Intestinal obstruction and Surgical problems

Question 1

Pathophysiology of DISTAL bowel obstruction:

Answer 1

• Bowel distension > Increased hydrostatic pressure > bowel wall edema > Ischemia > Bacterial overgrowth and translocation.

Question 2

Presentation of bowel obstruction: Proximal versus Distal

Answer 2

• Proximal intestinal obstruction: bilious emesis, minimal distension.
• Distal intestinal obstruction: Distension. Bowel wall edema, Third spacing/hypovolemia/shock. Ischemia/sepsis.

Question 3

Exam on obstruction

Answer 3

• hyperactive BS progress to hypoactive/absent bowel sounds
• tender abdomen (watch for peritoneal signs)
• abdominal mass
• keep incarcerated inguinal hernia on DDX

Question 4

imaging to obtain for obstruction

Answer 4

• KUB (Free air on decubitus views), (Dilated loops/air fluid levels), (air in colon or rectum in prone position).
• ABD US: Intussusception.
• UGI: malrotation/volvulus.
• CT/MRI with PO contrast: watch for transition zone, partial/complete obstruction. Extrinsic/intrinsic.

Question 5

Management of bowel obstruction

Answer 5

• NGT with bowel decompression (reduces pressure, prevents ischemia).
  Ischemia warning signs: persistent pain, peritoneal signs, hematochezia, fever, acidosis.
• fluid resuscitation.

Question 6

Newborn obstruction DDX

Answer 6

• Polyhydramnios suggests high level obstruction (esophageal, duodenal, high intestinal atresia). (lower atresia have less distension because SI is absorbing the fluid
• Other congenital anomalies: atresia, aganglionosis, malrotation.
• Intestinal contents: Meconium ileum, meconium plug.

Question 7

Newborn obstruction work up

Answer 7

• Prenatal US: polyhydramnios, dilated loops of bowel.
• Bilious emesis.
• Failure to pass meconium.
• KUB: Double bubble stomach and proximal duodenum.

Question 8

Duodenal atresia

Answer 8

• 1:5,000 to 1: 10,000 live births.
• Incomplete recanalization: 8-10 weeks gestation (can be a/w annular pancreas).
• 20-25% association with Trisomy 21 (Down’s).
  Other associations: Cardiac (35%), Renal (14%), Esophageal (6%), Anorectal (5%), Vertebral (6%)

Question 9

Intestinal Atresia

Answer 9

• 1:1,500-1:5,000 live births.
• Possible intrauterine vascular insult.
• A/w maternal smoking and thrombophilia.

Question 10

Intestinal Atresia Types

Answer 10

• Type 1: intact membrane.
• Type 2: Gap with fibrous band.
• Type 3a: gap and mesenteric defect.
• Type 3b: absence of large segment of bowel supplied by SMA with distal foreshortening “apple peel”
• Type 4: multiple atresias. genetic association: TTC7A gene (Autosomal recessive), also identified with severe immunodeficiency, also with VEOIBD.

Question 11

Intestinal atresia types diagram

Answer 11

Question 12

Infant Obstruction DDX

Answer 12

• Pyloric Stenosis
• Malrotation/volvulus
• Strictures (ileal or colonic)
• NEC
• Antral web
• Annular pancreas
• Jejunal web

Question 13

Intestinal malrotation, midgut volvulus

Answer 13

• Normal: Ligament of Treitz should be left of the midline at the level of the pylorus.
• malrotation: LOT NOT left of midline at level of pylorus, and cecum in RUQ.
• Pathophys: Ladd’s bands obstructing duodenum, shortened base of mesentery.
• Volvulus: “corkscrew” appearance. “Beaked” appearance at obstruction.

Question 14

Intestinal malrotation symptoms: newborn vs child

Answer 14

• Newborn: bilious emesis, volvulus progressed rapidly to ischemia. Emergency UGI or directly to OR.
• Child: may have protracted course, can present with abdominal pain, vomiting, malabsorption, FTT.

Question 15

Ladd’s procedure

Answer 15

• reduce volvulus: counterclockwise
  -divide peritoneal bands
• position small and large bowel in non-rotated position.
  -appendectomy
• does not rule out future volvulus.

Question 16

Malrotation associations

Answer 16

• Congenital diaphragmatic hernia
• gastroschisis
• omphalocele and intestinal atresia (less common)
• Heterodoxy syndrome 70% (asplenia/R atrial isomerism, polysplenia/left atrial isomerism, fix heart, not malrotation).

Question 17

Appendicitis

Answer 17

• peaks 10-14 years in boys, 15-19 in girls. Male: female: 1.4 : 1.
• high risk diseases if delay in diagnosis.
• thought to be due to lymphatic tissue in children.

Question 18

Appendix

Answer 18

• Diverticulum arising from cecum.
• length and anatomic position: variable. Retrocecal position is a challenge.
• Lymphatic nodules increase until puberty (highest incidence of appendicitis).

Question 19

Pathophysiology of Appendicitis

Answer 19

• Obstruction of appendices lumen (fecalith or swollen lymphoid tissue)
• increased intraluminal pressure > luminal bacteria proliferate > infection, gangrene, perforation.

Question 20

presentation of appendicitis

Answer 20

• appendicitis begins with periumbilical pain (due to stretch receptors referred to periumbilical region).
  pain migrates to RLQ (inflammatory fluid with mediators results in irritation of peritoneal afferent nerves).
• Perforation: 20% in 24 hours, 80% in 48 hours.
• Peritonitis
• Abscess walled off by omentum.

Question 21

Appendicitis labs

Answer 21

unlikely appendicitis if both WBC and CRP are normal.

Question 22

US with appendicitis

Answer 22

• normal appendix visible in <805 of children.
• Visible and normal: not appendicitis.
• classic signs of appendicitis non compressible and >6mm (with or without appendicolith).
• Secondary signs, local collection.

Question 23

Peritonitis/abscess

Answer 23

• pain may transiently improve after perforation.
• high fever, diffuse tenderness, low volume diarrhea
• abscess can persist for days
  Treatment: IV antibiotics, possible appendectomy/percutaneous drainage.