve permits reflux of colonic bacteria into small bowel.  Intestinal dysmotility increases colonization.  Bacterial overgrowth & change in flora results in pH alteration & deconjugation of bile salts.  This results malabsorption, fluid loss, decreased vit B12 absorption. Nir Hus
  18. 18. Q11: Effect of ASA on Plt.  Irreversiblyacetylates cyclooxygenase  Results in inhibiting plt synthesis of Thromboxane A2.  Decreases plt function.  Higher doses than > 80 – 160mg PO / day donot have a higher efficacy. Nir Hus
  19. 19. Q12: Synergism Ampicillin / Sulbactam (Unasyn)  PCN:   GPC – streptoccocci, syphilis,   GPR - Neisseria m., C. perfringens,   Beta-hemolytic strep, antrax   Not effective for Staph or Enterococcus  Ampicillin/amoxicillin: PCN + Enterococcus coverage  Unasyn: PCN + GPC (staph & strep), GNR +/- anaerobic coverage, enterococci.   NOT FOR Pseudomonas, Acinetobacter, or Serratia.   Sulbactam & Clavulanic acid – are beta-lactamase inhibitors. Nir Hus