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