What are the possible causes and recommended work‑up for white frothy vomit in a newborn?

White Vomit in Neonates: Diagnostic Approach and Management

Critical First Distinction: White vs. Bilious Vomit

White or non-bilious vomit in a neonate is fundamentally different from bilious (green/yellow) vomiting and suggests obstruction proximal to the ampulla of Vater or a non-obstructive cause, whereas bilious vomiting is a surgical emergency until proven otherwise. 1

White, frothy vomit typically indicates:

• Gastroesophageal reflux (GER) – the most common cause of non-bilious vomiting in infants 2
• Hypertrophic pyloric stenosis (HPS) – if projectile and forceful 2
• Overfeeding or swallowed air – benign causes 2
• Functional vomiting disorders – stress-related or behavioral 3

Immediate Red-Flag Assessment

Evaluate for life-threatening conditions that require urgent intervention:

• Bilious (green) vomit – indicates obstruction distal to ampulla of Vater; 20% of cases in first 72 hours represent midgut volvulus requiring immediate surgical evaluation 1
• Toxic appearance with fever – suggests sepsis, meningitis, bacterial pneumonia, or urinary tract infection requiring prompt recognition and treatment 2
• Severe dehydration (≥10% fluid deficit) – manifested by prolonged skin tenting >2 seconds, cool extremities, decreased capillary refill, and lethargy mandates immediate IV fluid resuscitation 2
• Bloody vomitus – indicates mucosal damage from serious pathology 2
• Altered mental status or inconsolable crying – may signal increased intracranial pressure, metabolic disorder, or intussusception 2, 4

Age-Specific Differential Diagnosis for White Vomit

Newborns (0-2 weeks)

• Gastroesophageal reflux (GER) – intermittent regurgitation from birth with normal weight gain; imaging not indicated 2
• Overfeeding – benign; adjust feeding volume and frequency 2
• Duodenal atresia – presents with "double bubble" sign on radiograph, though vomit may initially appear white before becoming bilious 1, 2
• Sepsis or meningitis – fever, lethargy, poor feeding; requires immediate evaluation 2, 4
• Metabolic disorders – inborn errors of metabolism, congenital adrenal hypoplasia 4

Infants 2 weeks to 3 months

• Hypertrophic pyloric stenosis (HPS) – forceful, projectile non-bilious vomiting typically beginning at 3-6 weeks of age; distinct from GER by progressive nature and absence of regurgitation from birth 2
• Gastroesophageal reflux (GER) – continues to be most common cause if present from birth with normal weight gain 2
• Intussusception – though more common at 6-18 months, can occur earlier; associated with intermittent crampy pain, "currant jelly" stools, lethargy 5, 2

Diagnostic Work-Up Algorithm

Step 1: Clinical History and Physical Examination

Document specific characteristics:

• Vomitus appearance – white/milky, frothy, projectile vs. effortless regurgitation 2, 4
• Timing – present from birth (suggests GER) vs. onset at 3-6 weeks (suggests HPS) 2
• Feeding pattern – normal weight gain (benign GER) vs. poor weight gain or weight loss (pathologic) 2, 3
• Associated symptoms – fever, altered mental status, abdominal distension, bloody stools 2, 4
• Stool pattern – normal, absent, bloody, "currant jelly" 2

Perform focused abdominal examination:

• Palpate for masses (pyloric "olive" in HPS, intussusception mass) 2, 6
• Assess for distension, tenderness, bowel sounds 2
• Evaluate hydration status: skin turgor, mucous membranes, capillary refill, extremity temperature 2

Step 2: Imaging Based on Clinical Presentation

For suspected hypertrophic pyloric stenosis (projectile non-bilious vomiting at 3-6 weeks):

• Abdominal ultrasound is the initial imaging modality of choice 2
• Upper GI series should NOT be performed if ultrasound confirms HPS 2
• Upper GI series is reserved for atypical presentations or to exclude malrotation if bilious vomiting develops 2

For uncomplicated GER with normal weight gain:

• No imaging is indicated 2
• Clinical diagnosis based on intermittent regurgitation from birth and normal growth 2

If any concern for obstruction or atypical features:

• Obtain abdominal radiograph immediately as first imaging study to identify obstruction patterns 2
• If radiograph shows "double bubble" or other obstruction signs, proceed to upper GI series or surgical consultation 1, 2

For suspected intussusception (intermittent pain, lethargy, "currant jelly" stools):

• Ultrasound should be the initial imaging modality 5, 2

Step 3: Laboratory Evaluation

Obtain laboratory studies when:

• Severe dehydration is present – check serum electrolytes, blood gases, renal function 4
• Toxic appearance or fever – complete blood count, blood cultures, urinalysis 2, 4
• Concern for metabolic disorder – glucose, ammonia, lactate, metabolic screen 4
• Bloody stools – stool cultures, stool white blood cell count 2

Management Approach

For Benign GER (Normal Weight Gain, No Red Flags)

• Reassurance and conservative management – most cases resolve with age 2
• Small, frequent feedings; upright positioning after feeds 2
• No pharmacologic therapy needed for uncomplicated GER with normal growth 2

For Hypertrophic Pyloric Stenosis

• Surgical consultation for pyloromyotomy once diagnosis confirmed by ultrasound 2
• Correct electrolyte abnormalities (hypochloremic, hypokalemic metabolic alkalosis) before surgery 4

For Dehydration

• Mild to moderate dehydration – oral rehydration therapy is cornerstone of treatment 2
• Severe dehydration – immediate IV fluid resuscitation 2
• Ondansetron (0.2 mg/kg oral; 0.15 mg/kg parenteral; maximum 4 mg) may be used for persistent vomiting preventing oral intake 4

For Suspected Obstruction or Surgical Causes

• Stop oral fluids/feeds immediately 4
• Nasogastric tube decompression for bilious vomiting 4
• Immediate surgical consultation 1, 5

Critical Pitfalls to Avoid

• Never dismiss vomiting as "just reflux" without confirming normal weight gain and absence of red flags – failure to thrive, projectile vomiting, or onset at 3-6 weeks suggests pathology 2, 3
• Do not confuse GER (present from birth, normal growth) with HPS (onset 3-6 weeks, progressive, projectile) – this distinction determines whether imaging is needed 2
• Normal abdominal radiographs do not exclude malrotation or volvulus – if bilious vomiting develops, proceed to upper GI series regardless of radiograph findings 1, 2
• Never use antidiarrheal agents (loperamide, kaolin-pectin) in infants – they are ineffective and can cause severe complications including ileus and death 2
• Do not perform upper GI series for typical HPS when ultrasound has confirmed the diagnosis – reserve upper GI for bilious vomiting or atypical presentations 2
• Recognize that vomiting may be the presenting symptom of non-GI conditions – meningitis, sepsis, urinary tract infection, metabolic disorders, increased intracranial pressure must be actively excluded 2, 4