Appendicitis

Dr. Terry Murphy

ED Medical Director

Samaritan Hospital

The appendix is a narrow tubular pouch of the intestines that is attached to the large intestine at the spot where the small and large intestine join.  The appendix appears as a finger shaped structure that, like the intestine, has 3 layers – an internal layer that secretes mucous; a middle layer of muscle; and an outer layer of tough, fibrous material.

Appendicitis is an acute condition caused by infection and inflammation of the appendix afflicting 6 – 7% of the US population, the majority of who are 10-30 years of age.  However, appendicitis can occur anytime in life and has been reported in newborns and 90-year olds.  People at the extremes of age are more difficult to diagnose, and more often have delayed diagnosis and worse outcomes.

Appendicitis occurs because the opening of the appendix into the large intestine becomes obstructed, causing the mucous being secreted by the inner layer to become trapped inside the appendix.  As more mucous continues to be secreted and trapped inside the appendix, two bad things occur.  The first is that the inside of the appendix overfills its normal capacity and pressure builds up inside the appendix.  Over time the pressure built up inside the appendix exceeds the pressure of blood to the wall of the appendix. As blood cannot get into the appendix, portions of the wall die and can rupture allowing the infection to spread outside of the appendix, into the abdominal cavity.

 The second is that bacteria invade the mucous and begins multiplying into huge numbers causing infection and inflammation.  Over time, the infection of the mucous spreads to the tissue of the appendix wall, then into the tissue of the abdomen around the appendix.

From the description above, it is easy to understand that appendicitis is a disease that progresses and worsens over time.  The initial process of appendiceal opening obstruction and mucous secretion to cause luminal distention takes several hours.  The spread of infection from mucous to appendicial wall and the weakening of the wall leading to its rupture take several more hours.

One of the old adages in medicine is that there is no typical clinical presentation for appendicitis; however symptoms most often begin as a generalized “aching” pain around the navel associated with nausea and, perhaps, vomiting; as the inside of the appendix fills from its obstruction.  Over the next 4-8 hours, as the infection spreads from the inside of the appendix to the appendix wall and the tissues in the abdomen around the appendix, the pain begins to localize to the right lower portion of the abdomen.  If the appendix is anterior (in front of the intestine next to the abdominal wall), as the inflammation involves the abdominal wall; it hurts to stand up straight, cough or sneeze, and the abdomen is very tender to touch.  If the appendix is posterior (behind the intestines and away from the abdominal wall), there will be much less localized abdominal wall tenderness. In these circumstances, the correct diagnosis can be very difficult to make. The development of infection of the wall of the appendix and surrounding tissues can take 6 – 24 hours.  It is during this latter period when a low grade fever and worse pain develops.

Abdominal pain that is in the right lower portion of the abdomen, especially that progress in intensity over 6 – 24 hours should be evaluated by a physician.  A careful history and complete exam, including a pelvic exam in most adult females is needed. Typically blood tests are needed to determine the white blood cell count and in females of childbearing age to determine the possibility of an ectopic pregnancy.  A urine test to determine pregnancy or urinary infection is also important. In many instances, if the diagnosis remains uncertain, an abdominal CT scan will be necessary.

The treatment for acute appendicitis in the US remains surgical removal.  Current practice includes standard (open) appendectomy to remove the appendix, and laparoscopic appendectomy where the small incisions are made in the abdominal wall and the appendix is removed using visualization with a small camera and external instruments.  Not all situations can be done laparoscopically, and this approach generally takes longer; but patients can usually go home the next day rather than several days later.

When the appendix has ruptured, the infection may be walled off to an abscess by the tissues inside the abdomen, or have spread into the abdominal cavity causing general peritonitis.  In these situations, and when dealing with the very young or elderly; a more aggressive surgical approach, IV antibiotics and fluids, and a longer hospitalization are required.

This article is intended to provide useful information, not medical advice. This information cannot, and is not meant to, replace consultation with your physician regarding your individual circumstances.