Appendicitis, Acute

Basics

Acute inflammation of appendix; can be uncomplicated or complicated (perforated, abscess).
Location: base of cecum in RLQ; variable appendix position.
Blood supply: appendicular artery (ileocolic branch).
Nerve supply: superior mesenteric plexus.
Most common cause of acute surgical abdomen.

Age: predominantly 10-30 years; rare in infancy; diagnosis challenging in elderly.
Sex: slight male predominance (3:2 in 10-30 years, equal after 30).
Incidence: ~1/1000/year; lifetime risk 7%.
Pregnancy: common extrauterine surgical emergency; higher perforation and peritonitis risk.

Obstruction of appendiceal lumen leads to distension, ischemia, bacterial overgrowth.
Obstruction causes:
Fecaliths (most common)
Lymphoid hyperplasia (children)
Foreign bodies, seeds
Worms (ascarids)
Strictures, fibrosis, neoplasms
Family history increases risk but no direct genetic link.

Vague periumbilical pain → anorexia, nausea, vomiting → migrates to RLQ over 4-48 hrs.
Only 50% present classically.
Pain precedes vomiting (~100% sensitivity).
Atypical pain in retrocecal or pelvic appendix.

GI: gastroenteritis, IBD, diverticulitis, ileitis, cholecystitis, pancreatitis, intussusception, volvulus.
Gynecologic: PID, ectopic pregnancy, ovarian cyst/torsion, tubo-ovarian abscess, endometriosis.
Urologic: testicular torsion, epididymitis, kidney stones, prostatitis, cystitis, pyelonephritis.
Systemic: DKA, Henoch-Schönlein purpura, sickle cell crisis, porphyria.
Others: mesenteric lymphadenitis, hernias, psoas abscess, rectus sheath hematoma, epiploic appendagitis, pneumonia.

Labs:
Leukocytosis (>10,000/mm3, 70%)
Left shift (>90%)
Urinalysis: hematuria, pyuria (30%)
hCG to exclude pregnancy
CRP nonspecific; higher predictive value with leukocytosis
Imaging:
CT with contrast: sensitivity 91-98%, specificity 95-99%; preferred.
Ultrasound: preferred in pregnancy, children, gynecologic suspicion; variable sensitivity.
MRI: alternative in pregnancy or contrast allergy.
Plain films: minimal utility.
Radioisotope WBC scans: rare use.

Surgery (appendectomy) is standard for acute uncomplicated appendicitis.
Nonoperative antibiotic treatment may be considered in select cases but has higher recurrence.
Complicated cases with abscess/phlegmon: surgical drainage or percutaneous drainage + antibiotics.

Perioperative antibiotic prophylaxis: single dose cefoxitin or ampicillin/sulbactam or cefazolin + metronidazole.
Nonoperative antibiotics: IV ertapenem 2 days, then PO levofloxacin + metronidazole 5 days (2)[B].
Complicated appendicitis: broadened aerobic/anaerobic coverage (piperacillin-tazobactam, 3rd-gen cephalosporin + metronidazole).
Antibiotics duration: ≥7 days post-op or until afebrile and WBC normal.
Alternatives: clindamycin + fluoroquinolone/aminoglycoside for uncomplicated; carbapenems for complicated.

Endoscopic retrograde appendicitis therapy (ERAT) under study; high success and low complication rates.

Admit all appendicitis patients.
Fluid resuscitation (NS or LR).
Correct electrolyte abnormalities.
Discharge: tolerating oral intake, bowel function returned, afebrile, normal WBC.

Return to work: 1-2 weeks post uncomplicated appendectomy.
Activity restriction: 4-6 weeks; no heavy lifting or strenuous activity.
Nonoperative management >40 years: consider colonoscopy for malignancy exclusion.

Post-op warning: anorexia, nausea, vomiting, abdominal pain, fever, chills, wound infection signs.