A potential role of hypophosphatemia for diagnosing convulsive seizures: A case‐control study

Abstract

Objective Transient loss of consciousness (TLOC) is a common presentation in the emergency room, where patient history can usually differentiate syncope from generalized tonic‐clonic (GTC) seizures. Several serum markers, such as creatine kinase and lactate, can be helpful, especially when history is unreliable. Here, we explore a potential supporting role of electrolyte plasma levels in a case‐control study. Methods In our electroencephalographic database, we retrospectively identified consecutive episodes of loss of consciousness in adults seen over 3 years in our hospital emergency department for a case‐control study. We investigated plasma levels of several electrolytes (sodium, potassium, phosphate, calcium, magnesium) at the emergency visit, as well as demographics, diagnosis, blood‐sample delay time, and history of alcohol abuse. Results Of the 126 patients identified, 75 had GTC seizures and 46 had other TLOC causes. Among electrolyte levels, only hypophosphatemia was associated with GTC seizures (median = 0.79 mmol·L–1, range = 0.34‐1.37 in GTC seizures vs 0.93 mmol·L–1, range = 0.52‐1.56, P = 0.001 in TLOC). After adjusting for blood sampling delay, alcohol abuse, and other electrolyte levels, only hypophosphatemia was associated with GTC seizures, occurring in 37 (51%) of GTC seizures and 12 (22%) of other TLOC (odds ratio = 3.5, 95% confidence interval = 1.5‐8.3, P = 0.003). Hypophosphatemia < 0.6 mmol·L–1 was 93% specific and 20% sensitive for GTC seizure occurrence. In follow‐ups, hypophosphatemia was transitory. Significance Transient hypophosphatemia is common after GTC seizures and could represent an additional biological marker to help differentiate GTC seizures from other TLOC, especially when history is unclear. This hypothesis needs to be tested prospectively.

Pathology testing in non‐trauma patients presenting to the emergency department with recurrent seizures

“…Among patients presenting with a reported generalised seizure and who underwent phosphate testing, 36.6% (53/145) yielded a low phosphate result. These results support existing literature that suggests that hypophosphatemia is frequently observed in patients presenting to the ED with generalised seizures and may represent a potential biomarker for these patients 20 . The broader clinical significance of detecting a low phosphate remains unclear.…”

Elevated body temperature and leukocyte count are associated with elevated creatine kinase after seizures

“…Thus, the results of this study were more applicable for “seizures” but possibly not for “epileptic seizures”. CK was evaluated as a marker for differentiating GTCS from syncope [ 44 ]; a level of CK > 200 U/L was unlikely to be the result of vasovagal syncope [ 10 ]. In this study, we considered that PHCK should be patients with epileptic seizures.…”

Neurologie

“…35 L'hypophosphatémie est fréquemment détectée suite à une crise d'épilepsie, surtout convulsive. 36 Il s'agit le plus probablement d'une conséquence des crises et non de la cause. Ce lien souligne l'aide diagnostique potentielle que cette mesure peut fournir lors du bilan des pertes de connaissance aux urgences, bien que sa sensibilité et spécificité soient relatives.…”