History

Fact Explanation
Non bilious projectile vomiting following a feed occurring at around 6 weeks of age. Due to pyloric muscle hypertrophy associated with clusters of tonic and phasic pyloric contractions beginning postnatally [1].
Blood stained vomitus. Due to gastric stasis and gastro-oesophageal reflux leading to superficial ulceration of the gastric and esophageal mucosa [2].
Poor weight gain, weight loss, decreased urinary output, lethargy, etc. These are features of dehydration and malnutrition which occur as a result of the gastric outlet obstruction and vomiting after each feed [3].
Jaundice. This maybe due to various associations of the condition such as prematurity and abnormal glucuronyl transferase activity as a result of starvation [2].
It is more common among first born males. Four times more likely to occur in first born male children. [4]
References
  1. KAWAHARA H. Intravenous atropine treatment in infantile hypertrophic pyloric stenosis. [online] 2002 July, 87(1):71-74 [viewed 07 August 2014] Available from: doi:10.1136/adc.87.1.71
  2. DODGE J A. Infantile hypertrophic pyloric stenosis in Belfast, 1957-1969.. Archives of Disease in Childhood [online] 1975 March, 50(3):171-178 [viewed 07 August 2014] Available from: doi:10.1136/adc.50.3.171
  3. COOK-SATHER SCOTT D., TULLOCH HEATHER V., CNAAN AVITAL, NICOLSON SUSAN C., CUBINA MARIA L., GALLAGHER PAUL R., SCHREINER MARK S.. A Comparison of Awake Versus Paralyzed Tracheal Intubation for Infants with Pyloric Stenosis. Anesthesia & Analgesia [online] 1998 May, 86(5):945-951 [viewed 07 August 2014] Available from: doi:10.1213/00000539-199805000-00006
  4. KROGH C., GORTZ S., WOHLFAHRT J., BIGGAR R. J., MELBYE M., FISCHER T. K.. Pre- and Perinatal Risk Factors for Pyloric Stenosis and Their Influence on the Male Predominance. American Journal of Epidemiology [online] December, 176(1):24-31 [viewed 10 August 2014] Available from: doi:10.1093/aje/kwr493

Examination

Fact Explanation
A firm, nontender, mobile and hard pylorus that is 1-2 cm in diameter (felt as an olive), present in the right upper quadrant at the lateral edge of the rectus abdominus muscle. Due to pyloric muscle hypertrophy [1].
Visible gastric peristalsis. Strong peristaltic activity occurs in an effort to overcome the pyloric obstruction [2].
Depressed fontanelles, dry mucous membranes, poor skin turgor, etc. These are features of dehydration which occurs as a result of the vomiting of gastric contents [3].
Anthropometric examination including length and weight of the infant. Malnutrition can occur as a result of the gastric outlet obstruction and vomiting after each feed [3].
References
  1. KAWAHARA H. Intravenous atropine treatment in infantile hypertrophic pyloric stenosis. [online] 2002 July, 87(1):71-74 [viewed 07 August 2014] Available from: doi:10.1136/adc.87.1.71
  2. ROBERTSON DE. CONGENITAL PYLORIC STENOSIS Ann Surg [online] 1940 Oct, 112(4):687-699 [viewed 07 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1388024
  3. COOK-SATHER SCOTT D., TULLOCH HEATHER V., CNAAN AVITAL, NICOLSON SUSAN C., CUBINA MARIA L., GALLAGHER PAUL R., SCHREINER MARK S.. A Comparison of Awake Versus Paralyzed Tracheal Intubation for Infants with Pyloric Stenosis. Anesthesia & Analgesia [online] 1998 May, 86(5):945-951 [viewed 07 August 2014] Available from: doi:10.1213/00000539-199805000-00006

Differential Diagnoses

Fact Explanation
Viral gastroenteritis. It also presents with vomiting and dehydration but diarrhea is a prominent feature [1].
Urinary tract infection. It also presents with failure to thrive and vomiting, but fever, malodorous urine and polyuria also occur [2].
Adrenal insufficiency. It also presents with vomiting and dehydration, but skin pigmentation also occurs [3].
References
  1. CHEN S.-Y., CHANG Y.-C., LEE Y.-S., CHAO H.-C., TSAO K.-C., LIN T.-Y., KO T.-Y., TSAI C.-N., CHIU C.-H.. Molecular Epidemiology and Clinical Manifestations of Viral Gastroenteritis in Hospitalized Pediatric Patients in Northern Taiwan. Journal of Clinical Microbiology [online] December, 45(6):2054-2057 [viewed 07 August 2014] Available from: doi:10.1128/JCM.01519-06
  2. CHANG STEVEN L., SHORTLIFFE LINDA D.. Pediatric Urinary Tract Infections. Pediatric Clinics of North America [online] 2006 June, 53(3):379-400 [viewed 07 August 2014] Available from: doi:10.1016/j.pcl.2006.02.011
  3. GRANT D B, BARNES N D, DUMIC M, GINALSKA-MALINOWSKA M, MILLA P J, VON PETRYKOWSKI W, ROWLATT R J, STEENDIJK R, WALES J H, WERDER E. Neurological and adrenal dysfunction in the adrenal insufficiency/alacrima/achalasia (3A) syndrome.. Archives of Disease in Childhood [online] 1993 June, 68(6):779-782 [viewed 08 August 2014] Available from: doi:10.1136/adc.68.6.779

Investigations - for Diagnosis

Fact Explanation
Thickened pyloric muscle on abdominal ultrasonography (thickness greater than 4 mm). Ultrasound is non-invasive, does not use ionising radiation, and reduces the need to perform repeated clinical examinations [1].
The "shoulder sign" and "string sign" on a barium meal. These signs occur due to the compression of the duodenal bulb along with indentation of the gastric antrum (shoulder sign), and a narrow and elongated pylorus (string sign) [2].
References
  1. GODBOLE P, SPRIGG A, DICKSON J A, LIN P C. Ultrasound compared with clinical examination in infantile hypertrophic pyloric stenosis.. Archives of Disease in Childhood [online] 1996 October, 75(4):335-337 [viewed 08 August 2014] Available from: doi:10.1136/adc.75.4.335
  2. DOYLE D., O’NEILL M., KELLY D.. Changing trends in the management of Infantile Hypertrophic Pyloric Stenosis-an audit over 11 years. Ir J Med Sci [online] 2005 April, 174(2):33-35 [viewed 08 August 2014] Available from: doi:10.1007/BF03169126

Investigations - Fitness for Management

Fact Explanation
Serum electrolyte levels and arterial blood gas analysis revealing a Hypochloremic, hypokalemic metabolic alkalosis. vomiting of gastric contents results in excessive loss of hydrogen chloride and potassium chloride. Also, diminished secretion of pancreatic bicarbonate into the gastrointestinal tract as a result of the inability of hydrogen ions entering the duodenum contributes to the alkalosis [1].
Elevated blood urea nitrogen levels and serum creatinine levels. The dehydration resulting from the vomiting of gastric contents would lead to reduced renal blood flow, and subsequent acute renal failure [2].
References
  1. Pyloric Stenosis. Pediatrics in Review [online] 2000 July, 21(7):249-250 [viewed 08 August 2014] Available from: doi:10.1542/pir.21-7-249
  2. SCHRIER ROBERT W., WANG WEI, POOLE BRIAN, MITRA AMIT. Acute renal failure: definitions, diagnosis, pathogenesis, and therapy. J. Clin. Invest. [online] 2004 July, 114(1):5-14 [viewed 08 August 2014] Available from: doi:10.1172/JCI22353

Investigations - Screening/Staging

Fact Explanation
Elevated unconjugated bilirubin levels in blood. This maybe due to various associations of the condition such as prematurity and abnormal glucuronyl transferase activity as a result of starvation [1].
References
  1. DODGE J A. Infantile hypertrophic pyloric stenosis in Belfast, 1957-1969.. Archives of Disease in Childhood [online] 1975 March, 50(3):171-178 [viewed 07 August 2014] Available from: doi:10.1136/adc.50.3.171

Management - General Measures

Fact Explanation
Immediate intravenous infusion of a fluid bolus (20 mL/kg) of crystalloids. To overcome the dehydration which occurs as a result of the vomiting of gastric contents [1].
Maintenance of proper fluid and electrolyte balance. 5% dextrose in 0.25% or 0.33% sodium chloride with 2-4 mEq KCl per 100 mL replacement. Vomiting of gastric contents results in excessive loss of hydrogen chloride and potassium chloride [2].
References
  1. COOK-SATHER SCOTT D., TULLOCH HEATHER V., CNAAN AVITAL, NICOLSON SUSAN C., CUBINA MARIA L., GALLAGHER PAUL R., SCHREINER MARK S.. A Comparison of Awake Versus Paralyzed Tracheal Intubation for Infants with Pyloric Stenosis. Anesthesia & Analgesia [online] 1998 May, 86(5):945-951 [viewed 07 August 2014] Available from: doi:10.1213/00000539-199805000-00006
  2. Pyloric Stenosis. Pediatrics in Review [online] 2000 July, 21(7):249-250 [viewed 08 August 2014] Available from: doi:10.1542/pir.21-7-249

Management - Specific Treatments

Fact Explanation
Corrective surgery (treatment of choice). Ramstedt pyloromyotomy: the underlying antro-pyloric mass is split leaving the mucosal layer intact. It is curative for gastric outlet obstruction and the prognosis is excellent [1].
Intravenous atropine injection of 0.01 mg/kg. clusters of tonic and phasic pyloric contractions are transiently abolished by atropine and transpyloric flow is improved [2].
References
  1. Pyloric Stenosis. Pediatrics in Review [online] 2000 July, 21(7):249-250 [viewed 08 August 2014] Available from: doi:10.1542/pir.21-7-249
  2. KAWAHARA H. Intravenous atropine treatment in infantile hypertrophic pyloric stenosis. [online] 2002 July, 87(1):71-74 [viewed 08 August 2014] Available from: doi:10.1136/adc.87.1.71