3.radiation Inj

Surgery Dr. Faruq 17-Oct-06

Lec: -3-

Radiation inj.of intestine • • • •

Radiation Therapy-a component of multimodality therapy for many intraabdominal & pelvic cancers,such as those of cervix, endomertrium, ovary, bladder, prostate &rectum. An undesired S.E of radiation therapy is radiation inj. To intestine, which can present as 2 distinct syndromes; 1-Acute radiation enteritis Chronic radiation enteritis.

Acute radiation enteritis • • • • • •

Transient condition Occurs in approximately 75% of patients. Main effects on mucosa Radiation induces cellular inj directly & via the generation of free radicals. Clinical presentations; nausea,vomiting,diarrhea & crampy abd. Pain. Dx. Obvious, & the condition is transient

Chronic Radiation enteritis(CRE) • • •

Inexorable. Develops in approximately 5-15 % . There is a progressive occlusive vasculitis---that leads to chronic ischemia & fibrosis, that affects all layers of intestinal wall--- these changes ---strictures, abscesses & fistula formation.

CRE( Presentations) • • • • • •

Usually become evident within 2 years. Terminal ileum most commonly affected. Partial small bowel obstruction-Nausea ,vomiting,intermittent abd. Distension, crampy abd. Pain & wt loss. Complete bowel obstrcution. Acute or ch. Intestinal haemorrhage. Abscess or fistula formation.

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CRE( Dx) • •

Enteroclysis-contrast radiograph of small intestine:1-widely separated loops of small bowel.2- luminal narrowing.3-loss of mucosal folds.4-ulcerations. CT scan to exclude recurrent cancer.

Rx • • • •

Acute RE- self limited. Supportive Rx CRE-Surgery- very difficult with high M&M.( M.R=10%) Surgery indicated for;high grade obstruction. Haemorrhage.Intra-abd. Abscess & fistulas. Limited resection + anatamosis

Intestinal Fistulas (Epidemiology) • • • • • • •

Definition- a fistula- abnormal communication bet.2 epithelialized surface. Internal fistulas- communications bet.2 parts of GIT( enterocolic F.), or bet. GIT a & adjacent organ ( colovesicular F). External F.( enterocutaneous F., or rectovaginal F.)involves the skin or another ext.surface epithelium. Low-output F-drains <500ml/d. High-output F- drains >500ml /d 80% iatrogenic inj.( complications), as a result of enterotomies or intestinal anastamotic dehisence. Spontaneous F—Crohn’s dis, Cancer,CRE

Aetiology A- Congenital –patent vitello-intestinal duct B-acquired- most common causes are: • 1-anastomotic leakage • 2-inflam. Bowel disease • 3-malignancy • 4-radiotherapy • 5-trauma

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Pathophysiology • • • • • •

Enteroenteric F-››››malabsorption syndrome. Enterovesical F- Recurrent UTI Enterocutaneous F– skin excoraition. High-output F.—dehydration, electrolyte abnormalities & malnutrition Fistulas have the potential to close spontaneously. Factors inhibiting spontaneous closure are:malnutrition,sepsis, Inflam. Bowel dis, cancer,radiation, distal obstruction, F.B,high-output, & epithelialization of fistula

Clinical presentations •

Iatrogenic enterocutaneous F. clinically evident bet 5th & 10th postoperative days. • Initial signs :. Fever. Leukocytosis. Prolonged ileus, abdominal tenderness & wound infection • Dx- becomes obvious,when drainage of enteric material viaabd. Wound or existing drains occur. These fistulas are often ass. With intra-abd. Abscesses.

Dx • • •

Enhanced CT scan Small bowel series- enteroclysis Fistulogram

Rx Step 1(Stabilization) • • • •

Fluid & electrolyte resuscitation. Nutrition, usually parentral route initially. Sepsis is controlled- Ab, localisation & drainage. Skin- care & protection with ostomy appliances or fitula drains.

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Step 2 ( Investigation) Definition of anatomy • • • •

Anatomy of fistula is defined using: CT scan Small bowel series Fistulogram

Step 3(Rehabilitation) Carrying out the definitive procedure (where necessary) • • • • • •

Probability of spontaneous closure is maximized. Nutrition & time are the key components Most patients will require TPN, however, a trial of oral or entral nutrition should be attempt in low-output fistulas, originating from distal ileum. Octreotide- somatotatin analogue;reduces the volume of fistula output & may accelerate the rate of closure. 2 to 3 months are allowed for spontaneous closure, after that they are unlikely to do so. Surgery-remove of fisltua tract + the involved segment of bowel from which the fistula originated

OUTCOME • • • • •

M.R- 10-15 %- mostly related to sepsis or underlying disease. Overall 50% close spontaneously FRIEND- a useful mnemonic designates factors that inhibit spontaneous closure F.B. Radiation enteritis. Infection/inflammation at the fistula origin.Epithelialization of the fistula tract.Neoplasm at the fistula origin.Distal obstruction of the intestine. Surgery for fistulas is associated with >50%MR, including a 10 % recurrence rate.

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Mesenteric ischemia 1-Acute.Causes • • • •

1-Arterial embolus2-arteial thrombosis 3-Vasospasm( also known as ;nonocclusive mesenteric ischemia, or NOMI) 4-venous thrombosis

Art.Embolism • • •

Most common cause of art.Emb.>50% of cases Source of Emboli- usually-Heart.95% LA,or ventricular or valvular lesions. SMA- embolism 50% of cases.

Art.thrombosis •

Usually superimposed on pre-existing atherosclerotic lesions

NOMI The result of vasospasm & usually diagnosed in critically –ill-patients who are receiving vasopressor agents

Mesenteric venous thrombosis • • • •

Accounts for 5-15% of cases of acute mesenteric ischemia. Involves the SM vein in 95% of cases. IMV- only rarely involved. Classified as primary-if no etilogic factor is identifiable, or as sec.if an etilogic factor, such as heritable or acquired coagulation disorders, is identified

Regardless of the cause: Acute mesenteric ischemia can--• •

Intestinal mucosal sloughing within 3 hours of onset Full- thickness intestinal infarction by 6 hours.

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2-Chronic mesenteric ischemia • • • •

Develops insidiously, allowing for development of collat. Circulation. Rarely leads to intestinal infarction Ch.mesent. Art. Ischemia- from atherosclerosis in the main splanchnic art.s(caeliac, SMA, IMA) Chronic form of mesenteric venous thrombosis can involve the portal or splenic veins—portal HT

Clinical presentation • • • • •

The hallmark of acute Mesent. Isch is :Severe abd. Pain out of proportion to the degree of tenderness O/E . The pain – colicky & most severe in the mid-abd Associated symptoms can include; nausea,vomiting & diarrhea. Physical exam.- characteristically absent early in the course of ischemia. With onset of bowel infarction;abd. Distension, peritonitis &passage of bloody stools occur

Presentation ( Chronic mesent. Isch) • • •

-presents insidiously. Postprandial abd. Pain- the most prevalent symptom, producing a characteristic aversion to food (food-fear) & wt. loss. Often thought to have malignancy & suffer a prolonged period of symptoms before the correct Dx is made.

(Ch. Mesent. Venous thrombosis) • • •

Mostly asymptomatic bec. Of collat. Usually discovered as an incidental finding on imaging studies. Some patients- present with bleeding from esophagogastric varices

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Dx • • • • •

Lab.tests abnormalities, such as leukocytosis,acidosis, Increase in amylase are late findings. Patients suspected of having acute mesent. Ischemia & who have physical findings suggestive of peritonitis should undergo emergent laparotomy CT Scanning- sensitive in 64-82% . If negative & the case suspicious Do angio Angiography-sensitivity of 74-100% & specificities approaching 100% Angiography- is invasive, time-consuming & costly

Rx(imp. Considerations in selecting Rx options) • • • •

The presence or absence of signs of peritonitis The presence or absence of ischemic but viable intestine The general condition of the patient The specific vascular lesions lesion causing mesenteric ischemia

Signs of peritonitis -detected • • • •

Emergent laparotomy . Assess the viability of bowel Resection& anastamosis Sec look laparotomy

Embolus or thrombus-induced ischemia • • • • • •

1-Standard Rx-surgical revascularization: Embolectomy Thrombectomy Mesenteric bypass B- C.I to these op. are: 1-if most bowel supplied by the affected art. Infarcted 2-unstable patients

Chronic radiation inj of the intestine (Epidemiology) • • • •

May occur in any patient who has radioRx to the abdomen or pelvis. Most patients –young or middle –aged women treated for pelvic malign. Occurs in elderly men with ca. prostate. Occurs in adolescents treated for testicular tumors

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Aetiology • • •

The intestine is radiosensitive , particularly the small intestine with its rapid mucosal cell turnover cycle. Inj- directly related to total radiation dose Possible factors – previous abd. Op. previous pelvic sepsis Atherosclerosis D.M Concomitant chemoRx

Pathology • • •

Progressive ischemia- any part, usually the distal ileum & rectosigmoid region Gross-appearance- bowel –white ,telangectasia, thickened,indurated & narrowed. adhesion, fistulas to vagina, bladder, or other loops of bowel Microscopic-thickening of submucosa by fibrosis.Obliterative vasculitis in arterioles & venules. Infiltration of the bowel wall with lymphocytes & bizarre fibroblasts

Clinical features Essential to the Dx-is past Hy of irradiation, therapeutic or otherwise. 1-Strictures—Partial I.O-symptoms—intermittent. 2-Necrosis---free perforation or fistulas 3-Ulceration-may cause haemorrhage 4-Malabsorption-wt loss 5-Urinary symptoms-freq.,dysuria or hematuria-(radiation cystitis). 6-Defecatory symptoms-loss of compliance of rectum-urgency, frq, & tenesmus

NOMI • •

Standard Rx-infusion of vasodilator papaverine

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Acute mesenteric venous thrombosis • •

Standard Rx- Anticoagulation Heparin

Outcome • • • •

MR- acute art.mesenteric isch—59-93% MR- mesenteric venous thrombosis-20-50% MR- of surgery-0-16% Recurrent rate after surgery < 10%

Prepared by: Rand Aras Najeeb

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