27. Acute appendicitis

Staining: HE

Organ: Appendix

Description:

The mucosa cannot be seen and is replaced by ulceration. There is haemorrhage in the whole sample. The whole appendix wall is infiltrated by granulocytes. Some places we can see liquefactive necrosis. The muscular layers are almost obliterated, very little muscle remains. On the serosal side can we see some fibrin.

Diagnosis: Acute appendicitis

Causes:

• Often idiopathic, sometimes due to closure of the lumen
  • Fecalith (hard piece of feces)
  • Part of fruits etc.

Theory:

Acute appendicitis can be a fatal disease. Because of the extensive liquefactive necrosis (wet gangrene) there can be a perforation of the appendix wall. This can cause the inflammation to spread to the peritoneum. Peritonitis is life-threatening as it can cause sepsis. The fibrin we see is the beginning of a peritonitis.

The type of inflammation is a phlegmone, which means that the inflammation is inside connective tissue (in contrast to an abscess or empyema).

It usually presents with periumbilical pain or pain in the lower right quadrant and tenderness at the McBurney’s point. Symptoms can be similar to cholecystitis and uterine tube inflammation.

In some cases can a periappendicular abscess develop. The pyogenic membrane around the abscess can prevent it from spreading.

The treatment of acute appendicitis is removal.

Overview of the slide

The top of the picture is the lumen. We can see that the mucosa is unrecognizable and is instead replaced by ulceration.

Here we can see some remnants of the muscular layer. Even the muscular layer is infiltrated by granulocytes.

Here we can see some liquefactive necrosis.

The upper part is the tunica serosa, which is also infiltrated by lymphocytes. The lower, eosinophilic part is fibrin, which shows the early phase of peritonitis.