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Appendicitis, Emergency Medicine

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Appendicitis, Emergency Medicine

Basics

Description

Typical signs of peritonitis may be absent in elderly.

American College of Radiology recommends US followed by CT as needed for suspected appendicitis

Patients with abdominal pain thought not to be appendicitis may be discharged if they meet the following criteria:

  • Most common abdominal emergency
  • Acute obstruction of appendiceal lumen results in distension followed by organ ischemia, bacterial overgrowth, and eventual perforation of the viscus
  • Pain migration:Periumbilical pain: Appendiceal distension stimulates stretch receptors, which relay pain via visceral afferent pain fibers to 10th thoracic ganglion.RLQ pain: As inflammation extends to surrounding tissues, pain occurs owing to stimulation of parietal nerve fibers and localizes to position of appendix.
  • Periumbilical pain: Appendiceal distension stimulates stretch receptors, which relay pain via visceral afferent pain fibers to 10th thoracic ganglion.
  • RLQ pain: As inflammation extends to surrounding tissues, pain occurs owing to stimulation of parietal nerve fibers and localizes to position of appendix.
  • 28-57% misdiagnosis in patients <12 yr (nearly 100% in patients <2 yr)
  • 70-90% perforation rate in children <4 yr
  • Perforation correlates strongly with delayed diagnosis.
  • Decreased inflammatory response
  • 3 times more likely to have perforation owing to anatomic changes
  • Diagnosis often delayed owing to atypical presentations
  • Slightly higher rate in 2nd trimester compared to 1st/3rd/postpartum periods
  • Increased perforation rate (25-40%), highest in 3rd trimester
  • RLQ pain remains the most common symptom
  • 7-10% fetal loss, up to 24% in perforated appendicitis

Etiology

  • Luminal obstruction of appendix
  • Appendiceal lumen becomes distended, inhibiting lymphatic and venous drainage.
  • Bacterial invasion of wall, with edema and blockage of arterial blood flow
  • Perforation and spillage of contents into peritoneal cavity, causing peritonitis (usually 24-36 hr from onset)
  • May wall off and form abscess
  • Gram-negative rods and anaerobic organisms predominate

Diagnosis

Signs and Symptoms

  • Abdominal pain: Primary symptom:Normal location:RLQ pain35% of patients have appendix located within 5 cm of "normal" location.Retrocecal appendix (28-68%):Back painFlank painTesticular painPelvic appendix (27-53%):Suprapubic painUrinary or rectal symptomsLong appendix (<0.2%):Inflamed tip may cause pain in RUQ or LLQ.AnorexiaVomiting
  • Change in bowel habits: Diarrhea (33%), constipation (9-33%)
  • Classic presentation (<75% adults):Initially periumbilical painFollowed by anorexia (1st symptom in 95%) and nauseaLocalizes to RLQ (1-12 hr after onset)Finally, vomiting with fever
  • Normal location:RLQ pain35% of patients have appendix located within 5 cm of "normal" location.
  • Retrocecal appendix (28-68%):Back painFlank painTesticular pain
  • Pelvic appendix (27-53%):Suprapubic painUrinary or rectal symptoms
  • Long appendix (<0.2%):Inflamed tip may cause pain in RUQ or LLQ.AnorexiaVomiting
  • RLQ pain
  • 35% of patients have appendix located within 5 cm of "normal" location.
  • Back pain
  • Flank pain
  • Testicular pain
  • Suprapubic pain
  • Urinary or rectal symptoms
  • Inflamed tip may cause pain in RUQ or LLQ.
  • Anorexia
  • Vomiting
  • Initially periumbilical pain
  • Followed by anorexia (1st symptom in 95%) and nausea
  • Localizes to RLQ (1-12 hr after onset)
  • Finally, vomiting with fever
  • Presentations often nonspecific and difficult to localize (<50% have classic presentation)
  • Anorexia, vomiting, and diarrhea more common (half-eaten meal hours before complaints of pain may more accurately indicate duration of symptoms)
  • Observe child before exam for subtle indicators of local inflammation:Limping gaitHesitation to move or climbFlexed right hip
  • Limping gait
  • Hesitation to move or climb
  • Flexed right hip
  • Vital signs:Often normalFever: Normal to mild elevation (<1 °F) initially, increases with perforation
  • Abdominal exam:Tenderness at McBurney point (1/3 of distance from right anterior iliac spine to umbilicus)Guarding:Voluntary guarding early owing to muscular resistance to palpationInvoluntary guarding (rigidity) later as inflammation progresses and perforation occursRebound:Pain with any rapid movement of peritoneum (e.g., bumping stretcher)Specific signs (less useful in pediatrics):Rovsing sign: Pain in RLQ when palpating LLQPsoas sign: Increased pain on extension of right hip with patient lying on her or his left side, owing to inflamed appendix touching iliopsoas muscle.Obturator sign: Pain with passive internal rotation and flexion of right hip
  • Rectal exam:Limited value: May localize tenderness/mass
  • Pelvic exam:Important to differentiate gynecologic diseaseVaginal discharge and/or adnexal tenderness or mass suggests gynecologic disease.Cervical motion tenderness when present suggests PID, but can be seen in up to 25% of women with appendicitis
  • Patient position:Supine or decubitus with legs (particularly the right) drawn upPrefer not to move
  • Shuffling gait-known as "appy walk"
  • Often normal
  • Fever: Normal to mild elevation (<1 °F) initially, increases with perforation
  • Tenderness at McBurney point (1/3 of distance from right anterior iliac spine to umbilicus)
  • Guarding:Voluntary guarding early owing to muscular resistance to palpationInvoluntary guarding (rigidity) later as inflammation progresses and perforation occurs
  • Rebound:Pain with any rapid movement of peritoneum (e.g., bumping stretcher)
  • Specific signs (less useful in pediatrics):Rovsing sign: Pain in RLQ when palpating LLQPsoas sign: Increased pain on extension of right hip with patient lying on her or his left side, owing to inflamed appendix touching iliopsoas muscle.Obturator sign: Pain with passive internal rotation and flexion of right hip
  • Voluntary guarding early owing to muscular resistance to palpation
  • Involuntary guarding (rigidity) later as inflammation progresses and perforation occurs
  • Pain with any rapid movement of peritoneum (e.g., bumping stretcher)
  • Rovsing sign: Pain in RLQ when palpating LLQ
  • Psoas sign: Increased pain on extension of right hip with patient lying on her or his left side, owing to inflamed appendix touching iliopsoas muscle.
  • Obturator sign: Pain with passive internal rotation and flexion of right hip
  • Limited value: May localize tenderness/mass
  • Important to differentiate gynecologic disease
  • Vaginal discharge and/or adnexal tenderness or mass suggests gynecologic disease.
  • Cervical motion tenderness when present suggests PID, but can be seen in up to 25% of women with appendicitis
  • Supine or decubitus with legs (particularly the right) drawn up
  • Prefer not to move
  • Enlarging uterus displaces appendix upward and laterally.
  • Hyperemesis gravidarum and other nonsurgical causes of vomiting should not cause abdominal tenderness.

Essential Workup

  • Suggestive history and physical exam sufficient to establish preoperative diagnosis and warrant surgical consultation
  • Tests listed below may be used to assist in diagnosis
  • Atypical cases: Repeat serial exams in conjunction with some of the tests listed below is effective, with decreased rates of negative appendectomies and no increase in rates of perforation

Diagnosis Tests & Interpretation

  • CBC:WBC >10,000, with left shift (80%)Normal WBC does not exclude diagnosis
  • C-reactive protein:Overall sensitivity 62%, specificity 66%May not be elevated early (<12 hr)Increased sensitivity with serial measurements
  • Urinalysis:Generally normalMild pyuria, bacteriuria, or hematuria (25-30%)Pyuria present if inflamed appendix lies near ureter or bladder
  • Pregnancy test for females of child-bearing age
  • WBC >10,000, with left shift (80%)
  • Normal WBC does not exclude diagnosis
  • Overall sensitivity 62%, specificity 66%
  • May not be elevated early (<12 hr)
  • Increased sensitivity with serial measurements
  • Generally normal
  • Mild pyuria, bacteriuria, or hematuria (25-30%)
  • Pyuria present if inflamed appendix lies near ureter or bladder
  • Unnecessary when diagnosis is clear
  • Most helpful in female patients of child-bearing age where diagnosis is often unclear
  • Abdominal radiographs-not recommended
  • US: Sensitivity 86-90%; specificity 92-95%:Noncompressible appendix 6 mm anteroposterior (AP) diameterPresence of appendicolithPeriappendiceal fluid/massLimited by obesity, bowel gas, retrocecal appendix, and operatorNegative study of limited use
  • CT: Sensitivity 91-100%; specificity 94-97%:Highest yield using oral and rectal contrast with focused appendiceal technique (5 mm cuts from 3 cm above cecum extending distally 12-15 cm)Fat stranding (100%)Appendix 6 mm in diameter (93%)Focal cecal apical thickeningDefines appendiceal masses (phlegmon vs. abscess)Best study for finding alternative diagnosesNonvisualized appendix does not rule out appendicitis
  • MRI: Sensitivity 97-100%, specificity 92-94%:Appendix 7 mm in diameterPeriappendiceal fat strandingAdvantages: Lack of ionizing radiation, excellent safety profile of gadolinium contrast agentsDisadvantages: High cost, limited availability, lengthy exam, lack of radiologist familiarity in appendicitisNo gadolinium in early pregnancy (class C drug)
  • Noncompressible appendix 6 mm anteroposterior (AP) diameter
  • Presence of appendicolith
  • Periappendiceal fluid/mass
  • Limited by obesity, bowel gas, retrocecal appendix, and operator
  • Negative study of limited use
  • Highest yield using oral and rectal contrast with focused appendiceal technique (5 mm cuts from 3 cm above cecum extending distally 12-15 cm)
  • Fat stranding (100%)
  • Appendix 6 mm in diameter (93%)
  • Focal cecal apical thickening
  • Defines appendiceal masses (phlegmon vs. abscess)
  • Best study for finding alternative diagnoses
  • Nonvisualized appendix does not rule out appendicitis
  • Appendix 7 mm in diameter
  • Periappendiceal fat stranding
  • Advantages: Lack of ionizing radiation, excellent safety profile of gadolinium contrast agents
  • Disadvantages: High cost, limited availability, lengthy exam, lack of radiologist familiarity in appendicitis
  • No gadolinium in early pregnancy (class C drug)
  • Laparoscopy:Diagnostic and therapeutic useGross pathology may be absent with positive microscopic findings
  • Open appendectomy
  • Percutaneous drainage
  • Diagnostic and therapeutic use
  • Gross pathology may be absent with positive microscopic findings

Differential Diagnosis

  • Gastroenteritis
  • Meckel diverticulum
  • Epiploic appendicitis
  • Crohns disease
  • Diverticulitis
  • Volvulus
  • Abdominal aortic aneurysm
  • Intestinal obstruction
  • UTI
  • Pyelonephritis
  • PID
  • Ectopic pregnancy
  • Ovarian cyst/torsion
  • Tubo-ovarian abscess
  • Endometriosis
  • Renal stone
  • Testicular torsion
  • Mesenteric adenitis
  • Henoch-Sch ¶nlein purpura
  • Diabetic ketoacidosis
  • Streptococcal pharyngitis (children)
  • Biliary disease

Treatment

Initial Stabilization/Therapy

  • Airway, breathing, and circulation management (ABCs)
  • Fluid resuscitation with LR or 0.9% NS

Ed Treatment/Procedures

  • IV fluids, correct electrolyte abnormalities
  • Immediate surgical consult for convincing history and physical exam:Laparoscopic versus open techniqueNegative appendectomy rate of 10% in males and 20% in femalesPercutaneous drainage, IV antibiotics, bowel rest and possible interval appendectomy in 6-8 wk in appendiceal abscesses
  • Perioperative antibiotics
  • NPO
  • Order CT if palpable mass is present in RLQ to define phlegmon versus abscess
  • If diagnosis is uncertain, send serial labs, observe, and repeat exams (6-10% negative appendectomy rate with observation protocols)
  • Analgesics:Administration of analgesics, including narcotics, does not adversely affect abdominal exam or mask pathology
  • Laparoscopic versus open technique
  • Negative appendectomy rate of 10% in males and 20% in females
  • Percutaneous drainage, IV antibiotics, bowel rest and possible interval appendectomy in 6-8 wk in appendiceal abscesses
  • Administration of analgesics, including narcotics, does not adversely affect abdominal exam or mask pathology

Medication

  • Ampicillin/sulbactam: 3 g (peds: 100-200 mg ampicillin/kg/24 h) IV q6h
  • Cefoxitin: 2 g (peds: 80-100 mg/kg/24 h) IV q6h
  • Ceftriaxone: 1 g (peds: 50-100 mg/kg) IV q24h
  • Ciprofloxacin: 400 mg (peds: 20-40 mg/kg) IV q12h
  • Ertapenem: 1 g IM/IV q24h
  • Metronidazole: 500 mg (peds: 30-50 mg/kg/24 h) IV q8-12h
  • Morphine sulfate: 3-5 mg (peds: 0.1-0.2 mg/kg per dose q2-q4h) IV, every 15 min titrated to effect
  • Piperacillin/tazobactam: 3.375 g (peds: 150-300 mg/kg/d if <6 mo; 240-400 mg/kg/d if >6 mo) IV q6h

Follow-Up

Disposition

  • Surgical intervention of acute appendicitis
  • Observation or further diagnostic workup if diagnosis is uncertain
  • Resolved or resolving symptoms
  • Minimal or no abdominal tenderness
  • No lab/radiologic abnormalities
  • Able to tolerate PO intake
  • Adequate social support and able to return if symptoms worsen

Followup Recommendations

Pearls and Pitfalls

  • Pediatric and geriatric patients present atypically and have increased perforation rates
  • Imaging is not required in a classic presentation of acute appendicitis
  • Appendicitis cannot be ruled out on any imaging modality if the appendix is not visualized

Additional Reading

  • Basaran A, Basaran M. Diagnosis of acute appendicitis during pregnancy: A systematic review. Obstet Gynecol Surv. 2009;64(7):481-488.
  • Hennelly KE, Bachur R. Appendicitis update. Curr Opin Pediatr. 2011;23:281-285.
  • Long SS, Long C, Lai H, et al. Imaging strategies for the right lower quadrant pain in pregnancy. AJR Am J Roentgenol. 2011;196:4-12.
  • Singh A, Danrad R, Hahn PF, et al. MR imaging of the acute abdomen and pelvis: Acute appendicitis and beyond. Radiographics. 2007;27:1419-1431.

See Also (Topic, Algorithm, Electronic Media Element)

  • Abdominal Pain
  • Vomiting, Adult; Vomiting, Pediatric

Codes

ICD9

  • 540.1 Acute appendicitis with peritoneal abscess
  • 540.9 Acute appendicitis without mention of peritonitis
  • 541 Appendicitis, unqualified
  • 540.0 Acute appendicitis with generalized peritonitis
  • 540 Acute appendicitis
  • 542 Other appendicitis

ICD10

  • K35.3 Acute appendicitis with localized peritonitis
  • K35.80 Unspecified acute appendicitis
  • K37 Unspecified appendicitis
  • K35.89 Other acute appendicitis
  • K35.2 Acute appendicitis with generalized peritonitis
  • K35.8 Other and unspecified acute appendicitis
  • K35 Acute appendicitis
  • K36 Other appendicitis

SNOMED

  • 74400008 Appendicitis (disorder)
  • 85189001 Acute appendicitis (disorder)
  • 266439004 Acute appendicitis with appendix abscess (disorder)
  • 286967008 Acute perforated appendicitis
  • 51036000 Acute appendicitis with peritoneal abscess (disorder)
  • 9124008 Subacute appendicitis (disorder)