Pathology of the Acute Abdomen Flashcards
What is the underlying pathology of a twisted ovarian cyst?
The cyst is attached by a pedicle of blood vessels, which twists around and increases the pressure. Venous flow away is decreased, if it twists further, even the arterial flow into the ovary will be reduced. Decreased venous return leads to congestion because blood is still continually pumped in. The ovary becomes haemorrhagic and necrotic (despite blood coming in, perfusion isn’t good).
What are some causes of a twisted ovarian cyst?
Mature cystic teratoma
Lesion
Which condition is associated with 1/2 of all causes of ectopic pregnancy?
Chronic salpingitis
What is the pathology of chronic salpingitis?
There is chronic inflammation in the fallopian tube which disturbs the movement of the fertilised ovum.
The ovum implants while still in the fallopian tubes and grow within the narrow tube.
Increased pressure can cause the fallopian tube to burst open, leading to major haemorrhage.
Why is an ectopic pregnancy a surgical emergency?
Rupture of the fallopian tubes can lead to life-threatening haemorrhage.
What is the epidemiology of ectopic pregnancy?
Occurs in 1 in 150 pregnancies
90% occurs in the fallopian tubes
How do you diagnose ectopic pregnancy?
Pregnancy test
Ultrasound
Culdocentesis with traces of blood
In which demographic does meconium ileus occur?
Children with cystic fibrosis.
What is the cause of meconium ileus?
Meconium ileus is a bowel obstruction that occurs when the meconium in a child’s intestine is even thicker and stickier than normal meconium, creating a blockage in the ileum.
In which pattern does a colonic adenocarcinoma typically grow?
Annular, ring-like fashion around the bowel wall, causing constriction and obstruction.
What is caecal volvulus?
Twisting of the caecum.
Why is caecal volvulus a surgical emergency?
The twisting of the bowel can cause necrosis and ultimately gangrene.
What are the symptoms of caecal volvulus?
Abdominal pain
Distension
Absolute constipation
What is a the typical pathology of appendicitis?
Obstruction of lumen by faecolith (very hard piece of faeces) which leads to inference with the blood supply which decreases the wall’s resistance to infection.
The appendix constricts to try and drive the faecolith out of the appendix which leads to an increased pressure in the bowel wall.
Blood flow is disturbed which leads to ischaemic changes; therefore the bowel wall is more prone to bacterial invasion.
Inflammation of the wall is cause by bacterial invasion.
What are the usual pathogens associated with appendicitis?
E. Coli
Streptococci
What is the underlying pathology of ACUTE appendicitis?
The earliest lesion is superficial ulceration of mucosa.
Interference with circulation leads to areas of necrosis and perforation which spread to the peritoneal cavity.
If the infection becomes walled off, this leads to a localised abcess which can eventually lead to generalise peritonitis.
Ulceration stops at the mucosal surface.
Where is the pain from appendicitis typically localised?
Generalised dull pain which becomes sharp and localised to the RIF.
What is a diverticulum?
Blind ending pouch (outpocketing from bowel) whch is an area of weakness.
What is the pathology of perforated diverticulitis?
Increased pressure in these areas of weakness can drive the mucosa through these areas of weakness which can become infected and perforated.
What are some signs and symptoms of diverticulitis?
Severe LIF pain
Nausea, loss of appetite, constipation
Patients are usually pyrexial and have a tachycardia
There may be a tender indistinct mass lying parallel to the inguinal ligament
What is the most common cause of a CHRONIC peptic ulcer?
Helicobacter pylori
What are some common causes of an ACUTE peptic ulcer?
NSAIDs
Alcohol
Smoking
What is the epidemiology of a perforated peptic ulcer?
Occurs in 2% of patients
2/3 of ulcer deaths are due to trupture of ulcers.
What is the clinical presentation of a perforated peptic ulcer?
Epigastric pain
Patient with acute peptic ulceration present with acute pain of short duration but may have had previous similar episodes interspersed with periods of relief which last for many months or even years.
