Gastrointestinal Acute Abdomen

Question 1

What is the definition of an acute abdomen?

Answer 1

Abdominal pain of acute onset of duration less than 24hours

Question 2

What is visceral pain?

Answer 2

Visceral – dull, generalised, poorly localised; associated with nausea and vomiting. Primitive type of pain: generated by distension, traction or spasm of viscus
Pain from an organ

Question 3

What is somatic pain?

Answer 3

Somatic pain – Localised, described as cutting, sharp, burning pain
Pain from the body wall

Question 4

Causes of acute abdomen if pain is….

Epigastric

Answer 4

Gastritis

Oesophagitis

Question 5

Causes of acute abdomen if pain is….

Central abdomen

Answer 5

Pancreatitis

Ischaemic Small Bowel

Question 6

Causes of acute abdomen if pain is….

Suprapubic

Answer 6

Cystitis
Pelvic Inflammatory Disease
Ectopic Pregnancy

Question 7

Causes of acute abdomen if pain is….

RIF

Answer 7

Appendicitis

Question 8

Causes of acute abdomen if pain is….

LIF

Answer 8

Diverticulitis
Ovarian Abscess
Ischaemic colitis

Question 9

Causes of acute abdomen if pain is….

RUQ

Answer 9

Cholecystitis
Hepatitis
Hepatic Abscess

Question 10

Causes of acute abdomen if pain is….

LUQ

Answer 10

Splenic Abscess

Splenic Infarct

Question 11

Take a history of a patient presenting with an acute abdomen

Answer 11

Onset of pain – sudden or gradual
Nature of pain
Radiation of pain – to back, to thighs and testicles, to shoulder
Exacerbating and relieving factors
Intensity of pain – response to painkillers
Associated symptoms – nausea, vomiting, bowel movements, bleeding
Remember urinary symptoms and gynaecological history

Question 12

In a clinical examination of a patient with an acute abdomen look out for…

Answer 12

Signs of sepsis
Peritonitis (localised or generalised) – rigid abdomen, absent bowel sounds
Pulsatile tender mass
Tender mass in the groin or umbilicus
Distended abdomen with high pitched bowel sounds
Peripheral pulses – disparity or absent
Skin changes – aortic occlusion, pancreatitis
Cullen’s sign
Gray Turners sign

Question 13

Baselin Tests and Analgesia

Answer 13

Large bore venflon + Fluid resuscitation
Morphine Sulphate + Cyclizine / Metoclopramide
Blood – FBC, U&Es, LFTs, Amylase, CRP, Group and save, ABG
ECG
Erect CXR, Plain AXR
Urine exam including Pregnancy testing and ketones
Consider catheterisation/NG tube insertion

Question 14

Catastrophic Surgical Conditions with an acute abdomen

Answer 14

Perforated viscus – Duodenal Ulcer or DD
Leaking AAA or haemorrhage (ectopic pregnancy)
Occlusion of the aorta
Acute Mesenteric ischaemia
Diabetic ketoacidosis, Addisonian crisis
Acute pancreatitis ** (diagnosis is paramount)

Question 15

Catastrophic Non Surgical Conditions with an acute abdomen

Answer 15

Diabetic ketoacidosis
Addisonian crisis
MI/Pericarditis
Pneumothorax/PE/Basal pneumonia
Aortic dissection

Question 16

Mesenteric Ischaemia

Answer 16

Symptoms worse than signs
Metabolic acidosis may be a late sign
Rise in serum lactate levels
Normal investigations including CT scan do not rule out mesenteric ischaemia
If in doubt, operate!

Question 17

Priority Conditions with an acute abdomen

Answer 17

Strangulated hernia
Acute appendicitis
Twisted ovarian cyst
Bowel obstruction
Obstructed kidney
 Non-operative management – Biliary, renal colic, gastroenteritis

Question 18

“Low” Priority Conditions with an acute abdomen

Answer 18

Acute diverticulitis
Acute cholecystitis
Cystitis
Ruptured ovarian cyst 
Mid-cycle pain
PID
UTI
Mesenteric adenitis

Question 19

Why is the timing of the pain important?

Answer 19

As peristalsis comes in waves, a
patient with a GI tract obstruction
tends to experience pain that “comes
and goes”
• this is called “colicky pain”

Question 20

Name the nerves that supply the organs within the abdominal cavity (include the visceral peritoneum)

Answer 20

The visceral afferents (sensory nerves)

The enteric nervous system (an extensive network of nerves found only within the walls of the GI tract which can act independently of other parts of the nervous system to bring about peristalsis but can also be influenced by autonomic motor nerves)

The autonomic motor nerves which can influence the enteric nervous system

• Parasympathetic nerves (speed up peristalsis)
• Sympathetic nerves (slow down peristalsis)

Question 21

Name the nerves that supply the abdominal wall of the abdominal cavity (skin through to parietal peritoneum):

Answer 21

• Somatic sensory nerves
• Somatic motor nerves
• Sympathetic nerve fibres

Question 22

How Do Sympathetic Nerve Fibres get from the CNS to the Abdominal Organs?

Answer 22

• Leave the spinal cord between levels T5 and L2
• Enter the sympathetic chains (bilaterally) but do not synapse
• Leave the sympathetic chains within abdominopelvic splanchnic nerves
• Synapse at prevertebral ganglia which are located anterior to the aorta at the exit points of the major branches of the abdominal aorta
• Postsynaptic sympathetic nerve fibres pass from the prevertebral ganglia (celiac, superior mesenteric etc) onto the surface of the arterial branches leaving the abdominal aorta
• They take part in “periarterial plexuses” (around the arteries) with other nerve fibres (parasympathetic and visceral afferent) as they “hitch a ride” with the arteries, and their branches, towards (or away from if sensory) the smooth muscle and glands of the organs
• The nerve supply to the adrenal glands is unique.
  Sympathetic nerve fibres destined for the adrenal gland leave the spinal cord (approx. T10-L1) and enter the abdominopelvic splanchnic nerves, do not synapse at the prevertebral ganglia, and are carried within periarterial plexuses to the adrenal gland where they “synapse” directly onto cells

Question 23

How Do Parasympathetic Nerve Fibres get from the CNS to the Abdominal Organs?

Answer 23

CNX (vagus nerve)
•presynaptic parasympathetic nerve fibres within the vagus nerves enter the abdominal cavity on the surface of the oesophagus (“vagal trunks”)
•travel towards and into the periarterial plexuses around the abdominal aorta
•carried to the walls of the organs where they synapse in ganglia
•supply parasympathetic nerve fibres to the GI tract + abdominal organs up to the distal end of the transverse colon
pelvic splanchnic nerves (S2,3,4)
pelvic splanchnic nerves (S2,3,4) presynaptic parasympathetic nerve fibres destined for the smooth muscle/glands of the descending colon to anal canal

Question 24

How Do Visceral Afferent Nerve Fibres get from the Abdominal Organs to the CNS?

Answer 24

• pain fibres from the vast majority of the abdominal organs run alongside sympathetic fibres back to the spinal cord
• pain from these organs tends to be perceived by the patient in the dermatomes of the levels at which they enter the spinal cord, (there is a little overlap)
• this can be considered a type of “referred pain”

Question 25

Which organs have pain which can be referred to the shoulder (due to diaphragmatic irritation)

Answer 25

Liver and Gallbladder

Question 26

Which organs have pain which can radiate through to the back?

Answer 26

Stomach and pancreatic pain can radiate through to the back.

Question 27

What pain can be referred from loin towards groin?

Answer 27

Kidney and Ureter pain can refer from the loin towards the groin

Question 28

Describe and explain the pain presented in a patient with appendicitis

Answer 28

1. the appendix is a midgut organ usually located in the right iliac fossa
2. pain from midgut organs tends to be felt in the umbilical region because the visceral afferents from these organs enter the spinal cord between levels T8-T12 (appendix specifically is T10 – umbilicus)
3. however, as appendicitis worsens, the inflamed appendix will start to irritate and inflame the parietal peritoneum in the right iliac fossa which lies anterior to it. The parietal peritoneum is part of the soma

Question 29

What is conveyed within the thoracoabdominal nerves, subcostal nerve, iliohypogastric nerve and ilioinguinal nerve?

Answer 29

The somatic motor, somatic sensory and sympathetic nerve fibres (axons) supplying the structures (including the muscles) of the abdominal part of the “body wall”

Question 30

Where do the thoracoabdominal nerves come from?

Answer 30

the 7th to the 11th intercostal nerves travel anteriorly then their terminal branches leave the intercostal spaces, in the plane between the internal oblique & the transversus abdominus, as the thoracoabdominal nerves

Question 31

Where is the subcostal nerve?

Answer 31

T12 Anterior Ramus

Question 32

Where is the iliohypogastric nerve

Answer 32

Half of L1 anterior ramus

Question 33

Where is the ilioinguinal nerve

Answer 33

Other half of L1 anterior ramus

Question 34

What is paracentesis?

Answer 34

Excess fluid (ascitic fluid) can collect within the peritoneal cavity and paracentesis is the procedure to remove some or all of this fluid.
The needle used in the paracentesis procedure must be inserted lateral to the rectus sheath to avoid the inferior epigastric vessels.

Question 35

Where do visceral afferent nerve fibres from foregut structures enter the spinal cord?

Answer 35

Visceral afferent nerve fibres from the foregut structures enter the spinal cord at approx. T6-T9

Question 36

Where do visceral afferent nerve fibres from the midgut structures enter the spinal cord?

Answer 36

Visceral afferent nerve fibres from midgut structures enter the spinal cord at approx. T8-T12

Question 37

Where do visceral afferent nerve fibres from the hindgut structures enter the spinal cord?

Answer 37

Visceral afferent nerve fibres from hindgut structures enter the spinal cord at approx. T10-L2