Febrile Seizure

Brief HPI:

An 8-month old female, fully-immunized, otherwise healthy is brought in by paramedics after 1 minute of witnessed generalized tonic-clonic shaking. The patient had otherwise been well, eating and behaving normally earlier that day. On EMS arrival, the patient was post-ictal but grew increasingly responsive en-route and upon presentation to the pediatric emergency department she was crying and appeared normal to her parents. Capillary glucose was 118g/dL. On examination the patient was noted to be febrile with a rectal temperature of 39.4°C. The remainder of the physical examination was normal.

ED Course:

The patient received anti-pyretics and a urinalysis was obtained which was not suggestive of urinary tract infection. During the 3-hour period of observation in the emergency department the patient remained at her normal baseline, had no further seizure activity, and tolerated oral intake with difficulty. The patient was suspected to have a simple febrile seizure and was discharged home.

Algorithm for the Diagnosis of Febrile Seizure

Algorithm for the Evaluation of Febrile Seizure


  1. Syndi Seinfeld DO, Pellock JM. Recent Research on Febrile Seizures: A Review. J Neurol Neurophysiol. 2013;4(165). doi:10.4172/2155-9562.1000165.
  2. Whelan H, Harmelink M, Chou E, et al. Complex febrile seizures-A systematic review. Dis Mon. 2017;63(1):5-23. doi:10.1016/j.disamonth.2016.12.001.
  3. Millichap JJ, Gordon Millichap J. Methods of investigation and management of infections causing febrile seizures. Pediatr Neurol. 2008;39(6):381-386. doi:10.1016/j.pediatrneurol.2008.07.017.
  4. Subcommittee on Febrile Seizures, American Academy of Pediatrics. Neurodiagnostic evaluation of the child with a simple febrile seizure. Pediatrics. 2011;127(2):389-394. doi:10.1542/peds.2010-3318.



Pathologic neuronal activation leading to abnormal function
Recurrent unprovoked seizures


  • Cause
    • Primary: Unprovoked
    • Secondary: Provoked, caused by trauma, illness, intoxication, metabolic disturbances, etc.
  • Effect on mentation
    • Generalized: involvement of both hemispheres with associated loss of consciousness (tonic-clonic, absence, atonic, myoclonic)
    • Focal: Involving single hemisphere with preserved level of consciousness
  • Status epilepticus
    • Witnessed convulsions lasting >5min
    • Recurrent seizure without recovery from postictal period

Causes of Seizures

Causes of Seizures

Management of Seizures

Management of Seizures

Medications for Treatment of Seizures

Medication Dose (adult) Dose (peds) Comment
1st Line
Lorazepam 4mg IV <13kg: 0.1mg/kg (max 2mg)
13-39kg: 2mg

>39kg: 4mg
Repeat in 10min
Midazolam 10mg IM 0.2mg/kg IM (max 5mg) Repeat in 10min
Midazolam 10mg buccal 0.5mg/kg buccal (max 5mg) Repeat in 10min
2nd Line
Fosphenytoin 20mg PE/kg IV    
Phenytoin 20mg/kg IV   May cause hypotension
3rd Line
Midazolam 0.05-2mg/kg/hr    
Propofol 1-2mg/kg bolus then 20-200mcg/kg/min    
Pentobarbital 5-15mg/kg bolus then 0.5-5mg/kg/hr    
Special Conditions
Glucose 50mL D50/W   Hypoglycemia
MgSO4 6g IV over 15min   Eclampsia (20wks gestation to 6wks post-partum)
Pyridoxine 0.5g/min until seizures stop, max 5g   INH ingestion
3% saline 100-200mL over 1-2h   Confirmed hyponatremia


Points suggestive of seizure over alternative process
Abrupt onset
Duration < 120s
Purposeless activity: automatisms, tonic-clonic
Provocation: fever in children, substance withdrawal
Postictal state
Retrograde amnesia
Incontinence, oral trauma (buccal maceration, tongue laceration)
Rapidly resolving lactic acidosis
Important historical points for patients with seizure history
Recent illness
Medications (adherence, changes, interactions)
Substance use
Ictogenic factors
Recent/remote head trauma
Developmental abnormalities
Substance use
Sleep deprivation

Key Physical Examination Findings

  • Vital sign abnormalities persisting beyond immediate postictal state (may suggest drug/toxin exposure, CNS lesion)
  • Nuchal rigidity
  • Signs of IVDA
  • Sequela

    • Head trauma
    • Tongue laceration
    • Shoulder dislocation (posterior)
  • Neurological exam

    • Stroke
    • Elevated ICP
    • Failure to note improvement in postictal confusion (encephalopathy, subclinical seizures)


  • Glucose
  • BMP (Na, Ca, Mg)
  • AED levels
  • CBC (leukocytosis and bandemia common post-seizure)
  • CSF
  • B-hCG
  • LFT (hepatic dysfunction, alcoholic hepatitis)
  • Lactate (rapidly resolves on repeat)

Indications for Imaging

  • New seizures
  • History of trauma
  • History of malignancy
  • Immunocompromised
  • Headache
  • Anti-coagulation
  • Focal neurological exam
  • Persistent AMS


  1. McMullan, J., Davitt, A., & Pollack, C. (2013). Seizures. In Rosen’s Emergency Medicine – Concepts and Clinical Practice (8th ed., Vol. 1, pp. 156-161). Elsevier Health Sciences
  2. WikEM: Seizure



Seizure - 2.2cm rim-enhancing lesion in the right occipital lobe.

2.2cm rim-enhancing lesion in the right occipital lobe.

26M with a history of retroperitoneal embryonal carcinoma (IIIC, known liver/lung metastases) presenting with new-onset “seizures” for one week. The patient reports the first episode occurred 6 days ago, he noted progressive loss of vision on the left side (over 1-2min), followed by loss of consciousness and awoke in an ambulance. He denies any urinary/fecal incontinence, tongue biting, or post-spell confusion, and he awakes spontaneously and is able to get up under his own power. Episodes are not associated with palpitations, nausea or diaphoresis. An episode of identical character occurred 4 days later and triggered his presentation today. He otherwise denies fevers/chills, headaches, nausea/vomiting, changes in vision outside of episodes.

A witness, the father, described the patient reporting vision loss, followed by collapse and tensing of trunk and limb muscles for 1-2 minutes (without rhythmic shaking) during which the patient was unresponsive. The patient then awoke but was confused, unaware of what had happened and unable to recognize his father.

The patient was initially diagnosed with his malignancy several months ago, presenting with flank pain, weight loss and hemoptysis and recently completed a third cycle of chemotherapy (VIP: etoposide, ifosfamide, cisplatin).


  • Retroperitoneal embryonal carcinoma. Stage IIIC


  • None


  • Relative with testicular malignancy.


  • No t/e/d use
  • Lives at home with family


  • Norco 5/325mg p.o. q.4.h. p.r.n. pain



Physical Exam:

VS: T 98.4 HR 67 RR 17 BP 116/67 O2 98% RA
Gen: Well-appearing, no acute distress
HEENT: PERRL, MMM, no lesions, discs sharp b/l
CV: RRR, normal S1/S2, no M/R/G
Lungs: CTAB, no crackles/wheezing, no focal consolidation
Abd: +BS, soft, NT/ND, no hepatosplenomegaly
GU: Testes descended b/l, no masses, non-tender
Ext: Warm, well-perfused, no rashes/ecchymoses
Neuro: AAOx4, CN II-XII intact, OS 20/40 OD 20/70, normal visual fields to confrontation, no dysmetria/dysdiadochokinesia, normal gait


  • CBC: 7.8/14.4/43.3/179
  • BMP: 138/4.0/105/25/7/0.66/94
  • AFP: 3.5
  • B-hCG: 4222
  • MRI Brain: 2.2 cm rim-enhancing heterogeneous lesion in the right occipital lobe concerning for a metastatic focus.


26M w/hx retroperitoneal embryonal carcinoma with known liver/lung metastases presenting with syncope x1wk.

# Syncope: Likely neurogenic (seizure) given imaging findings of brain mass concerning for metastasis. Location of mass correlates with seizure characteristics as likely focus of complex partial seizure with apparent secondary generalization. Currently, no evidence of significant mass effect or increased intracranial pressure (no headaches, nausea/vomiting, papilledema). Patient discussed with neurosurgery who will evaluate the patient for surgical resection of mass.  Start levetiracetam for seizure prophylaxis.

# Retroperitoneal embryonal carcinoma: Stage IIIC with known liver/lung metastases, now with evidence of extension of disease. Consulted heme/onc who are familiar with the patient and do not plan for chemotherapy during this admission. Continue monitoring AFP, B-hCG levels which have remained stable.


CT Abdomen/Pelvis: Axial
CT Abdomen/Pelvis: Coronal
CT Abdomen/Pelvis: Sagittal
MRI Brain: Axial

Download: (.mp4)

Differentiating Seizure and Syncope:

The differential diagnosis of syncope is broad (and has been explored previously). This case explores the clinical features that have been shown to be most useful in differentiating syncope from seizure.1,2

Differentiating Seizure and Syncope


Feature Points
Tongue laceration 2
Déjà vu 1
Emotional stress associated with LOC 1
Head turning during spell 1
Unresponsive, unusual posture, limb movement, amnesia 1
Confusion 1
Lightheadedness -2
Sweating -2
Prolonged sitting/standing -2

Score: >1 likely seizure, <1 likely syncope


  1. McKeon, A., Vaughan, C., & Delanty, N. (2006). Seizure versus syncope. Lancet neurology, 5(2), 171–180. doi:10.1016/S1474-4422(06)70350-7
  2. Sheldon, R., Rose, S., Ritchie, D., Connolly, S. J., Koshman, M.-L., Lee, M. A., Frenneaux, M., et al. (2002). Historical criteria that distinguish syncope from seizures. Journal of the American College of Cardiology, 40(1), 142–148.



A 50 year-old male with a reported two-year history of infrequent spells, presenting with two spells in the past two days.


The patient’s spells began two years ago, he recounts that he was watching television when he lost consciousness and a friend noted he started shaking; he does not recall the event, and awoke in the hospital. The next spell occurred one year later, though the patient is unable to recall much about this episode. The patient remained spell-free until yesterday when he was on a bus, lost consciousness and awoke in a hospital. He notes that he had bit his tongue and lost control of his bladder. He was discharged hours later with a prescription for an AED which he was unable to fill. This morning, the patient had another spell while in the bathroom. His roommate heard him fall, found him on the ground, and noted that his mouth was moving but did not see any other movements.

The patient’s episodes are all associated with loss of consciousness and are followed by 5-10 minutes of disorientation after which he recovers fully. The episodes are sometimes preceded by a feeling of “euphoria”, though this feeling sometimes occurs without subsequent LOC.

The patient denies any associated palpitations, dizziness/LH, chest pain or muscle pain.  He has not had any recent fevers/chills, dysuria, cough, headache, changes in vision, numbness/tingling, weakness, difficulty speaking or swallowing or weight loss. He also denies any history of head trauma.

Physical Examination:

  • VS: Stable and WNL
  • General: Well-appearing, pleasant, and in NAD.
  • HEENT: NC/AT. MMM. Small lesion on tongue.
  • Lungs: CTAB.
  • CV: RRR with occasional ectopic beats, no M/R/G.
  • Abdomen: S/NT/ND. Bowel sounds present.
  • Neurological exam: AAOx4, CN II-XII intact, motor/sensation/reflexes/coordination/gait WNL


  • EKG: Occasional PAC/PVC
  • CT Brain: Unremarkable except for mild age-related cerebral atrophy

Assessment & Plan:

50 year-old male with a history of HTN and a reported two-year history of infrequent spells presenting with two spells in the past two days. The description of the patient’s episodes could be consistent with seizures. Aspects supporting this notion include loss of consciousness and period of confusion following each episode. One of the recent episodes was also associated with tongue-biting and loss of bladder control. Additionally, some episodes are associated with a sensation of euphoria rising from the abdomen to the head which could be indicative of an aura. Characteristics that suggest other causes include the absence of noted convulsions and non-stereotyped nature of each episode which could be due to the patient’s poor recollection of these events and absence of reliable witnesses. In the case of true seizures, the possible etiologies in this patient include a mass, metabolic abnormalities, substance use, or concomitant infection exacerbating an existing propensity for seizure activity. Other, non-seizure causes warranting evaluation include cardiogenic syncope particularly given the evidence of ectopic beats on examination and electrocardiogram.

Differential Diagnosis of Syncope

First, is it syncope? History is very important for distinguishing syncope from other causes (seizure, dizziness, vertigo, presyncope). Ask about precipitating events, prodromal symptoms, post-ictal confusion. Common causes of syncope and their associated symptoms are detailed in the figure below.


  1. Kapoor, W. N. (2000). Syncope. The New England journal of medicine, 343(25), 1856–1862. doi:10.1056/NEJM200012213432507