Case of Severe Hiccups Causing SIADH, Treated With Lorazepam

This is a presentation of severe hiccups which led to the syndrome of inappropriate antidiuretic hormone (SIADH). The patient presented after 3 days of severe hiccups associated with vomiting and oral intake intolerance. SIADH was diagnosed by hyponatremia (initial 128 millimoles/liter (mmol/L), nadir 119 mmol/L; normal range 136-146 mmol/L) and urine studies; this was initially attributed to sertraline, but a 48-h medication hold did not improve sodium and caused withdrawal. An upper gastrointestinal (GI) study demonstrated mesenteroaxial gastric malrotation with hiatal hernia; these were non-operative. Hyponatremia was corrected with 3% sodium, fluid restriction, and urea; hiccups continued despite sodium correction to 138 mmol/L. Various treatments of hiccups including chlorpromazine, gabapentin, baclofen, metoclopramide, and antacids were trialed, but ultimately hiccups persisted for 11 days. Hiccups ceased following IV lorazepam administration, and sodium normalized thereafter. The patient was eventually able to discontinue all hyponatremia interventions post-discharge with continued normal sodium (138-142 mmol/L) upon 2 months of follow-up, and hiccups have remained in remission. Although other case reports have described hyponatremia causing hiccups whereby correcting the hyponatremia treated the hiccups, this is the first case demonstrating the reverse causal relationship. The anatomic findings of unusual GI anatomy (mesenteroaxial gastric malrotation with hiatal hernia) were assessed to be potential contributing factors to the refractory hiccups. The case also highlights the need to avoid anchoring to other common causes of SIADH, and supports a trial of lorazepam in refractory, severe hiccups.