Believe it or not, but cyclic vomiting syndrome (CVS) is a real diagnosis. I will describe a patient I encountered who fits the classic description.
The patient is a male in his 50s who presented to the emergency department with one week of intermittent vomiting and epigastric pain. He has a few of these episodes every year and was diagnosed with CVS during his previous hospitalization, but was unaware of his diagnosis. The current episode was brought on by a severe weeklong headache. The patient took Tums for the abdominal pain, which did not help. Certain foods, such as spicy and fatty food, worsen the vomiting. He smokes cannabis to help relieve the nausea. Taking warm showers alleviates the epigastric pain and vomiting. He vomited about a spoonful of clear sputum during each episode. The vomiting and pain usually occur in the early morning hours. The patient decided to come to the ED because the abdominal pain and vomiting have become so severe that they are interfering with his daily activities.
CVS is actually more common in children, but it is becoming more recognized in adults as the public becomes more aware of the diagnosis. Most physicians have not even heard of CVS.
CVS is a diagnosis based on the patient’s history and exclusion of other diagnoses. When thinking of a differential diagnosis, group diagnoses by categories or systems. Here, it is important to think of diagnoses for vomiting and abdominal pain, if present.
First, think of medication-induced vomiting, such as from chemotherapy. Look at the patient’s medication list and see if any of them could be causing vomiting.
Next, consider gastrointestinal causes, such as inflammatory bowel disease (IBD), a gastric outlet obstruction that could be from gastric adenocarcinoma or pancreatitis. A patient with IBD tends to have extraintestinal manifestations, such as uveitis and erythema nodosum. IBD is confirmed by biopsy. A patient with a gastric outlet obstruction feels food sitting in their stomach after they eat and may regurgitate it. This is diagnosed by imaging, such as with an esophagogastroduodenoscopy. When evaluating pancreatitis, think of “GET SMASHED” and see if the patient fits any of the criteria, paying particular attention to major causes such as gallstones and alcohol abuse. Neurologic causes of vomiting can be from a tumor, so order a CT scan if considering that. If the patient is female and of reproductive age, think of pregnancy and order a urine pregnancy test.
This patient was diagnosed by a GI consult when the other possible diagnoses were ruled out. The consultant used the Rome III criteria to support the diagnosis, which requires episodic vomiting lasting less than a week, at least three episodes per year, and lack of nausea and vomiting between episodes. The patient must fulfill these criteria for at least three months.
The pathogenesis is unknown but some possible associations are present. Some patients may have a cycle of vomiting, abdominal pain and migraines. Some think that the vomiting leads to abdominal pain, which then leads to migraines, but this is not always present. Of note, abdominal migraines, which are also known as “stomach aches,” differ from CVS in that the patient mainly has abdominal pain, with or without vomiting. In addition, patients with migraines tend to have a family history of migraines.
Certain foods, such as chocolate and cheese, are inciting factors, as is cannabis use. Cessation of cannabis usually causes an episode of CVS to resolve. However, CVS is distinct from cannabis-induced emesis. In CVS, the patient has episodic vomiting, which may or may not be induced by smoking cannabis, and is symptom free between these episodes. In cannabis-induced emesis, the patient has daily emesis due to smoking cannabis.
The episodes last under a week, occur several times a year, and often occur during the early morning hours between 2 a.m. and 7 a.m. Patients may or may not have to be hospitalized, which often depends on how dehydrated the patient becomes.
The management of CVS includes giving fluids and replenishing electrolytes if needed. Amitriptyline, which is a tricyclic antidepressant, is given if the patient has associated migraines. Ondansetron (Zofran) is given for nausea and vomiting. Upon discharge, the patient may take amitriptyline for prophylaxis against migraines. Pain medication may also be helpful for abdominal pain, but has the potential to worsen nausea, especially if given orally.
Before I discharged the patient, I talked to him about his diagnosis. I made a simplified information packet with pertinent facts from UpToDate and the Cyclic Vomiting Syndrome Association. He was able to read the packet I assembled and ask me questions. He was especially interested to learn about the risk factors, which trigger attacks, so he now knows to avoid them.
This case taught me to be more open-minded in building a differential diagnosis when a patient has an unusual presentation. If you hear hoofbeats, occasionally a zebra really is around the corner.