INFANTILE (IDIOPATHIC/BENIGN) HYPERTROPHIC PYLORIC STENOSIS

In hypertrophic pyloric stenosis, the musculature of the pylorus and adjacent antrum is grossly hypertrophied, the hypertrophy being maximum in the pylorus itself.

• It occur in approximately 3 in 1000 live births and is the most common surgical cause of vomiting in infancy. Males are affected more commonly as compared to females and characteristically the first born male child is affected.
• The condition is most commonly seen at 4 week after birth ranging from 3rd week to 7th week in rare occasions. Only 20% of infants are symptomatic from birth.
• The diagnosis of pyloric stenosis usually can be made on clinical examination by palpation of the typical “olive” in the upper quadrant and the presence of visible gastric waves on the abdomen. In healthy infants when palpation is difficult, feeding can help in the diagnosis. After feeding peristalsis waves may be visible. After the infants vomits, the abdominal musculature is more relaxed and the mass is easier to palpate.
• “When the olive cannot be palpated, USG can diagnose the condition accurately in 95% of patients”.
• Surgical operation done for hypertrophic pyloric stenosis is Fredet- Ramstedt pyloromyotomy. (In it the pyloric mass is split without cutting the mucosa)

Ref: Schwartz 9/e, Page 1425; Bailey & Love 25/e, Page 78; Rudolph’s Pediatrics 21/e, Chapter 17

Laboratory Findings of congenital hypertrophic pyloric stenosis:

Infants with HPS present with nonbilious vomiting that becomes increasingly projectile over the course of several days to weeks.

Infants with HPS develop a hypochloremic, hypokalemic metabolic alkalosis.

Dehydration causes elevated hemoglobin and hematocrit. Mild unconjugated bilirubinemia occurs in 2%–5% of cases.

The urine pH is high initially but eventually drops because hydrogen ions are preferentially exchanged for sodium ions in the distal tubule of the kidney as the hypochloremia becomes severe. 

Infants with hypertrophic pyloric stenosis (HPS) present with nonbilious vomiting that becomes increasingly projectile over the course of several days to weeks.

The diagnosis of pyloric stenosis usually can be made on physical examination by palpation of the typical “olive” in the right upper quadrant and the presence of visible gastric waves on the abdomen.

When the olive cannot be palpated, ultrasonography can diagnose the condition accurately in 95% of patients.

Criteria for ultrasonographic diagnosis include a channel length of >16 mm and pyloric thickness of >4 mm.

Ramstedt pyloromyotomy is the treatment of choice and consists of incision down to the mucosa along the pyloric length.

Hypertrophic pyloric stenosis (HPS) is postnatal muscular hypertrophy of the pylorus.

HPS occurs in approximately 1–8 per 1000 births and originally was believed to occur in first-born males between 3 and 6 weeks of age.

Ans. is ‘b’ i.e., Erythromycin

o Maternal and infant use of erythromycin and other macrolide antibiotics have been reported as risk factors for infantile hypertrophic pyloric stenosis (IHPS).

Ans. is ‘c’ i.e., Around 2 weeks after birth

• The symptoms vomiting usually starts after 3 weeks of age but symptoms may develop as early as 1^st week of life and as late as 5 months of life.  – Nelson
  

Congenital hypertrophic pyloric stenosis

• Hypertrophic pyloric stenosis is the commonest surgical disorder of the stomach during infancy.
• Pylorus is thickened and elongated and its lumen is narrowed due to hypertrophy of circular muscle fibers of pylorus.
• More common in boys.

o More common in infants of blood group ‘B’ and ‘O’.

o Associated congenital defects are —> Tracheoesophageal fistula and hypoplasia or agenesis of inferior labial frenulum.

o May be associated with Turner syndrome, Trisomy 18.

o Symptoms are not present at birth.

The vomiting usually starts after 3 weeks of age.

Ans. is ‘b’ i.e., Diarrhea

Diarrhea does not occur in pyloric stenosis, there is vomiting.

Treatment of congenital hvpertrophic pyloric stenosis

o The surgical procedure of choice is Pyloromyotomy.

o The traditional Ramstedt procedure is performed through a short transverse skin incision.

o Other methods are —>  i) Atropine therapy         ii) Endoscopic ballon dilatation

Ans is ‘d’ ie Ultrasonography is diagnostic test

Hypertrophic Pyloric Stenosis (HPS)

• The musculature of the pylorus and adjacent antrum is grossly hypertrophied, the hypertrophy being maximum in the pylorus itself.
• It occurs in approximately 3 in 1000 live birth and is the most common surgical cause of vomitting in infancy.
• M > F (4 : 1)*
• Characterstically the first born male child is affected.
• The conditon is most commonly seen at 4 wks after birth ranging from the 3^rd wk to on rare occasion, the 7th. However, 20% of infants are symptomatic from birth, and most are symptomatic within the first 2 months after birth.
• Non-bilious vomiting, becoming increasingly projectile, occurs over several days to weeks. Eventually the infant will develop a nearly complete obstruction by the second to fourth week of life and will not be able to hold down even clear liquids. This invariably proceeds to severe dehydration if not t/t.
• These infants develop a metabolic alkalosis with severe depletion of potassium and chloride ions.
• ” The diagnosis of pyloric stenosis usually can be made on physical examination by palpation of the typical ‘olive’ in the right upper quadrant and the presence of visible gastric waves on the abdomen.
• When the olive cannot be palpated, ultrasound in experienced hands will diagnose the condition accurately in 95 percent of pts.” – Schwartz.

Treatment

• Pyloric stenosis is never a surgical emergency although dehydration and electrolyte abnormalities may present a medical emergency
• Fluid resuscitation and correction of electrolyte abnormalities and metabolic alkalosis is essential before surgery.
• Surgery : Fredet-Ramstedt pyloromyotomy. (In it the pyloric mass is split without cutting the mucosa)

Also know

• Administration of erythromycin in early infancy has been linked to the subsequent development of HPS.
• Jaundice may be seen in HPS, although cause is not clear.

Ans is ‘d’ i.e. High gastric residue 

Ultrasound is the investigation of choice. It can diagnose HPS accurately in 95% of patients. Criteria for ultrasound diagnosis of HPS:

a.     channel length of > 16mm

b.  pyloric thickness of > 4mm

“The diagnosis of pyloric stenosis usually can be made on physical examination by palpation of the typical “olive” in the right upper quadrant and the presence of visible gastric waves on the abdomen. When the olive cannot be palpated, ultrasonography can diagnose the condition accurately in 95% of patients. Criteria for ultrasonographic diagnosis include a channel length of >16 mm and pyloric thickness of >4 mm. “- Schwartz

Ans. is ‘b’ i.e., The pyloric tumor is best felt during feeding

Option (a)

– HPS classically presents in a first born male child between 3 and 6 weeks of age. However, children outside this age range also are commonly seen, and the disease is not restricted to either males or first borne children.

Option (d)

–  After vomitting the child has voracious appetite, that leads to a cycle of feeding and vomiting.

Option (c)

“Greater awareness of pyloric stenosis has led to earlier identification of patients with fewer instances of chronic malnutrition and severe dehydration” -Nelson I7/e

Option (b)

– The diagnosis of pyloric stenosis is usually made by palpation – of the typical olive shaped hard pyloric mass located in right upper quadrant. In healthy infants when palpation is difficult, feeding can help in the diagnosis. After feeding gastric peristalsis waves may be visible. After the infant vomits, the abdominal musculature is more relaxed and the mass is easier to palpate. Sedation can also be used to facilitate examination but is usually unnecessary. In cases of doubt ultrasound can confirm the diagnosis.

Ans. is ‘c’ i.e., Metabolic alkalosis with paradoxical aciduria 

• Repetitive vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic (paradoxical aciduria)
• Cause of paradoxical aciduria

– Initially the kidney compensate for metabolic alkalosis by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate. But gradually as the body stores of sodium and especially potassium become depleted, kidney starts retaining these ions in exchange of hydrogen ions. thus the urine becomes acidic and metabolic alkaline state is further aggravated.

Ans. is ‘b’ i.e., Hypochloremic alkalosis 

Heller’s myotomy is the surgery for Achlasia Cardia, not HPS.

Ans is ‘a’ ie. U/S is not useful for diagnosis

• Option A is absolutely wrong statement as U/S is the inv. of choice for hypertrophic pyloric stenosis.
• Already explained in Previous question.

Ans is ‘b’ i.e. Hypokalemic alkalosis 

Answer is B (The pyloric tumor is best felt during feeding)

• First born male child is characteristically most commonly affected
• It is four times more common in males as in females .
• The condition does not present at birth. It is most commonly seen 4 weeks after birth

Presentation

• Vomiting is the presenting symptom (child vomits milk and no bile is presentQ)
• Immediately after vomiting the child is hungry i.e. loss of appetite does not occur.
• Weight loss is striking and rapidly the infant becomes emaciated and dehydrated.

However, greater awareness of pyloric stenosis has led to earlier identification of patients and hence with fewer incidences of chronic malnutrition and severe dehydration – Nelson 10th/1130

• The diagnosis is usually made with a test feed : In this the baby is fed with the bottle by a nurse or mother and surgeon :

– palpates the abdomen with a warm hand to detect the lump

– observes the characteristic peristatic waves pass across the upper abdomen.

• Pathologicall^y musculature of pylorus adjacent to antrum is grossly hypertrophied
• Ultrasonographv is the investigation of choice
• Hyperchloremic alkalosis is common and following diagnosis first concern is to correct metabolic abnormalities -child is rehydrated with dextrose saline & potassiumQ
• Treatment of choice Ramsted’s operation – ‘Pyloromyotomy’

The answer is B (Hypochloremic alkalosis) :

The vomiting of hydrochloric acid results in hypochloremia and alkalosis i.e. hypochloremic alkalosis.

Characteristically firstborn male infant is most commonly affected (Males > Females) 

The onset of symptoms has its, peak incidence between the third & sixth weeks of life and it is rarely present at birth.

The most common presenting symptom is vomiting & accounts for the hypochloremic alkalosis.

The procedure of choice is a Halsted’s operation & not a Heller’s myotomy.

– Heller myotomy is the procedure of choice for achalasia cardia.

Ans. C i.e. Metabolic alkalosis with paradoxical aciduria

Ans. A i.e. Presence of palpable lump

Ans. B i.e. Diarrhoea

Congenital hypertrophic pyloric stenosis

• Presents about 4 weeks after birth,
• Weight loss,
• Hypochloremic alkalosis,
• Fluid of choice: Isotonic normal saline