CROHN ' S AND COLITIS FOUNDATION OF CANADA What complications are there that I should look out for ?

COM PLJCA T !ONS CAUSED BY lNflammatory howel disease (lBD) can be chiss ified hroadly into three subgrour~ (Table 1). The first subgroup consists of complications directly related Lo the activity or extent of the underlying intestinal disease. They may occur with acute exaccrharions Of ulcerative colitis or Crohn's disease. The second ~ubgrour, nutritional complications, arc either Jue to an increased energy requirement of the patient or decreased nutri tion intake because of symptoms related to eating. Finally, there arc a variety of nonbowel or extraintest inal manifestations of IBD which may become symptomatic at the time of acute exacerbations of the underlying disease.

C OM PLJCA T !ONS CAUSED BY lN- flammatory howe l disease (lBD) can be chiss ified hroadly into three sub-grour~ (Table 1).The first subgroup consists of complications directly related Lo the activity or exte nt of the underlying intestinal disease.They may occur with acute exaccrharions Of ulcerative colitis or Crohn's disease.The second ~ubgrour, nutritional complications, arc either Jue to an inc reased energy requirement of the patient or decreased nutri tion intake because of symptoms related to eating.Finally, there arc a variety of nonbowel or extraintestinal manifestations of IBD which may become symptomatic at the time of acute exacerbati ons of the underlying disease.

COMPUCA TIO NS RELATED TO BOWEL INFLAMMATION
Stricture: A stricture is a narrowing of a segme nr of howel, eid,er the small or large howel.It may be more appropriate LO considera stricture as a clinical manifestation ,)f C rohn's disease rather than a complication.In Crohn's di sease, strictures can affect approximately 40% of patienrs and can be short o r lo ng, single or multiple (Figure I).S trictures in Crohn's disease can be due rn e ither acute inflammation or c hronic fibrosis.Steroids can be effective in reduc ing acute inflammation hut not improving strictures when there is chronic fibrosis.Small bowel strictures: These strictures are asymptomatic until they cause Ottawa Civic HosJ1ira!, Ottawa, Ontario obstruction.Obstruction is defined as a slowing or stopping of the flow of bowel contents.Obstruction can be clinicall y subdivided into subacute (partial) or acute (complete) obstruction.Patients may present with abdominal pain, nausea and bloating, which nonm1lly occurs after eating and is exacerbated by large meals.The patient does not have any bowel movements or pass any flatus (gas).These symptoms may be relieved by vomiting.Passing a large amount of gas or liquid stool heralds relief of the episode of obstruction.
Became of the tendency of Crohn's disease to recur after surgery, surgical correction of the stric ture is postponed until the patient is having significant symptoms of subac ute obstruction, or the patie nt presents with complete bowel ohstruction.Comple te bowel obstruction requires surgery.A patient presenting with partial small bowel obstructio n is trea ted with bowel rest, which may involve nasogastric aspirat ion o ( the gastric contents together with intravenous fluids and stero ids.If they J o not respond, surgery is required.ln the 1990s the re are two c ho ices of surgery.The first is simple resection of the narrowed segme nt of bowel a nd reanasta mosis of t he two ends of the bowel togeth er.The second is a stricturnplasty.A stricturoplasty invo lve~ dividing a narrowed portion of bowel and re-anastomosing it to re move the narrow ing without removing any of the occur (Figure 2).
Large bowel strictures: Stricturing of the colon can be seen in bo th ulcerati ve colitis and Crohn's disease.In ulcerat ive colitis, its inc idence has been reported to be as high as 11 %.It is more commo n in Crohn's disease because of the full thic kness inflammation of the bowel wall.A colonic stric ture in ulcerative colitis raises concern of carcinoma of the colon.Colonoscopy a nd hi opsy of the stric ture arc necessary.Ho wever, this may not exclude an underl ying carcinom,1 and it may he nee-  GASTROINTESTINAL BLEEDING Bloody howcl moveme nts are a common manifestation of ulcerative colitis.They also occur with Crohn's disease but lcs~ commonl y.C h ronic bleeding can result in anemia which may requ ire long term iron suppl e men tation.Blood transfusio ns a re ra rely req uired , but are indicated when the hemoglobin is parti c ula rly low.A large gastroinrestin.il CAN J GASTRl1FNTl•Rl11 VUL 7 Nl1 7 SFPTI.MBER/0<.TOBER 1993 hl ecd is rare with ulcerative colitis or Cnih n 's disease.Rarely il ca n he presen t ing fearurc of sm,11!bowel Cmhn's disease.
Mnst patient:, presenting with sign ifi cant hlced ing due to !RD will scop b leeding withou t requi ring surge ry.Init ial managemen t is intrnvenous fluid and blood t ransfu~ion, together with aggressive management of t heir inflammation.
Aggressive managcmem of coli tis a nd Croh n's disease include the use of int rnvenous steroid~ and a minosal icylic acid preparations.Surgery rnrcly is nee -essary to re move the area of localized bleeding in the small or large bowel with C rohn's disease.ln patients with ulce ra ti ve colitis with a significant he morrhage, a subtotal o r total coleccomy is inJicated.Before surgery, the source of bleeding will need to be defined with endoscopy or an angiogram.An a ngiogram is an intra-arterial injection of dye followed by x-rays which arc taken to show <lye leaking into the bowel from the blood vesse l.Toxic megacolon: T ox ic megacolon occurs when the colon d ilates and the patient simultaneously develops systemic toxicity with fairly rapid clinical deterioration (Figure 3).This normally is associated with an acute exacerbation of IBO and more commonly occurs with ulcerative colitis.Its incidence in the literature is reported to be as high as 2.5%.However, with better manageme nt of the acute exacerbations of IBO, it is rare that one secs a case of toxic mcgacolon in the l990s.In toxic mcgacolo n, the affccteJ seg ment of the bowel becomes intensely congested and the bowel wall becomes thin anJ necrotic.In ulcerative colitis chis is due co ulcers and associateJ inflammation extending through the full thickness of the howel wall.Although rare, toxic megacolon can occur in C rohn's disease.lf it Joes occur, it usually is early in the course of the J iseasc before the colnn has become thickened and fibrotic.Several factors have been implicated in precipitating toxic megacolon.These arc the use of na rcotic painkillers, anticholinergic drugs, othe r drugs useJ to treat diarrhea and hypokalemia because of the diarrhea.A barium ene ma a t acut e infla mmation has also been implicated in precipita ting toxic megacolon.
T oxic mcgacolon appears to be more common in patients who have total colonic involvement.The clinical prese ntation is that of a severe attack of colitis with feve r and a raised pulse.Blood tests normally show a n increased white cell count and low albumin.Impending dilation often is heralded by a sudden decrease in the stool frequency because of decreased colonic evacuation.This frequently is associated with an increase in the amount of rectal 524 bleeding, abdominal distention and tenderness.The most common complication of toxic megacolon is perforation of the bowel wall which results in shock and peritonitis due to leakage of the bowel contents into the abdominal cavity.
TrC'atment largely is preventative.Aggressive management of colitis with hospitalization of severe attacks has resulted in a significant decrease in the incidence of toxic megacolon.When it does occur, the patienL requires aggressive rehydration a nd correction of any electrolyte abnormalities (particularly low potassium) .Patients arc also given intravenous steroids to decrease the inflammation and intraven ous antibiotics to cover potential infections.The patient is followed closely by both the gastroenterologist a nd surgeon.The first 72 h are cri tical and ifa patient docs not respond to medical management, a subtotal colectomy with ileostomy is indicated.This aggressive management has resulted in a significant drop in mortality from 60% to between 5 and [0%.

PERFORATION CAUSING ABCESSES OR PERITONITIS
Perfora tion occurs when a hole appears in the lining of the bowel a nd the bowel contents leak into the abdominal cav ity causing inflammation of the peritoneum and peritoni tis.Approximately 75% of perforations a re associated with toxic megacolon.When it occurs in the absence of toxic megacolon, it usually is associated with an acute exacerba tion of the IBD.The perforation occurs because of transmural (full thic kness) inflammation of th e bowel wall which resu lts in a localized area breaking down and a ho le forming.The resulting leakage can cause peritonitis or, in the case of small perforations, can become localized a nd fo rm an abscess.
An abscess is a coll ection of pus and bowel contents in a walled-off or localized part of the abdominal cavity.It can be small (1 to 5 mm) or large ( 10 co 15 c m) , single or multiple.Abscesses occur more commonly with Crohn's disease, but are rare in ulcerative coli tis.
Perforation is suspected when a patient de monstrates a sudden deterioration with an increase in abdominal pain, fever and a raised white cell count.With gene ralized peritonitis, the patient is much more sick a nd toxic whereas with localized abscesses the patient may have less severe sy mptoms.On examination, the abdomen will be very tender and will demonstrate rebound tenderness (an increase in pain when the hand is taken away from palpating the abdomen).With an abscess this tenderness will be more localized and a mass may be palpable.These patients arc often on steroids, which may mask the symptoms, but steroids have not been implicated in causing perforation.With peritonitis the tenderness and pain will be more generalized.The diagnosis of peri tonitis can be confirmed by a plain abdominal x-ray which may show the presence of free ai r in the abdomi nal cavity.Abscesses may be demonstrated on these plain abdominal x-rays or alternatively by using ultrasound or a computed tomography (CT) scan of the abdomen.However, abscesses can be very difficult to demonstrate by radiological techniques.
The treatment for both peritonitis and abscesses is surgery.With pe ritonitis, the patient needs urgent surgery and, at the same time, will be rehydrated with intravenous fluids and started o n intravenous antibiotics.With abscesses, localized drainage may be attempted but abdominal surgery more often is necessary.At surgery, the area of bowel involved is removed (a sub total colectomy in ulcerative colitis anJ a loca lized resection in C rohn's disease ).Fistula: A fistul a is an abdominal communication between any part of the gastroin testinal tract and either the body surface or a nother portion of Lh e gastrointestinal tract or othe r organ.This means that fistulas can communicate with another part of the bowel ( eg, ileal-colonic fistula), the skin (cnteroc utaneous fistu la), the bladJe r (enterovesical fi stula) and th e vagina (cntcrovaginal fistula ).Fistulas between differenr parts of the bowel arc often asymptomatic but may present with d ia rrhea a nd pain.When a fistula opens either to the skin, bladder or vagina, there may be a small or la rge amount of fcculent material draining from Lhe fistula.Fistulas occuronly with Crohn's d isease.If a fistula occurs in a patient with ulcerative colitis, then the question has to be asked whether the patient has Crohn's coli t is or ulcerative colitis.
A fistula often begins as an abscess chat adheres to adjacent organs o r the skin and then discharges its contents through a fistulous tract (Figure 4 ).This tract then becomes permanent.Fistulas can occur at any time bu r they are most often seen during the very active phases of the disease and particularly in the postoperative period after surg ical resection.
Most fistulas eventua lly require surgery if they arc caus ing s igni(icant symptoms.A small a mo unt of discharge and no serious infections often is tolerated rather than subjecting the patient to major surgery.Medical management often is unsuccessful hut includes bowel rest (often with total parenteral nutrition) and aggressive management o f the underlying innammation with steroids and aminosali cy lic acid compo unds.Some physicians may use 6-mercaptopurinc which may be more beneficial than other med ications in healing fistulas.Unfortun.itcly,after havi ng closed a fistula with meJical therapy, the recurrence rate is at least 50% over the next year.Carcinoma: Colonic carcinoma is probably the most serious com.plication of IBD, but fo rtunately it is rare (Figure 5).lt tends to occur more frequently in ulcera tive coli tis than in Crohn's disease.The risk of cancer in patients with ulcerative colitis has been shown to beg in after seven years and then rises by approx im ate ly 10% every 10 years, reach ing an approximate inc ide nce of 35% at 30 years.A more rece nt study has demo nstrated a cumulative 25-year risk fo r patients with extensive colitis, with an intact colo n, to be about 12%.

Complicatio ns of IBD
The risk of colo recta l cancer is not re lated to patient age o r severity of bowel d isease.H owever, patients whose colitis involves a greater portion of the bowel arc at a highe r risk of developing ca rci noma .Patients with ulcerative proctitis do not have a n increased risk of developing carcinoma.
The symptoms of carc inoma of the bowel are the same as for an exacerbation of colitis.Patients may complain of abdom inal pain, a change in bowel pattern and may have rectal bleeding.O n examination, an abdominal mass may be palpable.A patient with a carc ino ma of the colo n will n ot improve with conventional treatment for IBO.A diagnosis will be made e ither by barium enema or colonoscopy.T rearmenr is surgical, normally with a meal colectomy.
There is a great deal of controve rsy in the li terature regard ing surve illance in patients who have longstanding ulcerative coli tis to predict which patients are at risk of developing a cancer of the bowel.There is an assoc iation between dysplasia of the lining of the colon and the risk of cancer.Patients with marked dysplasia are at a Jcfinlte risk of developing cancer of the colon.For this reason colonoscopy with multiple biopsies of in vo lved bowel has been recommendeJ on a regu lar basis.It is recommended that colonoscopic surveillance sh ould be performed every o ne to two years after e ight years of tota l coli tis and after 13 years of left-sided colitis.If the biopsies do not show any evidence of dysplasia, then the interval between surve illance colonoscopy can be increased according to the indi vidual gastroenterologist's interpretatio n of the literature.Many experts bel ieve that the risk of carcino ma in ulcerative colitis has been exaggerated and that colonoscopies arc being performed too early and too frequently in patients with longstanding ulcerative coli tis.lt is th erefore expected chat the recommend ations for surveilla nce colonoscopy will change over the next few years.Perianal disem,e: Anal fo,sure,, abscesses anJ fistulas arc uncommon complications of ukerative coln1s but occ ur 111 as many as 82% of pat icnrs with Crohn\ d1se,1s1..•.An ,rnal fissure 1s a linear ulcer within the an,1 1 canal.Patients will comphun of ram when defecating ,md may have a sma ll amount of bleeding.Trcatmt•nt is to avoiJ consti pation together with local therapy with suppositories or creams normally umtain ing a small amount of steroids.
A pcrian,11 ,1hsccss usually presems during exacerbntion of d isease.A patient will experience pai n whe n defe-GHing ,mJ tlrn, pain often is aggravated by sining.The patient may complain of a hard, tender lump 111 the anal reg ion .The abscess will drain spontaneously e ither in ro the rectum nr on tn the skin.W hen I his happens ,1 fbtula-in-ano can occur in whK h there ts a separa tc fistulous tract bypassing the an us bet ween the rectum ,md the , kin.The patient may nouce a small nr large amou nt nf discharge from the fisrulous opening which 1s normally m•ar the anus.
Pcria na l abscesses need aggressive treatment w11 h ant 1h1ot1cs as soon as they art• nn11 ced.Early treat ment re-duLes the n;;k lif fistulous devdop111em.
Different amihimics can he used but metnm1da:ole (Flagyl; Rh(1ne-Po ulenc) has he(.'11 shown ro he particularly effective in perianal ( 'rohn's disease.Some fistulas w ill c lose spontan eous ly whereas others w1ll l lose\\ nh the used antihint 1cs.Rl•cu rrent fistu las unrc- spnnsive to medical treatment may need surgery.l lmvcver, surgery 1s d1ff1c ult and a successful o utcome is not guaranteed.This may mean that the pat icnt has to accept a small :1mount of discharge rather than undergo extensive surgery or even a colec tomy.

NUTRITIONAL COMPLICATIONS
Nutritiona l deficiencies are more commo n in Crohn's disease than in ulcerative coliti s.This 1s beLausc in Crohn's di sease more of the small bowel is invo lvcJ; therefore, symptoms arc often brought o n by eating and absorption of nutrients.Malnutrition occurs fro m a combination of poor appetite, avoiding fooJ because eating produces symptoms, and the loss of prntein from the bowel anJ through fistu las.Patients with active inflammation abo have a higher energy requirement beca use lif their disease.The most common nutritional complication of !BD is anemia due to iron deficiency.The iron defic iency is Jue to ch ronic blood loss, m quantities too small fo r the patient to notice.In addition, poor dieta ry intake and decreased absorption of iron may exacerbate this deficiency.
Involvement of the differen t parts of the bowel can result in specific types of malabso rption.Jejuna!involvement can result in ma labsorption of fo latc or iron, both nf which can contribute to the patient's anemia.Crohn's J1sease of the terminal ileum can result in vitamin B 12 malahsorption and <leficiency of bile salts; for this to occur, at least 90 cm of ileum must be di eased or re moved.With bile salt defic iency, fat ah orption a bo is impaired, resulting in decreased ahsorption of fat-soluble vitamins ( vitamins A, D, E and K).Malabsorption of vitamin D can result in bone disease (ostco pnrnsis a nd/or osteoma lac ia) .Finally, in patients with diarrhea, there 1s a number of electrolytes which can become depicted, particu larly potassium.
T he treatment of nutritiona l complications related to IBD large ly is preventative.A hea lthy balanced d ie t is impmtant in all patients.Some physicians may prescribe a high fi bre diet whereas patients with sma ll bowel 1>trictures wi ll nce<l a low residue diet.In the patient with mild C rohn's disease or Crohn\ disease in remission, there docs not seem to he any spec ific recommendations for ,I diet.Patients should avoid foods which cxaccrharc thei r sy mptoms, hut rigid elimination diets arc controvcrbial.Some patie nts will have acqum•d lactose intolerance and benefit from avniding milk and milk products.
Patients with particular nutritional JefiLiencics will requ ire replaccmenr therapy, such as iron, fo la tc, vitamin D or calcium oral supplementation.Vitamin R1 z has tn he given by an intramuscular mJecuon, normall y once a month.
Patients wllh significant malnutritio n require caloric supplementation, initially using one of the many liquid enteral ieedings available on the market.These cnteral feedings can be sub-J1vided inw e le mental and defined formula preparntinns.Normally L ml of these supplements conta ins 4 .187 J and thts means a large number of calorics ca n be given in a sma ll volume ofliquid.The defined formula preparatiom a re high in calorics but require some digestion pnor to absorption.The e lemental preparations J o no t require digest ion as the fat, protein and carbo hydra tes arc already tn their d 1ge:.tedform and arc ready for ahsorption.In C ro hn's disease aggressive nutritional therapy duri ng an attack may have a primary therapeut ic role as well.Bowel rest (ie, through total parenteral nu tri tion) probabl y is unnecessary and patients can be treated with a n e lemen tal di et as part of their meJ1rnl management.This can be admmistered v ia cont inuo us infu~iom through a small nasogastric t ube if the patient cannot tolerate oral feed ings.Alternativel y, the newer elemental diets arc more palatable and can he taken orally.lntnwenous nutritional ~upport (total parenteral nutritio n) may be necessary for the seve rel y ill a nd nutritiona ll y depleted patient, in those with fistulas or in Crnhn's disease patie nts who have lost a la rge amount of small bowel function tO disease nr rc~ection .

EXTRA INTESTINAL MANIFEST ATlONS
Extraintcstinal manifestations, such as arthritis, skin rashes, inflammation of the eye, galbtnnes ,md liver bile duct disorJers, occur m one-quarter to onethird of patients wiLh eiLher ulcerative colilis or Crohn's disease (Tahle l ).Although Crohn's disea~e and ulcerative colitis differ in the way d1ey affect the bowel, d1ey arc qui te similar in the kind of 1-ystemic complications they cause, and the inc idence i~ about the same for both diseases.In most patients these comp I ications arc re lati,•ely mild and more of a nuisance than an ything else; however, in approximately l <\1 of patients, they cause maim difficulucs.
Some manifestations, including arthritis, erythema noJosum and eye inflammation, occur mainly when the howel is actively inflamed (Table 2).One can usually predict that these specific problems will he controlled or dimmated when the intestinal disease is ~uppressed hy medical therapy or when the entire colon b removed from the patient with ulcerative colitis.Sometimes these symptoms arc an early sign llf an exacerbation of a pattent's IBD.
Certain types nf chronic extrninrcstinal problems, such as ankylos ing ,pondylitis and sclcrosing cholangitis, .ireprohahly related to the howcl disease, but the ir act ivity may continue long after the colitis 1s quiescent or a colcccomy has been performed.
Other extraint estina l manifestations of Crnhn\ disease, such as gall-,tnnes and kidney stones, ofrcn arc due to an inadequate or disordered intest inal function, with resultant effects on ocher orgam.Arthritis: Arthritis is the mnst common extramtcstinal manifestation in lwh Crohn's disease and ulcerative colitis, with an incidence of 4 to 23%.It 1, possibly more common in Crohn's lli~ease.The arthritis may effect the peripheral joints or the lower spine.
Peripheral arthritis may present with punful, red, swollen joints, most commonly the hips, ankles, wrists and c l-h>w:,.Small joints arc rarely involved.
Thr arthritis only affects Li1e lining nf rhe joint cavity (synov ium) and there b n1) erosive damage which often is seen 111 patients with rheumatoid arthritis.A fl:ire-up of arthritis usually occurs du r-111g an exacerbation of the I BD and wi 11 rt,p<.mJto med ical therapy for the !Bl).
Figure 7) Erychema nodo.rnm-patient wich eryr/iema nodo.rnm(!Ssociawd with ac111e Jlare-11p ofCrohn \ d1.1ease.Sewral small red nodules on r/ie antenar aspec1 of che legs are .1eentcroids have a strong anti-inflammatory action and arc used in the treatment of other causes of arthritis.Sulphasalazinc (Salozopyrinc; Pharm,1cia) also is effective in treating arthritis, and was originally first designed as an anti-arth r itis medication.Together with physiothe rapy, patients often improve and do not require nonstcroidal anu-inflammatory drugs (NSAms).NSAIDs arc particu larly effective in treating arthritis hut unfortunately some NSAIDs have heen implicated in exacerbating !BO.For this reason, NSAIDs should only he used with the careful supervision of the patient's physician.Sometimes the joint complicatiom recur when patients with bowel disease arc being withdrawn from prcdnisone therapy.This can be p.-1rt icularly frustrating for the patient who 1s trying to get off long term corticosteroids, and it is in these patients that NSAIDs may he helpful.
Ankylosmg spondylitis is an inflammation of the spine which presents with pam and stiffness of the spinal column.It occurs in 3 to 6% of patients with IBO and it is equall y frequent in Crohn's disease and ulcerative colitis.The pain and lower hack stiffness is worse in the C~\ j GA,TROENTFR( )I VOi 7 No 7 SFPlHH\ER/0.T l)BER 199 3 morning and is relieved hy exercise and physiotherapy.The symptoms arc worsened hy inactivity and rest.This disorder usually is associated with a specific tissue type (I ILA B27).Treaunent is difficult and improvement is not related ro improvement in the activity of the bowel disease.
Sacrnileins 1s an inflammation of the 101nts between rhe lower hack (sauum) and 1he pelvic hone (ilinl}.It often is asymptomatic and may he found on routine x-rays.A high proporrrnn of these patients will have coexis1 ing spnndylitis (inllammation of the spin\:).The main symptom of sacro1leit1s rs ,1 low hack pain which is worse in the morning and relieved hy exercbe (Figure 6).
The maimtay of treatment for ankylosing spondyliti~ and sacroi lcills is rcgu lar physiot hcrapy and exercises to maintain the mohility and flex1hd1ty of the spmal column.Together with simple analgesics, such as acetaminophen (Tylenol; McNeil), patients often do not re4uirc th<.. stronger NSAIDs.M ou th lesio ns: Aphthous sromatitis often occurs 111 the mouth at the same time as an exacerbation of !BD. lt can occur in up to 20% of patients with IBD and is more common m patients with Crohn's d isease.Most episodes of aphthous ulceration arc self-limiting and last three to five days regardless of the treatment of the underlymg bowel disease.More painful lesions sometimes improve with local therapy using steroids (prednisone oluuon) and local anesthetic c ream.
On rare occasions Crohn's disease can involve the lips, gums and buccal Figure 9) Eye complications of inflammawry bowel disease.Top Conjunctivitis; Middle Episclericis; Bottom Uveitis mucosa .It always is assoc iateJ with intestinal involve ment anJ responc.ls to therapy for intestim1l Crohn's Jisease.Skin rashes: Erythema no<losum occurs in approximately 2 to 10% of patients with IBD.This condition appears to be more common in women and consists of painful red nodules which usually occur be low the knee on the shins but can occur on the upper legs (Figure 7).It often is associated with a n exacerbation of the IBD and subsides as the inflammation im proves.Diagnosis is made clinically but a skin biopsy rarely is necessary.It is most common with Crohn's disease of the colon and most patients have had an episode ofarthritis some time during the course of Lheir disease.
Therapy is directed at treating the bowel inflammation.This may involve medical or surgical treatment.Some dermatologists may use potassium iodine applied topica lly to the lesion , or altem::nively prescribe an NSAID co be taken orally.
Pyoderma gangrenosum starts with a ra ised , red, tender area normally on the lower leg, e ither on the shin or ankle.This lesion then progresses into a boil 528 or bullous-like lesion whic h breaks down resulting in ulceration (Figure 8).This ulceration can be quite extensive and can result in widespread tissue skin damage and necrosis.Pyoderma gangrenosum has a n overall inc idence of 0 to 5% and occurs more commonly in ulcerative colitis than in Crohn's disease patients.Most patients ( 85%) have pancolitis, and persistent and extensive pyoderma gangrenosum is a very rare indication for a colectomy.
Steroids have been shown both to halt progression of the disease and to prevent development of new lesions.Sometimes even higher doses of prednisone arc used for pyoclcrma gangrenosum than is normal in the treatment of IBO.Other drugs which can be used include: sulphasalazine, dapsonc (Avulosulfon; Ayerst) and, more recently, ch lofazamine.Eye problems: There arc a variety of eye or ocular lesions which can occur in patients with IBO.le is difficult to ascertain the true incidence as many patients do nor have routine eye examinations and these lesions can be asymptomatic.The incidence varies between 4 and LO%, with most common conditions being conjunctivitis, episcleritis o r uveitis.O ther frequent complications includes cataracts, ulceration of the cornea and retrobulbar neuritis.
The mechanism for eye problems related to IBD is unknown but there is a definite assoc iation between eye lesions and exacerbations of I BO.Eye proble ms with IBD a rc often associated with other nonsystcmic manifestations such as arthritis and crythcma n o<losum.
Treatment fo r eye complications (Figure 9) includes treating the underlying active bowel disease as well as the use of hydrocortisone solution in the eye.Serious v isual loss can occur with some forms of uvcitis, requiri ng expert oph thalmological care.Hepatobiliary problems: There arc a number of liver and bile duct complications found in patients with IBO.
Stcarosis occurs when the re is an increased amount of fat deposited into the li ve r. lt may present with a n enlarged liver or abnorma l liver function blood tests.Its true inc idence is unknown , but it is thought to occur com, monly in patients who have active infla mma tion of the bowel.The cause i~ unknown but it possibly is secondary Lo malnutrition and protein depletion due to the active disease.
Treatment is the same as for the underlying howcl disease.Steatosis has not been demonstrated to progress to more serious liver disease such as c irrhosis.
Peri cho la ngitis is a condition in which the small bile ducts in the liver become edematous and filled with inflammatory cells.It occurs in approximate ly 5% of the patients with lBD.In patients who ha ve had li ver biopsies performed because of nbnormnl liver function hloo<l tesL s, about one-third have this hile Juct problem.This is usually in association with inflammation of the bile ducts outsiJc the liver.Pericholangitis is norma lly asymptomatic but may present wiLh abnormal li ver function bl ood te&ts or an enlarged liver.lt occurs more frequently in pr1ti cnts wi Lh extensive bowel disease, particu larly colitis.Evaluation of Lhc patient with pericholangitis on live r biopsy should include an x-ray of the hile ducts, normally pcrformeJ by endoscopic retrograde cholm,giogrnph ic pancreatography (ERCP) to rul e out large duct Jisease, namel y sckrosing cholangiLis.
Sclerosing cholangitis is inflammation of the large hilc ducts, both within the liver and in the biliary system.It is a progressive d isease which resu lts in fibrosis and stric wring of the bile ducts.lt occurs in up to 4% of patients with IBD and is more common with coli Lis of e ither etiology.It is rare wiLh small bowel Crohn's disease.It may progress eve n after the colon hr1s heen removed surgicall y.This disease usually affects males a nd there is no relationship L o the durat ion or activity of the colitis.It presents with jaundice, itc hing anc.l abnormal blood test~.There is evidence of marked elevation of ~ome of the li ver func ti on blood tests anti ERC P examination demonstrates stric turing a nd fibrosis of the bile ducts, hoth outside and within Lhe li ve r.
There is no definitive curmive Lrcatme nt for pericholangitis or sclerosi ng c hola ngitis.Some patients may benefit temporarily from drainage of the hile ducts, with a synthetic tuhe (srent) be-mg placed inside the ducts re lieve an area of blockage.This can normally be achieved endoscopically.Other patients with very severe sclerosing cho langitis go on to receive liver transplants.
Cholangiocarcino ma (cancer of the bile ducts) occurs 10 times mo re frequently in patients wit h IBD than in the general population.It occurs primarily in patients with ulcerative colitis and rarely is seen in patients with Crohn's disease.Despite this increased incidence, it is a rare complication of IBD.It is associated with sclerosing cholangitis and patients may complain of weight loss, progressive jaundice and right upper quadran t pain.Surgical resection rarely is successful and patients are usually managed palliatively with insertion of scents endoscopically or surgically.Unfoccunately liver transplantation has not improved the survival of these patients.
Gallstones occur in up to 30% of patients with C rohn's disease of the terminal ileum .This results from decreased bile salt absorption in the distal ileum and subsequent decrease in the amount of bile salts available to allow cholesterol to dissolve in the bile.This imbalance of insoluble cholesterol leads co the formation of ga llstones.Patients with symptomatic gallsrones require a cholecystectorny.Asymptomatic gallstones discovered on routine ultrasound examination or other x-rays do not require surgery.Thromboembolic disease: The incidence of thrornboembolic cornplicanons in IBO has been quoted as high as ACKNOWLEDGEMENTS: D r C h a mpiongratefully acknowledges Dr H T ao, Department of Radiology, Ottawa Civ ic Ho:;p1tal, for supplying the x-rays.6%, but overall it appears to be a rare complication .The risk of increased thrombosis is thought to be due ro an increase in some of the clotting factors and platelets which are found in some patients with IBD.This tendency for increased thrombosis means IBO patients should use the oral contraceptive pill with caution as it has also been implicated in causing thromboembo lic disease.

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Treatmenl large ly is preventative, with early mobilization after surgery and regular leg exercises if the patient is on prolonged bed rest.Should a deep venous t hrombosis develop in the legs, the patient should be given anticoagulants to thin the blood, initially intravenous h epar in and subsequently warfa ri n (Coumarin; DuPont) fo r up to one year.Kidney stones: The incidence of kidney stones is two ro 10 times h igher in patien ts with IBO.In some patients th is is due to uric acid crystals caused by increase cell turnover in patients with chronic inflammation.In others it is due to calcium oxalate o r calcium phosphate making up the bulk of the stones.
Kidney scones composed of oxalate crystals are more common in patients with C rohn's d isease of the ileum, usually after one or two bowel resections.The mechanism for the formation of these oxalate kidney stones also involves bile salts.When the amount of bile salts available for promoting fat absorptio n is coo low, excess ive amounts of d ietary fat remain unabsorbed in the in testine.The malabsorbed fa t binds calcium from the diet and Most kidney stones will pass spontaneously and surgery rarely is required.At present, lithotripsy can be used to break up the kiJ ney scones usi ng high energy sound waves.T rcatment also includes reducing the dietary intake of oxalaLc-con tain ing foods, including tea, cola, chocolate, cocoa and vegetables wit h a h igh oxalate con tent.If the patient has malabsorption offal, lowering t he fat intake may be helpful m decreasing t he amount of oxalate m the urine.A high uri ne output is also important, facili tated by ingesting large quantities of fluid daily.

CONCLUSIONS
There are many complications of IBD.Fortunately, most palients will experience only one or two of these comp I ica t ions, and some wi ll not experience any.A few patients, however, wi ll have multiple complicauons.The fi rst approach to complicauons of IBO is an understanding and awareness of potential problems.Patients must rely on the expertise of their gastroenterologist in t reating Lhese complications.W hen necessary, further 111put may be required from specialist:; in surgery, rheumacology, dermatology or oph thalmology.

TABLE 2 Extraintestinal
3. Complications of ulcerative colitis,Complications of C rohn's disease.In: Thompson WG, ed.T he Angry G ut. Copmg with Colins and Croh n's Disease.New York: Plenum Press, 1993:97-l 13,139-64.Complications of IBD from hodily secrcuons.Normally this calcium wou ld bmd with oxalate in the d iet an<l carry them out in the feces.Oxalates which are not bound by calcium are absorbed and excreted in the urine.When there are large quantities of oxalates in the urine 1t can precipitate an<l form kidney stone:;.
CAN J GASTROENTEROL VOL 7 No 7 SEPTEMBER/OCTOBER 1993