Gastric outlet obstruction

overview of gastric outlet obstruction

1. SABNAM BHATTA INTERN SURGERY DEPARTMENT GASTRIC OUTLET OBSTRUCTION

2. 9/24/17 CHITWAN MEDICAL COLLEGE 2 Contents Introduction Causes Etiology (Benign and Malignant) Pathophysiology Clinical features Physical examinations Metabolic effects Investigations Management (conservative and surgical along with indications) Summary

3. 9/24/17 CHITWAN MEDICAL COLLEGE 3 INTRODUCTION Gastric outlet obstruction (GOO, pyloric obstruction) is not a single entity Clinical and pathophysiological consequence of any disease process that produces a mechanical impediment to gastric emptying

4. 9/24/17 CHITWAN MEDICAL COLLEGE 4 CAUSES Two well-defined groups of causes BENIGN AND MALIGNANT Benign causes include pyloric stenosis secondary to peptic ulceration While, Malignant causes include Gastric cancer. Previously, peptic ulcer diseases were more common. Now, with the decrease in the incidence of peptic ulceration and the advent of potent medical treatments, gastric outlet obstruction should be treated as malignant unless proven otherwise.

5. 9/24/17 CHITWAN MEDICAL COLLEGE 5 Only 37% have benign disease, with the rest having malignant cause. The term ‘pyloric stenosis’ is a misnomer as the stenosis is seldom at the pylorus . Commonly, when the condition is due to underlying peptic ulcer disease the stenosis is found in the first part of duodenum(most common site for peptic ulcer ) True pyloric stenosis however, can occur as a result of fibrosis around a pyloric channel ulcer.

6. 9/24/17 CHITWAN MEDICAL COLLEGE 6 Diagnostic and treatment dilemma Exclude functional non-mechanical causes of obstruction, such as diabetic gastroparesis Once mechanical obstruction is established, differentiate between benign and malignant ( definitive treatment varies) Diagnosis and treatment is Urgent, because delay further compromises patient’s nutritional status Delay also further compromises edematous tissue and complicates surgical intervention

7. 9/24/17 CHITWAN MEDICAL COLLEGE 7 Frequency The incidence occurs in less than 5% in patients. With peptic ulcer disease being the leading benign cause Peripancreatic malignancy, the most common malignant etiology- 15-20%.

8. 9/24/17 CHITWAN MEDICAL COLLEGE 8 Etiology Major benign causes of gastric outlet obstruction (GOO) are: PUD Gastric Polyps Ingestion of caustics   Pyloric Stenosis Congenital duodenal webs Gallstone obstruction ( Bouveret syndrome) Pancreatic pseudocysts B ezoars

9. 9/24/17 CHITWAN MEDICAL COLLEGE 9 Etiology PUD : 5% of all patients with GOO Ulcers within the pyloric channel & first part of duodenum is responsible for outlet obstruction Obstruction – Acute obstruction is caused secondary to acute inflammation and edema Chronic obstruction is secondary to scarring and fibrosis Helicobacter pylori 

10. 9/24/17 CHITWAN MEDICAL COLLEGE 10 Pediatric age group- Congenital Pyloric stenosis  Occurs in 4 per 1000 births Boys˃ Girls (4 : 1) More common in first-born children It is familial. PYLORIC STENOSIS occurs between 3 rd and 6 th week of age of an infant, which is the time taken for gradual hypertrophy of the circular smooth muscle of the pylorus   to cause complete obstruction. Visible gastric peristalsis is seen.

11. 9/24/17 CHITWAN MEDICAL COLLEGE 11 Etiology Pancreatic cancer is the most common malignancy causing GOO Outlet obstruction may occur in 10-20% Other tumors include Ampullary cancer Duodenal cancer Cholangiocarcinoma Gastric cancer Metastases to the gastric outlet by other primary tumors

12. 9/24/17 CHITWAN MEDICAL COLLEGE 12 Pathophysiology Intrinsic or extrinsic obstruction of the pyloric channel or duodenum Intermittent symptoms that progress until obstruction is complete. Vomiting is the cardinal symptom. Initially, better tolerance to liquids than solid food In a later stage, significant weight loss due to poor caloric intake. Malnutrition is a late sign, very profound in patients with concomitant malignancy

13. 9/24/17 CHITWAN MEDICAL COLLEGE 13 Continuous vomiting may lead to dehydration and electrolyte abnormalities When obstruction persists, may develop significant and progressive gastric dilatation The stomach eventually loses its contractility. Undigested food accumulates Constant risk for aspiration pneumonia

14. 9/24/17 CHITWAN MEDICAL COLLEGE 14 Clinical features Gastric outlet obstruction from a duodenal ulcer or incomplete obstruction typically present with symptoms of the following: Gastric retention, including early satiety, bloating or epigastric fullness, indigestion, anorexia, nausea, vomiting, epigastric pain, and weight loss Pain is severe, persistent, in the epigastric region, and also with feeling of fullness Nausea and vomiting are the cardinal symptoms

15. 9/24/17 CHITWAN MEDICAL COLLEGE 15 Clinical features Vomiting – Non-bilious, and it characteristically contains undigested food particles Loss of periodicity. Early stages: vomiting, intermittent and usually occurs within 1 hour of a meal Very often it is possible to recognize foodstuff taken several days previously Patient loses weight, appears unwell and dehydrated

16. 9/24/17 CHITWAN MEDICAL COLLEGE 16 Frequently malnourished and dehydrated and have a metabolic insufficiency Weight loss , most significant with malignant disease Abdominal pain is not frequent and usually relates to the underlying cause, such as PUD or Pancreatic Cancer.

17. 9/24/17 CHITWAN MEDICAL COLLEGE 17 Physical examination Chronic dehydration and Malnutrition On examination : Distended abdomen and a succussion splash may be audible on shaking the patient’s abdomen Positive succussion splash is done with 4 hours empty stomach, by placing a stethoscope over the epigastric region and shaking the patient adequately .

18. 9/24/17 CHITWAN MEDICAL COLLEGE 18 A dilated stomach may be appreciated as a tympanic mass in the epigastric area and/or left upper quadrant Visible gastric peristalsis (VGP) may be elicited by asking the patient to drink a cup of water. Auscultopercussion test shows dilated stomach. ( This test is done by placing a stethoscope over epigastric region. Skin is scratched from left side downwards, at several points away from the epigastrium using finger and these points are joined. Normally the greater curvature of the stomach lies above the level of umbilicus, while in GOO it lies below the level of umbilicus .)

19. 9/24/17 CHITWAN MEDICAL COLLEGE 19 Goldstein saline load test: half and hour after installation of 750ml of saline, if volume remained and if more than 250ml is present, suggests obstruction.

20. 9/24/17 CHITWAN MEDICAL COLLEGE 20 Metabolic effects Dehydration and electrolyte abnormalities- Increase in BUN and creatinine are late features of dehydration Prolonged vomiting causes loss of hydrochloric acid & produces an increase of bicarbonate in the plasma to compensate for the lost chloride, hypokalemic hypochloremic metabolic alkalosis Alkalosis shifts the intracellular potassium to the extracellular compartment, and the serum potassium is increased factitiously

21. 9/24/17 CHITWAN MEDICAL COLLEGE 21 With continued vomiting, the renal excretion of potassium increases in order to preserve sodium The adrenocortical response to hypovolemia intensifies the exchange of potassium for sodium at the distal tubule, with subsequent aggravation of the hypokalemia

22. 9/24/17 CHITWAN MEDICAL COLLEGE 22 Electrolyte changes in pyloric stenosis Hyponatremia Hypokalemia Hypomagnesemia Hypochloraemia Metabolic alkalosis Paradoxical aciduria

23. 9/24/17 CHITWAN MEDICAL COLLEGE 23 Paradoxically acidic urine Initially, the urine has a low chloride and high bicarbonate content, reflecting the primary metabolic abnormality This bicarbonate is excreted along with sodium and so, with time, the patient becomes progressively hyponatremic and more profoundly dehydrated. Because of the dehydration, a phase of sodium retention follows and potassium and hydrogen are excreted in preference. This results in the urine becoming paradoxically acidic Alkalosis leads to a lowering of the circulating ionised calcium, and gastric tetany can occur.

24. 9/24/17 CHITWAN MEDICAL COLLEGE 24 Clinical features of Paradoxical aciduria Irritability, confused status, dehydration Often convulsions can occur. Features of alkalosis like rapid breathing ( Cheyne -stokes breathing and tetany ) Investigations Serum electrolytes Arterial blood gas analysis S erum calcium level estimation Treatment : Double strength normal saline with IV potassium under ECG monitoring. Plus IV magnesium.

25. 9/24/17 CHITWAN MEDICAL COLLEGE 25 I nvestigations Barium meal study : Absence of duodenal cap. Dilated stomach where greater curvature is below the level of iliac crest. Mottled stomach Barium does not pass into duodenum. Gastroscopy to rule out stomach carcinoma and to visualize the stenosed area. Electrolyte study for the correction of electrolyte imbalance. E CG to check for hypokalemia.

26. 9/24/17 CHITWAN MEDICAL COLLEGE 26 Management Correcting the metabolic and electrolyte abnormality by IV fluids. Rehydrated with intravenous isotonic saline with potassium supplementation or double strength slaine , calcium, potassium, magnesium. Replacing the sodium chloride and water allows the kidney to correct the acid–base abnormality Following rehydration it may become obvious that the patient is also anemic. Blood transfusion if given if there is anemia .

27. 9/24/17 CHITWAN MEDICAL COLLEGE 27 TPN support. STOMACH WASH : The stomach should be emptied using a Wide-bore gastric tube/ Eswald’s tube. Pass an orogastric tube and lavage the stomach until it is completely emptied. It reduces the edema of the stomach wall and improves gastric emptying time by increasing the gastric muscle tone. Then endoscopy and contrast radiology Biopsy of the area around the pylorus is essential to exclude malignancy The patient should also have an anti-secretory agent, initially given intravenously to ensure absorption

28. 9/24/17 CHITWAN MEDICAL COLLEGE 28 Management Early cases : settle with conservative treatment, presumably as oedema around the ulcer diminishes as the ulcer is healed Endoscopic treatment with balloon dilatation useful in early cases (Dilating the duodenal stenosis may result in perforation, and the dilatation may have to be performed several times and may not be successful in the long term)

29. 9/24/17 CHITWAN MEDICAL COLLEGE 29 Surgical management Highly selective vagotomy (HSV) with gastrojejunostomy is present recommendation even though it is technically difficult. HSV is better than Truncal vagotomy as it maintains the nerve supply of the chronically obstructed antrum and so may eventually reduce the chronic emptying problems. Vagotomy , antrectomy (acid secreting area) with Billroth I anastomosis along with feeding jejunostomy for nutrition is the other option.

30. 9/24/17 CHITWAN MEDICAL COLLEGE 30 Indications for Surgery Gastric outlet obstruction due to benign ulcer disease may be treated medically if results of imaging studies or endoscopy determine - acute inflammation and edema are the principle causes (as opposed to scarring and fibrosis, which may be fixed) If medical therapy fails, then surgical therapy Typically, if resolution or improvement is not seen within 48-72 hours, surgical intervention is necessary

31. 9/24/17 CHITWAN MEDICAL COLLEGE 31 The choice of surgical procedure depends upon the patient's particular circumstances In cases of malignant obstruction, weigh the extent of surgical intervention for the relief of obstruction against the malignancy's type and extent, as well as the patient's anticipated long-term prognosis As a guiding principle, undertake major tumor resections in the absence of metastatic disease

32. 9/24/17 CHITWAN MEDICAL COLLEGE 32 In patients with largely metastatic disease, determine the degree of surgical intervention for palliation in the light of patient’s realistic prognosis and personal wishes.

33. 9/24/17 CHITWAN MEDICAL COLLEGE 33 Summary Gastric outlet obstruction is most commonly associated with longstanding peptic ulcer disease and gastric cancer The metabolic abnormality of hypochloraemic alkalosis is usually only seen with peptic ulcer disease and should be treated with isotonic saline with potassium supplementation. Endoscopic biopsy is essential to determine whether the cause of the problem is malignancy

34. 9/24/17 CHITWAN MEDICAL COLLEGE 34 Endoscopic dilatation of the gastric outlet may be effective in the less severe cases of benign stenosis Operation is normally required, with a drainage procedure being performed for benign disease and appropriate resectional surgery if malignant.

35. 9/24/17 CHITWAN MEDICAL COLLEGE 35 Other causes of G astric outlet obstruction Adult pyloric stenosis T his is a rare condition and its relationship to childhood condition is unclear, although some patients have a long history of problems with gastric emptying. It commonly treated by pyloroplasty that pyloromyotomy . Pyloric mucosal diaphragm The origin of this rare condition is unknown. It usually does not become apparent until mid life. When found, simple excision of mucosal diaphragm is all that is required.

36. 9/24/17 CHITWAN MEDICAL COLLEGE 36 References BAILEY AND LOVE SHORT PRACTICE OF SURGERY ; 25 TH EDITION 2. SRB’s Manual of Surgery; Fourth edition 3. CLASS NOTES

37. 9/24/17 CHITWAN MEDICAL COLLEGE 37 THANK YOU

38. 9/24/17 CHITWAN MEDICAL COLLEGE 38