Chapter 382. Approach to the Child with Acute, Chronic, or Cyclic Vomiting

Vomiting is a coordinated motor response of the gastrointestinal tract, abdominal muscles, and thoracic muscles that results in the forceful expulsion of stomach contents. Vomiting must be differentiated from regurgitation, which is the effortless expulsion of gastric contents through the mouth (discussed in Chapter 394).1 Vomiting is a common presenting symptom in acute and chronic disorders of both gastrointestinal and nongastrointestinal origin. Evaluation and management requires consideration of a broad differential diagnosis, recognition of alarm symptoms requiring immediate intervention, treatment aimed at the symptom and/or cause, and prevention of potential complications.

Pathophysiology

The physiological role of vomiting is to provide rapid clearance of ingested toxins.2 This patterned response often combines repeated emetic and diarrheal events that act efficiently to clear the entire intestinal tract of toxins in both orad and aboral directions.3 Vomiting consists of three distinct phases that may each occur independently: (1) Nausea is the sensation of impending vomiting, often associated with autonomic symptoms of pallor, diaphoresis, salivation, and anorexia. (2) Retching represents the spasmodic respiratory movements against a closed epiglottis. (3) Emesis is the retrograde expulsion of gastrointestinal contents through the mouth.

The act of vomiting is an integrated gastrointestinal and thoracoabdominal muscular response to noxious stimuli; it is coordinated by a central nervous system program.4 The gastrointestinal tract becomes atonic, the gastric fundus relaxes, and intestinal contents are swept into the stomach by a single retrograde contraction of the small intestine.5 Concerted rhythmic contractions of the respiratory, abdominal, and pharyngeal musculature increase intra-abdominal and intrathoracic pressure and either contract against a closed glottis in the case of retching or expel the gastric contents though the pharynx and out the mouth in the case of vomiting.6-8

Afferent stimulation of the vomiting center initiates the programmed, integrated motor responses just described as well as vasomotor activity (tachycardia and pallor) and hypersalivation. The vomiting center is not one locus but comprises the nucleus solitarius and a series of nearby nuclei in the brainstem medulla.9-11 Afferent input may arise from the posterior pharynx (eg, gagging), gastrointestinal tract (eg, bowel obstruction, inflammation), brain (eg, stress, increased intracranial pressure), or via circulation. Blood-borne substances such as apomorphine, opiates, cytotoxins, ammonia, and ketonesstimulate the chemoreceptor trigger zone in the area postrema, which lies outside the blood-brain barrier on the floor of the fourth ventricle.12 Neurotransmitters and their receptor subtypes (medications shown in parenthesis) that play a physiological role in vomiting include dopamine D2 (metoclopramide), histamine H1 (meclizine), serotonin 5-hydroxytryptamine3 (ondansetron), γ-aminobutyric acid (diazepam), vasopressin, and substance P (aprepitant).

Clinical Features and Differential Diagnosis

The evaluation of vomiting begins by distinguishing vomiting from other common disorders, such as regurgitation, and recognizing the temporal (acute-recurrent, chronic-recurrent, episodic, or cyclic) pattern of vomiting, as shown in eTable 382.1.13,14 Vomiting and regurgitation can occur concomitantly in gastroesophageal reflux, but they are distinctly different in regard to the underlying mechanics, associated autonomic signs, and potential clinical implications. Regurgitation occurs following the effortless retrograde expulsion of gastric contents, unaccompanied by autonomic signs. In contrast, vomiting is a forceful expulsion accompanied by autonomic signs (pallor, sweating, tachycardia) and can be caused by both mild and serious disorders.

The acute vomiting pattern is usually observed in a pediatric office, urgent care facility, or emergency department with the abrupt onset of vomiting in a previously well child. When associated with fever, the high likelihood of viral gastroenteritis or systemic infection (eg, urinary tract infection, sepsis) should initiate a search for an infectious locus. When fever is absent, possible toxin or toxic ingestion (eg, Bacillus cereus), intestinal obstruction (eg, malrotation with volvulus), or nongastrointestinal obstruction (eg, acute hydronephrosis) may require radiographic investigation. Recurrent vomiting is defined as at least 3 episodes occurring over a 3-month period. Recurrent vomiting is further subdivided into chronic vomiting, which is associated with mild but frequent vomiting episodes, and episodic or cyclic vomiting, which describes severe episodes that occur sporadically between asymptomatic intervals. Cyclic vomiting syndrome is a distinct clinical entity discussed separately in this chapter.

The time of day at which vomiting occurs may provide some clues to diagnosis. Vomiting that consistently occurs in the early morning is more common with chronic sinusitis, cyclic vomiting syndrome, and increased intracranial pressure from various causes. Brainstem neoplasms may present with chronic vomiting alone, but the symptom presentation often does not fit the classic description of morning vomiting without nausea, such that affected children can have both nausea and vomiting throughout the day.15 The appearance of the vomitus also provides hints about potential etiologies. Undigested, nonacidic vomitus suggests a lack of admixture with gastric contents such as may occur with esophageal stricture or achalasia. Bilious emesis is an alarm sign suggestive of an obstructive lesion distal to the ampulla of Vater (eg, midgut volvulus) and deserves particular attention. Vomiting following acute weight loss may be due to superior mesenteric artery syndrome. The absence of physical signs or positive tests may point toward functional vomiting or, rarely, Munchausen-by-proxy syndrome from ipecac poisoning.16 The presence of comorbid conditions (and complications), such as prior surgery (postoperative adhesions), small intestinal malrotation (volvulus17), hydrocephalus (shunt dysfunction), and cystic fibrosis (distal intestinal obstructive syndrome18), may provide useful clues regarding a potential cause for vomiting.

The most frequent causes of vomiting vary with age, as shown in Table 382-1. The most common causes of vomiting at any age include gastrointestinal (eg, viral, bacterial, and parasitic gastroenteritis) and nongastrointestinal infections (eg, pyelonephritis, sepsis) for acute vomiting; acid-peptic (eg, gastroesophageal reflux, Helicobacter pylori gastritis) and allergic (eg, formula protein sensitivity, eosinophilic esophagitis) disorders for chronic vomiting; and cyclic vomiting syndrome for episodic or cyclic vomiting. Gastrointestinal obstruction and metabolic disorders must be suspected in neonates, infants, and toddlers, especially those with an acute presentation. Obstruction may present within the first days of life (eg, duodenal atresia, Hirschsprung disease), at 3 to 6 weeks (pyloric stenosis), at 6 to 12 months (eg, intussusception), or in childhood (eg, inguinal hernias, intermittent volvulus).19-21 Metabolic disorders may manifest following a change in diet (eg, organic acidemias, amino acidemias), longer periods of fasting (eg, disorders of fatty acid oxidation,22 mitochondriopathies, or an intercurrent illness.23,24). Associated symptoms include lethargy, poor feeding, failure to thrive, seizure, and hypertonia or hypotonia. In toddlers, unusual causes of chronic vomiting include chronic granulomatous disease–induced antral obstruction,25 Ménétrier gastropathy associated with hypoalbuminemia,26 and subtentorial neoplasms (eg, cerebellar medulloblastoma, brainstem glioma).27 In school-aged children, ages 5 to 11 years, acute appendicitis, traumatic duodenal hematoma, or pancreatitis may present with acute vomiting. Less common causes include neurological (eg, pseudotumor cerebri, Chiari malformation) and renal disorders (eg, acute hydronephrosis).28 In adolescence, gastrointestinal disorders (eg, achalasia, peptic ulcer disease), hepatobiliary disorders (cholelithiasis, cholecystitis, and gallbladder dyskinesia), and pancreatic disease (pancreatitis) are seen more frequently than in younger children.29 Adolescent pregnancy can present to the pediatrician with vomiting as the major complaint. Acquired gastroparesis can begin after either long-standing insulin-dependent diabetes mellitus or following an acute viral illness.30 In all age groups, toxin exposure may present with vomiting (see Table 17-2).

Diagnostic Evaluation

The presence of specific alarm symptoms requires a more thorough diagnostic evaluation. An approach to the initial evaluation of a patient with vomiting is outlined in Figure 382-1. In a child with acute vomiting, the initial diagnostic focus is on likely acute infections and exclusion of surgical gastrointestinal and nongastrointestinal obstructions by radiographic means. If the vomitus is nonbloody and nonbilious, the two most important diagnostically helpful variables are the child’s age and the temporal pattern of vomiting.

The approach to a child with chronic vomiting centers around acid-peptic and allergic disorders of the upper gastrointestinal tract and an empiric therapeutic trial of acid suppression and upper endoscopy. If the history is more consistent with a diagnosis of regurgitation, evaluation should be focused on gastroesophageal reflux, as discussed in Chapter 394. If bilious vomiting is present, the possibility of congenital (duodenal atresia), intermittent (volvulus), or acquired (surgical adhesions) obstructions must considered, as discussed in Chapter 389. If there is hematemesis, diagnosis and management are directed toward mucosal (gastric ulcer), portal varices (cirrhosis), and vascular lesions (hemangiomas), as described in Chapter 387.

Treatment

The child who presents with an acute vomiting episode of any cause must first be evaluated for dehydration. If severe (5–10%) dehydration is present, immediate intravenous access and fluids are provided. In most instances of acute vomiting with mild dehydration, short-term (6–12 hours) oral rehydration can be tolerated and is effective in replenishing fluid deficits. Diagnostic evaluation must proceed while fluid resuscitation is in progress, especially in children in whom gastrointestinal obstruction or an acute neurologic cause is suspected. In acute or chronic vomiting, if the emesis is frequent, empiric use of the 5-hydroxytryptamine3 antiemetic agents may reduce vomiting and subsequent need of intravenous fluid therapy.31,32 If the etiology of vomiting can be determined by history taking, physical examination, or laboratory testing, specific therapy can be initiated.

In a child with chronic vomiting pattern without alarm symptoms, the most likely diagnosis is an acid-peptic disorder (eg, gastroesophageal reflux, gastritis) that can be empirically treated with a 2-week to 4-week course of acid suppression using an H2-receptor antagonist or proton pump inhibitor.14 If a time-limited trial fails to improve symptoms, screening laboratory tests (eg, complete blood count, sedimentation rate, celiac screening, hepatic aspartate aminotransferase and alanine aminotransferase, and pancreatic lipase) and an abdominal ultrasound (to evaluate for hydronephrosis, cholelithiasis, and pancreatic pseudocyst) can be obtained. If these results are unrevealing, a pediatric gastroenterology consultation should be requested. An upper endoscopy with biopsies may be performed to identify potential acid-peptic, allergic, and inflammatory lesions.

The episodic or cyclic or vomiting pattern is most commonly diagnosed with cyclic vomiting syndrome and can be managed using both preventative and acute management approaches, as described next.

Cyclic vomiting syndrome is the most common diagnosis in children who present with an episodic or cyclic pattern of recurrent vomiting. It was first described in English by Samuel Gee in 1882.33 It is a syndrome characterized by repeated, discrete attacks of vomiting to the point of dehydration requiring intravenous rehydration in the emergency or in-hospital setting, and it is associated with intervening periods of normal or baseline health.34 The typical child is a 5- to 7-year-old girl who develops recurrent episodes of fast-paced vomiting (mean peak 6 emeses/h) every 2 to 4 weeks that begin in the early morning hours or upon awakening and last 24 to 48 hours. These episodes begin quickly and end suddenly and are stereotypic within the child with regard to time of onset, duration of episode, and symptomatology. Over half of children experiencing an episode of cyclic vomiting require intravenous rehydration. The prominent symptoms of listlessness (comalike to the point of being unable to walk or talk), pallor (shocklike), anorexia, nausea, and abdominal pain render the child more ill appearing than those with gastroenteritis. Parents of children having episodic (irregular) episodes can usually identify a psychological (birthdays or holidays) or infectious (respiratory or sinus) trigger, whereas those with cyclic (regularly timed) episodes tend not to have identified triggers. A family history of migraine headaches is found in the majority of patients.35 As the child approaches or enters adolescence, the cyclic vomiting abates but may be replaced by classical migraine headaches.36

Cyclic vomiting syndrome is defined by its clinical pattern rather than by its etiology or pathophysiology.37 Although it is strongly associated with migraine headaches, recent investigations have shown potential relationships to mitochondrial dysfunction and susceptibility to energy deficits, autonomic dysfunction with a sympathetic predominance, and corticotropin-releasing factor as a potential trigger of vomiting.38-40

Diagnosis

A detailed discussion of the diagnosis and treatment of Cyclic Vomiting Syndrome is available at: http://www.naspghan.org/user-assets/Documents/pdf/PositionPapers/CVS%20statement.pdf.

Although a broad array of serious conditions can cause the cyclic vomiting pattern, in a child with a typical history and no alarm symptoms, the initial evaluation should simply include an upper gastrointestinal contrast study to exclude malrotation and should also include electrolytes, glucose, blood urea nitrogen, and creatinine levels during the episodebefore initiation of intravenous fluids.37 The alarm symptoms that entail further testing include (1) abdominal distension, severe abdominal pain, and/or tenderness; (2) precipitation by fasting, illness, and high protein intake; (3) altered neurological state, lateralizing neurological findings, and papilledema; and (4) progressive worsening (eg, weight loss) or unresponsiveness over time (Table 382-2). If a specific lesion is identified, further diagnostic evaluation and consultation will be required.

Treatment

The treatment of cyclic vomiting syndrome remains empiric, and because of its relationship to migraine, antimigraine medications are primarily used to prevent subsequent episodes and to abort the acute ones in progress. The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition consensus statement recommends for first-line prophylactic therapy the use of cyproheptadine (0.2–0.3) in children under 5 years old and amitriptyline (1 mg/kg/day) for those 5 years or older; low-dose propranolol (10 mg b.i.d. or t.i.d.) is recommended as the second line of prophylactic therapy.41 For abortive therapy, nasally administered triptans are used off-label in older children to stop episodes at the onset. If these prophylactic and abortive treatments fail, additional measures can ameliorate the episode and occasionally shorten it. These include placing the child in a quiet, dark room; prompt administration of intravenous fluids with 10% dextrose; and administration of 5-hydroxytryptamine3 antagonist antiemetics (eg, ondansetron, 0.3–0.4 mg/kg/dose), sedatives (eg, lorazepam), and analgesics as necessary for pain. Further information is available through the Cyclic Vomiting Syndrome Association (http://www.cvsaonline.org/).