Appendicitis and role of ultrasound scan in diagnosis Nchanji Nkeh Keneth

APPENDICITIS: ROLE OF
ULTRASOUND IN DIAGNOSIS
Nchanji Nkeh Keneth
kennchanji@yahoo.com
B.TECH/HPD MDIRT
POLYVALENT RADIOLOGIC TECHNOLOGIST/SONOGRAPHER
St. Blaise Clinic, Big Mankon- Bamenda
Medical Imaging Dpt.
Thursday March 1, 2018
10/2/2018
NCHANJI NKEH KENETH, HPD/B.TECH-
MDIRT. ST LOUIS UNIHEBS
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Our proud surgical team of ST. Blaise at Work

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Objectives of the presentation
Review basic gross anatomy of the
abdomen
To review the pathophysiology and clinical
presentation of acute appendicitis
To understand which patient groups are at
high risk of misdiagnosis
To discuss the use of Ultrasound scan in the
diagnosis of acute appendicitis
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Key take home Points
6 % lifetime incidence
69 % are ages 10years to 30years
Up to 30 % misdiagnosed initially
20 to 30 % ruptured at surgery
Mortality : 0.1 to 0.2 % unruptured,
3 to 5 % ruptured
Significant morbidity
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Basic Abdominopelvic anatomy
and the appendix
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Basic Abdominopelvic anatomy and the
appendix
Blind pouch off of cecum
Contains lymphoid tissue which peaks in
adolescence, atrophies with age
Function still unclear
Appendix can be anywhere within peritoneal
cavity
One study showed 65 % retrocecal, 31 %
pelvic
Review of 70,000 cases showed 4 % in RUQ,
0.06 % LUQ, 0.04 % LLQ
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Pathophysiology of Appendicitis
Lymphoid hyperplasia leads to luminal obstruction
Often follows viral illness
Epithelial cells secrete mucus
Appendix distends, bacteria multiply
Visceral pain begins an average of 17 hours after
obstruction
Increased pressure compromises blood supply
Somatic pain develops
Average time to perforation = 34 hrs.
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Classic Presentation
Seen in 60 %
Anorexia
Periumbilical pain, nausea, vomiting
RLQ pain developing over 24 hrs.
Anorexia and pain are most frequent
Usually nausea, sometimes vomiting
Diarrhea, esp. with pelvic location
Usually tender to palpation
Rebound is a later finding
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Physical Exam
Tenderness at McBurney's point
Cutaneous hyperesthesia in T 10 to
12 dermatomes
Rovsing's sign
Psoas sign
Obturator sign
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MANTRELS Score
Established in 1986
Migration of pain
Anorexia
Nausea / vomiting
Tenderness RLQ
Rebound
Elevated temp.
Leukocytosis
Shift to left
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MANTRELS Score, cont'd.
RLQ tenderness and leukocytosis = 2
points each ; all others 1 point
Score of 5 to 6 = possible appendicitis
Score of 7 to 8 = probable
appendicitis
Score of 9 to 10 = very probable
appendicitis
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High Risk Patients
1.Ovulating women
PID, TOA, ovarian cyst rupture
can mimic appendicitis
Look for cervical motion
tenderness, adnexal tenderness,
history of STD’s
Can have CMT (cervical motion
tenderness) with pelvic appendix
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High Risk Patients, cont'd.
2.Pregnancy
Most common surgical emergency
in pregnancy
Mortality rate if missed = 2 % for
mother, up to 35 % for fetus
WBC elevated in pregnancy
Appendix changes location
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3.Pediatrics
Most common surgical disorder in kids
Accounts for 5 % of abd. pain visits
Up to 50 % initially misdiagnosed
ƒ< 2 yrs. : perforation rate approaches 100 %
ƒ3 to 5 yrs. = 71 %
ƒ6 to 10 yrs. = 40 %
Most common misdiagnosis is AGE
Sequence of pain and vomiting may be helpful
Localized tenderness not a feature of AGE
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4.Elderly
Vital signs and exam may not reflect
severity
> age 60 : only 5 to 10 % diagnosed
without delay
Perforation rate = 46 to 83 %
RLQ tenderness absent in 23 %
N/V, anorexia less common
Leukocytosis less pronounced
Only 20 % classic presentation
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5.Immunocompromised
HIV, chronic steroids, sickle cell,
chemotherapy, DM, dialysis
Increased risk of complications
and misdiagnosis
Inflammatory response decreased
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Differential Diagnosis
Gastroenteritis
Mesenteric
lymphadenitis
PID
Mittelschmertz
Crohn's disease
Diverticulitis
Endometriosis
TOA
Ectopic pregnancy
UTI
Pyelonephritis
Other processes
involving appendix
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" No single evaluation can
substitute for the diagnostic
accuracy of the experienced
physician."
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Laboratory Studies
CBC
75 to 85 % have elevated WBC, but it is
nonspecific
WBC normal in 80 % in the first 24 hrs.
Can see elevated ANC in up to 89 %
WBC usually 12 to 18,000 in appendicitis
Chemistry panel
May help with diagnosis of dehydration
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Laboratory Studies, cont'd.
Urinalysis
Specific gravity, ketones
Can see WBC’s, RBC’s, bacteria if
inflamed appendix close to ureter
> 30 WBC’s = probable UTI
HCG
Essential in women of child-bearing age
CRP
Acute phase reactant
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The role of medical Imaging: Focus on
US, relative to CT Scan and Plain AXR
Plain films
Low sensitivity and specificity
Appendicolith specific, but seen in only 2
%
May see local air-fluid levels, psoas
obliteration, soft tissue mass, gas in
appendix : all nonspecific
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Imaging Studies, cont'd.
Ultrasound
75 to 90 % sensitive, 86 to 100 % specific
Noninvasive, low cost, but operator-
dependent
Good for diagnosing GYN disorders
3 criteria for diagnosis
ƒ Tender, noncompressible appendix
ƒ No peristalsis of appendix
ƒ Overall diameter > 6 mm
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Ultrasound (US)
Appendix may not be seen, due to obesity,
guarding, bowel gas, perforation,
retrocecal location
2.4 to 56 % of normal appendixes seen
One study of 736 pediatric patients
showed 36.6 % without preop US had
negative appendectomy vs. 9.8 % who had
US
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Ultrasound
Study from Australia showed total
WBC and neutrophil count were more
accurate than US. They recommended
pts. with unequivocal presentation go
to OR. If equivocal, obtain CBC. If
WBC > 15,000, go to OR. If < 11,000,
obtain CT (US only in pregnancy).
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CT
Early studies showed low yield, but helical
CT much more accurate
Sensitivity 97 to 100 %, specificity 95 %
(similar no matter what type or whether
contrast is used)
Often shows alternative diagnosis
More expensive, radiation exposure
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CT
Criteria for appendicitis :
ƒ Diameter > 6 mm
ƒ Failure to completely fill with contrast or
air
ƒ Appendicolith
ƒ Wall thickening or enhancement
Other contributory signs include fat
stranding, fluid, inflammatory mass,
adenopathy
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CT
One study showed negative laparotomy
rates of 4 % in men, 8 % in ovulating
women with CT (typical is 20 % and 45 %
respectively), but no change in perforation
rate
Another study showed increase in CT use
led to earlier diagnosis, less severe
pathologic findings, and decreased length of
stay
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Do We Need Imaging Studies?
Literature conflicting
Pediatric Imaging -Evidence-Based
Guidelines
Imaging most useful in clinically equivocal
cases
Costs of imaging minor compared to cost of
unnecessary surgery or delayed diagnosis
US and CT both specific enough to rule in
appendicitis, but only CT sensitive enough to
rule it out
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Do We Need Imaging Studies?
Study from Austria
350 patients divided into low, intermediate, and
high probability
All had US
10 % of low prob., 24 % of intermediate prob.,
and 65 % of high prob. had appendicitis
Specificity and sensitivity of US = 98 %
Concluded imaging should be done even in
high probability patients
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Risk Management
Misdiagnosis of appendicitis = 5th leading
cause of successful litigation against EPs
7 features of misdiagnosed cases :
No nausea / vomiting
Lack of distress
No rebound
No guarding
No rectal exam (controversial)
Narcotic pain meds given
Diagnosis of acute gastroenteritis
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Summary of key issues
Appendicitis is a common surgical
emergency with a varied clinical
presentation
Several patient groups are at high risk of
misdiagnosis
imaging studies with use of Ultrasound
are helpful, but no single study is a
substitute for good clinical judgement
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REFERENCES
Jim Holliman, M.D., F.A.C.E.P. Professor of
Military and Emergency Medicine
Uniformed Services University of the Health
Sciences
Clinical Professor of Emergency Medicine
George Washington University
Bethesda, Maryland, USA
Arabinda Pani and Gillian Liebernan. Radiologic
Diagnosis of Appendicitis. Harvard Medical
School. 2005
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Appendicitis and role of ultrasound scan in diagnosis Nchanji Nkeh Keneth

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