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]
Laboratory Findings
"Obtaining postictal levels of prolactin (within 20 minutes after a convulsive event), lactate (within 1 to 2 hours), ammonia (within several hours), or creatine kinase (especially 24 to 48 hours postictally) can help differentiate convulsive seizures from psychogenic nonepileptic attacks"[1]
Serum Prolactin Level
Two meta-analyses have quantified the role of an elevated serum prolactin.
The first meta-analysis found that:[3]
"If a serum prolactin concentration is greater than three times the baseline when taken within one hour of syncope, then in the absence of test "modifiers":
The patient is nine times more likely to have suffered a GTCS as compared with a pseudoseizure positive LR = 8.92 (95% CI (1.31 to 60.91)), SN = 0.62 (95% CI (0.40 to 0.83)), SP = 0.89 (95% CI (0.60 to 0.98))Five times more likely to have suffered a GTCS as compared with non-convulsive syncope positive LR 4.60 (95% CI (1.25 to 16.90)), SN = 0.71 (95% CI (0.49 to 0.87)), SP = 0.85 (95% CI (0.55 to 0.98)). "
The second meta-analysis found:[4]
"Elevated serum prolactin assay, when measured in the appropriate clinical setting at 10 to 20 minutes after a suspected event, is a useful adjunct for the differentiation of generalized tonic-clonic or complex partial seizure from psychogenic nonepileptic seizure among adults and older children (Level B).""Serum prolactin assay does not distinguish epileptic seizures from syncope (Level B)."The use of serum PRL assay has not been established in the evaluation of status" epilepticus, repetitive seizures, and neonatal seizures (Level U)."
The serum prolactin level is less sensitive for detecting partial seizures.[5]
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:[6]
- Hypoglycemia
- Hyponatremia
- Uremia
- Drug intoxication
- Ammonia levels
- Creatine kinase (CK) levels
- Lactate levels
- Prolactin levels
Serum Prolactin Level
- A study 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.
- 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):
- Another study found that:[4]
- 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).
References
- ↑ Wu, Ken; Hirsch, Lawrence J.; Babl, Franz E.; Josephson, S. Andrew (2020). "Choosing Anticonvulsant Medications to Manage Status Epilepticus". New England Journal of Medicine. 382 (26): 2569–2572. doi:10.1056/NEJMclde2004317. ISSN 0028-4793.
- ↑ Nass RD, Sassen R, Elger CE, Surges R (2017). "The role of postictal laboratory blood analyses in the diagnosis and prognosis of seizures". Seizure. 47: 51–65. doi:10.1016/j.seizure.2017.02.013. PMID 28288363.
- ↑ 3.0 3.1 Ahmad S, Beckett MW (2004). "Value of serum prolactin in the management of syncope". Emergency medicine journal : EMJ. 21 (2): e3. PMID 14988379.
- ↑ 4.0 4.1 Chen DK, So YT, Fisher RS (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.
- ↑ Shukla G, Bhatia M, Vivekanandhan S; et al. (2004). "Serum prolactin levels for differentiation of nonepileptic versus true seizures: limited utility". Epilepsy & behavior : E&B. 5 (4): 517–21. doi:10.1016/j.yebeh.2004.03.004. PMID 15256189.
- ↑ 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.