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Persistent Vomiting

Michael A. Davis, MD

Vomiting is defined as the forceful expulsion of gastric contents through the mouth. Vomiting can be caused by a benign, self-limited process or it may be indicative of a serious underlying disorder.

Pathophysiology of Vomiting

Vomiting is usually preceded by nausea, increased salivation, and retching. It is distinct from regurgitation, which is characterized by passive movement of gastric contents into the esophagus.

Projectile vomiting results from intense gastric peristaltic waves, usually secondary to gastric outlet obstruction caused by hypertrophic pyloric stenosis or pylorospasm.

Retching often precedes vomiting, and it is characterized by spasmodic contraction of the expiratory muscles with simultaneous abdominal contraction.

Nausea is an imminent desire to vomit, usually induced by visceral stimuli.

Clinical Evaluation of Vomiting

The age of the patient at presentation suggests the differential diagnoses of persistent vomiting.

Clinical Evaluation of Vomiting in the Neonate

Bilious Vomiting

Bilious vomiting, at any age, suggests intestinal obstruction or systemic infection.

Anatomic abnormalities of the gastrointestinal tract that may present in the first week of life with bilious vomiting and abdominal distention include malrotation, volvulus, duplications of the bowel, bowel atresia, meconium plug, meconium ileus, incarcerated hernia, and aganglionosis (Hirschsprung disease).

Necrotizing Enterocolitis

NEC is the most common inflammatory condition of the intestinal tract in the neonate. Symptoms of NEC include abdominal distention, bilious vomiting, and blood in the stool.

The infant who has NEC also may present with nonspecific signs of systemic infection, such as lethargy, apnea, temperature instability, and shock.

NEC occurs mainly in preterm infants, although 10% of affected newborns present at term.

Metabolic Disorders

Inborn errors of metabolism should be considered in any acute neonatal illness, including persistent vomiting. Factors that suggest a metabolic disorder include early or unexplained death of a sibling, multiple spontaneous maternal abortions, or history of consanguinity.

Associated features may include lethargy, hypotonia, and convulsions.

Neurologic Disorders. Central nervous system abnormalities, such as intracranial hemorrhage, hydrocephalus and cerebral edema, should be suspected in the neonate who has diffuse or focal neurologic deficits, a rapid increase in head circumference, or an unexplained fall in hematocrit.

Clinical Evaluation of Vomiting in Infancy

Pyloric Stenosis

Pyloric stenosis is a major consideration in infants. Hypertrophy of the pylorus causes gastric outlet obstruction at the pyloric canal. Five percent of infants whose parents had pyloric stenosis develop this disorder.

Males are affected more often than females, and firstborns are more likely to be affected than subsequent siblings.

Symptoms of pyloric stenosis usually begin at age 2 to 3 weeks, but may occur at birth or present as late as 5 months.

An olive-size mass may be palpable in the right upper quadrant. A metabolic alkalosis frequently results from the vomiting.

Gastroesophageal Reflux

Gastroesophageal reflux (GER) is defined as retrograde movement of gastric contents into the esophagus. GER occurs in 65% of infants and is caused by inappropriate relaxation of the lower esophageal sphincter.

GER is considered "pathologic" if symptoms persist beyond 18 to 24 months and/or if significant complications develop, such as failure to thrive, recurrent episodes of bronchospasm and pneumonia, apnea, or reflux esophagitis.

Reflux esophagitis should be suspected when regurgitation is accompanied by irritability during feeding, refusal to feed, failure to thrive or occult blood loss in the stool.

Gastrointestinal Allergy

Cow milk allergy is rare in infancy and early childhood and generally resolves by 2 to 3 years of age. Vomiting, diarrhea, colic and gastrointestinal loss of blood may occur.

Other clinical manifestations may include anaphylaxis, atopic dermatitis, urticaria, angioedema, and wheezing.

Clinical Evaluation of Vomiting in Childhood

Peptic Ulcer

Peptic ulcer disease in early childhood is often associated with vomiting. Primary ulcer disease more often presents with epigastric pain in children by 11 years of age. Peptic ulcer disease should be suspected if there is a family history of ulcer disease, or if there is hematemesis or unexplained iron deficiency anemia.

Abdominal pain typically wakes the patient from sleep. There may be epigastric tenderness and occult blood in the stool.

Pancreatitis

Pancreatitis is a relatively rare cause of vomiting, but should be considered in the child who has sustained abdominal trauma. Patients usually complain of epigastric pain, which may radiate to the mid-back.

Other factors predisposing to pancreatitis include viral illnesses (mumps), drugs (steroids, azathioprine), congenital anomalies of the biliary or pancreatic ducts, cholelithiasis, hypertriglyceridemia, and a family history of pancreatitis.

Central Nervous System Disorders

Persistent vomiting without other gastrointestinal or systemic complaints suggests an intracranial tumor or other lesions that increase intracranial pressure.

Subtle neurologic findings (eg, ataxia, head tilt) should be assessed and a detailed neurologic examination should be performed.

Physical Examination of the Child with Persistent Vomiting

Volume depletion often results from vomiting, manifesting as sunken fontanelles, decreased skin turgor, dry mouth, absence of tears, and decreased urine output.

Peritoneal irritation often causes the child to keep his knees drawn up or to bend over. Abdominal distension, visible peristalsis, and increased bowel sounds are consistent with intestinal obstruction.

Abnormal masses, enlarged organs, guarding, or tenderness should be sought. A hypertrophic pylorus is indicated by a palpable "olive" in the right upper quadrant.

Intussusception is often associated with a tender, sausage-shaped mass in the right upper quadrant and an empty right lower quadrant (Dance sign).

Digital Rectal Exam. Decreased anal sphincter tone and large amounts of hard fecal material in the ampulla suggests fecal impaction. Constipation, increased rectal sphincter tone, and an empty rectal ampulla suggests Hirschsprung disease. Blood suggests an inflammatory disease or peptic ulcer disease.

Laboratory Evaluation

Serum electrolytes should be obtained when dehydration is suspected.

Urinalysis may detect a urinary tract infection or suggest the presence of a metabolic disorder.

Plasma amino acids and urine organic acids should be measured if metabolic disease is suspected because of recurrent, unexplained episodes of metabolic acidosis.

Serum ammonia should be obtained in cases of cyclic vomiting to exclude a urea cycle defect.

Liver chemistries and serum ammonia and glucose levels should be obtained if liver disease is suspected.

Serum amylase is frequently elevated in patients who have acute pancreatitis. Serum lipase levels may be more helpful because they remain elevated for a number of days following an acute episode.

Imaging Studies

Ultrasonography of the abdomen is the initial imaging test for suspected pyloric stenosis; however, two thirds of vomiting infants will have a negative sonogram and will subsequently require an upper gastrointestinal series.

Plain Radiographs of the Abdomen

Supine and upright or left lateral decubitus radiographic views are necessary for detecting congenital anatomic malformations or obstructive lesions.

Air-fluid levels suggest obstruction, although this finding is nonspecific and also may be seen with gastroenteritis.

Free air in the abdominal cavity indicates a perforated viscus. Upright plain films may demonstrate free air under the diaphragm; a left decubitus view will show air outlining the liver.

Upper gastrointestinal series with nonionic, iso-osmolar, water-soluble contrast is indicated when anatomic abnormalities and/or conditions that cause gastric outlet obstruction are suspected.

Barium enema should be performed to detect lower intestinal obstruction, and it may also be therapeutic in intussusception.

Endoscopy. If radiographic studies are negative for intestinal obstruction, upper endoscopy should be considered in patients suspected of having inflammatory conditions of the proximal gastrointestinal tract, such as peptic ulcer disease, or reflux esophagitis.

Treatment

Initial therapy should correct hypovolemia and electrolyte abnormalities. In acute diarrheal illnesses with vomiting, oral rehydration therapy is usually adequate for treatment of dehydration.

Bilious vomiting and suspected intestinal obstruction is managing by giving nothing by mouth, and by passing a nasogastric tube connected to intermittent suction. Bilious vomiting always requires surgical consultation.

Pharmacologic Therapy

Antiemetic agents usually are not required because most instances of acute vomiting are caused by self-limited, infectious gastrointestinal illnesses. Conditions where effective antiemetic drugs may be indicated include postoperative emesis, motion sickness, cytotoxic drug-evoked emesis, and gastroesophageal reflux disease.

Diphenhydramine and dimenhydrinate are useful in treating the symptoms of motion sickness or vestibulitis. Anticholinergics, such as the scopolamine patch, also are useful in the treatment of motion sickness.

Prochlorperazine and chlorpromazine have anticholinergic and antihistaminic properties. These drugs also decrease dopamine transmission in the chemoreceptor trigger zone.

These agents are used to treat vomiting caused by drugs, radiation, and gastroenteritis.

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