The document provides information on evaluating and diagnosing an acute abdomen. It describes how the causes of an acute abdomen vary by age and include appendicitis, biliary disease, bowel obstruction, and diverticulitis. A thorough history, physical exam, and lab tests are needed for diagnosis. The exam focuses on locating the pain and assessing for peritoneal irritation or inflammation. Common lab tests include complete blood count, electrolytes, and tests to check for conditions like pancreatitis or pregnancy. Imaging studies may also be used to diagnose the specific cause of the acute abdomen.

1. ACUTE ABDOMEN
CHAPTER-47

2. Objectives
anatomy and physiology
history
evaluation and diagnosis
preparation for emergency operation
atypical patients
algorithms in the acute abdomen
summary

3. Acute abdomen refers to
signs and symptoms of abdominal
pain and tenderness,
that often requires emergency
surgical therapy.
Diagnoses associated with an acute
abdomen:
Vary according to age and gender
E.g.>Appendicitis common in
younger,
whereas biliary disease, bowel
obstruction, intestinal ischemia and
infarction, and diverticulitis are
more common in older adults.
result from infection, obstruction,
ischemia, or perforation.

4. Nonsurgical
causes:
• Uremia
• Diabetic crisis
• Addisonian crisis
• Acute intermittent porphyria
• Acute hyperlipoproteinemia
• Hereditary Mediterranean fever
1)Endocrine
and
Metabolic
Causes:
• Sickle cell crisis
• Acute leukaemia
• Other blood dyscrasias
2)
Hematologic
Causes:

5. • Lead poisoning
• Other heavy metal poisoning
• Narcotic withdrawal
• Black widow spider poisoning
3)Toxins and Drugs:
• An expeditious workup proceeds in the usual order—
• history, physical examination, lab. tests, and imaging studies.
Bcoz of potential surgical nature of the acute abdomen:

6. ANATOMY
AND
PHYSIOLOGY
Abdominal pain is
into:
1)Visceral pain > vague,
poorly localized to the
epigastrium, periumbilical
region, or hypogastrium
result of distention of a
hollow viscus.
2)Parietal pain > sharper
and better localized.
corresponds to the
segmental nerve roots
innervating the
peritoneum.

7. Referred pain is pain
perceived at a site distant
from the source of
stimulus.
Locations and Causes of Referred Pain:
Right Shoulder
• Liver
• Gallbladder
• Right hemidiaphragm
Left Shoulder
• Heart
• Tail of pancreas
• Spleen
• Left hemidiaphragm
Scrotum and Testicles
• Ureter

8.  Bacteria or irritating chemicals into the peritoneal cavity can cause an
outpouring of fluid from the peritoneal membrane.
Peritoneum responds to inflammation by
 increased blood flow,
 increased permeability, and
 Formation of a fibrinous exudate on its surface.
 The fibrinous surface and decreased intestinal movement cause
adherence between the bowel and omentum or abdominal wall and
help localize inflammation.
 As a result, an abscess may produce sharply localized pain, with
normal bowel sounds and GI function.
 Where as a diffuse process, such as a perforated duodenal ulcer,
produces generalized abdomen pain, with a quiet abdomen.

9. Peritonitis is peritoneal inflammation of any cause, recognised on PE by:
 severe tenderness
 with or without rebound tenderness, and guarding.
 secondary to an inflammatory insult
 a gram (-) infection with an enteric organism or anaerobe.
 It can result from non-infectious inflammation(E.g. pancreatitis)
Primary peritonitis
 commonly in children
 caused by Pneumococcus or haemolytic Streptococcus spp.
 Adults with end-stage renal disease develop infections of their
peritoneal fluid, gram(+)cocci.
 Adults with ascites and cirrhosis can develop primary peritonitis >
E.coli and Klebsiella spp.

10. HISTORY
 The history must focus on:
 investigation of the pain complaints,
 past problems and
 associated symptoms
 Questions should be:
 onset, character, location, duration, radiation, and
chronology of the pain experienced
 Anything makes the pain better or worse.
 Pain identified with one finger >more Localized, typical of
parietal pain;
 Whereas indicating the area of discomfort with the palm of
the hand> more typical of the visceral discomfort
 intensity and severity of the pain >underlying tissue damage.

11. Pain that develops and worsens over several hours is typical >progressive inflammation or infection such as cholecystitis, colitis, and bowel obstruction.

12.  Solid organ visceral pain > generalized in the quadrant of the involved organ, (liver
pain across RUQ)
 Small bowel pain > poorly localized periumbilical pain,
 colon pain > centered between the umbilicus and pubis symphysis.
 As inflammation expands to involve >peritoneal surface+parietal nerve fibers from
the spine >focal and intense sensation.
 This is responsible for the classic diffuse periumbilical pain of early
 appendicitis that later shifts to become an intense focal pain in
 the RLQ at McBurney’s point.
 The liver >referred pain to the right shoulder from the C3-C5 nerve roots.
 Genitourinary pain is radiates to the scrotum or labia via the hypogastric plexus of
S2-S4.
 Sxs: primarily in the flank region,
 Originating from the splanchnic nerves of T11-L1.

13.  Activities that exacerbate or relieve the pain are also
important.
 Eating > worsen the pain of bowel obstruction, biliary
colic, pancreatitis, diverticulitis, or bowel perforation.
 Food can provide relief from the pain of nonperforated
peptic ulcer disease or gastritis.
 Peritonitis: worsening with any sudden body movement
and less pain if knees are flexed.
 Associated symptoms:
 Nausea, vomiting, constipation, diarrhoea , pruritis ,
melena, haematochezia, and/or haematuria.
 Vomiting >because of severe abdominal pain of any cause
or result of mechanical bowel obstruction or ileus.

14. The pain of an acute surgical abdomen presents first and stimulates vomiting via
medullary efferent fibers.
Constipation or obstipation >a result of mechanical obstruction or decreased
peristalsis.
Diarrhoea >several medical causes
acute abdomen,
including infectious enteritis,
inflammatory
bowel disease or parasitic contamination.

15.  The past medical history could be more helpful than any other single part of the patient’s
evaluation
 During the abdominal examination, all scars on the abdomen should be accounted.
 A history of medications and the gynecologic history of female patient are also important.
 Medications, several common drugs :
High-dose narcotic use :
 obstipation and obstruction,
 suppress pain sensation and alter mental status,
 spasm of the sphincter of Oddi.
NSAIDs :
 increase risk of upper GI inflammation and perforation;
 block protective gastric mucous production
 increase a pt.'s risk of acquiring various bacterial or viral illnesses
 Diminishing the pain and the overall physiologic response.
 cause of GI bleeds, retroperitoneal haemorrhages, or rectus sheath hematomas

16. • coagulopathy and portal hypertension from liver impairment.
Chronic alcoholism:
• create an intense vasospastic reaction, which can create life-
threatening
Cocaine and methamphetamine:
hypertension and cardiac and intestinal ischemia.
• specifically the menstrual history, is crucial in the evaluation of
lower abdominal pain in a young woman.
Gynaecologic health:

17. PHYSICAL
EXAMINATION
 Skilled clinicians >able to develop a narrow and accurate
differential diagnosis in most pts at the conclusion of the history
and PE.
 Laboratory and imaging studies can then be used.
 PE >should always begin with a general inspection of the
patient.
 Pts with peritoneal irritation >maintain flexion of their knees and
hips to reduce tension.
 Pain without peritoneal irritation >cause pts to shift and fidget in
bed continually >position that lessens their discomfort.
 Fascial hernias >suspected & confirmed during palpation.
 Evidence of erythema or oedema of skin >suggest cellulitis of
the abdominal wall,
 Ecchymosis is sometimes observed with deeper necrotizing
infections of the fascia or abdominal structures, such as the
pancreas.

19. Auscultation
information
about the GI
tract and
vascular
system.
 A quiet abdomen suggests an ileus, whereas
 Hyperactive bowel sounds >in enteritis and early
ischemic intestine.
The pitch and pattern:
 Mechanical bowel obstruction >high-pitched tinkling
sounds that tend to come in rushes and are associated
with pain.
 Echoing sounds present >when significant luminal
distention exists.
 Bruits heard >reflect turbulent blood flow in the
vascular system, in high-grade arterial stenosis (70% to
95% but also heard if an arteriovenous fistula is present)

20.  Percussion is used to assess for gaseous distention of the
 bowel,
 free intra-abdominal air,
 degree of ascites, and/or
 presence of peritoneal inflammation.
 Hyperresonance, commonly termed tympany to percussion,
characteristic of underlying >gas-filled loops of bowel.
 In the setting of bowel obstruction or ileus:
 this tympany is heard throughout all but the RUQ, where the
liver lies beneath the abdominal wall.
 If localized dullness to percussion is identified anywhere
 other than RUQ >an abdominal mass displacing the bowel
should be considered

21.  When liver dullness > lost & resonance is uniform throughout >free
intraabdominal air should be suspected.
 Ascites is detected by looking for fluctuance of abdm cavity (Test for fluid
wave)
Peritonitis is also assessed by percussion:
 Firmly tapping the iliac crest, flank, or heel of an extended leg will jar the
abdominal viscera and elicit characteristic pain when peritonitis is present.
 The final major step in the abdominal examination is palpation.
 Palpation should always begin gently and away from the reported area of
pain.
 If considerable pain is induced at the outset of palpation, the pt is likely to
guard voluntarily.
 Involuntary guarding, or abdominal wall muscle spasm, is a sign of
peritonitis.
 In the setting of voluntary guarding, the abdominal muscles will relax
during the act of inspiration;
 if involuntary, they remain spastic and tense.

22.  A pelvic examination should be included for all women when evaluating pain
located below the umbilicus.
EVALUATION AND DIAGNOSIS:
Laboratory Studies for the Acute Abdomen
 Hgb level
 WBCs count with differential
 Electrolyte, BUN, creatinine levels >(vomiting or third space fluid losses)
 Urinalysis >(bacterial cystitis, pyelonephritis)
 Urine hCG level >(pregnancy)
 Amylase, lipase levels >(pancreatitis)
 Total and direct bilirubin levels >(Liver function test)
 Alkaline phosphatase level ‘ ‘ ‘ ‘
 Serum aminotransferase ‘ ‘ ‘ ‘
 Serum lactate levels >(intestinal ischemia or infarction)
 Stool for ova and parasites
 C. dificile culture and toxin assay

23. Imaging
Studies
CT Scan.(Appendicitis)
Plan X-Ray(Upright x-ray chest detect 1ml in peritoneal cavity, Lateral
decubitus abdml x-ray detect pneumoperitoneum in duodenal ulcer
Plain films also show abnormal calcifications.
Cecal volvulus >distended loop of colon, concavity facing inferiorly and
the right.
Sigmoid volvulus > appearance of a bent inner tube, with its apex in the
RUQ.

24. Abdominal ultrasonography
detecting gallstones and assessing gallbladder wall thickness
presence of fluid around the gallbladder.
Its usefulness in detecting common bile duct stones is limited.
detection of abnormalities of the ovaries, adnexa, and uterus.
detect intraperitoneal fluid.

25. INTRA-ABDOMINAL PRESSURE
MONITORING Normal IAP 5 to7 mm Hg
 Abnormally increased intra-abdominal pressures diminish the
 blood flow to abdominal organs and
 venous return to the heart while venous stasis (venous thrombosis).
 Press upward on the diaphragm, thereby peak inspiratory pressures and
ventilatory efficiency
 Morbid obesity normal pressures by 4 to 8 mm Hg while elevation the head of
the bed to 30 degrees pressure by 5 mm Hg (average).
 Pressures measured via the bladder (Foley catheter)

27. Diagnostic Laparoscopy
high sensitivity and specificity
decreased morbidity and mortality,
length of stay, and overall hospital costs

28. Findings Associated
With Surgical
Disease In the
Setting of Acute
Abdominal Pain
Physical Examination and Laboratory Findings
Abdominal compartment pressures >30 mm Hg
Worsening distention after gastric decompression
Involuntary guarding or rebound tenderness
Gastrointestinal hemorrhage requiring >4 U of blood without
stabilization
Unexplained systemic sepsis
Signs of hypoperfusion (e.g., acidosis, pain out of proportion to
examination findings, increasing liver function test results)

29. Findings Associated
With Surgical
Disease In the
Setting of Acute
Abdominal Pain
Radiographic Findings
Massive dilation of intestine
Progressive dilation of stationary loop of intestine (sentinel
loop)
Pneumoperitoneum
Extravasation of contrast from bowel lumen
Vascular occlusion on angiography
Fat stranding, thickened bowel wall with systemic sepsis
Diagnostic Peritoneal Lavage (1000 mL)
>250 white blood cells/mL
>300,000 red blood cells/mL
Bilirubin level higher than plasma level (bile leak)
Particulate matter (stool)
Creatinine level higher than plasma level (urine leak)

30. PREPARATION
FOR
EMERGENCY
OPERATION
Regardless of the severity of illness, all pts require preop. preparation.
IV access should be obtained
Fluid or electrolyte abnormalities corrected
Antibiotic infusions.
The bacteria common in acute
abdominal emergencies are gram(-) enteric organisms and anaerobes.
Pts with generalized paralytic ileus >nasogastric tube.
Foley catheter >assess urine output(0.5 mL/kg/hr, with systolic at least 100 mm Hg, HR=100
Beats/min or less=an adequate intravascular volume)

31.  A common electrolyte abnormality requiring correction is hypokalemia. and
 Its peripherally administration is limited by phlebitis.
 Preop. acidosis may respond to fluid repletion and IV HCO3- infusion.

32. ATYPICAL PATIENTS:
Pregnancy
 Laparoscopy has had a major impact on the dx and tx of the gravid female with AAP.
 The appendix rises out of the pelvis to within a few cm of the right anterolateral costal margin
late in the 3rd trimester.
 Surgery, especially in the pelvis, is associated with increased risks of spontaneous abortions in
the 1st trimester and increased risk of preterm labor in the 2nd and 3rd trimesters
 Risk is minimized by maintaining O2 and CO2 levels during surgery, avoiding episodes of
hypotension, and minimally manipulating the uterus.
 Leukocytosis as high as 16,000 cells/mm3 is common in pregnancy
 A neutrophil shift more than 80% is suspicious for an acute inflammatory process, such as
appendicitis.
 Appendicitis is the most common nonobstetric disease requiring surgery.

33.  Ultrasound 1st imaging study
 Helical CT 2nd line
 MRI recognize an enlarged
appendix, periappendiceal
fluid, and inflammation.

34. Pragnency
 The 2nd and 3rd most common surgical diseases seen in pregnancy are biliary
tract disorders and bowel obstructions.
 Sxs > pain, nausea, and anorexia.
 Dx > Ultrasound
 Gallstone pancreatitis associated with fetal loss as high as 60%.
 If a woman not respond to conservative treatment, surgical treatmen performed.
 3 periods during gestation with an increased risk of obstruction and rapid
changes in uterine size.
 The 1st is from 16 to 20 weeks, when the uterus grows beyond the pelvis.
 The 2nd is from 32 to 36 weeks, when the fetal head descends, and
 the 3rd is in the early postpartum period.

35. CRITICAL ILL PATIENT
Many of the underlying diseases and
treatments encountered in the ICU can
predispose to acute abdominal disease.
Cardiopulmonary bypass (CPB) has been
associated with several acute abdominal
illnesses.
Linked to the low-flow state of CPB
•Mesenteric ischemia
•paralytic ileus
•Ogilvie’s syndrome
•Stress peptic ulceration
•Acute acalculous cholecystitis, and
•Acute pancreatitis

36. Immunocompromised
Patients
Immunocompromised patients have
variable presentations with
acute abdominal diseases.
These patients may not be able to
mount a full inflammatory response
and therefore may experience less
abdominal pain and have delayed
development of fever and a blunted
leukocytosis.
Mild to moderate compromise is
experienced by:
older patients,
malnourished individuals,
diabetics,
transplant recipients on
routine maintenance therapy,
Cancer patients
renal failure patients
HIV patients with CD4 counts
higher than 200/mm3

37. Severely
compromised
patients would
typically include:
transplant recipients having received immunosuppressant therapy for
rejection in the past 2 months,
cancer patients on chemotherapy,
especially those with Neutropenia
HIV patients with CD4 counts lower than 200/mm3.
These pts present late, with little or no pain, no fever, and vague
constitutional symptoms, followed by an overwhelming systemic collapse

38. Pseudomembranous
colitis associated
with: antibiotic use,
In immunocompromised pts (Leukemia, Lymphoma, AIDS)
Sxs : diarrhea, dehydration, abdominal pain, fever, and leucocytosis.
(Immunocompromised fail to exhibit these findings)
Dx : CT Scan Findings are : bowel wall thickening, pancolonic distribution, and
pericolonic standing, ascites, mucosal enhancement, diffuse bowel dilation,
and adouble-halo sign.

40. Morbidly
Obese
Patients
Alterations in the signs and symptoms of peritonitis in
the morbidly obese.
Findings of overt peritonitis are often late and usually
ominous, leading to sepsis, organ failure, and death.
Abdominal sepsis is a more subtle diagnosis in this
population.
Laparoscopy is a valuable tool in these patients.