Acute abdomen is the acute onset of abdominal pain that requires prompt diagnosis and immediate intervention to prevent patient
deterioration. The decision to operate depends on efficient diagnostic evaluation, and the timing of the surgery should be
based on what will maximize survival and minimize morbidity.
Clinical Signs, Initial Patient Management, Signalment, History, and Physical Examination
Abdominal pain may be noted as peculiar posture, reluctance to move, stilted ambulation, avoidance reaction, vocalization,
guarding ("splinting"), or hypersalivation (pain-induced nausea). Other clinical signs are dictated by the underlying cause.
A primary survey is performed to set diagnostic and therapeutic priorities. Signalment and history help develop the appropriate
differential diagnoses. Complete physical examination is performed as soon as the patient's status allows. The abdomen is
examined by visual inspection, auscultation, percussion, ballottement, superficial and deep palpation, and digital rectal
Clinical Pathology and Diagnostic Imaging
Blood and urine testing characterizes the patient's hematologic and metabolic status, and may aid in reaching a definitive
diagnosis. When waiting on laboratory tests is potentially detrimental to the patient's well-being, an emergency minimum data
base is performed, and the remaining tests are done later on pretreatment samples. Some testing may aid in establishing a
quick prognosis. One example is blood lactate. Lack of tissue perfusion results in elevation of blood lactate, and higher
elevations seem to correlate with more severe ischemia. Dogs with gastric dilatation-volvulus that have blood lactate less
than 6 mmol/L have much greater chance of survival (99%) than those with lactate greater than this concentration (58%).
Abdominal radiography, ultrasonography, and contrast studies provide valuable direction for patient management. Notable radiographic
findings include fluid (abdominal effusion), gas-distended intestines (obstruction or ileus), free abdominal air (ruptured
viscus), masses, organomegaly, foreign bodies, urinary calculi, and signs of pancreatitis (loss of detail in the right cranial
quadrant and lateral displacement of a gas-filled descending duodenum). Abdominal radiographs may be omitted in cases of evisceration,
penetrating trauma, postoperative peritonitis confirmed on abdominocentesis, and suspected gastric dilatation-volvulus in
which the patient is unstable. Abdominal ultrasonography is helpful in defining masses, enlarged organs, and fluid-filled
lesions (such as abscesses). Contrast radiography of the gastrointestinal and urinary systems is sometimes necessary after
survey radiographs fail to define a suspected abnormality.
Abdominocentesis/Diagnostic Peritoneal Lavage
When other diagnostic techniques fail to clearly define the diagnosis and course of therapy, abdominocentesis is aseptically
performed. Traditionally, a four-quadrant tap is performed with hypodermic needles or catheters. When possible, the author
prefers to use a multiholed catheter to perform a single abdominocentesis just to the right of the umbilicus and, if insufficient
fluid is obtained, progress directly to diagnostic peritoneal lavage.
Diagnostic peritoneal lavage is performed with a multiholed catheter such as a commercially available dialysis catheter, a
standard intravenous catheter modified by adding side holes (taking care to avoid breakage at the holes and resultant intraperitoneal
foreign body), or a commercially available thoracocentesis catheter that has a protected needle/stylet and four offset side
holes. The catheter is inserted just to the right of the umbilicus to avoid fat associated with the falciform ligament and
median ligament of the bladder. The right side is used to minimize the chance of iatrogenic damage to the spleen and descending
colon. A subcutaneous bleb of local anesthetic (9:1 solution of 2% lidocaine:sodium bicarbonate) is placed at the proposed
entry site and a tiny stab incision is made in the skin with a number 11 scalpel blade. The catheter is advanced through the
skin stab and into the abdomen, and gentle aspiration is applied with a syringe. In the absence of an adequate sample, 22
ml/kg of warm sterile isotonic saline is infused. After completing the infusion the patient is gently rolled from side to
side and the abdomen is gently balloted to disperse the saline. Then, careful slow aspiration with a syringe is performed
to collect a 10 to 20 ml sample.
Abdominal fluid is evaluated for color, packed cell volume, white blood cell count, and cytology. Occasionally, bacterial
cultures and chemistries should be performed. The most useful chemistry evaluation for abdominal fluid is creatinine. Diagnostic
peritoneal lavage creatinine that is (two or more times) greater than serum creatinine indicates uroabdomen. Potassium concentrations
can also be used to detect uroabdomen. A ratio of abdominal fluid potassium to peripheral blood potassium greater than 1.4:1
indicates uroabdomen. Glucose concentration may be used to diagnosis septic peritonitis. Abdominal fluid glucose concentration
that is more than 20 mg/dl lower than simultaneously measured blood glucose indicates that the animal has septic peritonitis.