Question

Case study #2

Digestive system

Ms. K, age 79yrs old, has developed a partial obstruction in her colon. She was having difficulty with bowel movements and was nauseated, anorexic, and dehydrated. Surgery revealed diverticulitis with considerable fibrosis causing the obstruction. A colostomy was required.

Diverticulitis - Diverticulosis happens when pouches (diverticula (Links to an external site.)Links to an external site.) form in the wall of the colon (Links to an external site.)Links to an external site.. If these pouches get inflamed or infected, it is called diverticulitis (Links to an external site.)Links to an external site.. Diverticulitis can be very painful.

1) Why would she have difficulty passing feces?

2) Why do you think she would be nauseated and anorexic?

3) Why would she be dehydrated?

4) How would fibrosis affect the functioning of the colon?

5) Why would a colostomy be necessary?

Answer 1

1.She is having difficulty passing feces

1. The intestinal obstruction is caused by fibrosis
2. This causes distension of the bowel proximal to the obstruction.
3. The distension obstructs the arterial blood flow.
4. This leads to ischemia
5. Bowel distension also causes venous flow obstruction. This leads to edema of the bowel wall. This edema further reduces arterial blood flow
6. The net effect is there is ischemia of the bowel wall.
7. This ischemia creates a gangrenous segment of bowel.
8. Lack of blood flow impairs peristalsis. ( peristalsis is the rhythmic contraction and relaxation of the bowel that move its contents from the mouth to the anus)
9. Impaired peristalsis causes stasis of the bowel content.
10. Therefore the patient has difficulty passing stool.

2.The patient is experiencing nausea and anorexia because

1. The intestinal obstruction has caused proximal distension of the bowel
2. This distension is caused due to obstruction to the movement of flatus and fecal matter.
3. Distension causes obstruct venous blood flow - this results in edema
4. Distension causes obstruct arterial blood flow - this results in ischemia
5. Ischemia -> leads to necrosis -> necrosis leads to perforation -> perforation leads to leakage of bowel content into the peritoneum
6. The leakage of bowel content into the sterile peritoneal cavity leads to infections.
7. Infection stimulates inflammation.
8. Pro-inflammatory factors are responsible for nausea and anorexia

3.She is dehydrated because

1. Bowel obstruction causes proximal bowel distension
2. This bowel distension causes third space volume loss
3. Third space volume loss is an accumulation of fluid in the extracellular spaces - bowel lumen.
4. This fluid loss can lead to dehydration and hypotension

4.Effect of fibrosis on the colon:

1. Normal functional tissue of the colon is replaced with fibrous tissue
2. This causes a reduction in the absorptive capacity of the bowel
3. it also distorts the anatomy of the bowel.
4. The presence of myofibroblast lead to stricture formation
5. In the present case, the cause of fibrosis is repeated inflammation the diverticulum
6. Repeated episodes of inflammation and healing (with fibrosis) has to lead to the formation of strictures.
7. The fibrous tissue destroys the normal neuronal connections in the bowel wall.
8. This impairs peristalsis
9. Therefore, there is mechanical and functional obstruction of the bowel due to fibrosis

5.A colostomy is performed because:

1. This will help relieve the bowel obstruction. ( proximal to the fibrosed segment)
2. It will allow the evacuation of fecal matter.
3. It will also allow the disease segment to rest and heal.