Hyperemesis gravidarum (HG) is the most common indication for hospitalization in the first half of pregnancy [1]. Although 70—90% of pregnant women experience nausea and vomiting, few develop HG. Maternal complications include malnutrition and vitamin deficiencies, peripheral neuropathy, and serious neurological complications, including central pontine myelinolysis and Wernicke’s encephalopathy (WE) [2].
WE is an acute, potentially fatal but preventable neuropsychiatric disorder induced by thiamine deficiency, characterized by the symptom triad of encephalopathy, ataxic gait, and oculomotor dysfunction (nystagmus in 93% of cases) [3]. It is commonly associated with alcohol abuse and malnutrition [4], including malnutrition due to prolonged vomiting, with a reported prevalence in non-alcohol abuse cases of 0.04—0.13% [5].
Herein, we present a case of WE in a 38-year-old woman at 16 weeks of gestation of her second pregnancy. The patient had been previously evaluated and treated for HG at the Clinic of Gynecology and Obstetrics. One week after discharge, she presented with complaints of vomiting more than 10 times daily, headache, vertigo, photophobia, fatigue, and sleepiness lasting 4 days before consultation.
Laboratory analyses showed elevated levels of alanine transaminase (350 U/l) and aspartate transaminase (640 U/l). Other liver tests, such as cholestatic parameters, were within the normal range. Abdominal ultrasound revealed no abnormalities that could explain the elevated transaminase levels. Serological tests for viral hepatitis and autoimmune disease markers returned negative, and blood levels of ceruloplasmin and iron were within normal ranges. Neurological evaluation yielded normal findings. Electroencephalography findings were normal, and the visual evoked potential test indicated reduced conduction in the optic nerve without other abnormalities. Given the patient’s symptoms, we indicated brain magnetic resonance imaging (MRI), which showed no focal lesions in the cerebellum, hyperintensities and cloudiness in the periaqueductal region, edematous mammillary bodies with signal hyperintensity, and symmetrical hyperintensities in the dorsomedial thalamus on T2-weighed and fluid-attenuated inversion recovery images, with zonal restriction predominantly at the level of the dorsomedial thalamus on diffusion-weighted images. In addition, incipient global cortical cerebral atrophy was observed.
Based on the MRI findings, the patient was diagnosed with WE and hospitalized at the Clinic of Gynecology and Obstetrics. Vitamin supplementation therapy was initiated with vitamins B1 (thiamine), B6, and B12, resulting in rapid neurological status improvement after 3 days. The Gynecology Advisory Board indicated medically induced abortion. During the 2-week follow-up period, the patient’s neurological status and liver function test results significantly improved.
With a daily requirement of thiamine of 1.4 mg/day and reserves of only 30—50 mg, any malnutrition condition lasting more than 3—4 weeks can totally deplete the body’s reserves. WE due to HG usually occurs at 14−16 weeks of gestation, following more than 3 weeks of vomiting [6]. More than 50% of patients with HG and WE show liver function abnormalities, probably due to nutritional causes. In addition, HG with liver dysfunction increases the risk for developing WE [6, 7]. Our patient was at 16 weeks of gestation and had biochemical evidence of liver dysfunction, which, coupled with the neurological symptoms, prompted us to consider WE and indicate brain MRI.
Generally, WE diagnosis is established clinically, based on the classic symptom triad. There is no specific diagnostic laboratory test, and serum thiamine levels do not accurately reflect the total body thiamine status. In our case, diagnosis was established using MRI, which yields high diagnostic sensitivity for typical signs of WE, including symmetrically increased signal intensity in the mesencephalic tegmentum, mammillary bodies, and medial thalamus on T2-weigthed, fluid-attenuated inversion recovery, and diffusion-weighted sequences [8].
WE treatment consists of administration of thiamine as soon as possible to avoid irreversible neurological damage. Pregnant women experiencing prolonged or excessive vomiting should receive parenteral thiamine supplementation at a dose of 100 mg/day to reduce the risk for WE. However, when WE is suspected, thiamine should be administered at a dose of 500 mg/day during the first 2 days and 250 mg/day thereafter until the resumption of oral feeding [9]. Importantly, thiamine replacement should always precede the replacement of sugars during WE treatment.
With mortality rates as high as 20%, WE is considered a medical emergency. In terms of maternal prognosis, the clinical presentation can evolve from completely reversable disorders to motor sequelae, Alzheimer’s and Korsakoff syndromes, and even death [10]. In terms of fetal prognosis, WE is associated with an increased risk of low birth weight, neurodevelopmental disorders, preterm delivery, and fetal and neonatal death. Early diagnosis and vitamin therapy within the first 24 h are vital to prevent poor fetal outcomes.
In conclusion, WE is a rare but serious neurological complication of HG that must be suspected in women in the first trimester of pregnancy exhibiting neurological symptoms.
