CASE STUDYCASE STUDY

BYBY

Dr. Noor AA SelimDr. Noor AA Selim

MBBCh, MSci, MRCP(UK)MBBCh, MSci, MRCP(UK)

Consultant Physician & GastroenterologistConsultant Physician & Gastroenterologist

KFH, Al-TaifKFH, Al-Taif

Mr. AH 60 y old SA retired clerk Mr. AH 60 y old SA retired clerk

C/OC/O

* Abdominal pain, diffuse, more in the lower * Abdominal pain, diffuse, more in the lower quadrantsquadrants* Vomiting* Vomiting* Loose motions following eating ‘Hamburger’, * Loose motions following eating ‘Hamburger’, started same day of admission started same day of admission * Polyuria, 2 w * Polyuria, 2 w

PMHPMH

* DM 25 y on oral hypoglycaemic drugs* DM 25 y on oral hypoglycaemic drugs

* Cholecystectomy 25 y* Cholecystectomy 25 y

* ? PUD, no report for gastroscopy* ? PUD, no report for gastroscopy

* PTCA with CA stent 4 y on aspirin, lipitor, * PTCA with CA stent 4 y on aspirin, lipitor, plavix, and amlorplavix, and amlor

* ORIF for fracture right femur one month ago* ORIF for fracture right femur one month ago

EXAMINATIONEXAMINATION

Dry tongue, afebrile, BP 170-190/100, PR 100, wt Dry tongue, afebrile, BP 170-190/100, PR 100, wt 88 kg88 kg

Mild LL oedemaMild LL oedemaLaparotomy scarLaparotomy scarDiffuse abdominal tendernessDiffuse abdominal tendernessP/R showed soft bloody stoolP/R showed soft bloody stoolRest of examination unremarkableRest of examination unremarkable

INVESTIGATIONSINVESTIGATIONS

* CBC (WBC = 10.5, HGB 12.7, PLT 221)* CBC (WBC = 10.5, HGB 12.7, PLT 221)* Coagulation profile = normal* Coagulation profile = normal* Stool = soft, mucus +2, RBC 0-1, PUS 2-3,* Stool = soft, mucus +2, RBC 0-1, PUS 2-3, ascaris ova 0-1/hpf, frank blood = nil ascaris ova 0-1/hpf, frank blood = nil* RBS 31mmol/l* RBS 31mmol/l* Urine = glucosuria, protienuria, granular * Urine = glucosuria, protienuria, granular casts, wbc ++, rbc +casts, wbc ++, rbc +* U&E normal* U&E normal* KUB normal * KUB normal

Course in hospitalCourse in hospital

Admitted, as ? GE ? Food relatedAdmitted, as ? GE ? Food relatedinsulin, fluids, primperan, buscopan, ppi, insulin, fluids, primperan, buscopan, ppi, ciprofloxacin, co-diovanciprofloxacin, co-diovan

Gastroscopy was done and showed, a lot of Gastroscopy was done and showed, a lot of bile in the stomach and duodenum, 500 ml bile in the stomach and duodenum, 500 ml sucked, also it showed a Mallory-Weiss tear sucked, also it showed a Mallory-Weiss tear

Plain X-ray abdomen showed signs of small Plain X-ray abdomen showed signs of small bowel obstruction bowel obstruction

Spiral CT abdomen was requested Spiral CT abdomen was requested

Also, the patient was put on iv antibiotics, NPO, iv Also, the patient was put on iv antibiotics, NPO, iv fluids, Heparin (clexane), and referred for surgical fluids, Heparin (clexane), and referred for surgical consultationconsultation

Spiral CT abdomen & chest showedSpiral CT abdomen & chest showed

- Calcified atheroma of aorta and its branches.- Calcified atheroma of aorta and its branches.- Complete occlusion of SMA, even distal and - Complete occlusion of SMA, even distal and middle parts of SMA shows filling defects.middle parts of SMA shows filling defects.- Splenic artery stenosis with calcified atheromas and - Splenic artery stenosis with calcified atheromas and filling defects.filling defects.- Stenosis at the origin of both renal arteries.- Stenosis at the origin of both renal arteries.- Calcified atheroma at the level of both iliac arteries.- Calcified atheroma at the level of both iliac arteries.

- Bilateral pulmonary emboli- Bilateral pulmonary emboli

Other findings:Other findings:- Distended thickened bowels.- Distended thickened bowels.- Mild thickening of certain loops.- Mild thickening of certain loops.- Left ventricular hypertrophy.- Left ventricular hypertrophy.

So, patient was transferred to surgical side for So, patient was transferred to surgical side for possibility of laparotomy.possibility of laparotomy.

Then the patient refused to go through the Then the patient refused to go through the operation and transferred to another hospital. operation and transferred to another hospital.

ISCHAEMIC COLITISISCHAEMIC COLITIS

Mesenteric vascular supplyMesenteric vascular supply

Anatomy and vascular supply of the large bowel

IMA: inferior mesenteric artery; SMA: superior mesenteric artery.

Distribution of ischemic areas in the colon

It is the most common form of intestinal ischemia and comprises a It is the most common form of intestinal ischemia and comprises a spectrum of disorders: The majority of patients (85%) develop spectrum of disorders: The majority of patients (85%) develop non-gangrenous ischemia, which is usually transient and non-gangrenous ischemia, which is usually transient and resolves without sequelae. Only a minority of these patients resolves without sequelae. Only a minority of these patients develop long-term complications, which include persistent develop long-term complications, which include persistent segmental colitis and the development of a stricture. segmental colitis and the development of a stricture. Approximately 15% of patients with colonic ischemia develop Approximately 15% of patients with colonic ischemia develop gangrene, the consequences of which are life-threatening, gangrene, the consequences of which are life-threatening, sepsis, bowel infarction, and death. sepsis, bowel infarction, and death. Reversible colopathy Reversible colopathy Transient colitis Transient colitis Chronic colitis Chronic colitis StrictureStricture Gangrene Gangrene Fulminant universal colitis Fulminant universal colitis

COLON ISCHEMIACOLON ISCHEMIA

Causes of colonic ischemiaCauses of colonic ischemia

Major vascular occlusionMajor vascular occlusion Mesenteric artery thrombosis Mesenteric artery thrombosis Cholesterol emboli Cholesterol emboli Colectomy with IMA ligation Colectomy with IMA ligation Aortic dissection Aortic dissection Aortic reconstruction Aortic reconstruction Mesenteric venous Mesenteric venous thrombosis thrombosis Hypercoagulable state Hypercoagulable state Lymphocytic phlebitis Lymphocytic phlebitis Portal hypertension Portal hypertension Pancreatitis Pancreatitis

Small vessel diseaseSmall vessel disease Diabetes Diabetes Vasculitis Vasculitis Polyarteritis nodosa Polyarteritis nodosa Lupus erythematosus Lupus erythematosus Takayasu arteritis Takayasu arteritis Wegener's granulomatosis Wegener's granulomatosis Anticentromere antibodies Anticentromere antibodies Buerger's disease Buerger's disease Antiphospholipid antibodies Antiphospholipid antibodies Amyloidosis Amyloidosis Rheumatoid arthritis Rheumatoid arthritis Radiation Radiation

Mechanical obstructionMechanical obstruction

Strangulated hernia Strangulated hernia

Colon cancer Colon cancer

Adhesion Adhesion

Rectal prolapse Rectal prolapse

Fecal impaction or Fecal impaction or pseudoobstruction pseudoobstruction Shock Shock

Cardiac failure Cardiac failure

Hemodialysis Hemodialysis

Pancreatitis Pancreatitis

AnaphylaxisAnaphylaxis

Blood dyscrasiaBlood dyscrasia

Hypercoagulable state Hypercoagulable state

Sickle cell disease Sickle cell disease

IatrogenicIatrogenic Surgical Surgical

Aortoiliac reconstruction Aortoiliac reconstruction

Cardiopulmonary bypass Cardiopulmonary bypass

Renal transplant Renal transplant

Colonoscopy Colonoscopy

Barium enema Barium enema

Drugs Drugs

Digitalis Digitalis

Diuretics Diuretics

Cocaine Cocaine

Estrogens Estrogens

Danazol Danazol

NSAIDs NSAIDs

Tegaserod Tegaserod

Vasoactive substances Vasoactive substances

Paclitaxel and carboplatin Paclitaxel and carboplatin

Sumatriptan Sumatriptan

SimvastatinSimvastatin

OthersOthers Long distance running Long distance running Dialysis Dialysis Neurogenic Neurogenic Spontaneous in young Spontaneous in young adults adults Infections (CMV, E. coli Infections (CMV, E. coli O157:H7) O157:H7) Airplane flight Airplane flight

In the majority of patients with colonic ischemia, a In the majority of patients with colonic ischemia, a specific occluding lesion cannot be identified on specific occluding lesion cannot be identified on angiography. Such patients are referred to as angiography. Such patients are referred to as having non-occlusive ischemia. having non-occlusive ischemia.

Nonocclusive colonic ischemiaNonocclusive colonic ischemia

Most commonly affects the "watershed" areas of the Most commonly affects the "watershed" areas of the colon that have limited collateralization, splenic flexure colon that have limited collateralization, splenic flexure and rectosigmoid junction. A study of more than 1000 and rectosigmoid junction. A study of more than 1000 patients with ischemic colitis demonstrated that the left patients with ischemic colitis demonstrated that the left colon was involved in approximately 75 % of patients, colon was involved in approximately 75 % of patients, with about one-quarter of lesions affecting the splenic with about one-quarter of lesions affecting the splenic flexure. The rectum was involved in only 5 % of flexure. The rectum was involved in only 5 % of patients, which can be explained because of patients, which can be explained because of collateralization of the inferior mesenteric artery with collateralization of the inferior mesenteric artery with the systemic circulation through the hemorrhoidal the systemic circulation through the hemorrhoidal vessels. vessels.

CLINICAL MANIFESTATIONSCLINICAL MANIFESTATIONS

Vary depending upon the clinical setting and the Vary depending upon the clinical setting and the extent and duration of the ischemia. Patients extent and duration of the ischemia. Patients with acute colonic ischemia usually present with acute colonic ischemia usually present with rapid onset of mild abdominal pain and with rapid onset of mild abdominal pain and tenderness over the affected bowel, most often tenderness over the affected bowel, most often involving the left side. Mild to moderate involving the left side. Mild to moderate amounts of rectal bleeding or bloody diarrhea amounts of rectal bleeding or bloody diarrhea usually develops within 24 hours of the onset of usually develops within 24 hours of the onset of abdominal pain. abdominal pain.

As a general rule, three progressive clinical stages have been As a general rule, three progressive clinical stages have been described: described: Hyperactive phase: Soon after occlusion or hypoperfusion, Hyperactive phase: Soon after occlusion or hypoperfusion, severe pain dominates with frequent passage of bloody, loose severe pain dominates with frequent passage of bloody, loose stools. Blood loss is usually mild without the need for stools. Blood loss is usually mild without the need for transfusion. More than 80 % of all patients with colonic transfusion. More than 80 % of all patients with colonic ischemia show only mucosal and submucosal injury, symptoms ischemia show only mucosal and submucosal injury, symptoms resolved with conservative measures, and no long-term resolved with conservative measures, and no long-term sequelae.sequelae.Paralytic phase: The pain usually diminishes, becomes more Paralytic phase: The pain usually diminishes, becomes more continuous, and diffuses. The abdomen becomes more tender continuous, and diffuses. The abdomen becomes more tender and distended without bowel sounds.and distended without bowel sounds.Shock phase: Massive fluid, protein, and electrolytes start to Shock phase: Massive fluid, protein, and electrolytes start to leak through a damaged, gangrenous mucosa. Severe leak through a damaged, gangrenous mucosa. Severe dehydration with shock and metabolic acidosis may develop, dehydration with shock and metabolic acidosis may develop, requiring rapid surgical intervention. Fortunately, this most requiring rapid surgical intervention. Fortunately, this most severe form affects only 10 to 20 % of patients. severe form affects only 10 to 20 % of patients.

Symptoms may occur for days or weeks before Symptoms may occur for days or weeks before presentation, although patients with gangrene presentation, although patients with gangrene present within hours and cannot be present within hours and cannot be distinguished clinically from those with acute distinguished clinically from those with acute small intestinal ischaemiasmall intestinal ischaemia

Distinguishing features of acute colonic and small bowel ischemia

Acute colonic ischemia Acute mesenteric ischemia involving small bowel

90 % of patients over age 60 Age varies with etiology of ischemia

Acute precipitating cause is rare Acute precipitating cause is typical

Patients do not appear ill Patients appear very ill

Mild abdominal pain, tenderness present

Pain is usually severe, tenderness is not prominent early

Rectal bleeding, bloody diarrhea typical

Bleeding uncommon until very late

Colonoscopy is procedure of choice

Angiography indicated

DiagnosisDiagnosis

The diagnosis and treatment of patients can be The diagnosis and treatment of patients can be challenging since it often occurs in patients who are challenging since it often occurs in patients who are debilitated and have multiple medical problems. It debilitated and have multiple medical problems. It needs high rate of suspicion as it is easily missed and needs high rate of suspicion as it is easily missed and diagnosis is usually made late unless the physician diagnosis is usually made late unless the physician keeps it in mind. keeps it in mind.

Any patient who develops mild-to-moderate abdominal Any patient who develops mild-to-moderate abdominal pain, diarrhea, or lower intestinal bleeding with pain, diarrhea, or lower intestinal bleeding with minimal-to-moderate abdominal tenderness, minimal-to-moderate abdominal tenderness, especially one who has one of the predisposing especially one who has one of the predisposing conditions, should be investigated for CI. conditions, should be investigated for CI.

The diagnosis is usually established based upon the The diagnosis is usually established based upon the clinical setting, physical examination, and radiological clinical setting, physical examination, and radiological and/or endoscopic studies. It may be harder to make and/or endoscopic studies. It may be harder to make the diagnosis in patients who are unconscious, such the diagnosis in patients who are unconscious, such as those in an intensive care unit . as those in an intensive care unit .

Invasive studies such as angiography or laparoscopy Invasive studies such as angiography or laparoscopy are rarely needed but may be valuable when the are rarely needed but may be valuable when the diagnosis is unclear or as a means to follow patients diagnosis is unclear or as a means to follow patients after surgery for ischemia. after surgery for ischemia. Magnetic resonance Magnetic resonance angiography angiography andand Duplex sonography Duplex sonography are more are more recently introduced vascular studies to assess patients recently introduced vascular studies to assess patients with suspected proximal arterial mesenteric vessel or with suspected proximal arterial mesenteric vessel or mesenteric venous disease, but are hardly ever mesenteric venous disease, but are hardly ever required in the evaluation of suspected colonic required in the evaluation of suspected colonic ischemia. ischemia.

Differential diagnosisDifferential diagnosis

The differential diagnosis includes The differential diagnosis includes infectious colitisinfectious colitis, , IBDIBD, , diverticulitisdiverticulitis, , radiation enteritisradiation enteritis, , solitary rectal ulcer syndromesolitary rectal ulcer syndrome, , and and colon carcinomacolon carcinoma. Stool cultures for Salmonella, Shigella, . Stool cultures for Salmonella, Shigella, Campylobacter, Yersinia, E-coli O157:H7, and ova and Campylobacter, Yersinia, E-coli O157:H7, and ova and parasites to exclude parasites. Clostridium difficile infection parasites to exclude parasites. Clostridium difficile infection should be excluded in hospitalized patients exposed to should be excluded in hospitalized patients exposed to antibiotics. This infection produces marked thickening of the antibiotics. This infection produces marked thickening of the colon on CT scan as well as very high total white blood counts colon on CT scan as well as very high total white blood counts which resemble the findings of ischemic colitis. However, which resemble the findings of ischemic colitis. However, bloody stools are quite rare in C difficile infection. bloody stools are quite rare in C difficile infection.

Infection with Klebsiella oxytoca has been associated with Infection with Klebsiella oxytoca has been associated with right–sided hemorrhagic colitis that can mimic ischemic colitis. right–sided hemorrhagic colitis that can mimic ischemic colitis. This rare infection occurs in patients exposed to antibiotics, This rare infection occurs in patients exposed to antibiotics, particularly penicillin derivatives. The organism produces a particularly penicillin derivatives. The organism produces a cytotoxin that is thought to be involved in pathogenesis. cytotoxin that is thought to be involved in pathogenesis. Diagnosis is established by culture. Diagnosis is established by culture.

Laboratory evaluationLaboratory evaluation

There are no specific laboratory markers for There are no specific laboratory markers for ischemia, although an increased serum ischemia, although an increased serum lactate, LDH, CPK, or amylase may lactate, LDH, CPK, or amylase may indicate advanced tissue damage. White indicate advanced tissue damage. White blood count above 20,000 µL and blood count above 20,000 µL and metabolic acidosis in a patient with signs metabolic acidosis in a patient with signs and symptoms of acute colitis are highly and symptoms of acute colitis are highly suggestive of intestinal ischemia with suggestive of intestinal ischemia with infarction. infarction.

Plain abdominal x-ray —Plain abdominal x-ray —It is frequently non-specific. It is frequently non-specific.

Distension or pneumatosis are Distension or pneumatosis are typically seen only in advanced typically seen only in advanced ischemia. Thumbprinting ischemia. Thumbprinting (indicating submucosal edema) (indicating submucosal edema) and hemorrhage could be and hemorrhage could be identified in only 30 % of identified in only 30 % of patients with mesenteric patients with mesenteric infarction. However, when infarction. However, when present, radiographic findings present, radiographic findings suggesting ischemia may suggesting ischemia may portend a worse prognosis. portend a worse prognosis.

Computed tomography —Computed tomography —

A CT scan is often obtained in patients with A CT scan is often obtained in patients with unrevealing plain abdominal films. Typical unrevealing plain abdominal films. Typical findings are thickening of the bowel wall in a findings are thickening of the bowel wall in a segmental pattern. Pneumatosis and gas in the segmental pattern. Pneumatosis and gas in the mesenteric veins may be seen in the more mesenteric veins may be seen in the more advanced stages. CT findings are generally advanced stages. CT findings are generally nonspecific and scans may initially be normal nonspecific and scans may initially be normal

Colonoscopy — or sigmoidoscopyColonoscopy — or sigmoidoscopy

Can be considered if the diagnosis remains Can be considered if the diagnosis remains unclear unclear after the evaluation described above after the evaluation described above and there is no clinical or radiologic evidence of and there is no clinical or radiologic evidence of peritonitis or perforation.peritonitis or perforation. Colonoscopy is Colonoscopy is preferable to contrast enemas since it is more preferable to contrast enemas since it is more sensitive in detecting mucosal lesions, permits sensitive in detecting mucosal lesions, permits biopsies to be obtained, and does not interfere biopsies to be obtained, and does not interfere with subsequent angiography. Overdistention with subsequent angiography. Overdistention and associated high intraluminal colonic and associated high intraluminal colonic pressures should be avoided during pressures should be avoided during colonoscopy since they may worsen ischemic colonoscopy since they may worsen ischemic damage. damage.

Findings include, pale mucosa with petechial bleeding. Bluish Findings include, pale mucosa with petechial bleeding. Bluish hemorrhagic nodules may be seen representing submucosal hemorrhagic nodules may be seen representing submucosal bleeding; these are the equivalent to "thumbprints" detected on bleeding; these are the equivalent to "thumbprints" detected on radiological studies. More severe disease is marked by cyanotic radiological studies. More severe disease is marked by cyanotic mucosa and hemorrhagic ulcerations. mucosa and hemorrhagic ulcerations.

Occasional patients have pseudomembranous colitis with Occasional patients have pseudomembranous colitis with yellowish round plaques or confluent membranes not related to yellowish round plaques or confluent membranes not related to C. difficile infection. C. difficile infection.

Segmental distribution, abrupt transition between injured and non-Segmental distribution, abrupt transition between injured and non-injured mucosa, rectal sparing, and rapid resolution on serial injured mucosa, rectal sparing, and rapid resolution on serial endoscopy favor ischemia rather than inflammatory bowel endoscopy favor ischemia rather than inflammatory bowel disease. A single linear ulcer running along the longitudinal axis disease. A single linear ulcer running along the longitudinal axis of the colon (the "single-stripe sign") may also favor an of the colon (the "single-stripe sign") may also favor an ischemic cause of colitis.ischemic cause of colitis.

Biopsies taken from affected areas may show Biopsies taken from affected areas may show non-specific changes such as hemorrhage, non-specific changes such as hemorrhage, crypt destruction, capillary thrombosis, crypt destruction, capillary thrombosis, granulation tissue with crypt abscesses, and granulation tissue with crypt abscesses, and pseudopolyps, which may mimic Crohn's pseudopolyps, which may mimic Crohn's disease. disease.

In the chronic phase of ischemic colitis, mucosal In the chronic phase of ischemic colitis, mucosal atrophy and areas of granulation tissue may be atrophy and areas of granulation tissue may be found. Biopsy of a post-ischemic stricture is found. Biopsy of a post-ischemic stricture is marked by extensive transmural fibrosis and marked by extensive transmural fibrosis and mucosal atrophy. mucosal atrophy.

Barium enema —Barium enema —

Abnormalities on barium enema are typically Abnormalities on barium enema are typically segmental and transient. Thumbprinting is the segmental and transient. Thumbprinting is the most suggestive finding on double-contrast most suggestive finding on double-contrast study; it is seen early in the course of the study; it is seen early in the course of the disease and usually resolves or is replaced disease and usually resolves or is replaced within one or two weeks by an acute ulcerating within one or two weeks by an acute ulcerating colitis pattern. In patients with non-gangrenous colitis pattern. In patients with non-gangrenous ischemia, 75 % had thumbprinting and 60 % ischemia, 75 % had thumbprinting and 60 % showed longitudinal ulcers. showed longitudinal ulcers.

Angiography —Angiography —It is rarely helpfulIt is rarely helpful. In most cases, colonic blood flow has . In most cases, colonic blood flow has

already returned to normal by the time of symptom already returned to normal by the time of symptom onset, and therefore angiography will be normal. In onset, and therefore angiography will be normal. In addition, ischemic colon vessels are mostly involved at addition, ischemic colon vessels are mostly involved at the arteriolar level, whereas mesenteric vessels and the arteriolar level, whereas mesenteric vessels and arcades are patent. arcades are patent.

However, angiography may be indicated if the clinical However, angiography may be indicated if the clinical examination and other studies cannot exclude small examination and other studies cannot exclude small bowel ischemia due to acute proximal mesenteric bowel ischemia due to acute proximal mesenteric thrombus or embolus. Angiography may also be thrombus or embolus. Angiography may also be somewhat more sensitive than CT in the diagnosis of somewhat more sensitive than CT in the diagnosis of mesenteric infarction. mesenteric infarction.

Angiography has its limitations; it is not Angiography has its limitations; it is not always readily available and patients with always readily available and patients with ischemic colitis frequently suffer from ischemic colitis frequently suffer from chronic diseases, such as cardiac and chronic diseases, such as cardiac and renal failure, making contrast injection (60 renal failure, making contrast injection (60 to 100 mL) potentially more dangerous. to 100 mL) potentially more dangerous. Furthermore, patients are frequently Furthermore, patients are frequently markedly dehydrated and acidotic, which markedly dehydrated and acidotic, which requires time-consuming correction before requires time-consuming correction before angiography can be performed. angiography can be performed.

Laparoscopy —Laparoscopy —It can be an important diagnostic toolIt can be an important diagnostic tool, particularly , particularly

in the elderly patient with comorbid diseases in the elderly patient with comorbid diseases who may tolerate laparotomy poorly. It may who may tolerate laparotomy poorly. It may also be useful for a "second look" to assess the also be useful for a "second look" to assess the viability of remaining bowel and integrity of the viability of remaining bowel and integrity of the anastomosis after surgery for ischemic bowel. anastomosis after surgery for ischemic bowel. Laparoscopy can be completed using local Laparoscopy can be completed using local anesthesia with light intravenous sedation. anesthesia with light intravenous sedation.

A limitation of laparoscopy is that it permits visualization A limitation of laparoscopy is that it permits visualization of only the serosal surface of the gut, which may of only the serosal surface of the gut, which may appear normal in early or mild ischemia. In a more appear normal in early or mild ischemia. In a more progressive phase, dark peritoneal fluid may be progressive phase, dark peritoneal fluid may be present and the ischemic bowel may demonstrate present and the ischemic bowel may demonstrate edema, patchy hemorrhages, frank gangrene, or edema, patchy hemorrhages, frank gangrene, or perforation. perforation.

A concern about laparoscopy is the effect of A concern about laparoscopy is the effect of pneumoperitoneum on mesenteric blood flow. An pneumoperitoneum on mesenteric blood flow. An animal model showed that mesenteric blood flow was animal model showed that mesenteric blood flow was reduced by more than 70 % from baseline when the reduced by more than 70 % from baseline when the intraperitoneal pressure was more than 20 mmHg, as intraperitoneal pressure was more than 20 mmHg, as it may be during laparoscopy. In addition, a it may be during laparoscopy. In addition, a pronounced drop in femoral artery pressures was pronounced drop in femoral artery pressures was observed. It is therefore prudent that intraperitoneal observed. It is therefore prudent that intraperitoneal pressure should not exceed 10 to 15 mmHg in a pressure should not exceed 10 to 15 mmHg in a patient with suspected mesenteric ischemia.patient with suspected mesenteric ischemia.

ManagementManagement

It is often not possible to distinguish It is often not possible to distinguish colonic gangrene from acute small colonic gangrene from acute small intestinal ischaemia, but resuscitation with intestinal ischaemia, but resuscitation with iv fluids and laparotomy are indicated for iv fluids and laparotomy are indicated for both conditionsboth conditions

TREATMENT —TREATMENT —

Treatment of acute colonic ischemia depends upon its severity Treatment of acute colonic ischemia depends upon its severity and the clinical setting. As a general rule, embolectomy, bypass and the clinical setting. As a general rule, embolectomy, bypass graft, or endarterectomy are only very rarely used to treat graft, or endarterectomy are only very rarely used to treat colonic ischemia as large artery obstruction is hardly ever the colonic ischemia as large artery obstruction is hardly ever the cause of the ischemia. cause of the ischemia.

Nonocclusive ischemia — Supportive care is appropriate in the Nonocclusive ischemia — Supportive care is appropriate in the absence of colonic gangrene or perforation. Intravenous fluids absence of colonic gangrene or perforation. Intravenous fluids should be given to ensure adequate colonic perfusion, and should be given to ensure adequate colonic perfusion, and patients should be placed on bowel rest. patients should be placed on bowel rest.

Empiric broad spectrum antibiotics are recommended in moderate Empiric broad spectrum antibiotics are recommended in moderate to severe cases, as antibiotics reduce the severity and extent to severe cases, as antibiotics reduce the severity and extent of bowel damage and improve survival.of bowel damage and improve survival.

NGT should be inserted if an ileus is present. Any NGT should be inserted if an ileus is present. Any medications that can promote ischemia should be medications that can promote ischemia should be withheld promptly. Cardiac function and oxygenation withheld promptly. Cardiac function and oxygenation should be optimized. Although local infusion of should be optimized. Although local infusion of vasodilators (such as papaverine) to attenuate vasodilators (such as papaverine) to attenuate vasospasm has been described, its benefit is vasospasm has been described, its benefit is unproven in humans and data supporting its efficacy in unproven in humans and data supporting its efficacy in animal models have been conflicting. animal models have been conflicting.

Careful monitoring for persistent fever, leukocytosis, Careful monitoring for persistent fever, leukocytosis, peritoneal irritation, protracted diarrhea, and bleeding peritoneal irritation, protracted diarrhea, and bleeding is imperative. If clinical deterioration is evident despite is imperative. If clinical deterioration is evident despite conservative therapy, laparotomy and segmental conservative therapy, laparotomy and segmental resection are indicated. Adequate surgical margins resection are indicated. Adequate surgical margins should be ensured and primary anastomosis should should be ensured and primary anastomosis should be avoided in patients with severe colitis. be avoided in patients with severe colitis.

Colonic infarction —Colonic infarction —

Colonic infarction develops as a consequence of severe Colonic infarction develops as a consequence of severe hypoperfusion leading to transmural necrosis of the hypoperfusion leading to transmural necrosis of the bowel wall, which can progress to sepsis, peritonitis, bowel wall, which can progress to sepsis, peritonitis, free intraabdominal air, or extensive gangrene. Such free intraabdominal air, or extensive gangrene. Such patients require urgent surgical intervention. As a patients require urgent surgical intervention. As a general rule, the bowel should not be cleansed in general rule, the bowel should not be cleansed in preparation for surgery, because bowel preparations preparation for surgery, because bowel preparations can precipitate perforation or toxic dilatation of the can precipitate perforation or toxic dilatation of the colon. Antegrade intraoperative colonic irrigation has colon. Antegrade intraoperative colonic irrigation has been attempted in this setting but is nevertheless been attempted in this setting but is nevertheless associated with significant intraoperative mortality, associated with significant intraoperative mortality, anastomotic leaks, and wound infections. anastomotic leaks, and wound infections.

Right-sided colonic ischemia and necrosis Right-sided colonic ischemia and necrosis can be can be treated with right hemicolectomy and primary treated with right hemicolectomy and primary anastomosis.anastomosis.

Patients with left-sided colonic involvementPatients with left-sided colonic involvement may require may require a proximal stoma and distal mucous fistula or a proximal stoma and distal mucous fistula or Hartmann's procedure. Ostomy closure should be Hartmann's procedure. Ostomy closure should be delayed for four to six months, although some patients delayed for four to six months, although some patients never proceed to reversal because of comorbid never proceed to reversal because of comorbid conditions.conditions.

The rare patient with a fulminating typeThe rare patient with a fulminating type of colonic of colonic ischemia involving most of the colon and rectum may ischemia involving most of the colon and rectum may require colectomy with terminal ileostomy. Many require colectomy with terminal ileostomy. Many surgeons advocate a "second look" operation within surgeons advocate a "second look" operation within 12 to 24 hours to document bowel viability depending 12 to 24 hours to document bowel viability depending upon the findings during the first operation. Despite upon the findings during the first operation. Despite surgical intervention, mortality following large bowel surgical intervention, mortality following large bowel infarction is as high as 50 to 75 %. infarction is as high as 50 to 75 %.

Mesenteric vein thrombosis —Mesenteric vein thrombosis —

Many patients with mesenteric vein thrombosis have an Many patients with mesenteric vein thrombosis have an underlying thrombophilic condition. Thus, treatment underlying thrombophilic condition. Thus, treatment should include should include evaluation for hypercoagulabilityevaluation for hypercoagulability and and may include may include anticoagulant therapyanticoagulant therapy. Recanalization of . Recanalization of the thrombosed vein has been described following the thrombosed vein has been described following long-term anticoagulant therapy. Guidelines published long-term anticoagulant therapy. Guidelines published by the AGA suggests that patients who have had an by the AGA suggests that patients who have had an episode of acute mesenteric vein thrombosis and do episode of acute mesenteric vein thrombosis and do not have a contraindication to anticoagulation should not have a contraindication to anticoagulation should be anticoagulated with warfarin for three to six months be anticoagulated with warfarin for three to six months or for life if there is a hypercoagulable state or cardiac or for life if there is a hypercoagulable state or cardiac source.source.

Thrombectomy and thrombolysisThrombectomy and thrombolysis have been described in have been described in the acute setting, but experience is limited. the acute setting, but experience is limited.

CHRONIC ISCHEMIC COLITIS —CHRONIC ISCHEMIC COLITIS —

About 20 % of patients develop chronic colitis from irreversible About 20 % of patients develop chronic colitis from irreversible ischemic injury. These patients can present with recurrent ischemic injury. These patients can present with recurrent bacteremia, persistent sepsis, asymptomatic colonic bacteremia, persistent sepsis, asymptomatic colonic strictures, bloody diarrhea, weight loss from protein loosing strictures, bloody diarrhea, weight loss from protein loosing enteropathy, or abdominal pain. enteropathy, or abdominal pain.

Recurrent episodes of bacteremia or sepsis in patients with Recurrent episodes of bacteremia or sepsis in patients with unhealed areas of segmental colitis are indications for unhealed areas of segmental colitis are indications for segmental colon resection. Patients who are misdiagnosed as segmental colon resection. Patients who are misdiagnosed as having inflammatory bowel disease will respond poorly to having inflammatory bowel disease will respond poorly to immunosuppressive therapy and have an increased risk of immunosuppressive therapy and have an increased risk of perforation on steroids. perforation on steroids.

Ischemic strictures that produce no symptoms should be Ischemic strictures that produce no symptoms should be observed. Some strictures will return to normal within 12 to 24 observed. Some strictures will return to normal within 12 to 24 months without specific therapy. Segmental resection is months without specific therapy. Segmental resection is usually adequate if symptoms of obstruction develop. usually adequate if symptoms of obstruction develop. Endoscopic dilatation or stenting may be alternatives, albeit Endoscopic dilatation or stenting may be alternatives, albeit unproven ones. unproven ones.

PROGNOSIS —PROGNOSIS —The prognosis of patients with ischemic colitis depends The prognosis of patients with ischemic colitis depends

upon the disease severity and comorbidities.upon the disease severity and comorbidities.Most patients with nonocclusive ischemia improve within Most patients with nonocclusive ischemia improve within

one or two days, and have complete clinical and one or two days, and have complete clinical and radiological resolution within one to two weeks.radiological resolution within one to two weeks.

More severe ischemia causes ulceration and More severe ischemia causes ulceration and inflammation, which may develop into segmental inflammation, which may develop into segmental ulcerating colitis or strictures. These lesions may be ulcerating colitis or strictures. These lesions may be asymptomatic, but they should be followed to asymptomatic, but they should be followed to document healing or the development of persistent document healing or the development of persistent colitis or stricture. The prognosis may be worse in colitis or stricture. The prognosis may be worse in patients who have peripheral vascular disease or right patients who have peripheral vascular disease or right colonic involvement. colonic involvement.

As a general rule, non-gangrenous colonic ischemia is As a general rule, non-gangrenous colonic ischemia is associated with a low mortality (approximately 6 %, in associated with a low mortality (approximately 6 %, in contrast to gangrenous ischemia, which is associated contrast to gangrenous ischemia, which is associated with a mortality as high as 50 to 75 % with surgical with a mortality as high as 50 to 75 % with surgical resection and is almost always fatal if treated resection and is almost always fatal if treated conservatively. conservatively.

Recurrence is unlikely if predisposing conditions can be Recurrence is unlikely if predisposing conditions can be prevented. Although used for other forms of vascular prevented. Although used for other forms of vascular disease, disease, antiplatelet agentsantiplatelet agents have not been well have not been well studied in this setting, and are studied in this setting, and are generally not usedgenerally not used. As . As discussed above, discussed above, anticoagulant therapyanticoagulant therapy is usually is usually necessary only in patients who develop ischemia due necessary only in patients who develop ischemia due to mesenteric venous thrombosis or cardiac to mesenteric venous thrombosis or cardiac embolization. embolization.