15. Acute abdomen. Types. Aetiology. Symptoms, diagnosis and treatment. Traumatic, hypovolemic and septic shock. Emergency and critical care

What is an acute abdomen (AA)?

A sudden, severe abdominal pain, often indicating a medical emergency.

What are the three types of abdominal pain?

1. Visceral

2. Parietal

3. Referred (transform from spinal cord).

What are examples of acute abdominal conditions requiring immediate surgical intervention?

1. GIT obstruction (foreign body/intussusception)

2. Urinary obstruction

3. Thrombus

4. Rupture (spleen, bladder, vessels)

5. Perforation (intestines)

6. GDV → congestion of spleen

7. Pyloric stenosis

8. Trauma

9. Neoplasia

10. Hernia.

What are examples of less acute abdominal conditions not requiring immediate surgery?

1. Pancreatitis

2. Gastritis

3. Enteritis

4. Colitis

5. Acute hepatitis

6. Prostatitis

7. Peritonitis.

What are some aetiologies of acute abdomen?

Spine trauma, urinary stones, organomegaly, masses, flatulence, and constipation.

What are common causes of acute abdomen in puppies?

1. Foreign bodies

2. Intussusception

3. GIT infections

4. Pyloric obstruction

5. Trauma.

What are common causes of acute abdomen in adults?

1. Pancreatitis

2. Intestinal obstruction

3. GDV

4. Tumours

5. Intussusception

6. Hernias.

What are the clinical signs of acute abdomen?

Abdominal distension, appetite loss, lethargy, fever, vomiting, diarrhoea, ileus, various stages of shock, and dyspnoea.

How is acute abdomen diagnosed?

Anamnesis, detailed history, clinical examination, USG (faster), radiology, contrast study, haematology, biochemistry, analysis of aspirated fluid, and laparotomy.

What are some causes of abdominal distension?

The 6 F's (fat, food, fluid, flatus, faeces, foetus) and tumours.

What is the immediate treatment priority in acute abdomen?

Stabilisation of the animal (pain relief, fluids, and oxygenation).

What are the initial steps in stabilising a patient with acute abdomen?

Ventilation/intubation/oxygenation, IV catheter for fluid therapy and medication access, and potentially blood transfusion.

What is crucial before further therapy or surgical procedures in acute abdomen?

Establishing an exact and clear diagnosis.

What are the general principles of treating acute abdomen?

1. Treatment of shock

2. Fluid therapy

3. Antimicrobial therapy

4. Ensuring adequate tissue oxygenation

5. Protection of the gastric mucosal barrier.

What are some causes of abdominal trauma?

Blunt trauma, contusion, and laceration.

What are the clinical signs of abdominal trauma?

Dyspnoea and abdominal distension.

How is abdominal trauma diagnosed?

Clinical appearance, radiography (for organ herniation), and USG.

What is the treatment for abdominal trauma?

Diagnostic laparotomy.

What is shock?

A sudden drop in blood flow leading to inadequate tissue perfusion and impaired cellular metabolism.

What are the categories of shock?

1. Hypovolemic

2. Distributive (septic, anaphylactic, neurogenic)

3. Obstructive

4. Cardiogenic

What are the clinical signs of shock?

Pale mucous membranes, slow capillary refill time (> 2.5 s), tachycardia, weak pulse, tachypnoea, hypotension, hypothermia, lethargy, and collapse.

What is hypovolemic shock?

Shock caused by inadequate circulating blood volume.

What are the types of hypovolemic shock?

1. Haemorrhagic (due to blood loss e.g. trauma, surgery)

2. Fluid loss (due to dehydration e.g. gastrointestinal, renal, cutaneous/burns, surgery).

What is the treatment for hypovolaemic shock?

Vasopressin (causes vasoconstriction and increased blood pressure)

What is obstructive shock?

Anatomical blockage of the great vessels of the heart, leading to decreased venous return, increased afterload, and decreased cardiac output

What can cause obstructive shock?

1. Pulmonary thromboembolism

2. Pneumothorax

3. Constrictive pericarditis/cardiac tamponade

4. GDV

What is distributive shock?

Caused by excessive vasodilation → less venous return to the heart → less cardiac output → severely low blood pressure. There is no loss of blood, but severe reduction of tissue perfusion, causing ischaemia, necrosis, accumulation of endotoxins → acute multiple organ failure

What are some types of distributive shock?

1. Septic shock (associated with SIRS; NOT reactive to fluid therapy or vasopressors)

2. Anaphylactic shock (due to drug/toxin reactions)

3. Traumatic shock (severe damage to muscles/bones → vasomotor centre depression and peripheral vasodilation)

4. Neurogenic shock (due to disruption of the sympathetic nervous system by spinal cord injury or severe brain injury).

What is cardiogenic shock?

Shock caused by the heart's inability to pump blood effectively, leading to inadequate tissue perfusion.

What are some causes of cardiogenic shock?

Acute myocardial infarction, severe heart failure, and arrhythmias.

What is the basic procedure for emergency and critical care?

A: Airways

B: Breathing (breathing support, bronchodilators)

C: Circulation (control bleeding, give IV fluids)

D: Drugs (avoid drugs worsening shock e.g. NO vasodilators, alpha agonists, inhalation anaesthetics)

What are the emergency and critical care treatments for shock?

1. Fluid therapy (crystalloids like lactated Ringer's or NaCl)

2. Oxygen therapy

3. Maintaining normal body temperature

4. Pain therapy (e.g. morphine, tramadol, butorphanol)

5. Vasopressors (e.g., vasopressin)

6. Antibiotics (e.g., ampicillin for sepsis)

7. Adrenaline (for anaphylaxis), corticosteroids, and antihistamines.

8. Cardiac care

   1. Tachycardia (e.g. beta-blockers, lidocaine, digoxin)

   2. Hypertrophic cardiomyopathy (e.g. calcium channel blockers)

   3. Ventricular arrhythmias (e.g. lignocaine IV)

   4. Congestive heart failure/pulmonary oedema (e.g. furosemide IV)

What are the fluid bolus rates for moderate to severe shock?

20-40 ml/kg over 15-30 minutes, repeated if necessary.

What are the fluid bolus rates for very severe shock?

60-90 ml/kg (dog) and 40-60 ml/kg (cat).

What are common causes of abdominal tumours in dogs and cats?

Dogs: gastric adenocarcinomas

Cats: gastric lymphoma.

What are some other types of abdominal tumours?

Leiomyoma and benign adenomatous polyps.

What are the clinical signs of abdominal tumours?

Vomiting and regurgitation.

How are abdominal tumours diagnosed?

Biopsy and histopathology.

How are abdominal tumours treated?

Surgical resection if possible.

What are the visible differences between transudate and exudate?

Transudate: colourless to straw-yellow, low turbidity

Exudate: usually high turbidity due to the presence of cells, proteins, and other debris

What does GDV do in the abdomen?

Pain, compression of organs (spleen) and blood vessels (vena cava) → congestion

What is the effect of GDV on the spleen?

Congestion

What is the effect of compression of the vena cava during GDV?

Hypovolaemic/obstructive shock → tachycardia, tachypnoea, low blood pressure

What is the critical point of O2 saturation?

90%

What type of fluids is given in GDV?

Crystalloids

How are NSAIDs nephrotoxic?

Inhibit cyclooxygenase (COX) enzymes → decrease prostaglandins (cause pain and inflammation) → reduced renal blood flow (vasoconstriction)

What should be done when a dog comes in with GDV?

1. USG

2. Stabilise (ABCD) + remove excess gas from stomach (stomach tube, large IV catheter, small trochar)

3. Pain relief (opioids)

What are the types of fluids?

1. Crystalloids

   1. Isotonic: NaCl 0.9%, Hartmann’s, Plasmalyte

   2. Hypertonic: 7.2-23% saline

2. Colloids

   1. Dextran, starches, gelatins

What medications can be used for GDV surgery? (Premed, induction, maintenance)

AVOID ALPHA 2 AGONISTS AND ACEPROMAZINE!

1. Premed

   1. Midazolam/diazepam

   2. Hydromorphone/morphine/buprenorphine

2. Induction

   1. Ketamine

   2. Propofol

   3. Alfaxalone

3. Maintenance

   1. Isoflurane/sevoflurane + opioid