Acute abdomen: investigation

• Acute onset of abdominal pain.
• Prompt diagnosis and immediate medical or surgical intervention necessary to prevent deterioration of patient.

• Abdominal pain/abdominal splinting.
• Sometimes abdominal distension.
• Vomiting.
• Diarrhea.
• Postural changes.
• Gait changes: stiff stilted gait.
• Anorexia.
• Lethargy.
• Shock.

• Depends on severity of primary disease and rapidity of therapy and definitive diagnosis.
• Young dogs:
  • Foreign body.
  • Gastrointestinal obstruction Intestine: obstruction.
  • Intussusception Intussusception.
  • Parvoviral enteritis Canine parvovirus.
  • Severe parasitic infestation.
  • Abdominal trauma Abdomen: trauma.
  • Hemorrhagic gastroenteritis (HGE) Acute hemorrhagic diarrhea syndrome (AHDS).
• Older dogs:
  • Neoplasia causing abdominal effusion or abdominal hemorrhage.

• Young German Shepherd Dogs German Shepherd Dog :
  • Mesenteric volvulus.
• Deep chested dogs of any age:
  • Gastric dilatation-volvulus Stomach: gastric dilatation / volvulus (GDV) syndrome.

• Depends on primary cause.
• Sources of abdominal pain include the following systems:
  • Urogenital.
  • Gastrointestinal.
  • Splenic.
  • Hepatobiliary.
  • Pancreatic.
  • Peritoneal.

• Displacement, obstruction or distention, inflammation or infection, perforation or rupture, and/or vascular compromise in any of these systems can result in somatic or visceral pain and the presentation of an acute abdomen.

• Abdominal pain caused by distention/stretch, inflammation or ischemia of solid or hollow abdominal organs, mesentery or parietal peritoneum.
• Ischemia and inflammation can also result in activation of pain receptors via the release of mediators such as bradykinin, serotonin, histamine and eicosanoids.

• Acute onset.

• Ask yourself the following immediate questions:
  • Does the patient require IMMEDIATE resuscitation?
  • Does the patient require invasive cardiorespiratory monitoring?
  • Are diagnostic tests necessary?
  • Does the patient require urgent surgery?
  • Does the patient require a surgical work-up?

• Ask client specific questions:
  • Toxin exposure? (ethylene glycol, other).
  • Garbage ingestion or dietary indiscretion (deliberate or accidental)?
  • Foreign body exposure?
  • Possibility of trauma?
  • Nature and character of vomit? In relation to meals/eating?
  • Vaccination status Canine parvovirus.
  • Health status of other animals or humans in household?
  • Type, dose and duration of any drugs (NSAID Analgesia: NSAID , steroids)?
  • Recent heat cycle in unspayed female dogs?

Physical examination

• Perform a thorough physical examination.
  Perform abdominal examination LAST, as it can be painful and may lead you to miss vital clinical signs.

Head

• Eyes: sunken, anisocoria (trauma or toxin), mentation, seizures (metabolic or toxin).
• Tongue: look carefully under the tongue for the presence of string/linear foreign bodies (uncommonly lodged here in dogs).
• Fur around muzzle:
  • Look for evidence of excessive salivation (nausea).
  • Look at fur around muzzle for evidence of vomit or toxin (Wood's lamp used to detect ethylene glycol Ethylene glycol poisoning. Ethylene glycol may fluoresce under a black light/Wood's lamp  ).
• Mucous membranes:
  • Color.
  • Tachyness.
  • Capillary refill time.
  • Rapid CRT with endotoxin/sepsis.
  • Prolonged CRT with hypovolemic shock.

Thoracic auscultation

• Lungs Respiratory: disease - clinical investigation:
  • Normal or harsh/crackles (aspiration pneumonitis secondary to vomiting?).
  • Respiratory rate and effort.
• Cardiac Heart: disease - clinical investigation:
  • Murmurs?
  • Arrhythmias? (severe bradycardia if hyperkalemia and atrial standstill present with urinary tract obstruction or rupture).
  • Pulse quality and character/synchrony.
  • Bounding pulses with endotoxic/septic shock.
  • Poor pulse quality with hypovolemic shock.

Orthopedic and neurological examination

• In stable patients, perform complete neurological examination Neurological examination:
  • Cranial nerves: decreased function (botulism Botulism ).
  • Gait abnormalities: botulism, spinal pain due to intervertebral disk disease can be mistaken for abdominal pain.
  • Mentation: dull depressed with shock, trauma, seizures, toxins.
• Patients with abdominal pain can present with a stiff stilted gait and have gait abnormalities ("walking on eggshells").

Fur/hair/coat/skin

• Look carefully for evidence of penetrating trauma, blood on haircoat.
• Look carefully for evidence of bruising or hemorrhage.
• Look carefully at skin around umbilicus for discoloration.
  May appear red in color with intra-abdominal hemorrhage.
• Look at feet and prepuce/vulva for ethylene glycol with Wood's Lamp .

Abdominal examination

• Abdominal examination consists of 4 parts:
  • Visual inspection.
  • Auscultation.
  • Percussion.
  • Palpation.

Visual inspection

• Distention (hemoabdomen, mass effect, distended viscus like GDV).
• Deformity (mass effect, GDV).
• Bruising on skin.
• Discoloration around umbilicus (indicative of intrabdominal hemorrhage).
• Penetrating wounds.

Auscultation

• Increased borborygmi if acute obstruction, gastroenteritis, toxin.
• Decreased borborygmi if chronic obstruction, anorexia, peritonitis Peritonitis , ileus.

Percussion

• Hyperresonant with intraabdominal air.
• Hyporesonant if intraabdominal fluid.

Palpation/Ballottement

• Masses.
• Organomegaly Abdominal organomegaly.
• Plication of intestines (linear foreign body Intestine: linear foreign bodies ).
• Fluid.
• Distention.
• Pain? Localized versus generalized?
• Rectal examination (always look at both ends). Feel for:
  • Masses.
  • Sublumbar lymph nodes.
  • Pelvic urethra.
  • Feces.
  • Hematochezia.
  • Melena.
  • Prostate.
    Approximately 50% of physical examinations will have negative results!

First wave diagnostics

• PCV Hematology: packed cell volume/total solids.
• Decreased hematocrit with abdominal hemorrhage.
• Increased Hct and total solids (TS) with dehydration.

BUN Blood biochemistry: urea

• Increased with:
  • Prerenal azotemia Pre-renal azotemia.
  • Renal disease (acute toxin like ethylene glycol, acute ureteral or urethral obstruction).
• Decreased with:
  • Severe hepatic failure.
  • Polyuria/polydipsia.
  • Portosystemic shunt (PSS) Congenital portosystemic shunt (CPSS).

Glucose

• Decreased in sepsis Shock: septic.

Electrolytes/acid base

• Hyperkalemia Hyperkalemia with acute renal failure Kidney: acute renal injury.
• Hyperphosphatemia Hyperphosphatemia with ethylene glycol intoxication, acute bowel ischemia.
• Hypercalcemia Hypercalcemia: overview:
  • Renal failure.
• Hyperlactatemia Lactate measurement:
  • Poor perfusion, non-specific.
  • Used as a prognostic indicator, if > 6.0 increased risk of death, particularly if level doesn't decrease within 120 minutes of volume resuscitation.
• Hypochloremic metabolic alkalosis Hypochloremia:
  • Pyloric or upper duodenal obstruction.

Complete blood count

• Leukocytosis with left shift Hematology: complete blood count (CBC) Hematology: leukogram.
• Neutrophilia with sepsis (may also have a normal neutrophil count or neutropenia, depending upon stage of disease) Hematology: neutrophil.
• Inflammation.
• Neutropenia may be present if sequestration or decreased production (ie Parvoviral enteritis Canine parvovirus ).
• Severity of left shift dependent on degree of inflammation.

Serum biochemistry profile

• Non-specific changes according to affected systems.

Amylase/lipase

• May be elevated with pancreatitis Pancreatitis: acute Pancreatitis: chronic.

Coagulogram

• Elevated ACT, APTT, PT with suspect DIC Disseminated intravascular coagulation.
• Thrombocytopenia with DIC.
• Elevated fibrin degradation products with DIC.
• Hepatic disease, neoplasia, vasculitis.

Urinalysis Urinalysis

• Renal tubular casts, acute renal failure.
• Calcium oxalate monohydrate crystals (ethylene glycol).
• WBC's, bacteriuria, pyelonephritis Kidney: pyelonephritis , cystitis Cystitis.

Abdominal radiographs Radiography: abdomen or computed tomography Computed tomography

• Loss of detail in abdomen:
  • Peritonitis .
  • Lack of intrabdominal fat.
  • Hemoabdomen.
  • Ascites .
• Free gas:
  • Ruptured viscus.
  • Penetrating wound.

Always perform abdominal radiographs before performing abdominocentesis, as iatrogenic pneumoperitoneum can occur during procedure.

• Masses, organ displacement .
• Organomegaly Abdominal organomegaly.
• Obstruction Intestine: obstruction  .
• Plication of intestines (linear foreign body) .
• Foreign bodies.
• Diaphragmatic hernia.
• Calculi Urolithiasis (renal, ureteral, cystic, urethral).
• Intussusception Intussusception.

• Partial or complete obstructions may require contrast radiography Radiography: contrast media:
  • Barium sulfate indicated unless suspect gastrointestinal perforation Radiography: large intestine contrast.
  • Iodinated material if bowel perforation suspected.

• Free fluid .
• Masses.
• Architecture and size of abdominal organs.
• Ultrasound-guided abdominocentesis.

Abdominocentesis Abdominocentesis Effusion: overview

• Indications:
  • Loss of serosal detail on abdominal radiographs.
  • Penetrating injury, where penetration reaching the peritoneal cavity is unclear.
  • Persistent abdominal pain of unknown cause.
  • Post-operative complications following abdominal surgery.
  • Perform four quadrant abdominocentesis or ultrasound-guided abdominocentesis.

Diagnostic peritoneal lavage (DPL)  

• Indicated when peritonitis or other effusive disease is suspected but other techniques have failed to provide a diagnostic sample.

Fluid analysis Peritoneal fluid: bile Peritoneal fluid: urine  

• Grossly
  • Clear, turbid or flocculent, green, red.
• Cytology Peritoneal fluid: cytology
  • Bile.
  • WBC > 2000/mm3 Peritoneal fluid: differential cell count.
  • Neutrophils with or without bacteria.

• Biochemically:
  • Bilirubin Blood biochemistry: total bilirubin - greater than peripheral blood if biliary rupture.
  • Amylase Blood biochemistry: amylase - greater than peripheral blood if pancreatitis Pancreatitis: acute Pancreatitis: chronic.
  • Creatinine Blood biochemistry: creatinine - greater than peripheral blood with urinary rupture.
  • Aerobic and anaerobic culture.

• Stabilize shock Shock: septic Shock.
• Intravenous crystalloid fluids Fluid therapy , colloids, and blood products Blood: transfusion , as appropriate.
• Shock can be septic in origin or secondary to hypovolemia.
• Hypovolemic shock caused by:
  • Blood loss.
  • Third spacing.
  • Sepsis/endotoxin.
  • Vomiting/diarrhea.
  • GDV/mesenteric torsion.

• Oxygen.
• Broad spectrum antibiotics Therapeutics: antimicrobial drug. Gram positive, gram negative and anaerobic activity.
• Analgesics after initial assessment Analgesia: overview.
• Patient has presented due to abdominal pain. Some practitioners believe that giving analgesics may mask ongoing signs. However, appropriate diagnostics must be performed to further evaluate patient. Ongoing pain can decrease response to shock therapy, therefore, analgesics are absolutely necessary for treatment following initial assessment.

• Perfusion parameters:
  • Heart rate.
  • Capillary refill time.
  • Blood pressure.
  • Central venous pressure.
  • Mucous membrane color.
  • Urine output.

Treatment

• Non-surgical causes of acute abdomen:
  • Mild pancreatitis Pancreatitis: chronic.
  • Hemorrhagic gastroenteritis Acute hemorrhagic diarrhea syndrome (AHDS).
  • Parvoviral enteritis Canine parvovirus.
  • Hyperlipidemia Hyperlipidemia.
  • Acute hepatic disease Liver: acute disease.
  • Acute renal disease/nephritis Kidney: acute kidney injury (AKI).
  • Toxin ingestion Poisoning: overview.
  • Gastroduodenal ulceration Gastric ulceration.
  • Gastroenteritis.
  • Colitis Colitis: overview.

• Indications for Surgery:
  • Uncontrollable hemorrhage and inability to stabilize patient.
  • Free gas on plain abdominal radiographs.
  • GDV/mesenteric volvulus Stomach: gastric dilatation / volvulus (GDV) syndrome.
  • Intracellular bacteria, fecal or vegetable/fiber material on DPL.
  • Greater than 2000 cells/mm3 on DPL.
  • Predominantly toxic neutrophils on DPL.
  • Bilirubin in abdominal fluid or green abdominal fluid.
  • Complete bowel obstruction or linear foreign body.
  • Penetrating trauma/foreign body.
  • Splenic torsion.
  • Gunshot wound to abdomen.
  • Evisceration.
  • Abdominal impalement.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Walters J M (2003) Abdominal paracentesis and diagnostic peritoneal lavage. Clin Tech Small Anim Pract 18 (1), 32-38 PubMed.
• Walters P C (2000) Approach to the acute abdomen. Clin Tech Small Anim Pract 15 (2), 63-69 PubMed.
• Macintire D K (1988) The acute abdomen - differential diagnosis and management. Semin in Vet Med Surg (Small Anim) 3 (4), 302-310 PubMed.

Other sources of information

• Boag A & Huges D (2008) Emergency management of the acute abdomen in dogs and cats. 1. Investigation and stabilisation. In Practice 26, 9.
• Mann F A (2000) Acute Abdomen: Evaluation an Emergency Treatment. Current Veterinary Therapy XIII. Ed J D Bonagura. WB Saunders Company, Philadelphia. pp160-164.
• Holt D & Brown D (1999) Acute abdomen and gastrointestinal emergencies. In: Manual of Canine and Feline Emergency and Critical Care. Eds L G King and R Hammond R. British Small Animal Veterinary Association, United Kingdom. pp. 127-144.
• Kleine L J (1997) Radiology of acute abdominal disorders of the dog and cat (Parts I and II). In: Emergency Medicine in Small Animal Practice: The Compendium Collection.Veterinary Learning Systems, Trenton, NJ. pp. 336-351.