Seizure laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Shakiba Hassanzadeh, MD[2]
Overview
The laboratory tests for patients with seizure may include checking for: hypoglycemia, hyponatremia, uremia, and drug intoxication, and levels of ammonia, creatine kinase (CK), lactate, and prolactin. Elevated prolactin level may be helpful in differentiating generalized tonic-clonic or complex partial seizure from psychogenic nonepileptic seizures, only if the patient’s prolactin level is measured 10 to 20 minutes after a suspected seizure event. Analysis of the serum prolactin level is not effective in distinguishing a seizure from syncope. No conclusion could be established regarding serum prolactin changes following status epilepticus, repetitive seizures, and neonatal seizures.
Laboratory Findings
The chemical panel and laboratory tests for patients with seizure may include checking for:[1]
- Hypoglycemia
- Hyponatremia
- Uremia
- Drug intoxication
- Ammonia levels
- Creatine kinase (CK) levels
- Lactate levels
- Prolactin levels
Serum Prolactin Level
One interpretation is the "prolactin should at least double and achieve a minimum value of 15 ng/mL in order to meet criteria for marking an epileptic seizure."[2]
A meta-analysis in 2004 found that:[3]
- If the serum prolactin level is more than three times the baseline (taken within one hour of the event and in the absence of test modifiers):
- The patient is nine times more likely to have had a generalized tonic-clonic seizure (GTCS) compared to a pseudoseizure, and five times more likely to have had a GTCS compared to a nonconvulsive syncope.
A review by the American Academy of Neurology in 2005 found:[4]
- For GTCS versus pseudoseizure:
- Sensitivity: 60%
- Specificity: 96%
- Elevated prolactin level may be helpful in differentiating GTCS or complex partial seizure from psychogenic nonepileptic seizures, only if the patient’s prolactin level is measured 10 to 20 minutes after a suspected seizure event (grade B).
- Analysis of the serum prolactin level is not effective in distinguishing a seizure from syncope.
- No conclusion could be established regarding serum prolactin changes following status epilepticus, repetitive seizures, and neonatal seizures (Level U).
A cohort study in 2016 of patient in an epilepsy monitoring unit who has prolactin measured within 20 minutes found[5]:
- For diagnosis of generalized tonic-clonic seizure (GTCS)
- Sensitivity: 100%
- Specificity: 81%
References
- ↑ Gavvala JR, Schuele SU (2016). "New-Onset Seizure in Adults and Adolescents: A Review". JAMA. 316 (24): 2657–2668. doi:10.1001/jama.2016.18625. PMID 28027373.
- ↑ Fisher RS (2016). "Serum prolactin in seizure diagnosis: Glass half-full or half-empty?". Neurol Clin Pract. 6 (2): 100–101. doi:10.1212/CPJ.0000000000000228. PMC 5720615. PMID 29377043.
- ↑ Ahmad S, Beckett MW (2004). "Value of serum prolactin in the management of syncope". Emerg Med J. 21 (2): e3. doi:10.1136/emj.2003.008870. PMC 1726305. PMID 14988379.
- ↑ Chen DK, So YT, Fisher RS, Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (2005). "Use of serum prolactin in diagnosing epileptic seizures: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology". Neurology. 65 (5): 668–75. doi:10.1212/01.wnl.0000178391.96957.d0. PMID 16157897.
- ↑ Abubakr A, Wambacq I (2016). "Diagnostic value of serum prolactin levels in PNES in the epilepsy monitoring unit". Neurol Clin Pract. 6 (2): 116–119. doi:10.1212/CPJ.0000000000000232. PMC 5720616. PMID 29377044.