Infantile hypertropic pyloric stenosis.pptx

CPS

1. INFANTILE HYPERTROPHIC PYLORIC STENOSIS

2. INTRODUCTION A condition characterised by hypertrophy of the two circular muscle layers of the pylorus. Resulting in constriction and obstruction of gastric outlet. Described by Hirschprung in 1888

3. EPIDEMIOLOGY AND ETIOLOGY INCIDENCE - 1.5 to 4 per 1000 live births EPIDEMIOLOGY - Male : female ratio = 4:1 Increased risk in first born boys ETIOLOGY IDIOPATHIC GENETIC-11q14-22 and Xq23 Rarely autosomal dominant FAMILIAL ETHNIC ORIGIN (more in whites): more commonly seen in Caucasians ENVIRONMENTAL  Erythromycin or azithromycin exposure Transpyloric feeding of premature babies

4. ETIOLOGY (contd.) EMERGING NEW THEORIES GI hormones like gastrin, substance P (could produce chronic pylorospasm and stenosis) , Epidermal growth factor, deficiency of NO (can induce muscle spasm preventing smooth muscle relaxation in stomach). Muscle layer deficient in quantity of nerve terminals markers for nerve supporting cells peptide containing nerve fibres  This abnormal innervation of muscular layer leads to failure of relaxation of pyloric muscle, increased synthesis of growth factors

5. Associations Turner syndrome Tracheo- oesophageal fistula Oesophageal atresia Trisomy18

6. PATHOPHYSIOLOGY Hypertrophied muscles Gastric outlet obstruction Non bilious projectile vomiting Gastric fluid loss Hypochloraemic hypokalaemic alkalosis Paradoxical aciduria

7. PATHOPHYSIOLOGY contd Vomiting Loss of water ---- -> DEHYDRATION Loss of gastric acid from stomach ( HYPOCHLORAEMIA) ----- > Impairment of kidney’s ability to excrete bicarbonate ion ---- > prevents correction of alkalosis HYPOVOLAEMIA Secondary Hyperaldosteronism Acts on kidneys

8. PATHOPHYSIOLOGY contd Retains Na+ to correct intravascular volume depletion Excretes increased amount of K+ in urine --- -> HYPOKALAEMIA ---- > hypomagnesemia and hypocalcemia Excretion of H+ leading to aciduria Body’s compensatory response to metabolic alkalosis is HYPOVENTILATION ---> increased arterial pCO2 ( SECONDARY RESPIRATORY ACIDOSIS) Initial alkalotic urine becomes acidic - PARADOXICAL ACIDURIA

9. CLINICAL PRESENTATION ONSET at 2 to 8 weeks of age (commonly at around one month of age) SYMPTOMS Projectile ,forcible, frequent episodes of non- bilious coffee ground vomiting 30 to 60 minutes after feeding. Weight loss Persistent hunger Lethargy Constipation or hunger diarrhoea

10. CLINICAL PRESENTATION(contd) SIGNS Palpable,olive shaped, mobile, smooth, firm mass (1.5 to 2 cm) with all borders well made out, moves with respiration, with impaired resonance on percussion to right of epigastric area.(95% cases)

11. CLINICAL PRESENTATION(contd) SIGNS (contd.) Visible gastric peristalsis from left upper quadrant to epigastrium (golf ball waves) Signs of dehydration Jaundice (2%) (due to decreased hepatic glucuronosyl transferase associated with starvation)

12. DIAGNOSIS ABDOMEN X RAY (erect posture) upper abdominal gas bubble in the stomach.  ABDOMINAL ULTRASONOGRAPHY ( Gold standard at present) Doughnut sign or cervical pyloric sign pyloric muscle thickeness >4 mm pyloric length >16mm in presence of functional gastric outlet obstruction

13. DIAGNOSIS (contd.) BARIUM MEAL/ Fluoroscopy Peristaltic waves ( caterpillar sign ) Delayed gastric emptying Elongated and narrow pyloric canal- String sign / Railroad track sign The pylorus indents the contrast- filled antrum ( shoulder sign ) or base of the duodenal bulb ( mushroom sign)

14. The barium may outline crowded mucosal folds as parallel lines - DOUBLE TRACT SIGN Bulge in the distal antrum with streak of barium pointing towards pyloric canal- BEAK SIGN Double tract sign Beak sign

15. DIAGNOSIS ( contd.) BIOCHEMICAL CHANGES Dehydration Malnutrition Hypochloraemic hypokalaemic metabolic alkalosis Paradoxical aciduria Hyperbilirubinemia ARTERIAL BLOOD GAS ANALYSIS Low serum levels of potassium and chloride Increased blood pH and high blood bicarbonate level

16. MANAGEMENT Medical but not a surgical emergency RESUSCITATION MEDICAL TREATMENT – Atropine methyl nitrate orally is tried to relax the pylorus muscle.

17. PRE OPERATIVE PREPARATION Resuscitation with IV rehydration. Correct hypovolaemia with 10 ml/kg 0.9 % saline. Correct hypochloraemic alkalosis and hypokalaemia (over 24- 48 hrs): 0.45% NaCl in 5% dextrose with added KCl at a rate of 120-150 mL/kg/24hr. Nasogastric tube drainage to prevent aspiration of vomited secretions.

18. Surgery should take place when : Dehydration corrected Normal serum Na and K Chloride ion >90mmol/l Bicarbonate ion < 28 mmol/l

19. Surgery FREDET- RAMSTEDT’s PYLOROMYOTOMY >>> conventional open procedure LAPARASCOPIC PYLOROMYOTOMY > DOUBLE –Y PYLOROMYOTOMY>

20. PYLOROMYOTOMY FREDET-RAMSTEDT’s PYLOROMYOTOMY Division of pyloric muscle fibres without opening of bowel lumen. Done via right upper quadrant incision or laparoscopically. Caution not to open mucosa and avoid the prepyloric vein of Mayo.

21. LAPARASCOPIC PYLOROMYOTOMY Effective alternative Time to achieve full enteral feeding is significantly shorter ( 18.5hrs) in those treated laparoscopically vs those having open pyloromyotomy(23.9 hrs) Better cosmesis

22. A, Laparoscopic pyloromyotomy is started using a retractable blade. B, A spreader with grooves on the outer surface is used to complete the pyloromyotomy. Intact mucosal bulging along with independent muscular wall motion is confirmed.

23. DOUBLE –Y PYLOROMYOTOMY Has also been safely and effectively performed .

24. The double- Y pyloromyotomy (Alayet's pyloromyotomy) seems to be a good technique for the surgical management of IHPS. It offered a better functional outcome in terms of postoperative vomiting during the first postoperative week and weight gain during the first 10 days in our initial series while having a safety profile similar to Ramstedt's pyloromyotomy.

25. POST OPERATIVE CARE Patient started on feedings of glucose and water or an electrolyte infant formula ( eg - pedialyte) 4- 6 hrs after surgery. Gradual increase in oral fluids till feeds are accepted without emesis. Full feedings reached after 24 hrs from surgery. Antibiotic prophylaxis not required. Postoperative monitoring for 12 hrs required in patients with Hypoglycemia Hypothermia Respiratory depression and apnoea(due to CSF alkalosis and intraoperative hyperventilation)

26. COMPLICATIONS Duodenal perforation – may go undetected especially in laparoscopic RAMSTEDT’s. Continued postoperative bleeding Persistent vomiting (due to incomplete pyloromyotomy ) dehydration, weight loss and severe electrolyte imbalance . If persists >1 week, redo surgery. Foveolar cell hyperplasia (FCH), a rare cause of persistent gastric outlet obstruction.(This requires an extended pyloromyotomy) .

27. PROGNOSIS Excellent unless diagnosis is delayed and prolonged severe dehydration occurs. Once adequately treated, pyloric stenosis does not recur. Mortality is rare after pyloromyotomy.

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