Vomiting

Definitions

• Vomiting - Forceful oral expulsion of gastric contents associated with contraction of the abdominal, diaphragmatic, and chest wall musculature
• Nausea - The unpleasant sensation of the imminent need to vomit, usually referred to the throat or epigastrium; a sensation that may or may not ultimately lead to the act of vomiting
• Regurgitation - The act by which food is brought back into the mouth without the abdominal and diaphragmatic muscular activity that characterizes vomiting
• Anorexia - Loss of desire to eat; true loss of appetite
• Sitophobia - Fear of eating because of subsequent or associated discomfort
• Early satiety - The feeling of being full after eating an unusually small quantity of food
• Retching - Spasmodic respiratory movements against a closed glottis with contractions of the abdominal musculature without expulsion of any gastric contents, referred to as "dry heaves"
• Rumination - Chewing and swallowing of regurgitated food that has come back into the mouth through a voluntary increase in abdominal pressure within minutes of eating or during eating

Major Pathways of Nausea/Vomiting

• Vagal Afferent Pathway (triggered by mechanical or chemosensory responses)

  • Overdistension

  • Food poisoning

  • Mucosal irritation

  • Cytotoxic drugs

  • Radiation

• Area Postrema (chemoreceptor trigger zone)

  • Systemic chemical can induce vomiting due to location/ relatively permeable blood brain barrier region

  • Receptors for mediating vomiting: M1, D2, 5-HT3, and Neurokinin 1 (NK1)

• Vestibular system

  • Vestibular input is in conflict with visual sensations

  • Irritation of labyrinthine inflammation

  • H1 receptors and the vestibular nucleus also play a role

• Amygdala

  • Stress and emotional response

  • Aberrant activation may lead to sensation of nausea

Approach to Vomiting

1. Determine etiology and chronicity (Acute, Chronic, Episodic)

2. Identify Complications (dehydration, metabolic derangments) and correct

3. Provide therapy (Surgery, Fluids, Dietary changes, medications, etc…)

Acute Vomiting

• Rule out life-threatening causes first:

  • Bowel obstruction

  • DKA

  • Adrenal crisis

  • Toxic ingestion

  • Increased ICP

Evaluation

History

• Nature of vomiting

  • Bilious – obstruction: volvulus, malro, intestinal atresia

  • Projectile – IHPS (3-6wks of age)

  • Blood in vomit (hematemesis)

  • Periodic Vomiting

  • Early morning – pregnancy, ICP, CVS

  • Prolonged vomiting

  • Positional triggers – ICP

• Associated Symptoms:

  • Diarrhea –acute, infection, Sx in close contacts; chronic, enteritis/colitis, IBD, appy

  • Rectal bleeding intussusception (infants/toddlers) infectious colitis, IBD

  • Fever – infection, strep, UTI, appy, viral gastroenteritis, IBD. Consider recurrent infections

  • Prominent headache with nausea – migraine, Increased ICP
    
    

Physical Exam:

• Obstruction:

  • Visible bowel loops

  • Absent bowel sounds

  • Increased high pitched bowel sounds (borborygmi)

  • Severe abdominal pain

  • Vomitous (green/yellow or feculent)

• Focal abdominal tenderness

  • RLQ - appy or crohns

  • RUQ – Gallbladder disease (cholelithiasis or cholecystitis) or pancreatitis

  • CVA tenderness – pyelonephritis

  • Epigastric area – nonspecific (esophagitis, gastritis, PUD, pancreatitis

• Hepatosplenomegaly or jaundice may be caused by hepatitis, viral infection, metabolic disorders, CVD

• Neuro Exam

  • Altered consciousness, seizures, focal neuro abnormalities may be caused by toxin ingestion, DKA, CNS mass, inborn error of metabolism

  • Bulging fontanelle

  • Ataxia, dizziness, nystagmus (vestibular neuronitis, acute cerebellar ataxia)

• Others:

  • Ambiguous genitalia

  • Unusual odor (metabolic causes)

  • Enlarged parotid glands – bulimia

Labs:

• Prolonged vomiting

  • CBC

  • CMP

  • Amylase

  • Lipase

  • UA

• Fever

  • Urine Cx

  • Stool studies: Occult blood, Bacterial pathogens, O&P

Studies and potential etiologies

• Complete blood count -
  
• Anemia and iron deficiency may be associated with obstruction, IBD, gastritis, and ulcer disease.
  
• Elevated white blood cell count is associated with bacterial infections and sepsis.
• Electrolytes, BUN/Creatinine -
  
• Electrolyte abnormalities are associated with pyloric stenosis, adrenal insufficiency, and metabolic diseases.
  
• Elevated BUN/Creatinine are seen in renal disease.
• Liver function tests -
  
• Elevated AST, ALT, total bilirubin, and GGT are seen in liver and gallbladder disease.
• Amylase, lipase - Elevated in pancreatitis.
• Plasma ammonia, urine reducing substances -
  
• If an inborn error of metabolism is suspected.
  
• Ammonia is elevated in urea cycle disorders and organic acidemias.
  
• Non-glucose reducing substances are usually present in the urine in galactosemia or hereditary fructose intolerance.
• Radiology
• Plain radiograph of the abdomen - If intestinal obstruction is suspected.
• Upper gastrointestinal series - If an anatomic abnormality of upper GI tract is suspected (eg, neonate with bilious vomiting).
• CT of the head - If increased intracranial pressure is suspected (rule out mass).
• Abdominal ultrasound - If pyloric stenosis or intussusception are suspected; also useful for evaluation of liver, gallbladder, kidneys, and pancreas.
• Radionucleotide gastric emptying study - If gastroparesis is suspected. Gastroparesis typically has vomiting hours after ingestion unlike reflux which occurs immediately after ingestion
• Endoscopy -
  
• If peptic disease, eosinophilic esophagitis, IBD, or other causes of intestinal inflammation are suspected.

Postviral gastroparesis is often found in children who have experienced an acute short viral illness (often rotavirus gastroenteritis) and is associated with postprandial antral hypomotility. In most cases, the symptoms resolve spontaneously within 6 to 24 months