Acute Diverticular Disease

Department of the Navy
Bureau of Medicine and Surgery

Diverticular disease and its associated complications have increased over this century. While the incidence of diverticular disease increases with age, of importance to the GMO is that 2-6 percent of patients with diverticular disease are younger than 40 and include a preponderance of men.

A diverticulum is an abnormal pouch or sack consisting of mucosal and submucosa opening from a hollow viscus. Colonic diverticula are false diverticula that protrude through the colonic musculature alongside any of the three taenia. Diverticula are noted to protrude through the musculature at sites created by the small arteries that supply blood to the mucosa (vasa recta).

• The presence of protrusions of mucosa through the muscular wall of the colon is termed "diverticulosis". When inflammation is superimposed the term "diverticulitis" is used. The term "diverticular disease" is used to describe the entire spectrum of clinical consequences of the presence of diverticula of the colon.

The exact pathogenesis of diverticulosis is unknown and probably multi-factorial. There are different patterns of disease related to changes in colonic wall connective tissue and increased intraluminal pressure. Certain people will have a predisposition to colonic wall weakness and when associated with altered colonic motility and increased intraluminal pressure the result is mucosal protrusions through colonic wall defects, creating diverticula.

Natural History

Despite the prevalence of diverticulosis of the colon within the population, the majority of those with diverticulosis remain symptom free. It is estimated that as many as 30-40 percent of patients with diverticulosis develop symptoms related to the diverticula over a lifetime. Patients with diverticular disease may develop diverticulitis, fistulas, obstruction, or hemorrhage. In one large study of asymptomatic patients over 15 years, clinical diverticulitis developed in 25 percent, obstruction in 5 percent, clinical perforation in 5 percent, and significant hemorrhage in 5 percent. Approximately 30 percent of patients with symptomatic diveticular disease will eventually require surgical intervention.

1. In terms of duration of symptoms, half of those with symptomatic diverticular disease were free of symptoms up to 1 month before presentation. Three quarters have symptoms for less than 1 year. Patients who present with serious complications may be asymptomatic until hours before admission.

2. In terms of recurrence after an initial episode of diverticulitis, one-third to two-thirds of patients will have recurrent attacks or continue to have symptoms. About one-fourth will require hospitalization for recurrent episodes. Approximately half of those requiring admission for a second attack will do so within 1 year of the first attack, and 90 percent are admitted within 5 years. Medical management of recurrent attacks is less effective than treatment of the presenting attack. The complication rate increases with subsequent attacks, being 23 percent for one attack and 58 percent for more than one attack.

3. As far as younger patients are concerned (<40), their initial attack of diverticulitis tends to be more severe than their older counterparts and a significant number will require surgical intervention for the complications of diverticulitis during the initial hospitalization. However, follow up data varies as to incidence and severity of recurrent disease or complications between different studies.

4. Repeated attacks of diverticulitis increase the risk of a complication from diverticular disease. Complicated diverticular disease requiring emergent surgery is associated with increased morbidity and mortality compared to elective colon resection. Thus, in good risk patients who have required hospitalization for repeated attacks of diverticulitis, elective resection is recommended.

Inspissated stool or a fecalith within a thin walled diverticulum will cause erosion and inflammation leading to infection and perforation. This may vary from a minimal peridiverticular phlegmon, which progresses to a peridiverticular or mesenteric abscess, which may then become a walled off pelvic or intra-abdominal abscess, to one that perforates into the free peritoneal cavity causing generalized peritonitis. Usually only one diverticulum becomes inflamed leading to the different stages of inflammation noted.

Differential Diagnosis

Depending on the presenting symptoms, other entities should be considered in the differential diagnosis. This would include Crohn’s disease, ulcerative colitis, appendicitis, Meckel’s diverticulitis, penetrating ulcer, ureteral colic, urosepsis, pelvic inflammatory disease (PID), tubo-ovarian abscess (TOA), ovarian torsion, endometriosis, and small bowel obstruction. In older individuals include ischemic colitis, volvulous, and most importantly carcinoma. Rectal bleeding is distinctly uncommon in diverticulitis and should make one consider a different diagnosis.

Peridiverticular Inflammation / Phlegmon

This is the most common form of diverticulitis. Patients present with acute, steady, left lower abdominal discomfort. This may be associated with alteration in bowel habits with either constipation or diarrhea. There may be a low-grade fever but the patient is not tachycardic. Examination reveals mild left lower quadrant tenderness without an appreciable mass.

Treatment can be carried out on an outpatient basis and consists of clear liquids by mouth and a broad-spectrum oral antibiotic for 7-10 days. Trimethoprim-sulfamethoxazole, 1 tab BID, and metronidazole, 250mg QID, or ciprofloxacin, 500mg BID, and metronidazole are good combinations to use. Solid foods may be started as symptoms subside and a high fiber diet instituted after resolution of the inflammation. Follow-up evaluation should include flexible sigmoidoscopy and barium enema after the inflammation has resolved, usually at 3-4 weeks.

Pericolic or Mesenteric Abscess

The patient with this stage of inflammation will complain of moderate to severe left lower abdominal pain and anorexia. Alteration in normal bowel habits with constipation or diarrhea will occur. Abdominal exam reveals a tender mass and voluntary guarding in the lower abdomen. Rebound tenderness or referred rebound tenderness may be present. Pyrexia and tachycardia are usually present.

1. A chest x-ray along with flat and upright abdominal films can assist with excluding the presence of free intraperitoneal air or intestinal obstruction. Urinalysis can exclude urinary tract infection, fecaluria, and ureterolithiasis. Leukocytosis is usually present.

2. The patient is best treated with hospitalization, bowel rest, IV hydration, and IV antibiotics. Antibiotics should cover both aerobes and anaerobes. Cefoxitin or Unasyn are good single agents to start with. If patients appear more toxic, then an aminoglycoside with metronidazole and ampicillin for enterococcus coverage may be used. Imipenem or Trovan may be used as a single agent in this situation. Nasogastric suction is unnecessary except for persistent emesis or obstruction. A water-soluble contrast enema or CT scan is useful to confirm the diagnosis in atypical presentations or if not improving within 48 hours.

3. Again, most of these patients will resolve on medical management and should undergo further evaluation after resolution of the inflammation.

Generalized Purulent or Feculent Peritonitis

When the inflamed colon or abscess freely perforates into the peritoneal cavity generalized peritonitis and the true "acute abdomen" will occur. Patients will complain of severe diffuse abdominal pain with anorexia, nausea and vomiting. The patient is tachycardic, pyrexic, and dehydrated. Severe tachycardia and hypotension are signs of septic shock. On examination, the patient will have a diffusely tender abdomen with involuntary guarding, rebound and percussion tenderness, and absent or rare bowel sounds. An upright CXR and acute abdominal series may reveal free intraperitoneal air. The first step in management of peritonitis is volume replacement with IV fluids (NS or LR). Treatment also includes insertion of an NG tube, Foley catheter, and administration of IV antibiotics. Surgical exploration should follow immediately. Surgical treatment involves resection of the involved colon, abdominal irrigation, drainage of any abscess and formation of a colostomy. Post-operative complications of ARDS, stress ulcers, ongoing sepsis, and possible multi-organ system failure make early recognition and rapid resuscitation and treatment of this entity essential in decreasing its morbidity and mortality.

Diverticular Hemorrhage

Diverticular bleeding occurs in 5-15 percent of patients with diverticulosis. The average age is 65 years. Diverticular hemorrhage is usually massive but self-limited. Bleeding stops spontaneously with supportive management in 70 – 95 percent of cases. Recurrent episodes occur in 25 percent of patients. After a second hemorrhage, the chance of a third increases to 50%.

Classic bleeding in diverticulosis is painless and associated with the sudden passage of a large amount of bright red or maroon-colored stool. Orthostatic symptoms may ensue. Mild cramping abdominal pain is due to the cathartic effect of the intracolonic blood. Similar type bleeding may arise from other sources such as angiodysplasias, vascular malformations, Meckel’s diverticulum, or rarely, carcinoma. Associated symptoms of recent diarrhea suggest inflammatory bowel disease or infectious etiology.

Patients with massive lower GI bleeding need to be approached similar to those with UGI hemorrhage. Institute IV fluid resuscitation immediately while initially assessing patient. Document patient’s vital signs and hemodynamic stability. Draw blood for type and cross, CBC, electrolytes, liver functions, and coagulation profile. Document duration and amount of bleeding, presence of melena, or prior history of bleeding. A history of medication use to include ASA, NSAIDS, coumadin, or alcohol abuse, or a history of liver or renal disease may predispose the patient to rectal bleeding. Abdominal exam is usually unremarkable. Digital anal exam reveals gross evidence of rectal bleeding. Anoscopy and proctoscopy should be performed to eliminate an anorectal source of bleeding. A nasogastric (NG) tube is placed to exclude an upper GI source. If the NG aspirate does not contain bile an upper source cannot be excluded, but is less likely. If the aspirate contains evidence of bleeding an upper GI source is most likely and an urgent esophageal gastroduodenoscopy (EGD) will be required. All patients with an acute major GI bleed must be transferred to an MTF as soon as possible.

1. Gordon, Philip H.: Diverticular Disease of the Colon. In: Principles and Practice of Surgery for the Colon, Rectum, and Anus, 2^nd Edition. St.Louis: QMP. 1999: 975-1037.