Acute Appendicitis

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Acute Appendicitis
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Epidemiology

• The incidence of appendectomy appears to be
  declining due to more accurate preoperative
  diagnosis.
• Despite newer imaging techniques, acute
  appendicitis can be very difficult to diagnose.

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Appendicitis

• The most common surgical condition of the abdomen
• Lifetime occurrence of 7
• Peak incidence 10-30y
• The most common nonobstetric surgical
  intervention during pregnancy

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Pathogenesis

• Appendiceal lumen obstruction
• lymphoid hyperplasia
• fecaliths
• parasites
• foreign bodies
• crohns disease
• metastatic cancer
• carcinoid syndrome

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Pathophysiology

• Acute appendicitis is thought to begin with
  obstruction of the lumen
• Obstruction can result from food matter,
  adhesions, or lymphoid hyperplasia
• Mucosal secretions continue to increase
  intraluminal pressure

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Pathophysiology

• Eventually the pressure exceeds capillary
  perfusion pressure and venous and lymphatic
  drainage are obstructed.
• With vascular compromise, epithelial mucosa
  breaks down and bacterial invasion by bowel flora
  occurs.

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Pathophysiology

• Increased pressure also leads to arterial stasis
  and tissue infarction
• End result is perforation and spillage of
  infected appendiceal contents into the peritoneum

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Pathophysiology

• Initial luminal distention triggers visceral
  afferent pain fibers, which enter at the 10th
  thoracic vertebral level.
• This pain is generally vague and poorly
  localized.
• Pain is typically felt in the periumbilical or
  epigastric area.

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Pathophysiology

• As inflammation continues, the serosa and
  adjacent structures become inflamed
• This triggers somatic pain fibers, innervating
  the peritoneal structures.
• Typically causing pain in the RLQ

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Pathophysiology

• The change in stimulation form visceral to
  somatic pain fibers explains the classic
  migration of pain in the periumbilical area to
  the RLQ seen with acute appendicitis.

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Pathophysiology

• Exceptions exist in the classic presentation due
  to anatomic variability of the appendix
• Appendix can be retrocecal causing the pain to
  localize to the right flank
• In pregnancy, the appendix ca be shifted and
  patients can present with RUQ pain

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Pathophysiology

• In some males, retroileal appendicitis can
  irritate the ureter and cause testicular pain.
• Pelvic appendix may irritate the bladder or
  rectum causing suprapubic pain, pain with
  urination, or feeling the need to defecate
• Multiple anatomic variations explain the
  difficulty in diagnosing appendicitis

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symptoms

• Pain RLQ / RUQ / Flank
• Anorexia
• Vomiting
• Nausea
• Pain migration
• Fever

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Physical examination

• Tenderness RLQ
• Rebound Guarding (peritoneal signs)
• Rovsing sign
• Dunphys sign
• Psoas sign (retroperitoneal retrocecal appendix)
• Obturator sign (pelvic appendix)
• Rectal examination tenderness (cul-de-sac)
• Low grade fever

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Psoas sign
Obturator sign
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History

• Primary symptom abdominal pain
• ½ to 2/3 of patients have the classical
  presentation
• Pain beginning in epigastrium or periumbilical
  area that is vague and hard to localize

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History

• Associated symptoms indigestion, discomfort,
  flatus, need to defecate, anorexia, nausea,
  vomiting
• As the illness progresses RLQ localization
  typically occurs
• RLQ pain was 81 sensitive and 53 specific for
  diagnosis

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History

• Migration of pain from initial periumbilical to
  RLQ was 64 sensitive and 82 specific
• Anorexia is the most common of associated
  symptoms
• Vomiting is more variable, occuring in about ½ of
  patients

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Physical Exam

• Findings depend on duration of illness prior to
  exam.
• Early on patients may not have localized
  tenderness
• With progression there is tenderness to deep
  palpation over McBurneys point

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Physical Exam

• McBurneys Point just below the middle of a line
  connecting the umbilicus and the ASIS
• Rovsings pain in RLQ with palpation to LLQ
• Rectal exam pain can be most pronounced if the
  patient has pelvic appendix

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Physical Exam

• Additional components that may be helpful in
  diagnosis rebound tenderness, voluntary
  guarding, muscular rigidity, tenderness on rectal

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Physical Exam

• Psoas sign place patient in L lateral decubitus
  and extend R leg at the hip. If there is pain
  with this movement, then the sign is positive.
• Obturator sign passively flex the R hip and knee
  and internally rotate the hip. If there is
  increased pain then the sign is positive

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Physical Exam

• Fever another late finding.
• At the onset of pain fever is usually not found.
  
• Temperatures gt39 C are uncommon in first 24 h,
  but not uncommon after rupture

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Lab

• CBC WBC ( 80 ? 45 )
• CRP
• Urinalysis - mild pyuria
• mild proteinuria
• mild hematuria

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D.D.surgical gyneco

• Renal stone
• Gastroenteritis
• Pancreatitis
• Cholecystitis
• Mesenteric adenitis
• Hernia
• Bowel obstruction

• Preterm labor
• Placenta abruptio
• Chorioamnionitis
• Adnexal torsion
• Ectopic pregnancy
• Pelvic inflammatory
• Round lig. pain

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Diagnostic problems

• Position of appendix
• normally 70 intraperitoneal
• 30 pelvic, retroileal,
  retrocolic
• pregnancy anatomical changes
• gravid uterus ? displacement upward
• outward ? flank pain (3rd trimester)
  (Baer,1932)
• increased separation of peritoneum ? decreased
  perception of somatic pain and localization

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Diagnostic problems

• Symptoms complex physical changes
• anorexia, nausea vomiting in normal
• pregnancy
• Lab relative leukocytosis
• Imaging techniques

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Diagnosis

• Acute appendicitis should be suspected in anyone
  with epigastric, periumbilical, right flank, or
  right sided abd pain who has not had an
  appendectomy

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Diagnosis

• Women of child bearing age need a pelvic exam and
  a pregnancy test.
• Additional studies CBC, UA, imaging studies

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Diagnosis

• CBC the WBC is of limited value.
• Sensitivity of an elevated WBC is 70-90, but
  specificity is very low.
• But, predictive value of high WBC is 92 and
  predictive value is 50
• CRP and ESR have been studied with mixed results

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Diagnosis

• UA abnormal UA results are found in 19-40
• Abnormalities include pyuria, hematuria,
  bacteruria
• Presence of gt20 wbc per field should increase
  consideration of Urinary tract pathology

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Imaging

• KUB
• Barium enema
• Graded compression ultrasonography
• Helical CT scan

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Diagnosis

• Imaging studies include X-rays, US, CT
• Xrays of abd are abnormal in 24-95
• Abnormal findings include fecalith, appendiceal
  gas, localized paralytic ileus, blurred right
  psoas, and free air
• Abdominal xrays have limited use b/c the findings
  are seen in multiple other processes

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Graded compression ultrasound

• Normal appendix (lt6mm) rules out appendicitis.
• Nonpregnant Sensitivity 85
• specificity 92
• Pregnant cecal displacement uterine
  imposition makes precise examination difficult
  (Williams,21 edition)

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Diagnosis

• Graded Compression US reported sensitivity 94.7
  and specificity 88.9
• Basis of this technique is that normal bowel and
  appendix can be compressed whereas an inflamed
  appendix can not be compressed
• DX noncompressible gt6mm appendix, appendicolith,
  periappendiceal abscess

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Diagnosis

• Limitations of US retrocecal appendix may not be
  visualized, perforations may be missed due to
  return to normal diameter

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Diagnosis

• CT best choice based on availability and
  alternative diagnoses.
• In one study, CT had greater sensitivity,
  accuracy, -predictive value
• Even if appendix is not visualized, diagnose can
  be made with localized fat stranding in RLQ.

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Diagnosis

• CT appears to change management decisions and
  decreases unnecessary appendectomies in women,
  but it is not as useful for changing management
  in men.

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Special Populations

• Very young, very old, pregnant, and HIV patients
  present atypically and often have delayed
  diagnosis
• High index of suspicion is needed in the these
  groups to get an accurate diagnosis

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Treatment

• Appendectomy is the standard of care
• Patients should be NPO, given IVF, and
  preoperative antibiotics
• Antibiotics are most effective when given
  preoperatively and they decrease post-op
  infections and abscess formation

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Treatment

• There are multiple acceptable antibiotics to use
  as long there is anaerobic flora, enterococci and
  gram(-) intestinal flora coverage
• One sample monotherapy regimen is Zosyn 3.375g or
  Unasyn 3g
• Also, short acting narcotics should be used for
  pain management

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Disposition

• Abdominal pain patients can be put in 4 groups
• Group 1 classic presentation for Acute
  appendicitis- prompt surgical intervention
• Group 2 suspicious, but not diagnosed
  appendicitis- benefit from imaging and 4-6h
  observation with surgical consult if serial exam
  changes or imaging studies confirm

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Disposition

• Group 3 remote possibility of appendicitis-
  observe in ED for serial exams if no change and
  course remains benign patient can D/C with dx of
  nonspecific abd pain
• Patients are given instructions to return if
  worsening of symptoms, and they should be seen by
  PCP in 12-24 h
• Also advised to avoid strong analgesia

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Disposition

• Group 4 high risk population(including elderly,
  pediatric, pregnant and immunocomprimised)-
  require high index of suspicion and low threshold
  for imaging and surgical consultation

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Prognosis

• Generally good
• Disease found
• Surgery complications

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The end