Hypertrophic pyloric stenosis

Hypertrophic pyloric stenosis presents as forceful bile-free vomiting, with constipation rather than diarrhoea, in a baby about three weeks old[md]the range is 5 days to 5 months. It is more common in boys than in girls, and in the eldest child. To begin with he vomits one or two of his feeds each day, but as the obstruction gets worse, his vomiting becomes more constant and more projectile. Occasionally, he vomits brownish ''coffee grounds'. If he is not treated, he becomes dehydrated, alkalotic, hypochloraemic, hypokalaemic, and constipated; he loses weight, and becomes malnourished. Pyloric stenosis is not diagnosed as ]]it should be, and is too often thought to be yet another case of ''gastroenteritis'. But he does not have diarrhoea! Misdiagnosis is a tragedy, because surgery is not too difficult and is very effective.

You should be able to feel a child's hypertrophied pylorus as a smooth olive-shaped swelling to the right of the midline in his upper abdomen. If he cries you certainly won't be able to feel it, so sit him on his mother's lap, and feel for it while she feeds him from the breast. If you have difficulty, return a few minutes later, while she is still feeding him. Sit opposite her, look for waves of gastric peristalsis passing from his left upper quadrant towards the right. As they do so, his pyloric swelling will harden under your finger. Feel for the lump again. If you are persistent, you should be able to feel it in all cases[md]it establishes the diagnosis.

RAMSTEDT'S OPERATION RESUSCITATION. You can correct minor degrees of dehydration with oral fluids, but if a child becomes severely dehydrated and needs intravenous fluids, give him 20 ml/hour of half-strength Darrow's solution, and reduce this to 10 ml/hour when he is passing urine. Don't give him [mt]150[nd]180 ml/kg/24 hours. Provided he is not severely dehydrated, he should be ready for operation in 4 to 6 hours. Most children need intravenous fluids for about 4 hours preoperatively. He will usually stop vomiting as soon as his stomach is empty. If not, aspirate it through a nasogastric tube.

Alternatively, depending on what fluids you have, you may find this regime useful:

If he is only minimally dehydrated, with no significant electrolyte disturbance, give him 60 ml of Ringer's lactate orally. When his renal function is satisfactory, add 3 mmol of potassium chloride to each feed.

If he is moderately dehydrated, give him the first half of the calculated replacement intravenously as 5% dextrose in 0.45% saline, followed by 5% dextrose in 0.3% saline. As soon as he has passed urine, add 20 to 40 mmol/l of potassium to his intravenous fluid, depending on how ill he is.

If he is severely dehydrated, give him part of his initial replacement intravenously as 5% dextrose in 0.45% saline, partly as 0.9% saline, and partly as 5% dextrose in 0.3% saline. Add potassium as above.

ANAESTHESIA. (1) Ketamine (A 8.5). (2) Local anaesthesia. (3) Awake intubation and general anaesthesia. Sedate him preoperatively with chloral hydrate 300 mg, and place him on a Dennis Browne crucifix, with his limbs bandaged to prevent excessive movement. He will not be able to clear his throat, so suck out his pharynx frequently. Aspirate his stomach just before you anaesthetize him, and leave the tube down.

The maximum dose of 2% lignocaine you can use is 1 ml, so dilute this in 20 ml of saline and use it to infiltrate his skin and rectus sheath.

INCISION. Open his abdomen through a transverse incision, centered over the swelling to the right of the midline; it is usually half way between his xiphisternum and his umbilicus. Divide all his tissues in the line of the incision. Open his peritoneum.

Make the incision long enough (about 2.5 cm) to deliver the swelling into the wound. It may be quite difficult to find at first, because it may lie deep, partly covered by his transverse colon. Feel it with your finger. A small retractor may help to deliver it into the wound[md]it is always mobile. Hold the swelling between the thumb and index finger of your left hand. Keep your left middle finger against the distal extremity of his swollen pyloric muscle. Turn this so as to expose its antero- superior border.

Cut through the circular muscle along the length of his pylorus. Start just proximal to the white line (the junction of his pylorus and duodenum); at this point (the distal end of the swelling) the wall of his gut becomes thin suddenly. Extend the incision along the whole length of his thickened pylorus (the proximal end is less clear, because his stomach wall is also thickened). Spread its circular muscle, without harming the submucosa, which should bulge out of the incision. You are less likely to harm this, if you use the tip of a haemostat to separate the deeper muscle fibres.

Still using the tip of the haemostat, separate the fibres distally on the duodenal side, under the white line, so as to divide all circular fibres without perforating his duodenal mucosa. As you do this, continue to mark and protect his duodenum with the middle finger of your left hand.

CAUTION ! (1) Don't cut the white line at the site of the pyloric vein, or you may open his duodenum. (2) Don't sew up the muscle incision.

If, by mistake, you open his duodenal mucosa, close it with a few 4/0 atraumatic sutures, and suture omentum over the hole to fill the defect made by incising the muscle layer.

If a vessel bleeds, press with gauze for a few minutes; if this fails transfix it with 4/0 multifilament.

Return his stomach to his abdomen, and place omentum over the operation site. Close his peritoneum and posterior rectus sheath with continuous 3/0 chromic catgut. Close his anterior rectus sheath with interrupted 4/0 monofilament. Bring the skin edges together with fine monofilament.

POSTOPERATIVELY, if you succeeded in not perforating his duodenal mucosa, remove the nasogastric tube as he recovers from the anaesthetic. If you perforated it, leave the tube down for 24 to 48 hours, before you remove it and start feeding him. If he is alert and sucks well, start breast-feeding at 6 hours.

If he vomits frequently during the first 24 hours, wash out his stomach to remove the excess mucus.

If he is taking insufficient fluid by mouth to maintain an intake of 100 ml/kg/day, give him half-strength Darrow's solution.

If he continues to vomit after 24 hours, you may not have divided his pylorus adequately. If necessary, operate again. Wait until 14 days, if you can; but it is better to operate earlier than to let him get worse.

Fig. 28-4 ABNORMALITIES OF THE OMPHALO-MESENTERIC DUCT, are mostly rare. A, a harmless cyst in the cord. B, an umbilicus covered with red intestinal mucosa, which may dip down into the abdominal wall. Don't confuse this with an umbilical granuloma, which is much more common. C, a mucosa-lined cyst communicating with the skin. D, a communication between the ileum and the umbilicus. E, gut may herniate through this communication. F, the duct may persist as a cord around which a volvulus may form (28.3). G, a loop of gut may be caught across this cord. H, the duct may form a cyst. I, the remains of the duct may persist as Meckel's diverticulum, and become inflamed. J, some gastric mucosa in the duct may ulcerate and bleed. Adapted from Ravitch et. al., ''Paediatric Surgery'. Fig. 88-17, Yearbook Medical, with kind permission.