Most people with diverticulosis never develop symptoms, and those who do fall into a few recognisable patterns.
The spectrum from silent to symptomatic
Recent advances and the wider use of CT and colonoscopy have led to diverticulosis being found more often in patients who are completely asymptomatic. More than 80% of patients who have diverticulosis are asymptomatic during their lifetime, and in these cases there are no signs or symptoms at all — neither non-specific ones nor any related to the complications of the disease. Diverticulosis is also the most common abnormal finding at colonoscopy, which is part of why so much of it is discovered incidentally.
When a patient comes to attention with non-specific abdominal complaints and diverticular signs and symptoms but without signs and symptoms of diverticular complications, the picture is called symptomatic uncomplicated diverticular disease (SUDD). Its exact epidemiology is not known, for two reasons: most of the literature focuses on the complications of diverticulosis, such as bleeding and diverticulitis, and SUDD resembles irritable bowel syndrome (IBS) so closely that the two conditions are hard to distinguish in the population.
The clinical manifestation of SUDD is very similar to IBS in its signs, symptoms and physical examination. The typical features are left lower quadrant (LLQ) abdominal pain that is diminished after defecation or the passage of flatus; symptoms of colonic dysfunction such as bloating, constipation, diarrhoea and the passage of mucus per rectum; and abdominal fullness.
Diverticulitis
Diverticulitis is inflammation and, sometimes, infection of a diverticulum. It can be acute or chronic, and the practical division is into uncomplicated and complicated disease, based on whether the inflammation has stayed within the colonic wall.
Uncomplicated diverticulitis is inflammation confined to the colonic wall and the pericolic fat, without abscess, perforation, fistula or obstruction. It is the most common manifestation, seen in more than 80% of patients with a first attack. Its clinical picture is dominated by LLQ abdominal pain, which in Asians is more often right lower quadrant (RLQ) pain; LLQ pain reflects the most common location of diverticulitis in Western patients, the sigmoid colon. The pain is intermittent, with a changing bowel habit that alternates from diarrhoea to constipation, and it is mostly acute and lasts more than 24 hours. Fever appears in most patients and is accompanied by leukocytosis, anorexia, and nausea and vomiting. Dysuria and urinary frequency can occur when the inflamed sigmoid colon irritates the adjacent bladder (sympathetic cystitis).
The risk of developing diverticulitis in a patient with diverticulosis is about 4% over a course of 11 years. After a first attack, the risk of recurrent symptoms is about 15–30%, and more than 50% of second attacks happen within the first year.
Complicated diverticulitis
Approximately 15–20% of all patients with diverticulitis present with significant complications, in which the inflammatory process has spread beyond the colon. The complications are:
- perforation, which occurs with different severities classified by the Hinchey classification of colonic diverticular perforation;
- abscess, suggested by a tender abdomen on examination, a tender mass on abdominal palpation, unresolved leukocytosis despite appropriate intravenous antibiotics, and persistent fever;
- fistula;
- obstruction, which can occur because of the peri-colic inflammation of diverticulitis.
Diverticular bleeding
Diverticular bleeding is characterised as painless, abrupt and self-limited, with a moderate to large volume of blood. Rebleeding is common: in patients whose diverticular bleeding is treated endoscopically, about 15% bleed again within 30 days.