17. Diseases of the appendix and the peritoneum

What is acute appendicitis?

Acute inflammation of the appendix

Acute appendicitis is caused by?

Luminal obstruction

- cells keep secreting mucos, which will build up inside the appendix = increased luminal pressure

- the stasis gives the bacteria a perfect place to proliferate = trigger an inflammatory response

- as the luminal pressure increase, it can compress the capillaries = ischaemia = necrosis of the wall

Examples of luminal obstructions?

- Fecalith

- Foreign bodies

- Gallstones

- Tumors

- Lymphoid hyperplasia

What is a fecalith?

Hard stony mass of feces

What happens when the wall of the appendix becomes ischaemic and necrotic?

The growing colony of bacteria can invade the wall

- cause the wall to become weaker and weaker = can potentially rupture

What kind of necrosis happens in appendicitis?

Gangrenous

- bacterial infection of the necrotic wall

What is the criteria to diagnose acute appendicitiis?

Neutrophil infiltration of the muscularis propria

What can acute appendicitis result in?

Rupture of the appendix and pus-forming peritonitis

Symptoms of acute appendicitis?

Periumbilical pain in the right lower quadrant, followed by nausea, vomiting and mild fever

Chronic appendicites?

Shows the same symptoms as the acute ones, but much milder

- symptoms can come and go, and last for weeks to years

Tumors of the appendix?

- Carcinoid

- Adenocarcinoma

What is carcinoids?

Neuroendocrine tumors

Carcinoids in the appendix? (now: NET)

Yellow, solid swelling at the distal tip of the appendix

- produce hormones

What hormones does carcinoids in the appendix produce?

- Histamine

- Kallikrein

- Prostaglandines

- Serotonin

Adenocarcinoma of the appendix?

- Conventional adenocarcinoma

- Non-mucin producing adenocarcinoma

Can mimic the way acute appendicitis presents, with obstruction and enlargement of the appendix

What is peritonitis? what usually cause it?

Inflammation of the peritoneum

- usually caused by bacteria

Symptoms of peritonitis?

Severe pain, swelling of the abdomen, weight loss

- rebound tenderness

What is rebound tenderness?

Pain upon releasing the palpating hand pushing on the abdomen

Primary peritonitis?

Occurs due to bacterial infection of ascitic fluid

- spontaneous bacterial peritonitis

Secondary peritonitis?

Occurs due to perforation or inflammation of abdominal organs

- appendicitis

What can peritonitis result in?

- Paralytic ileus

- Adhesions of organs

- Sepsis

What is Ormond's disease?

= Retroperitoneal fibrosis

- condition characterized by the development of extensive fibrosis throughout the retroperitoneum

Pathogenesis of Ormonds disease?

The exact pathogenesis is unknown, but may be related to an immune response agains atherosclerotic plaques

- the fibrosis usually begins around a severely atherosclerotic aorta