44 Age, AED polytherapy, and the concomitant use of diuretics were found to be independent risk factors for sever hyponatremia following OXC treatment. A subsequent study found an incidence of severe (sodium levels ≤128 mEq/L) and symptomatic hyponatremia of 11.1% and 6.8%, respectively, in patients treated with OXC. 42 Hyponatremia during CBZ therapy seems to be particularly common in patients with intellectual disability, 43 which therefore should be considered a subset of subjects particularly at risk. Of note, sodium levels ≤128 mEq/L were found in 12.4% of patients treated with OXC and in 2.8% of those receiving CBZ ( p<0.001). One comparative study showed a much higher incidence of hyponatremia (defined as sodium levels ≤134 mEq/L) in patients treated with OXC compared to those receiving CBZ (29.9% vs. As this study shows, hyponatremia caused by polydipsia is a risk factor for aggravation of habitual seizures in patients with epilepsy and psychiatric disorders.ĬBZ, OXC, and ESL may lead to hyponatremia in a relevant number of patients. 31 In all cases, patients had received antipsychotic drugs, and the serum sodium levels returned to normal through restriction of fluids with consequent decrease in seizure frequency. Marked increases in the frequency of their complex partial seizures due to hyponatremia was observed in five patients with epilepsy and polydipsia-hyponatremia with a decrease in the serum sodium level to 118-127 mEq/L. 30 The authors identified from the database of a Swedish County hospital 363 in patients who were had serum sodium levels 115 mEq/L. A retrospective cross-sectional study was carried out to study the association between different levels of hyponatremia and the occurrence of epileptic seizures in patients without a prior epilepsy diagnosis. Polydipsia, commonly seen in patients with psychiatric disturbances, is another cause of hyponatremia with increased risk of seizures. An accurate and prompt diagnosis should be established for successful management of seizures, as rapid identification and correction of the underlying electrolyte disturbance are of crucial importance in the control of seizures and prevention of permanent brain damage. 3 Table 1 shows the different degrees of the electrolyte disturbances discussed in this review. Seizures are more frequently observed in patients with sodium disorders (especially hyponatremia), hypocalcemia, and hypomagnesaemia. 1 2 3 Acute and/or severe electrolyte imbalances can manifest with rapidly progressive neurologic symptoms or seizures, which may be the sole presenting symptom. The neurological manifestations reflect the severity of acute neuronal derangement and therefore require emergency treatment. Electrolyte disturbances may affect the brain among many other organs and tissues and need to be promptly recognized as they may lead to severe and life-threatening complications when overlooked or not appropriately treated. Keywords: EEG, electrolyte, epilepsy, seizures, hyponatremia, hypernatremia, hypocalcemiaĮlectrolyte abnormalities are commonly encountered in clinical daily practice, and their diagnosis relies on routine laboratory findings. An accurate and prompt diagnosis should be established for a successful management of seizures, as rapid identification and correction of the underlying electrolyte disturbance (rather than an antiepileptic treatment) are of crucial importance in the control of seizures and prevention of permanent brain damage.
The prominent EEG feature is slowing of the normal background activity, although other EEG findings, including various epileptiform abnormalities may occur.
EEG has little specificity in differentiating between various electrolyte disturbances. They do not entail a diagnosis of epilepsy, but are classified as acute symptomatic seizures. Seizures are more frequently observed in patients with sodium disorders (especially hyponatremia), hypocalcemia, and hypomagnesemia. Acute and severe electrolyte imbalances can manifest with seizures, which may be the sole presenting symptom. Electrolyte abnormalities are commonly encountered in clinical daily practice, and their diagnosis relies on routine laboratory findings. Quite surprisingly, despite its clinical relevance, this issue has received very little attention in the scientific literature. In this narrative review we focus on acute symptomatic seizures occurring in subjects with electrolyte disturbances.