Subclinical Hypothyroidism With Overt Symptoms in Patient With Well-Controlled Epilepsy on Valproate Therapy: A Case Report

Valproate is known to have various adverse effects including hormonal dysfunction. There is debate in literature regarding the association between valproate therapy and subclinical hypothyroidism, with some studies suggesting a potential link. However, none of the studies on our review have noted overt hypothyroid symptoms with subclinical hypothyroidism. We present a pediatric patient with generalized epilepsy on long-term valproate therapy who developed subclinical hypothyroidism with overt hypothyroid symptoms. Our patient initially presented as a 3-year-old with absence epilepsy and was well-controlled with valproate monotherapy. After more than 2 years of seizure freedom, the patient developed symptoms of hypothyroidism, leading to a diagnosis of grade 2 subclinical hypothyroidism. Symptom resolution occurred with discontinuation of valproate and with initiation of levothyroxine. Ultimately, thyroid studies normalized, and levothyroxine was also discontinued. Although subclinical hypothyroidism is a known potential side effect of valproate therapy, this case demonstrates that overt hypothyroid symptoms are rare, but possible.