Infantile hypertrophic pyloric stenosis

1. INFANTILE
HYPERTROPHIC PYLORIC
STENOSIS
PP Mubashir

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

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

9. CLINICAL PRESENTATION
 ONSET at 2 to 8 weeks of age
(commonly at around one month of age)
 SYMPTOMS
 Projectile ,forcible,frequent episodes of
nonbilious 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 >4mm
 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

16. 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

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

18. 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 120-150mL/kg/24hr.
 Nasogastric tube drainage to prevent aspiration of vomited secretions.

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

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

21. 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 andavoid the prepyloric
vein of Mayo.

22. 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

23. 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.

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

25.  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.

26. 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)

27. 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) .

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

29. Thanks