Acute AppendicitisAcute Appendicitis

Dr Ibrahim BashayrehDr Ibrahim Bashayreh

EpidemiologyEpidemiology

• 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.

PathophysiologyPathophysiology

• 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

PathophysiologyPathophysiology

• 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.

PathophysiologyPathophysiology

• Increased pressure also leads to arterial stasis and tissue infarction

• End result is perforation and spillage of infected appendiceal contents into the peritoneum

PathophysiologyPathophysiology

• 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.

PathophysiologyPathophysiology

• 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

PathophysiologyPathophysiology

• 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.

PathophysiologyPathophysiology

• 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

PathophysiologyPathophysiology

• 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

HistoryHistory

• 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

HistoryHistory

• 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

HistoryHistory

• 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

Physical ExamPhysical 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 McBurney’s point

Physical ExamPhysical Exam

• McBurney’s Point: just below the middle of a line connecting the umbilicus and the ASIS

• Rovsing’s: pain in RLQ with palpation to LLQ

• Rectal exam: pain can be most pronounced if the patient has pelvic appendix

Physical ExamPhysical Exam

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

Physical ExamPhysical 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

Physical ExamPhysical Exam

• Fever: another late finding.

• At the onset of pain fever is usually not found.

• Temperatures >39 C are uncommon in first 24 h, but not uncommon after rupture

DiagnosisDiagnosis

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

DiagnosisDiagnosis

• Women of child bearing age need a pelvic exam and a pregnancy test.

• Additional studies: CBC, UA, imaging studies

DiagnosisDiagnosis

• 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%

• C-Reactive Protien CRP (independent surgical

indication marker for appendicitis) and ESR have been studied with mixed results

DiagnosisDiagnosis

• UA: abnormal UA results are found in 19-40%

• Abnormalities include: pyuria, hematuria, bacteruria

• Presence of >20 wbc per field should increase consideration of Urinary tract pathology

DiagnosisDiagnosis

• Imaging studies: include X-rays, US, CT

• Xrays of abd are abnormal in 24-95%

• Abnormal findings include: fecalith, appendiceal gas, localized paralytic ileu, and free air

• Abdominal xrays have limited use b/c the findings are seen in multiple other processes

DiagnosisDiagnosis

• 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

DiagnosisDiagnosis

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

DiagnosisDiagnosis

• 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.

DiagnosisDiagnosis

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

Special PopulationsSpecial 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

TreatmentTreatment

• 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