What are the potential causes of severe vomiting in a patient?

Severe Vomiting: Causes and Diagnostic Approach

Severe vomiting requires immediate assessment for life-threatening causes, with bilious emesis indicating intestinal obstruction until proven otherwise, and the diagnostic approach varying significantly by patient age and clinical presentation. 1

Age-Specific Causes

Infants and Neonates

Bilious emesis or repeated forceful vomiting in infants demands urgent evaluation for underlying obstruction. 1

• Congenital abnormalities are primary considerations in the first week of life, including malrotation with or without volvulus, intestinal atresia/stenosis, annular pancreas, Hirschsprung disease, and meconium ileus 1
• Hypertrophic pyloric stenosis (HPS) presents outside the newborn period with forceful nonbilious vomiting; diagnosis confirmed by palpating the classic "olive" of hypertrophied muscle 1
• Intussusception (unusual before 3 months) manifests with crampy intermittent abdominal pain progressing to bloody stools and lethargy 1
• Gastroesophageal reflux (GER) is the most common cause of nonbilious vomiting in infants with normal weight gain and no alarm symptoms 1

Adults

In adults, severe vomiting warrants systematic evaluation for gastrointestinal, metabolic, neurologic, and medication-related causes. 2, 3

Critical Life-Threatening Causes by Category

Gastrointestinal Obstruction

• Gastric outlet or intestinal obstruction causes nausea and vomiting through distension and motor dysfunction 2
• Gastroparesis (from tumors, chemotherapy, or diabetes) generates chronic nausea and vomiting 2
• Severe constipation (present in ~50% of advanced cancer patients) causes symptoms through intestinal distension 2

Metabolic and Endocrine Emergencies

• Hypercalcemia (frequent in advanced cancers) directly stimulates the chemoreceptor trigger zone 2
• Other electrolyte abnormalities including hyperglycemia, hyponatremia, and uremia 2
• Diabetic ketoacidosis in older children and adults 4
• Inborn errors of metabolism and congenital adrenal hypoplasia in infants 4

Neurologic Causes

• Increased intracranial pressure from brain metastases, tumors, trauma, or hydrocephalus directly stimulates vomiting centers 1, 2
• Meningitis and encephalitis in all age groups 1, 4

Infectious Causes

• Sepsis requires immediate recognition and treatment 1, 4
• Gastroenteritis is the most common cause of acute vomiting but should not be assumed without excluding serious pathology 3, 5

Medication and Toxin-Related

• Opioids provoke nausea by stimulating the chemoreceptor trigger zone and slowing gastric emptying 2
• Chemotherapy causes nausea/vomiting in 70-80% of patients depending on emetogenic potential 2
• Anticholinergics (antidepressants, antispasmodics, phenothiazines, haloperidol) 2

Cyclic Vomiting Syndrome (CVS)

CVS represents a distinct diagnostic entity characterized by stereotypical episodes of acute-onset vomiting lasting <7 days, with at least 3 discrete episodes per year separated by at least 1 week of baseline health. 1

• Moderate-severe CVS (≥4 episodes/year lasting >2 days requiring ED visits/hospitalizations) requires both prophylactic and abortive therapy 1
• Common triggers include stress (70-80% of patients), sleep deprivation, hormonal fluctuations, infections, and surgery 1
• Associated comorbidities include anxiety/depression (50-60%), migraine (20-30%), and postural orthostatic tachycardia syndrome 1
• Hot water bathing provides temporary relief in ~48% of non-cannabis-using CVS patients and is not pathognomonic for cannabinoid hyperemesis syndrome 1

Critical Red Flags Requiring Immediate Evaluation

The following alarm symptoms mandate urgent investigation and cannot be attributed to benign causes: 1, 4

• Bilious or bloody vomiting at any age 1, 4, 6
• Altered sensorium or toxic/septic appearance 4
• Severe dehydration (one-third of bariatric surgery patients present to ER within 3 months for dehydration) 1
• Inconsolable cry or excessive irritability in infants 4
• Enlarging head circumference or bulging fontanelle suggesting increased intracranial pressure 1

Diagnostic Workup Strategy

Initial Assessment

History and physical examination lead to diagnosis in most instances, making a "routine" laboratory or radiologic screen inappropriate. 1, 4

Key historical elements to elicit:

• Timing (acute <7 days vs chronic ≥4 weeks), bilious vs nonbilious character 1, 3
• Relationship to food ingestion, trigger foods, and eating behaviors 7
• Associated symptoms (fever, diarrhea, abdominal pain, headache, neurologic signs) 1, 3
• Medication and substance use history 2, 3
• Pattern recognition for CVS (stereotypical episodes, prodromal phase, triggers) 1

Imaging in Infants with Bilious Vomiting

Upper GI series is the gold standard for diagnosing malrotation, though normal abdominal radiographs do not exclude this diagnosis. 1

• Only 44% of infants requiring surgery for bilious vomiting had definitively positive plain radiographs 1
• Ultrasound can identify the whirlpool sign specific for midgut volvulus 1
• Upper GI series is NOT useful for diagnosing gastroesophageal reflux (sensitivity 31-86%, specificity 21-83%) 1

Laboratory Testing

Investigations are required in any patient with dehydration or red flag signs, not as routine screening. 4

• Serum electrolytes, blood gases, renal and liver function for dehydrated patients 4
• Urinalysis and urine pregnancy testing in reproductive-age women 8
• Thyroid-stimulating hormone, amylase/lipase based on clinical suspicion 8

Management Priorities

Immediate Interventions

• Stop oral intake and decompress stomach with nasogastric tube in patients with bilious vomiting 4
• Correct dehydration and electrolyte abnormalities (consume ≥1.5 L liquids/day when stable) 1, 9
• Thiamin supplementation when vomiting persists >2-3 weeks to prevent neurological complications 1

Antiemetic Selection by Cause

For elderly patients with severe vomiting and lethargy, dopamine receptor antagonists are first-line treatment. 9

• Metoclopramide 5-10 mg PO/IV three times daily (reduce dose 25-50% in elderly) 9, 7
• Haloperidol 0.5-2 mg PO/IV every 4-6 hours 9
• Ondansetron 4-8 mg PO/IV 2-3 times daily for persistent symptoms 9, 4

Critical Pitfalls to Avoid

• Never assume gastroenteritis in infants with bilious vomiting without excluding malrotation 1
• Do not use metoclopramide indefinitely; limit to 12 weeks maximum to prevent tardive dyskinesia 7
• Monitor elderly patients closely for extrapyramidal side effects from antipsychotics and dopamine antagonists 9
• Do not ignore persistent vomiting beyond 1-2 weeks, as this indicates underlying pathology requiring investigation 7
• Avoid long-term benzodiazepine use in elderly patients; taper gradually when discontinuing 9