Vomiting as an occasional symptom is an adaptive physiological process where the body seeks to rid itself of offending substances ingested.  It may also occur in the setting of an acute illness such as a gastroenterentitis or as part of a more chronic condition such as a bowel obstruction. Because of neurological links to emotional centers, vomiting can occur during intense emotional distress.

The differential diagnosis of recurrent vomiting can include endocrine or metabolic disorders (pregnancy, diabetes, and hyperthyroidism), infections (both gastrointestinal and systemic, nongastrointestinal), bowel obstruction including Crohn’s disease and other sources of bowel obstruction, central nervous system disorders (migraine and increased intracranial pressure), seizure disorders, psychiatric disorders, or medication related.

The diagnostic evaluation includes taking a careful medical history seeking to identify the potential structural or metabolic causes as noted above.  One should identify the circumstances of the vomiting, i.e, after a meal (and how long after a meal), during emotional distress, whether there are other symptoms including abdominal pain, fever, nausea and if so which symptoms occurred first. A physical examination should evaluate for signs of dehydration, weight loss or muscle wasting and abnormal physical features such as an abdominal mass.  Routine studies would include CBC, sedimentation rate or CRP, complete metabolic panel, lipase, and in most cases some type of imaging which may include a flat plate of the abdomen, abdominal ultrasound, CT, MR or endoscopy depending on the clinical situation.

When the vomiting occurs recurrently and seemingly without clear recognition of cause, a variety of functional GI syndromes are to be considered including functional vomiting, gastroparesis and cyclic vomiting syndrome.  Today we will discuss functional vomiting.

Functional vomiting has been defined by the Rome III criteria as described below:

Must include all of the following –
1) On average one or more episodes of vomiting per week
2) Absence of criteria for an eating disorder, rumination, or major psychiatric disease according to DSM-IV
3) Absence of self-induced vomiting and chronic cannabinoid use and absence of abnormalities of the central nervous system or metabolic diseases to explain the recurrent vomiting
*Criteria must be fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.

Functional vomiting is often considered as a behavioral, stress-induced conditioning response, though the stressor may be unrecognized and possibly encoded from earlier experiences.  Examples would include being in situations (by visual or emotional cues) that remind the individual of an earlier noxious experience (e.g., childhood abuse, smelling a noxious substance previously experienced and conditioned,  a patient walking into the hospital where he or she received chemotherapy). Often these are associated with anxiety inducing conditions though the circumstances may not be apparent to patient or the healthcare provider.  Generally patients with functional vomiting do not lose weight unless the vomiting occurs so frequently as to impair nutritional intake.  In these rare situations, dehydration and metabolic imbalance may occur.  Routine diagnostic studies are negative except for any metabolic consequences of the vomiting.

Learn More: See previous post on gastroparesis and cyclic vomiting syndrome.

Resources

Cyclic Vomiting Syndrome Brochure from NIDDK

Douglas A. Drossman, MD