Seizure

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In humans, seizures are "Clinical or subclinical disturbances of cortical function due to a sudden, abnormal, excessive, and disorganized discharge of brain cells. Clinical manifestations include abnormal motor, sensory and psychic phenomena. Recurrent seizures are usually referred to as epilepsy or "seizure disorder.""[1]

Status epilepticus is a "prolonged seizure or seizures repeated frequently enough to prevent recovery between episodes occurring over a period of 20-30 minutes."[2]

Diagnosis

Determining whether a seizure occurred

Differentiating a seizure from other conditions such as syncope can be difficult. In addition, 5% of patients with a positive tilt table test may have seizure like activity that seems to be due to cerebral hypoxia.[3]

Medical history taking

Video-documented signs during video electroencephalography can help distinguish epileptic seizures and pseuodseizures; however, eye-witness reports of the presence of these signs are unreliable:[4]

  • predictive of psychogenic nonepileptic seizures: "preserved awareness," "eye flutter," and "bystanders can intensify or alleviate"
  • predictive of epileptic seizures: "abrupt onset," "eye-opening/widening," and postictal "confusion/sleep"

Interviewing witnesses must be carefully done.[5] Allowing observers to answer "I do not know" may be important.[5]

Physical examination

A small study found that finding a bite to the side of the tongue was very helpful when present[6]"

A more recent meta-analysis yielded similar results.[7]

Serum prolactin level

Two meta-analyses have quantified the role of an elevated serum prolactin. The first meta-analysis found that[8]: "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":

  1. 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))
  2. 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:[9]

  1. "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)."
  2. "Serum prolactin assay does not distinguish epileptic seizures from syncope (Level B).
  3. "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.[10]

EEG

An isolated abnormal electrical activity recorded by an electroencephalography examination without a clinical presentation is called subclinical seizure. They may identify background epileptogenic activity, as well as help identify particular causes of seizures.

About 25% of adults with a first, unprovoked seizure will have an abnormal EEG.[11] These patients are at higher risk of recurrence.[11]

Brain imaging

About 10% of adults with a first, unprovoked seizure will have an abnormal brain imaging study (CT or MRI).[11]

Complications

Status epilepticus

Status epilepticus is a "prolonged seizure or seizures repeated frequently enough to prevent recovery between episodes occurring over a period of 20-30 minutes."[2]

References

  1. Anonymous (2015), Seizure (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. 2.0 2.1 Anonymous (2015), Status epilepticus (English). Medical Subject Headings. U.S. National Library of Medicine.
  3. Passman R, Horvath G, Thomas J, et al (2003). "Clinical spectrum and prevalence of neurologic events provoked by tilt table testing". Arch. Intern. Med. 163 (16): 1945-8. DOI:10.1001/archinte.163.16.1945. PMID 12963568. Research Blogging.
  4. Syed TU, Lafrance WC, Kahriman ES, Hasan SN, Rajasekaran V, Gulati D et al. (2010). "Can semiology predict psychogenic nonepileptic seizures? a prospective study.". Ann Neurol. DOI:10.1002/ana.22345. PMID 21437930. Research Blogging.
  5. 5.0 5.1 Thijs RD, Wagenaar WA, Middelkoop HA, Wieling W, van Dijk JG (November 2008). "Transient loss of consciousness through the eyes of a witness". Neurology 71 (21): 1713–8. DOI:10.1212/01.wnl.0000335165.68893.b0. PMID 19015487. Research Blogging.
  6. Benbadis SR, Wolgamuth BR, Goren H, Brener S, Fouad-Tarazi F (1995). "Value of tongue biting in the diagnosis of seizures". Arch. Intern. Med. 155 (21): 2346-9. PMID 7487261[e]
  7. Brigo F, Nardone R, Bongiovanni LG (2012). "Value of tongue biting in the differential diagnosis between epileptic seizures and syncope.". Seizure 21 (8): 568-72. DOI:10.1016/j.seizure.2012.06.005. PMID 22770819. Research Blogging.
  8. Ahmad S, Beckett MW (2004). "Value of serum prolactin in the management of syncope". Emergency medicine journal : EMJ 21 (2): e3. DOI:10.1136/emj.2003.008870. PMID 14988379. Research Blogging.
  9. 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. Research Blogging.
  10. 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. Research Blogging.
  11. 11.0 11.1 11.2 Krumholz A, Wiebe S, Gronseth G, et al (2007). "Practice Parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society". Neurology 69 (21): 1996–2007. DOI:10.1212/01.wnl.0000285084.93652.43. PMID 18025394. Research Blogging.

See also