Diagnostic Considerations for Recurrent Nausea, Vomiting, and Headache

Primary Differential Diagnosis

The American Gastroenterological Association suggests that cyclic vomiting syndrome (CVS) should be considered given the recurrent pattern, characterized by stereotypical episodes of acute-onset vomiting lasting less than 7 days, at least 3 discrete episodes per year, with 2 occurring in the prior 6 months, separated by at least 1 week of baseline health, and absence of vomiting between episodes 1
The American Gastroenterological Association recommends assessing for prodromal symptoms, which occur in approximately 65% of patients, lasting a median of 1 hour before vomiting onset, and constitutional symptoms during episodes, such as fatigue, feeling hot/cold, mental fog, restlessness, anxiety, headache, bowel urgency, diaphoresis, flushing, or shakiness 1
The American College of Neurology suggests that migraine without aura is a strong alternative diagnosis, especially given the headache prominence, characterized by recurrent moderate to severe headache that is unilateral and/or pulsating, accompanied by photophobia, phonophobia, nausea, and/or vomiting 2
The American College of Neurology recommends assessing for specific features, such as duration of 4-72 hours when untreated, family history of migraine, and age of onset at or around puberty 2

The American Heart Association recommends actively excluding life-threatening causes, such as subarachnoid hemorrhage (SAH), characterized by "worst headache of life" described by 80% of SAH patients, sentinel/warning headache in 20% of patients, and associated features like brief loss of consciousness, nuchal rigidity, and focal neurological deficits 3
The American College of Neurology suggests that intracranial space-occupying lesions should be considered, characterized by headache brought on by sneezing, coughing, or exercise, headache with postures/maneuvers that raise intracranial pressure, associated weight loss, memory changes, or personality changes, and focal neurological symptoms on examination 4

The American Gastroenterological Association recommends a basic laboratory evaluation, including complete blood count, serum electrolytes and glucose, liver function tests, serum lipase, urinalysis, and urine drug screen to assess for cannabis use (cannabinoid hyperemesis syndrome) 5
The American College of Radiology recommends non-contrast head CT if any concern for intracranial pathology 3

The American Gastroenterological Association recommends ondansetron 8 mg sublingual/oral every 4-6 hours, promethazine 12.5-25 mg oral/rectal every 4-6 hours, and prochlorperazine 5-10 mg every 6-8 hours or 25 mg suppository every 12 hours for acute episode treatment 5
The American College of Neurology suggests that sumatriptan plus antiemetics during the prodromal phase and patient education on recognizing prodromal symptoms and "rehearsing" early intervention are critical for CVS-specific abortive therapy 1
The American College of Neurology recommends NSAIDs, triptans, and prokinetic antiemetics for migraine-specific treatment, and avoiding opioids and barbiturates 4

The American Heart Association recommends obtaining non-contrast head CT when SAH is possible to avoid the most common diagnostic error leading to preventable mortality 3
The American Gastroenterological Association suggests not dismissing abdominal pain as excluding CVS, as most CVS patients have abdominal pain during episodes 1
The American College of Neurology recommends asking about cannabis use, as prolonged use (>1 year) suggests cannabinoid hyperemesis syndrome rather than CVS 5

The American Gastroenterological Association suggests that prolonged fasting combined with the menstrual phase are the most likely precipitating factors of this episode of nausea, vomiting, and headache in a patient with a history of migraine 6

Prolonged fasting is a recognized trigger of cyclic vomiting syndrome (CVS) and migraine, although less common than other factors such as stress or sleep disturbances, according to the American Gastroenterological Association 6
The patient's pattern of eating only two complete meals a day with long periods of fasting represents a feeding pattern that can precipitate symptoms in susceptible individuals, as noted by the American Gastroenterological Association 6

Hormonal fluctuations related to the menstrual cycle are well-established triggers of both migraine and cyclic vomiting syndrome, affecting approximately 70-80% of patients with these disorders, as reported by the American Gastroenterological Association 6
The combination of hormonal changes with other physiological stressors (fasting, physical work) significantly increases the risk of precipitating an episode, according to the American Gastroenterological Association 6

Prolonged physical work (8 hours as a waitress) represents an additional physiological stressor, especially when combined with fasting and the menstrual phase, as noted by the American Gastroenterological Association 6
Intensive periods of exercise or physical activity are less common but recognized triggers of cyclic vomiting syndrome episodes, according to the American Gastroenterological Association 6

The temporal sequence (nausea and vomiting preceding headache) suggests a pattern of cyclic vomiting syndrome rather than classic migraine, where headache typically precedes or accompanies nausea, as reported by the American Gastroenterological Association 6
However, there is significant overlap between the two conditions, with 20-30% of patients with CVS also presenting with migraine, and both share common pathophysiological mechanisms, according to the American Gastroenterological Association 6

Educate the patient on the importance of avoiding prolonged periods of fasting, establishing a more frequent and regular meal pattern, especially during the menstrual phase, as recommended by the American Gastroenterological Association 6