What are the differential diagnoses for a girl presenting with vomiting and nausea?

Differential Diagnoses for Nausea and Vomiting in Girls

The differential diagnosis of nausea and vomiting in girls is extensive and includes gastrointestinal, central nervous system, endocrine/metabolic, infectious, and psychiatric conditions, with the specific age of the patient critically determining which diagnoses take priority. 1

Age-Specific Critical Considerations

Infants and Toddlers (0-3 years)

Bilious vomiting is a surgical emergency until proven otherwise and requires immediate evaluation for malrotation with midgut volvulus, which can cause complete intestinal necrosis within hours. 2, 3, 4

• Intussusception presents with the classic triad of crampy abdominal pain (manifested as inconsolable crying or drawing up legs), "currant jelly" stools, and progression to bilious vomiting 2, 3
• Malrotation with volvulus can present at any age beyond the newborn period, not just in neonates, and any bilious vomiting mandates immediate upper GI contrast study regardless of normal X-ray findings 2, 4
• Pyloric stenosis occurs in infants 2 weeks to 3 months old with non-bilious projectile vomiting 3

School-Age Children and Adolescents

• Pregnancy must be considered in any girl of childbearing age as the most common endocrinologic cause 5
• Cyclic vomiting syndrome may result from migraine, metabolic disorders (amino acidopathies, organic acidurias, fatty acid oxidation defects), or epilepsy 6

Gastrointestinal Causes

Obstructive Disorders

• Intestinal obstruction from adhesions, hernias, or masses presents with bilious vomiting, abdominal distension, and absent bowel sounds 1
• Intestinal atresia (duodenal, jejunal, ileal) in neonates 4
• Hirschsprung disease causing functional obstruction 4

Inflammatory and Infectious Conditions

• Acute gastroenteritis is the most common cause of acute vomiting but should only be diagnosed after excluding more serious conditions 7
• Appendicitis presents with fever, abdominal tenderness, and progression from periumbilical to right lower quadrant pain 2
• Pancreatitis with elevated amylase and lipase 8

Functional and Motility Disorders

• Gastroparesis (diabetic, idiopathic, or postsurgical) causes nausea, vomiting, and postprandial fullness, occurring in 20-40% of diabetic patients and 25-40% of those with functional dyspepsia 1
• Functional dyspepsia affects approximately 20% of the general population 1
• Gastroesophageal reflux disease (GERD) with poor weight gain or blood in vomit distinguishes it from benign reflux 2

Central Nervous System Causes

• Increased intracranial pressure from tumors, hydrocephalus, or pseudotumor cerebri causes vomiting with headache, altered mental status, or papilledema 1, 2
• Meningitis or encephalitis presents with fever, toxic appearance, altered mental status, and meningeal signs 2, 4
• Migraine headaches particularly in adolescent girls 5, 9
• Seizure disorders including temporal lobe epilepsy 2, 6

Endocrine and Metabolic Causes

• Pregnancy in any postmenarchal girl 5, 9
• Diabetic ketoacidosis with hyperglycemia, acidosis, and dehydration 1, 8
• Adrenal insufficiency (Addison disease) 8
• Hypercalcemia from various causes 8
• Uremia from renal failure 6, 8
• Inborn errors of metabolism including amino acidopathies, organic acidurias, fatty acid oxidation defects, and acute intermittent porphyria 6

Infectious Causes

• Viral gastroenteritis (most common acute cause) 7, 9
• Foodborne illness from bacterial toxins or infection 9
• Systemic infections including urinary tract infections, pneumonia, and sepsis 2, 4
• COVID-19 with GI manifestations occurring in 6-23% of cases 1

Medication and Toxin-Related

• Medication adverse effects from antibiotics, opioids, chemotherapy, NSAIDs, or selective serotonin reuptake inhibitors 5, 9
• Toxin ingestion including alcohol, heavy metals, or other substances 9, 8

Psychiatric and Behavioral Causes

• Bulimia nervosa must be differentiated from true vomiting 1
• Anxiety disorders and psychogenic vomiting 6, 8
• Rumination syndrome (voluntary regurgitation and rechewing) 1

Red Flag Symptoms Requiring Urgent Evaluation

Any of the following mandate immediate assessment and potential hospitalization: 2, 5, 8

• Bilious (green) vomiting indicates obstruction distal to the ampulla of Vater and requires immediate surgical consultation, nasogastric tube placement, and upper GI contrast study 2, 3, 4
• Hematemesis (blood in vomit) or hematochezia (blood in stool) 2
• Severe abdominal tenderness or distension suggesting peritonitis or obstruction 2
• Altered mental status or lethargy indicating CNS pathology or severe metabolic derangement 2
• Severe dehydration with decreased urine output, sunken eyes, dry mucous membranes, poor capillary refill 2
• Toxic appearance with fever suggesting sepsis or meningitis 2
• Seizures 2
• Hepatosplenomegaly 2

Diagnostic Approach Algorithm

Initial Assessment

1. Determine if bilious vomiting is present - if yes, proceed immediately to abdominal X-ray followed by upper GI contrast study and surgical consultation 2, 3, 4
2. Assess for red flag symptoms listed above requiring urgent evaluation 2, 5
3. Obtain pregnancy test in any postmenarchal girl 5, 9
4. Differentiate vomiting from regurgitation, rumination, or bulimia through careful history of timing, force, and voluntary nature 1

History Details to Elicit

• Duration and frequency: acute (<7 days) versus chronic (>4 weeks) 9, 8
• Timing relative to meals: immediate suggests obstruction; delayed suggests gastroparesis 1
• Character: bilious, bloody, projectile, or containing undigested food 2, 3, 4
• Associated symptoms: fever, diarrhea, headache, abdominal pain location and character, weight loss 5, 8
• Medication and substance use including recent antibiotic initiation 5, 9
• Menstrual history and sexual activity 5

Physical Examination Focus

• Hydration status: capillary refill, mucous membranes, skin turgor, vital signs 2
• Abdominal examination: distension, tenderness location, peritoneal signs, bowel sounds, masses, hepatosplenomegaly 2, 5
• Neurologic examination: mental status, papilledema, focal deficits, meningeal signs 2, 5

Initial Laboratory Testing

• Urine pregnancy test (mandatory in postmenarchal girls) 5, 9, 8
• Complete blood count to assess for infection or anemia 8
• Comprehensive metabolic panel including glucose, electrolytes, renal function, liver enzymes 8
• Urinalysis to exclude urinary tract infection or ketones 8
• Amylase and lipase if pancreatitis suspected 8

Imaging Studies

• Abdominal X-ray as first imaging study if obstruction suspected, looking for dilated bowel loops, air-fluid levels, or abnormal gas patterns 3, 4
• Upper GI contrast series is definitive for malrotation (96% sensitivity) and should be performed urgently for bilious vomiting even if X-ray is normal 3, 4
• Abdominal ultrasound for suspected intussusception, appendicitis, or pyloric stenosis 3, 7
• Head CT only if acute intracranial process suspected based on neurologic signs 8

Advanced Testing for Chronic Symptoms

• Esophagogastroduodenoscopy for patients with alarm symptoms (weight loss, dysphagia, GI bleeding) or risk factors for malignancy 8
• Gastric emptying scintigraphy (4-hour study preferred) if gastroparesis suspected 1

Critical Pitfalls to Avoid

Normal abdominal X-rays have up to 7% false-negative rate for malrotation, so clinical suspicion based on bilious vomiting alone mandates proceeding to upper GI contrast study regardless of normal radiograph findings. 2, 4

• Do not diagnose viral gastroenteritis without excluding serious causes, particularly in young children with bilious vomiting or severe symptoms 7
• Do not delay imaging or surgical consultation for bilious vomiting while awaiting laboratory results 2, 3
• Do not assume simple reflux in infants with poor weight gain, blood in vomit/stool, or bilious vomiting - these require aggressive investigation 2
• Midgut volvulus can cause complete intestinal necrosis within hours, requiring massive bowel resection or resulting in death if diagnosis is delayed 2, 4