Rosen & Barkin's 5-Minute Emergency Medicine Consult (592 page)

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  Nephrol Dial Transplant.
  2012;27:3391–3394.
  
• Lane D, Takher S. Diagnosis and management of UTI and pyelonephritis.
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  2011;29:539–552.
  
• Piccoli BG, Cresto E, Ragni F, et al. The clinical spectrum of acute uncomplicated pyelonephritis from an emergency medicine perspective.
  Int J Antimicrob Agents
  . 2008;31(suppl S):S46–S53.
  
• Talan D, Krishnadasan A, Abrahamian F, et al. Prevalence and risk factor analysis of trimethoprim-sulfamethoxazole and fluoroquinolone resistant
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See Also (Topic, Algorithm, Electronic Media Element)

• Pelvic Inflammatory Disease
  
• Urinary Tract Infection, Adult
  
• Urinary Tract Infection, Pediatric
  

The author gratefully acknowledges the contribution of Ingrid Carter for previous editions of this chapter.

CODES

• 590.10 Acute pyelonephritis without lesion of renal medullary necrosis
  
• 590.80 Pyelonephritis, unspecified
  
• 592.0 Calculus of kidney
  

BASICS

• Postnatal hypertrophy and hyperplasia of the circular smooth muscle cell layer causing a thickened pylorus and antrum leading to progressive gastric outlet obstruction
  
• Neuronal nitric oxide synthase (NOS-1) may be a genetic susceptibility locus.
  
• Administration of erythromycin in infants during 1st 2 wk of life may increase risk of hypertrophic pyloric stenosis.
  
• Jaundice due to transient glucuronyl transferase deficiency
  
• Adult: Caused by peptic ulcer disease
  

• Most common cause of GI obstruction in infants; incidence 1/150 males, 1/750 females (average: 3/1,000 live births)
  
• Males affected 5× more commonly than females; firstborn most common
  
• Familial, 15%:
  
  • Child of affected parent has 7% incidence.
    
  • Recurrence risk in subsequent male children is 10%; 2% in females.
    

DIAGNOSIS

• Vomiting:
  
  • Gradual onset, usually beginning at around 3–6 wk of age; rarely after 12 wk of age
    
  • Progressive, usually becoming projectile
    
  • Nonbilious
    
  • May be blood tinged (secondary to esophagitis, gastritis, gastric ulceration)
    
  • Progressively worsening
    
  • Postprandial
    
• Represents the hypertrophied pylorus:
  
  • Confirms diagnosis
    
• Constipation or small amount of stools
  
• “Lean and hungry” infant early in course; dehydrated and uninterested in feeding late in course; failure to thrive
  
• Variable dehydration and wasting depending on duration of symptoms
  
• Jaundice in 8% of children
  
• Adult presents with vomiting, anorexia, early satiety, and epigastric pain.
  

• Often normal unless a relaxed abdomen
  
• May feel olive-shaped mass at lateral margin of the right rectus abdominis muscle in the right upper quadrant (80% of patients), often after vomiting:
  
  • Best felt immediately after vomiting or after the stomach is emptied via gastric suction as the dilated body of the stomach overlies the pylorus
    
  • Represents the hypertrophied pylorus:
    
    • Helps confirm diagnosis
      
    • Peristaltic waves moving from the left to right in the left upper quadrant, seen best after feeding or just prior to vomiting
      

If “olive” palpable, further diagnostic evaluation may be unnecessary and surgical consultation should be sought; otherwise, imaging studies are indicated.

• Electrolytes, BUN/creatinine, glucose:
  
  • Hypokalemic, hypochloremic metabolic alkalosis
    
  • Normal electrolytes do not exclude the diagnosis.
    
• Bilirubin elevated, usually unconjugated
  
• CBC if blood in emesis
  
• Urinalysis for hydration
  

• Abdominal US:
  
  • Study of choice
    
  • US diagnosis hinges on identification and measurement of pyloric muscle mass (3 mm ring thickness, 1.5 cm pylorus channel or muscle length, and 10–14 mm pylorus diameter) and observation of fluid movement through the pylorus.
    
  • Positive predictive value approaches 100%; 19% false negatives.
    
  • Serial US for equivocal or negative study
    
• Upper GI series:
  
  • String sign representing contrast passing through a narrowed gastric outlet
    
  • 95% accurate
    
  • Remove contrast from the stomach after the study to prevent aspiration.
    
• Supine abdominal film:
  
  • Not diagnostic; rarely helpful
    
  • Dilated stomach and no air distal to the pylorus
    
  • Most useful with other views to begin evaluation for other abdominal pathology
    

• GI anatomic/functional disorder:
  
  • Gastroesophageal reflux
    
  • Hiatal hernia
    
  • Obstruction/atresia
    
  • Gastric or duodenal web
    
• Infection:
  
  • Gastroenteritis
    
  • UTI
    
  • Sepsis
    
• Metabolic:
  
  • Adrenal insufficiency
    
  • Inborn error of metabolism
    
• Feeding problems:
  
  • Psychosocial: Poor maternal interaction or stress
    
  • Chalasia
    
  • Formula intolerance
    
  • Overfeeding
    
• Drug withdrawal
  
• Increased intracranial pressure
  

TREATMENT

Fluid resuscitation if significant volume deficit

• IV access
  
• Rapid bedside glucose test to exclude hypoglycemia
  
• Correct volume deficit with 20 mL/kg bolus of 0.9% normal saline IV; may repeat.
  

• Correct electrolyte abnormalities.
  
• Hydrate with dextrose-containing solution after fluid resuscitation at 1–1.5× maintenance rate:
  
  • Add potassium after ensuring adequate urine output.
    
• Insert nasogastric tube to decompress the stomach.
  
• Restrict oral intake.
  
• Consult pediatric surgeon for pyloromyotomy.
  
• Adult: Proton pump antagonist (lansoprazole or omeprazole)
  

• Lansoprazole: 30 mg daily PO
  
• Omeprazole: 20 mg daily PO
  

FOLLOW-UP

• All pediatric patients should be admitted to the hospital for rehydration and surgical correction with either an umbilical pyloromyotomy or laparoscopic pyloromyotomy.
  
• Adult patients: Admit as necessary for rehydration; may be scheduled for elective pyloromyotomy if proton pump inhibitors fail to improve this condition.