The Acute Abdomen Flashcards
What is the acute abdomen
An abrupt onset of a combination of symptoms, associated with severe abdominal pain
What is the acute abdomen a result of
Inflammation Obstruction Infarction Perforation Rupture of intra-abdominal organs
What pathophysiology should be considered in the acute abdomen
Peritonitis
Intestinal obstruction
Abdominal pain
What is peritonitis
Inflammation of the peritoneum which can be localised or generalised
How does pain typically begin in peritonitis
As generalised and becomes localised later
Cause of generalised peritonitis
Occurs due to failure of localisation due to:
- contamination that is too rapid
- rupture of abscess and leakage of bodily fluids into the abdomen
Routes of infection to peritoneum
Perforation of GI / Biliary tract
Female genital tract
Penetration of abdominal wall
Haematogenous spread
In peritonitis, what happens to the population of aerobes and anaerobes
Aerobes - decrease
Anaerobes - increase
What tends to be the most common cause of obstruction
Cancer
What questions to ask about obstruction
Is obstruction outside or inside the bowel or on the bowel wall
Presentation of obstruction
Pain Vomiting Distension Constipation Borborygmi
What is the difference in presentation between an obstruction in the duodenum to one in the rectum
Duodenum - obstruction will cause vomiting and distension but will not cause constipation as there is nothing to build up
Rectum - obstruction will cause all the cardinal features, starting with constipation and progressing to bloating and vomiting as food backs up
Where does visceral pain come from and how is it transmitted
Pain comes from smooth muscle of viscera
- is transmitted by visceral afferent nerve fibres in response to stretching or excessive contraction
What is the nature of visceral pain
Dull and vague
How is visceral pain localised
Poorly to:
- foregut epigastrium
- midgut para-umbilical
- hindgut suprapubic
Where does somatic pain come from and how is it innervated
Comes from parietal peritoneum and is transmitted by somatic nerves in which afferent signals pass with segmental nerves
What is the nature of the pain
sharp and well localised
How is the pain exacerbated
Worse by moving
Better by laying still
What is referred pain
Pain felt some distance away from its origin
What is the theory of referred pain
Nerves transmitting visceral and somatic pain travel to specific sections of the spinal cord
This may result in irritation of sensory nerves which supply the corresponding dermatomes
Gallbladder example of referred pain
Inflammation of the gallbladder can irritate the diaphragm which is innervated by C3,4,5
Dermatomes of these spinal cord segments supply the shoulder and so hence the referred shoulder pain
What are the effects of peritonitis or intestinal obstruction
Can lead to fluid loss, bacteraemia and endotoxaemia
This can cause circulatory collapse and death
What is the first step in management of acute abdomen
History and examination
After H&E, what tests should be done
U&E, FBC, Amylase, LFT, CRP, ABG Urinalysis Erect X-Ray CT - if readily available and causes no delay USS - identify perforation or free fluid
Should you wait for tests even if you think surgery is urgent
No, urgent surgery should not be delayed for time consuming tests when the indication for surgery is clear
What may be useful when diagnosis is uncertain and risk of alternative intervention is greater
observation
What is a surgical emergency that requires laparotomy
- Rupture of an organ (spleen, aorta, ectopic pregnancy)
- Generalised peritonitis (perforation of ulcer, diverticulum, appendix, bowel or gallbladder)
What should be done pre-op to an emergent surgery and why
Resuscitation
Don’t rush to theatre as anaesthesia compounds shock. Resuscitation must be done properly first
What is the exception to resuscitation before surgery
Blood being lost faster than can be replaced, i.e. ruptured ectopic pregnancy, aneurysm leak, trauma
What are the steps to resuscitation
ABC Oxygen - ensure tissue perfusion Fluid resuscitation - restore circulating fluid volume IV antibiotics - sepsis Decompress gut Analgesia for pain
