02-24 Appendicitis and Diverticulitis

Question 1

Epidemiology of appendicitis

Answer 1

—Incidence: 2 / 1000 population per year for children between 1-20.
—Thus, 4% chance of appendicitis by age 20.
—The incidence drops off with age such that it is uncommon after age 50.
—Lifetime risk of developing appendicitis is 7-8%.

Question 2

Pathophysiology of appendicitis

Answer 2

1. gets obstructed
   —fecalith, carcinoma, lymphoid proliferation, foreign body
   —risk of fecalith ?incr w/ inadequate fiber
2. mucosa keeps making mucus
3. intraluminal HTN sets in
4. Causes lymphatic obstr & venous congestion
5. Leads to edema and local inflam
6. Finally: arterial obstruction, ischemia, gangrene and perforation

Question 3

Clinical manifestations of appendicitis
—History
—pain mechanism
—Phyical exam

Answer 3

HISTORY
1. Pain:
—constant, mild, gradual onsetAppendix swells.
—Stretch receptors → pain along mesenteric nn → T10 spinal nerve (supplies umbilical dermatome)
—4-8 hrs later: shifts to RLQ b/c direct contact or inflam fluid hits parietal petitoneum. (Hurts when going over bumps in car on way to hospital.)
2. Anorexia
—cheeseburger test
—Vomiting possible, but unusual, almost always comes after pain.

3. Tenderness
   —Pt points to McBurneys’ point

P.E.
—Gen: Lying still. Not writhing in pain.
—VS: T 38 C. (low grade)
—Tenderness: McBurney’s point
—Guarding: Tightening of abs. Distract & look for involuntary
—Rebound Tenderness: Movement of peritoneum hurts. Try percussion 1st (gentler). Refusal to hop.
—Ancillary Signs:
— 1) Rovsings (push pull out quickly in left hurts on right),
— 2) Psoas (retro-cecal cases; raise R leg against resistance OR roll pt on L side, grasp R leg and extend it)
— 3) Obturator (flex knee & internally rotate leg)

Question 4

Work-up and management of appendicitis

Answer 4

Labs: WBC (1/3 of patients absolute number will be normal)
Urinalysis, lipase, ß-HCG

Radiologic studies:
US: may be useful in pregnant women.

CT scan: Can be very useful in patients who present with equivocal findings (only)! If really high pre-test probability just take them to surgery.
Considered positive if appendiceal diameter is > 6 mm. Also evaluate appendiceal wall thickening or enhancement and peri-appendiceal fat stranding.

Positive predictive value: 95%
Finding a normal appendix at time of surgery can be decreased from 20% to 5%. AVOID UNNECSSARY SURGERY
Negative predictive value: 95%
Problem: may increase cancer risk for kids (0-1 excess cancer per 1000 kids)

Question 5

Complications of appendicitis

Answer 5

Ischemia, gangrene, perforation, abscess formation, peritonitis, death (68% mortality before tx discovered!)

Question 6

Surgical approach to appendicitis

—If perforated?

Answer 6

Laproscopic vs. Open
(2/3 are lap now)

PROS AND CONS
From review of 45 randomized prospective trials have compared lap vs open. Appx 5000 patients

—Laparoscopic approach takes longer (12 minutes more) and is more expensive.

—Laparoscopic approach has a higher risk of intra-abdominal abscess (1.6% lap vs 0.6% open, OR 2.48, CI 1.4 to 4.2)

—Lower wound infection rate in the lap group (3.5% vs 7%, OR 0.45, CI .35 to .58)

—Pain on day 1 after surgery was reduced after lap appy by 9 mm on a 100 mm visual analogue scale.

If perforated:
Opt 1: STAT surgery
—Carries surgical/anesthesia risk
Opt 2: Can drain abcess and tx w/ abx
—fails in 7% (need surg), misses cancer (1%) or Crohn’s dz (1%), and 7% recur in next dz.  **Consider “interval” appendectomy (i.e. treat w/ abx for acute situation and then do elective appy later).

Question 7

Epidemiology of diverticulitis

Answer 7

50% of Americans have diverticula by age 60

—Appx. 10% of these will develop symptoms

Question 8

Clinical manifestations of diverticulitis

Answer 8

History: LLQ pain, constant, gradual onset

Physical exam: T 37-39° C. Tenderness to deep palpation, LLQ. Guarding.

Question 9

Work-up and management of diverticulitis

Answer 9

WORK-UP
Labs: CBC, UA (r/o pyleo, etc.)
Radiologic studies: CT if long duration of sx, high fever, leukocytosis.

Question 10

Management and Surgical approach to diverticulitis:
—Mgmt of Uncomplicated Cases
—Name possible complications and their mgmt

Answer 10

MANAGEMENT

UNCOMPLICATED CASE
1a) Tender, no significant fever or leukocytosis: just oral Abx.

1b) If just a small “phlegmon” w/ fever & leukocytosis: Admit, CT scan, give IV abx covering Gm- bacteria and anaerobes.
2) Once resolved, colonoscopy to rule-out cancer.

COMPLICATED (i.E. SURGICAL) CASES
Perforation: 	Resection and colostomy, 
		followed by colostomy take-down
Obstruction: 	^^same^^
Large Abscess:   Resection and colostomy or
		CT guided percutaneous drainage, then 
		bowel prep, resection and primary 
		anastamosis

Question 11

What is current proposed purpose of the appendix?

Answer 11

To serve as a safe haven where commensal bacteria exist on biofilms and can replenish the GI tract in case of severe diarrheal illness.

Question 12

Definition of acute abdomen?

Answer 12

Characterized by peritonitis.

Physical exam findings:
tenderness, guarding, rebound tenderness – all findings in patients w/ acute abdomen (not just appendicitis)

Caused by several entities, including:
perf’d ulcer
perf’d sigmoid colon due to diverticulitis
ruptured appendix

Question 13

DDx for appendicitis

Answer 13

GI CAUSES
—Gastroenteritis
—Crohn’s Disease
—Cecal diverticultis
—Meckle’s diverticulitis
—Cholecystitis
—Pancreatitis
—Bowel Infarction

GI/GU CAUSES
—Nephrolithiasis
—Pyelo
—Torsed ovary
—Ectopic Pregnancy
—Ruptured ovarian cyst
—P.I.D.

Question 14

Name some factors that make the dx of appendicitis difficult

Answer 14

—Infants: can’t verbailze, often present perf’d
—Elderly: atypical presentations, false belief that geri pts don’t get appendicitis
—Patients taking: narcotics, steroids and antibiotics (pain/sx may be blunted)