2 EpidemiologyThe 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.
3 PathophysiologyAcute appendicitis is thought to begin with obstruction of the lumenObstruction can result from food matter, adhesions, or lymphoid hyperplasiaMucosal secretions continue to increase intraluminal pressure
4 PathophysiologyEventually 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.
5 PathophysiologyIncreased pressure also leads to arterial stasis and tissue infarctionEnd result is perforation and spillage of infected appendiceal contents into the peritoneum
6 PathophysiologyInitial 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.
7 PathophysiologyAs inflammation continues, the serosa and adjacent structures become inflamedThis triggers somatic pain fibers, innervating the peritoneal structures.Typically causing pain in the RLQ
8 PathophysiologyThe 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.
9 PathophysiologyExceptions exist in the classic presentation due to anatomic variability of the appendixAppendix can be retrocecal causing the pain to localize to the right flankIn pregnancy, the appendix ca be shifted and patients can present with RUQ pain
10 PathophysiologyIn 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 defecateMultiple anatomic variations explain the difficulty in diagnosing appendicitis
11 History Primary symptom: abdominal pain ½ to 2/3 of patients have the classical presentationPain beginning in epigastrium or periumbilical area that is vague and hard to localize
12 HistoryAssociated symptoms: indigestion, discomfort, flatus, need to defecate, anorexia, nausea, vomitingAs the illness progresses RLQ localization typically occursRLQ pain was 81 % sensitive and 53% specific for diagnosis
13 HistoryMigration of pain from initial periumbilical to RLQ was 64% sensitive and 82% specificAnorexia is the most common of associated symptomsVomiting is more variable, occuring in about ½ of patients
14 Physical Exam Findings depend on duration of illness prior to exam. Early on patients may not have localized tendernessWith progression there is tenderness to deep palpation over McBurney’s point
15 Physical ExamMcBurney’s Point: just below the middle of a line connecting the umbilicus and the ASISRovsing’s: pain in RLQ with palpation to LLQRectal exam: pain can be most pronounced if the patient has pelvic appendix
16 Physical ExamAdditional components that may be helpful in diagnosis: rebound tenderness, voluntary guarding, muscular rigidity, tenderness on rectal
17 Physical ExamPsoas 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
18 Physical 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
19 DiagnosisAcute appendicitis should be suspected in anyone with epigastric, periumbilical, right flank, or right sided abd pain who has not had an appendectomy
20 DiagnosisWomen of child bearing age need a pelvic exam and a pregnancy test.Additional studies: CBC, UA, imaging studies
21 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%C-Reactive Protien CRP (independent surgical indication marker for appendicitis) and ESR have been studied with mixed results
22 Diagnosis UA: abnormal UA results are found in 19-40% Abnormalities include: pyuria, hematuria, bacteruriaPresence of >20 wbc per field should increase consideration of Urinary tract pathology
23 Diagnosis 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 airAbdominal xrays have limited use b/c the findings are seen in multiple other processes
24 DiagnosisGraded 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
25 DiagnosisLimitations of US: retrocecal appendix may not be visualized, perforations may be missed due to return to normal diameter
26 DiagnosisCT: best choice based on availability and alternative diagnoses.In one study, CT had greater sensitivity, accuracy, -predictive valueEven if appendix is not visualized, diagnose can be made with localized fat stranding in RLQ.
27 DiagnosisCT appears to change management decisions and decreases unnecessary appendectomies in women, but it is not as useful for changing management in men.
28 Special PopulationsVery young, very old, pregnant, and HIV patients present atypically and often have delayed diagnosisHigh index of suspicion is needed in the these groups to get an accurate diagnosis
29 Treatment Appendectomy is the standard of care Patients should be NPO, given IVF, and preoperative antibioticsAntibiotics are most effective when given preoperatively and they decrease post-op infections and abscess formation