A Woman with Palpitations, Abdominal Pain, and Vomiting A 39-year-old woman with cyclic vomiting syndrome and polysubstance use disorder presented with abdominal pain and agitation. In the emergency department, she had a sudden episode of tachycardia with a narrow QRS complex, with a heart rate of more than 200 beats per minute. What is the most likely diagnosis? Presentation of Case Dr. Kelsey Hills-Evans (Medicine): A 39-year-old woman with cyclic vomiting syndrome and polysubstance use disorder was seen in the emergency department of this hospital because of abdominal pain and vomiting. Eleven weeks before the current presentation, the patient was admitted to a hospital affiliated with this hospital because of intractable nausea and vomiting. She also had loose stools and pain in the right lower abdomen in the presence of menses. Her symptoms were similar to those in previous episodes that had been attributed to cyclic vomiting syndrome. Testing for Clostridium difficile toxin and fecal leukocytes was negative, as was an examination of the stool for ova and parasites; a stool culture showed normal enteric flora. A urine toxicology screen was positive for cocaine and opiates. Imaging studies were obtained. Dr. Mark A. Anderson: Computed tomography (CT) of the abdomen and pelvis, performed after the administration of intravenous contrast material, revealed bilateral, punctate, nonobstructing renal calculi without hydronephrosis. There was no evidence of bowel obstruction or acute inflammation in the abdomen or pelvis, including the appendix. Normal premenopausal ovaries that contained functional follicles were noted. Dr. Hills-Evans: Ondansetron, hydromorphone, and intravenous fluids were administered. Nausea, vomiting, and abdominal pain resolved. On the second hospital day, the patient was able to eat normally and was discharged home. One day before the current presentation, the patient inhaled smoke from an electrical fire in her basement. After the smoke inhalation, pain in the left lower abdomen and severe fatigue developed, but she did not seek medical evaluation. On the day of the current presentation, menses began, and she awoke with nausea and profuse vomiting of dark-brown fluid. Her temperature at home was 39.4°C. During the next 12 hours, she had persistent nausea and repeated episodes of vomiting. Weakness, light-headedness, and dizziness developed, and she presented to the emergency department of this hospital for evaluation. Table 1.Laboratory Data.Figure 1. Electrocardiograms and Rhythm Strip.A 12-lead electrocardiogram obtained on the current presentation (Panel A) shows supraventricular tachycardia; the electrocardiogram also showed a long RP interval (see Fig. S1 in the Supplementary Appendix, available at NEJM.org). A rhythm strip obtained after the administration of adenosine (Panel B) shows termination of supraventricular tachycardia. After a ventricular ectopic beat and a brief episode of atrial ectopy, sinus tachycardia emerged. A subsequent 12-lead electrocardiogram (Panel C) confirms ongoing sinus tachycardia.Figure 2. CT Scan of the Abdomen and Pelvis.A CT scan of the abdomen and pelvis was obtained after the administration of intravenous contrast material. Coronal reconstruction images (Panels A through D) show normal‑appearing premenopausal ovaries that contain functional follicles (Panel A, arrows), as well as bilateral, punctate, nonobstructing renal calculi (Panels B and C, arrows) without hydronephrosis (Panel D). An axial image (Panel E) shows that, during the portal venous phase, the liver attenuation level is 27 Hounsfield units (HU) lower than the splenic attenuation level (see circles), a finding consistent with hepatic steatosis. In the emergency department, the patient reported ongoing nausea, vomiting, and pain in the left lower abdomen. She reported recent use of cannabinoids but no other drugs. Other medical history included nephrolithiasis, asthma, allergic rhinitis, chronic back pain, depression, gastroesophageal reflux disease, and severe dysmenorrhea. Past surgeries included shoulder replacement, reduction mammoplasty, and removal of an ovarian cyst. Medications included acetaminophen, intranasal fluticasone, inhaled fluticasone propionate, albuterol, promethazine, ondansetron, polyethylene glycol, and a multivitamin. She had no known allergies. She did not know of any medical problems in her family. Three years before presentation, she had moved to New England from the northwestern United States after marrying her husband. She had worked in the pharmaceutical industry but had stopped working 3 months previously because of cyclic vomiting syndrome. She did not use tobacco or alcohol. She had a history of using cocaine, heroin, marijuana, and 3,4-methylenedioxymethamphetamine (MDMA). The temperature was 37.2°C, the pulse 165 beats per minute, the blood pressure 152/70 mm Hg, the respiratory rate 22 breaths per minute, and the oxygen saturation 100% while the patient was breathing ambient air. The weight was 52.5 kg; at the affiliated hospital 11 weeks earlier, it had been 59.3 kg. She was alert and oriented but had a labile affect, with alternating periods of laughing and crying. Her gaze was noted to be intense, and her speech was rapid, pressured, and at times slurred. She was agitated and was seen thrashing in her bed, pulling at equipment and clothing. Her face and chest were erythematous, and her skin was warm to the touch. A fine tremor was noted in her hands, but no tongue fasciculations were seen. She did not cooperate during a neck examination. The heart sounds were rapid and regular; a systolic ejection murmur was noted. The abdomen was soft, with normal bowel sounds and no distention; there was tenderness on palpation of the left lower abdomen. Shortly after arrival in the emergency department, the patient vomited “coffee grounds” material. Twenty-five minutes later, the pulse increased from 165 beats per minute to 210 beats per minute. Dr. Conor D. Barrett: A 12-lead electrocardiogram obtained in the emergency department showed supraventricular tachycardia with a long RP interval (Figure 1A, and Fig. S1 in the Supplementary Appendix, available with the full text of this article at NEJM.org). Adenosine was administered intravenously, and after a ventricular ectopic beat and a brief episode of atrial ectopy, sinus tachycardia emerged. It is important to note that the last observed event on cessation of this patient’s supraventricular tachycardia was a QRS complex and not a P wave, and the previously observed P wave was of high-to-low atrial activation, as seen in lead II (Figure 1B). A subsequent 12-lead electrocardiogram confirmed ongoing sinus tachycardia (Figure 1C). Dr. Hills-Evans: The alkaline phosphatase level was 165 U per liter (reference range, 27 to 129); the results of other tests of liver function were normal. A urine test for beta human chorionic gonadotropin was negative. Urinalysis showed a specific gravity of 1.013, with 2+ ketones and 2+ blood per high-power field, as well as 2 leukocytes per high-power field (reference range, 0 to 4). A urine toxicology screen was positive for fentanyl, oxycodone, and cannabinoids. The results of other laboratory tests are shown in Table 1. Additional imaging studies were obtained. Dr. Anderson: A chest radiograph showed clear lungs, a normal cardiac silhouette, no pulmonary edema, and no mediastinal or hilar lymphadenopathy. A CT scan of the abdomen and pelvis, obtained after the administration of intravenous contrast material, showed bilateral, punctate, non-obstructing renal calculi without hydronephrosis. During the portal venous phase, the liver attenuation level was 27 Hounsfield units lower than the splenic attenuation level, a finding consistent with hepatic steatosis. There was no bowel obstruction or acute inflammation in the abdomen or pelvis. The appendix appeared normal, and the ovaries were premenopausal, containing functional follicles (Figure 2). Dr. Hills-Evans: Intravenous fluids, ondansetron, pantoprazole, fentanyl, and lorazepam were administered. The patient was admitted to the intensive care unit (ICU), and a diagnostic test was performed.   Question What is the diagnosis? Cast your vote. What diagnostic test is most likely to be helpful? Submit a comment about this case and about what diagnostic test is indicated.   Poll What is the most likely diagnosis in this case? Cyclic vomiting syndrome.5% Hyperthyroidism due to Graves' disease.19% Nephrolithiasis.3% Opiate withdrawal.25% Ovarian teratoma.3% Serotonin syndrome.42% 2203 Total Responses This open poll should not be interpreted as a scientifically valid physician survey.