On the surgical ward round this week there was a gentleman with sigmoid diverticulitis. It presented as continuous lower central-left abdominal pain, nausea and loss of appetite. He also had urinary symptoms- urinary frequency with low urine output. However, a urine dipstick came back clear of infection so the explanation was that the inflamed diverticula were pressing against the bladder leading to symptoms. CT showed diverticulitis and they are going to do a colonoscopy at 6 weeks, any earlier would carry a risk of perforation, to check for any underlying malignancy.
Definition: can be a bit confusing, but a diverticulum is an outpouching in the gut wall. Diverticulosis refers to diverticula being present. Diverticular disease means they are symptomatic and diverticulitis means they are acutely inflamed and infected.
Diverticulum can be acquired or congenital. The most important are acquired colonic diverticula, which this post focuses on, but you can get them in other places e.g. the bladder.
Aetiology/ risk factors:
-Right-sided and massive single diverticula can occur, but no
–Lack of dietary fibre (eat your veggies folks!) → increased intraluminal pressure in gut → mucosa forced to herniate through muscular layers of gut wall at weak points adjacent to perforating arteries
–Diverticulitis occurs when faeces obstruct the neck of the diverticulum leading to bacterial overgrowth = infection and inflammation
Epidemiology: Diverticula are common
30% of Westerners have diverticulosis by age 60
Peak age, 50-70 yrs. Rare < 40 yrs. But diverticular disease is increasing in frequency and occurring at a progressively younger age.
Right sided diverticula more common in Asia
-majority (~95%) of diverticula are asymptomatic (just diverticulosis)
–altered bowel habit– e.g. constipation
–left sided (as mostly affects sigmoid colon = Left Iliac Fossa) colicky abdominal pain relieved by defecation
–rapid onset of LIF pain
–loose stools (often)
Complications: PR bleed- usually spontaneous onset, large volume dark red, clotted blood due to rupture of peri-diverticular submucosal blood vessel.
–tender abdomen (LIF) +/- localised or generalised peritonism if perforation has occurred (pain, tenderness, abdominal guarding, rebound tenderness)
–febrile with moderate tachycardia
Complications: pneumaturia, faecaluria, recurrent UTI (see complications below)
–Colonoscopy- diverticula often a common incidental finding when colonoscopy is performed if suspicion of malignancy. But relatively poor investigation to assess number and extent of diverticula.
–Barium enema (Colorectal X-ray with barium contrast)- can clarify diagnosis e.g. if abdominal pain and altered bowel habit. Usually first choice for elective diagnosis and used to assess possible stricture formation.
-CT abdomen– best to confirm acute diverticulitis and can identify extent of disease and any complications. Barium Enema and colonoscopy risk perforation in the acute setting so you wouldn’t go for those.
-Abdominal x-ray- may show obstruction, free air (due to bowel perforation), or vesical fistulae = complications of diverticulosis
-Bloods- raised WCC, ESR and CRP in diverticulitis
–Clotting and cross-match- check if they’re bleeding
Diverticulosis/ diverticular disease:
-high fibre diet may be tried. Also, high fluid intake and stool softeners to reduce intracolonic pressure.
-antispasmodics: e.g. MEBEVERINE (135mg/8h PO, anti-muscarinic) may help
-may consider surgical resection
–Nil By Mouth (bowel rest)
–IV Antibiotics (amoxicillin, metronidazole, gentamicin)
–CT-guided percutaneous drainage– if abscess (pus collection)
-may need surgery if complications such as perforation or if recurrent attacks of diverticulitis
Surgical management = Hartmann’s Procedure on laparotomy (temporary colostomy and partial colectomy) or Primary Anastamosis if patient’s general condition is suitable (take a bit of colon out and stick the two ends left behind together) or Emergency Laparoscopic management
Patients may present with complications of diverticular disease/ diverticulitis.
–Perforation- ileus (absent bowel sounds, nausea, vomiting, constipation), faeculent peritonitis (high fever, severe abdo pain, generalised tenderness, rigidity, guarding) +/- shock (hypotension, tachycardia, pale, clammy, cold peripheries). Perforation of pericolic or paracolic abscesses can lead to purulent peritonitis.
–Haemorrhage- usually sudden and painless. Common cause of big rectal bleeds. Bleeding usually stops with bed/bowel rest- give IV fluids and ABx. May need transfusion; embolization or colonic resection after locating bleeding points by angiography or colonoscopy, if severe. Diathermy (electrically induced heat or electromagnetic currents which causes clotting) +/- local adrenaline injections may remove need for surgery.
–Fistulae- Enterocolic (gut to gut communication), colovaginal (faeculent per vagina discharge), or colovesical (between bowel & bladder = pneumaturia (bubbles in your pee!), faecaluria ± intractable UTIs).
–Abscesses- swinging fever, fluctuating tachycardia, unresolving abdo pain leucocytosis, & localizing signs, eg boggy rectal mass/ tender LIF mass. Drain pelvic abscesses rectally. If no localizing signs, consider a subphrenic abscess, so do an urgent ultrasound. Antibiotics ± ultrasound/CT-guided drainage may be needed.
–Post-infective strictures- may form in the sigmoid colon. Suggested by a history of recurrent diverticulitis with recurrent colicky abdominal pain, distension, and bloating. Treat by elective resection of balloon dilation.
-10-25% of patients will have one or more episodes of diverticulitis and of these, 30% will have a second episode.
-With perforation there is a mortality of 40%.