Dominic Heaney The presentation of a first seizure is a critical moment. Sometimes, diagnosis is straightforward if clear eyewitness accounts, recurrence patterns, and supportive investigations (e.g. EEG and MRI) all indicate an epileptic syndrome. In such cases, the clinician may feel confident to make a diagnosis and proceed with treatment and advise lifestyle adaptations. More often, however, the picture is uncertain. Events may be unwitnessed or vaguely described. The individual may have amnesia, or the seizure may have occurred during sleep. Neuroimaging and EEG may be normal. The presence of comorbidities, including psychiatric and metabolic disorders and cardiovascular pathology, can complicate the differential diagnosis. Even when the clinical evidence points to epilepsy, individuals and families may struggle to accept the implications. There are varied presentations of a first seizure, underscoring the spectrum of diagnostic uncertainty and highlighting the value of structured diagnostic pathways, including dedicated First Seizure Clinics (FSC). A consistent approach to diagnosis, communicate effectively with individuals is essential. Transient loss of consciousness and seizure‐like events are common in clinical practice and span multiple specialities: emergency medicine, general practice, cardiology, and neurology. Misdiagnosis of epilepsy remains a serious concern. A UK study found that nearly one in four individuals diagnosed with epilepsy in primary care were subsequently found to have alternative conditions.1 People with undiagnosed epilepsy remain at risk of unprotected seizure recurrence and morbidity. For clinicians, the dilemma often lies in managing diagnostic uncertainty without prematurely labelling an individual with epilepsy. The consequences of ‘overdiagnosis’ include loss of driving privileges, stigma, insurance implications, and unnecessary long‐term treatment. Conversely, underdiagnosis delays access to potentially lifesaving interventions. Dedicated FSC offer the possibility to improve early diagnostic accuracy. These clinics are typically staffed by neurologists and supported by timely access to EEG and neuroimaging. Structured protocols enable a thorough assessment of individuals with possible seizures, allowing for careful stratification of recurrence risk and the initiation of tailored management plans. Evidence supports the utility of FSC. In a prospective study, only about a quarter of people referred to an FSC were diagnosed with epilepsy at first assessment.2 Many were found to have seizure mimics or previously unrecognised non‐epileptic conditions. Importantly, a proportion of those with confirmed epilepsy had experienced earlier unreported seizures, highlighting the need for detailed history‐taking. FSC also facilitate education, psychosocial support, and coordinated follow‐up. Even in healthcare settings without access to such clinics, developing local pathways, with protocols for EEG, MRI, cardiology referral and neurology review, can confer many of the same benefits. The key is a consistent, multidisciplinary approach that respects the complexity of first seizure presentations. The cornerstone of diagnosis is a detailed clinical history from the individual concerned, as well as a witness. Reconstructing the event involves establishing a timeline that encompasses the events that occurred before, during, and after the episode (Table 10.1). Clinicians should note significant details, including: People may be amnestic or confused post‐ictally, so witness accounts are essential. In the digital age, smartphone videos, home monitors, and CCTV footage are useful in diagnosis, especially for nocturnal or other events that are not directly observed. Contextual clues are invaluable. A collapse following pain or prolonged standing in a hot environment may suggest vasovagal syncope. A seizure during exertion in a person with known heart disease should raise suspicion of arrhythmic syncope. Conversely, an event triggered by photic stimulation, menstruation, or sleep–wake transitions may indicate an epileptic nature. Table 10.1 Differential diagnostic features of tonic–clonic seizures, vasovagal syncope and functional dissociative seizures (See Chapter 24).
CHAPTER 10
First Seizure Clinic, Differential Diagnosis
MISDIAGNOSIS AND UNDERDIAGNOSIS: A PERSISTENT CHALLENGE
FIRST SEIZURE CLINICS: A STRUCTURED MODEL
THE DIAGNOSTIC PROCESS: BALANCING STRUCTURE AND CLINICAL JUDGEMENT
HISTORY AND EVENT RECONSTRUCTION
Tonic–clonic seizures
Vasovagal syncope
Functional dissociative seizures
Duration
Onset
Rapid
Preceded by pre‐syncopal seizures over minutes
Variable
Seizure duration
Usually <3 minutes
Brief (unless maintained in upright posture)
Often prolonged
Motor activity
General comments
Typical seizure pattern
Brief, myoclonic jerks after loss of postural tone
May be ‘waxing and waning’
Synchronised arm and leg movements
Common
Myoclonus may not be synchronised
Uncommon
Occurrence from lying
Possible
Very rare
Possible
Rhythmic pelvic movements
Rare
Very rare
Occasional
Opisthotonos
Rare
Occasional
Occasional
Facial features
Closed eyes
Rare
Rare
Common
Skin colour
May develop cyanosis
Pallor
No cyanosis despite long duration
Ictal behaviour
Ictal crying
Very rare
Very rare
Occasional
Purposeful movements
Very rare
Very rare
Occasional
Resistance to eye‐opening
Very rare
Very rare
Common
Pupillary reflexes
May be lost
Usually retained
Retained
Continence
May occur
May occur
May occur
Reacts to verbal or physical stimulus
Rare
Rare
May be retained
Postictal behaviour
Restoration of orientation
Usually, many minutes
Rapid
Variable, unpredictable
Injuries
Tongue biten
May occur (lateral)
Rare (tip)
Rare (tip)
Burns
May occur
Rare
Very rare
Bruises/
lacerations
Common
Common
Common
Persisting myalgia
Common
Rare
Rare
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