This document outlines a presentation on the pathophysiology and management of acute abdomen. It begins with definitions of acute abdomen and types of abdominal pain. Pathophysiological mechanisms including luminal obstruction, inflammation, peritonitis, ischemia and non-specific pain are described. Common causes like appendicitis, cholecystitis, bowel obstruction and perforated viscus are listed. Immediately life-threatening diagnoses of perforated viscus, bowel ischemia, ruptured abdominal aortic aneurysm and ruptured ectopic pregnancy are highlighted. Clinical assessment techniques and investigations are outlined. Management principles focusing on ABCs, fluid resuscitation and need for surgery in some cases are emphasized in the take-home message.
2. Outlines
Introduction
Pathophysiology of pain
Approach
Common causes for acute abdomen
Immediate life-threatening diagnosis
Management
Take home message
3. Introduction repair
Definition acute abdomen (Stedman's Medical
Dictionary, 27th Edition) –
Any serious acute intra-abdominal condition
Attended by
Pain
Tenderness
muscular rigidity
Emergency surgery must be considered
4.
5. Visceral Pain Somatic Pain Referred pain
Comes from abd visceral Comes from parietal
peritoneum
Perceived distant from its
source
Autonomic nerve fibers Somatic nerve fiber Convergence of nerve fibers at
spinal cord
Respond mainly to distension
and muscle contraction
Respond to cutting, infectious,
chemical or inflammatory
processes
Examples:
-Scapular pain – biliary colic
-Groin pain – renal colic
-Shoulder pain – blood or
infection irritating diaphragm
Usually vague, dull and
nauseating
Usually sharp and localized
Pathophysiology
6. 1. Luminal obstruction (luminal, mural and
extramural) with features of
Abdominal colic. Related to rate of peristalsis.
Vomiting. Common in high obstruction.
Constipation. Common in distal obstruction.
Abd distention. Prominent in large bowel obstruction.
BO should not rule out obstruction
Worsening symptoms may indicate adynamic
ileus, strangulation and perforation
7. 2. Inflammation
Many visceral organs are potential source for
inflammation within abdomen. Patient usually present
with
Pain
Vomiting (vagal response to pain)
Can be self limiting (spontaneously resolved or treated
with antibiotics)
May progress to gangrene and perforation causing
peritonitis.
8. 3. Peritonitis
Can be caused by bowel contents, bile, urine, pus or
blood from perforated viscus.
Classical signs of guarding, board like rigidity,
rebound tenderness, abdominal distension and
absent bowel.
Patients are often septic with/without shock
9. 4. Ischemia and infarction
Classification:
Arterial or venous
Intra/extraluminal
Usually presented with abdominal pain out of
proportion to physical finding a/w anorexia,
vomiting, diarrhea or GIT bleed.
Should be suspected in pt with vascular disease or
atrial fibrillation
10. 5. Non specific abdominal pain
Diagnosis of exclusion
In 40% of cases causes is unknown
Causes can be viral/parasitic infection, gastroenteritis,
mesenteric adenitis, ovulatory pain, IBS
Most cases require admission for observation and
investigation
11.
12. HISTORY: The main presenting complaint and the
characteristics of the abdominal pain.
Site , Time and mode onset , Severity , Nature, Progression,
Duration , Exacerbating and relieving factors, Radiation
Any associated symptoms
distension nausea, vomiting, fever, diarrhoea, constipation, PR
bleeding, anorexia, jaundice, gastrointestinal bleeding, dysuria,
oliguria
Other important Hx
Similar problems before? Underlying medical illness? H/O
surgical intervention before?Gynaecological hx – LMP,
pregnant?
Family Hx of malignancy?
Clinical Assessment
13. INSPECTION
Any abdominal swellings or distended due to enlargement of
the liver, kidneys or spleen, tumors of bowel. Scars from
previous surgery
PALPATION
Tenderness area, rebound tenderness, voluntary guarding,
involuntary guarding. Palpable mass, lymphadenopathy,
hernial orifices.
PERCUSSION
To determine presence of fluid within the peritoneal cavity.
ASCULTATION
Bowel sound, The absence of bowel sound over 30-s suggest
peristalsis has ceased (ileus)
Examination
14. Investigation
• Baseline: FBC BUSE RBS
• Other investigation: serum amylase, LFT, UPT, GSH/GXM,
UFEME
Abdominal x ray, CXR
Ultrasound abdomen
Endoscopy
Colonoscopy
OGDS
ERCP
Laparoscopy / laparotomy
In cases where diagnosis in unclear
May be the ultimate diagnostic investigation, in addition to being
therapeutic
15. Important Signs in Patients with Abdominal Pain
Sign Finding Association
Cullen's sign
Bluish periumbilical
discoloration
Retroperitoneal
haemorrhage
Grey-Turner's
sign
Discoloration of the flank
Retroperitoneal
haemorrhage
Murphy's sign
Abrupt interruption of inspiration on
palpation
of right upper quadrant
Acute cholecystitis
McBurney's sign
Tenderness located 2/3 distance from
anterior iliac spine to umbilicus on right
side
Appendicitis
Iliopsoas sign
Hyperextension of right hip causing
abdominal pain
Appendicitis
Obturator's sign
Internal rotation of flexed right hip
causing
abdominal pain
Appendicitis
Rovsing's sign
Right lower quadrant pain with palpation
of
the left lower quadrant
Appendicitis
17. Appendicitis
- Definition Inflammation of the appendix
Pathophysiology
Obstruction of the appendiceal lumen
Lymphoid hyperplasia
Fecolith
Sign and symtoms
RIF pain
Fever
Anorexia
Nausea and Vomiting
Rebound tenderness
Alvarado score
Lab & radiology : TWBC & neutrofil high, Ultrasound
Treatment
Appendicectomy
18. These images reveal a typical tubular structure with blind end, showing total diameter more than
6mm.(12 x 15 mm.). These sonographic images reveal hypoechoic content (purulent material)
distending the appendix with an echogenic focus floating within it
19. Biliary colic / acute cholecystitis
C/O
RHC pain + nausea and vomiting
Difference between biliary colic and acute cholecystitis:
fever, usually lasted > 24 hrs, Murphy’s sign, leukocytosis (in later)
Charcoat triad
fever, RHC pain and jaundiceascending cholangitis
Diagnostic Ix - ultrasound HBS and ERCP
Treatment
Fluid resuscitation
Antibiotics – broad spectrum (penicillin+aminoglycosides/
3rd generation cephalosporin+metronidazole)
Decompression of biliary tree – by ERCP, drain stone in
common bile duct by stenting
24. Perforated Viscus
Pt Might c/o generalized abdominal pain
O/e
tachycardic, profused sweating, abdominal guarding/rigidity,
tenderness aggravated by coughing
Investigation
Erect chest xray must be done if perforated viscus is suspected – to
look for air under diaphragm
Treatment
Definite treatment still surgical intervention Exploratory
laparotomy and proper lavage of peritoneum is needed if the cause
is unknown.
Hydration
correction of electrolyte imbalance
analgesic and
If infection is suspected antibiotics
25.
26. Bowel Ischemia
Caused by inadequate blood flow through the
mesenteric vessels, resulting in ischemia and eventual
gangrene of the bowel wall.
The vascular supply of the small and large bowel is
provided by three arteries:
1. celiac trunk
2. superior mesenteric artery (60%–70% cases)
3. inferior mesenteric artery
27.
28. c/0 :
generalized abd pain and some have bloody stool
Bowel motility reduces abdominal bloating.
o/e :
Fever, hypotension, tachycardia, tachypnea, and altered mental
status,Tenderness becomes severe.
Bowel sounds range from hyperactive to absent. Voluntary and involuntary
guarding appears.
Lab : Leukocytosis, metabolic acidosis
Abd xray : ileus, small bowel obstruction, edematous or thickened bowel
walls, and paucity of gas in the intestines.
Small bowel : >4cm
Colon : > 6cm
Caecum : > 8cm
Ultrasonography is highly specific (92-100%), but its sensitivity
(70-89%)
CT angiography has a sensitivity of 71-96% and a specificity of 92-
94%
29. Colon Cutoff Sign-dilated transverse colon, usually to splenic flexure, associated
with pancreatitis or ischemic colitis
31. Abdominal aortic anerysm
■ Male: female ratio is 4 : 1
■ 5–10% of males over 65 years of age have AAA
■ High incidence in patients with peripheral arterial
aneurysm (popliteal, femoral)
■ Ruptured AAA – clinical suspicion
➣ Severe back or abdominal pain
➣ may radiate to groin.
➣ sudden, together with sign and symptoms of shock
32.
33. Sn & Sx:
■ Pulsatile abdominal massin less than 30 % of patients
with significant AAA
■ Tender abdominal mass is suggestive of symptomatic
aneurysm
■ Sudden onset of lower limb numbness
■ Ruptured AAA
➣ Pulsatile mass + hypotension
➣ abdominal/back/groin pain + hypotension
34.
35. Ultrasound
Helpful only if aorta is clearly seen and completely normal
often not helpful due to bowel gas and patient discomfort
cannot rule out a leak from AAA
CT scan
Best test when diagnosis of AAA is unclear
Sensitivity nearly 100%
Size aneurysm (diameter), location, potential ruptured,
Determining surgical repair or endovascular repair (EVAR)
Treatment for ruptured AAA – emergency surgery (but
most of the time patient passed away before surgical
intervention)
36.
37. Ectopic Pregnancy
Early embryo (fertilized egg) that has implanted outside of
the uterus (womb), the normal site for implantation.
C/o
Pain (abdominal or pelvic)
Amenorrhea with abnormal uterine bleeding
Gastrointestinal symptoms
Anaemic symptoms
may have a pelvic mass.
beta-hCG level > 6000 mIU/mL, the gestational sac should be visible
in the uterus with an abdominal probe.
beta-hCG level : 1000-2000 mIU/mL, a gestational sac should be
seen in the uterus with a vaginal probe.
UPT positive
38.
39. Ultrasound scans ultrasound does not show a
pregnancy inside the uterus in the first 3 to 5 weeks
after conception .
show fluid or blood in the abdominal cavity,
suggesting bleeding from an ectopic pregnancy.
Laparoscopy
Treatment:
methotrexate treatment
salpingectomy
40. Management
Generally
Secure airway and breathing – put on oxygen depends
on oxygen status of the patient
Circulation
2 large bore branula both upper limb
Run fluid
Insert catheter to monitor urine output
Insert central venous line
Ryle’s tube for decompression
Monitor BP, PR, urine output, CVP
Keep patient nil by mouth with IV drip maintenance
Analgesia –either intravenous or subcutaneous
41. Take home message
Knowing anatomy of abdomen is most important to make
diagnosis.
Acute appendicitis is the commonest cause for acute abdomen
4 life threatening condition – ruptured ectopic pregnancy,
perforated viscus, leaking/ruptured AAA, bowel ischemia.
Air under diaphragm in erect CXR suspect perforated viscus.
Do UPT to rule out ectopic pregnancy in woman of childbearing
age
Fluid resuscitation is important in acute abdomen
Always perform ABC, Resuscitate before Dx – even of patient is
toxic and urgent surgery is required resusitation is essential
42. References
Janette KS, Dileep NL. Investigation of acute abdomen;
Elsevier 2008; Surgery 26:3
O. James Garden, John Forsythe, Andrew W. Bradbury,
Principles and Practice of Surgery; 4th edition; 2007
Oxford textbook of Surgery 2nd edition
Browse’s Introduction to the Symptoms and Signs of the
Surgical Disease; 4th edition.