Acute Appendicitis
Dr Ibrahim Bashayreh
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.
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
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.
Pathophysiology
• Increased pressure also leads to arterial
stasis and tissue infarction
• End result is perforation and spillage of
infected appendiceal contents into the
peritoneum
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.
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
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.
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
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
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
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
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
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 McBurney’s point
Physical 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 Exam
• Additional components that may be helpful
in diagnosis: rebound tenderness,
voluntary guarding, muscular rigidity,
tenderness on rectal
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
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
Diagnosis
• Acute appendicitis should be suspected in
anyone with epigastric, periumbilical, right
flank, or right sided abd pain who has not
had an appendectomy
Diagnosis
• Women of child bearing age need a pelvic
exam and a pregnancy test.
• Additional studies: CBC, UA, imaging
studies
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
Diagnosis
• UA: abnormal UA results are found in 1940%
• Abnormalities include: pyuria, hematuria,
bacteruria
• Presence of >20 wbc per field should
increase consideration of Urinary tract
pathology
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 air
• Abdominal xrays have limited use b/c the
findings are seen in multiple other
processes
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
Diagnosis
• Limitations of US: retrocecal appendix
may not be visualized, perforations may
be missed due to return to normal
diameter
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.
Diagnosis
• CT appears to change management
decisions and decreases unnecessary
appendectomies in women, but it is not as
useful for changing management in men.
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
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