New-Onset Seizure, Adult Case File

New-Onset Seizure, Adult Case File

Eugene C. Toy, MD, Ericka Simpson, MD, Pedro Mancias, MD, Erin E. Furr-Stimming, MD

CASE 14

A 23-year-old graduate student was studying late at night for an examination. He recalls studying, but his next memory is being on the floor and aching throughout his body. He was incontinent of urine but not stool, and he felt slightly confused. No one was with him, and he did not know what to do. He called his mother, who recommended that he go to the local emergency room. The student was too busy and decided not to go to the hospital. He visited the school infirmary the next day, and the school physicians examined him. His vital signs were normal, and the neurologic examination, including motor and sensory evaluation, reflexes, and cranial nerve function, was normal. His entire neurologic and physical examinations were normal.

▶ What is the most likely diagnosis?

▶ What is the next diagnostic step?

▶ What is the next step in therapy?

ANSWERS TO CASE 14:

New-Onset Seizure, Adult                                        

Summary: A 23-year-old man lost consciousness and when he awoke, he was confused, incontinent of urine, and had muscle soreness. His examinations, including neurologic examination the following day, were normal.

• Most likely diagnosis: Seizure
• Next diagnostic step: Electroencephalograph (EEG), magnetic resonance imaging (MRI) of the brain, and routine laboratory values
• Next step in therapy: Potential anticonvulsant medication, discuss driving

ANALYSIS

Objectives

1. Distinguish the diagnostic approach for the first seizure in an adult, including the importance of the history, examination, and testing.
2. Understand the different types of therapy and arguments for and against treatment of the first seizure.
3. Describe the recommended evaluation and appropriate follow-up for the patient.

Considerations

This young man had an episode in which he lost consciousness. If someone briefly has loss of consciousness and experiences subsequent confusion, he or she probably had a seizure unless he or she sustained a concussion. The diffuse muscle aches also suggest generalized tonic-clonic activity. Further, the urinary incontinence also suggests seizure, although if someone experienced syncope and had a full bladder, he or she might also have urinary incontinence. Stool incontinence, which this patient did not have, usually suggests seizure and is rare with syncope. It is important to determine whether this patient had previous seizures or previous episodes of loss of consciousness (he did not). It is also important to determine whether he has a family history of seizures, which he does not. Last, one needs to determine whether he had any predisposing factors to seizures, such as increased alcohol consumption, drugs that can lower seizure threshold (eg, cocaine, amphetamines, diphenhydramine, or antibiotics), or sleep deprivation. The patient described in this case stayed up late, and sleep deprivation could have lowered his seizure threshold.

Adult-onset seizure is caused by tumor or stroke until proven otherwise, but most young patients are found to have epilepsy without ascertainable cause. They need to be evaluated thoroughly with the suggested modalities discussed in the following text.

The EEG is an important assessment to determine a baseline and identify a possible epileptogenic focus; however, the diagnosis of seizure rests with the history, not EEG testing. EEGs examine the electrical activity of the brain but may only indicate real-time abnormalities. A normal EEG performed today does not preclude abnormal brain wave activity in the past. Neuroimaging, preferably an MRI of the brain, is recommended to evaluate for a possible underlying structural or vascular etiology. Routine laboratory studies should be obtained to assess for a metabolic derangement that can lower the seizure threshold, such as hypoglycemia or hyponatremia. Elevated white counts can point to infections or generalized convulsions, depending on the clinical presentation.

Patients need to be instructed to contact the Department of Public Safety regarding their driving and cautioned about being in situations in which they can harm themselves (ie, being on a roof, swimming alone, scuba diving, etc) if they have a seizure. Rules concerning driving vary by states. Some states require physicians to report all seizures to their driving agencies. It is important to document the advice given to patients. Some physicians ask their patients to sign a statement that they have been informed of their obligation to report themselves to the driving agency for their state and that they are not allowed to drive. The physician should also discuss the indication, dosing, and side effects of anticonvulsant medication and prescribe a medication based on the case.

APPROACH TO:

Adult-Onset Seizure                                        

DEFINITIONS

LOSS OF CONSCIOUSNESS: Lack of awareness of self and surroundings. These patients usually have a window of time they cannot recall.

SEIZURE: Temporary, self-limited cerebral dysfunction as a result of abnormal, self-limited hypersynchronous electrical discharge of cortical neurons. There are many kinds of seizures, each with characteristic behavioral changes and each usually with particular EEG recordings.

EPILEPSY: A disorder of the brain defined either by at least two unprovoked

seizures occurring more than 24 hours apart, or a single unprovoked seizure in which there remains an established risk of at least 60% for a recurrence in the next 10 years.

CLINICAL APPROACH

Etiologies

The current classification of seizures relates to the 1981 Classification of Epileptic Seizures promulgated by the International League Against Epilepsy (ILAE). Essentially, seizures are considered to relate to only one of the two cerebral hemispheres (these are referred to as partial or focal seizures) or both hemispheres of the brain (generalized seizures). Where the seizure pattern initiates and where it spreads determine the type of seizure, relates to prognosis, and frequently warrants different therapies.

According to the 2010 Classification of Epileptic Seizures of the ILAE (International League Against Epilepsy), seizures are now classified as either focal or generalized seizures as seen in the table above (Table 14–1). “Focal” refers to partial seizures. The terms simple partial, complex partial, and secondarily generalized are no longer used. A generalized seizure refers to seizures with an origin in the bilateral hemispheres of the brain. Subcategorization of generalized seizures primarily reflects the type of motor disturbances present during the convulsion (eg, tonic-clonic, tonic, atonic, myoclonus).

Seizures are further classified according to etiology: genetic (formerly idiopathic), structural-metabolic (formerly symptomatic), or unknown (formerly cryptogenic).

There is considerable controversy about this issue. The idiopathic epilepsy syndromes, whether focal or generalized, include benign neonatal convulsions, benign childhood epilepsy, childhood/juvenile absence epilepsy, juvenile myoclonic epilepsy, and idiopathic epilepsy (ie, not otherwise specified).

Structural-metabolic seizures can be focal or generalized and include infantile spasms (West syndrome), Lennox-Gastaut syndrome, early myoclonic encephalopathy, epilepsia partialis continua, Landau-Kleffner syndrome (acquired epileptic aphasia), temporal lobe epilepsy, frontal lobe epilepsy, posttraumatic epilepsy, and other forms not specified. There are other epilepsy syndromes of uncertain classification, including neonatal and febrile seizures and reflex epilepsy.

Predictors of a recurrent seizure that allow a diagnosis of epilepsy after a single seizure include a previous brain injury, an EEG with epileptiform discharges, a significant abnormality on brain imaging, and a seizure occurring during sleep.

Clinical Presentation

Seizure disorders can present as intermittent events. The initial event, whether reported by the patient or witnessed by an observer, is often clinically reliable as to whether a seizure begins with a focal onset or is immediately generalized.

However, the physician must recognize that the patient may not remember initial focal symptoms because of postseizure (ie, postictal) memory loss. Shortly after the onset of a focal seizure, the patient’s consciousness can be rapidly impaired; also, the area of the brain in which the seizure begins may not have focal symptoms.

In many cases, the classification of the kind of seizure the patient has is more important than the actual description of the seizure. This is because other relevant clinical information, of which the seizure may be only one variable, is also important. Within this context, the history (ie, brain trauma, recent fever or headaches rendering suspicion for meningitis, family history of epilepsy, etc) is important, as is the neurologic examination. Further, the results of EEG, neuroimaging, and blood tests are also important. Blood tests should include electrolytes, glucose, calcium, magnesium, renal and liver function, complete blood counts, and, if clinically suspected, lumbar puncture to rule out meningitis, as well as toxicology screens in the urine and blood.

Approximately 75% to 90% of patients who experience a seizure without an obvious etiology do not see a physician after having only one seizure. This is usually a tonic-clonic event and most have no risk factors for epilepsy. These patients usually have a normal neurologic examination, normal EEG, and normal neuroimaging. Of these patients, one-quarter will prove to have epilepsy.

Treatment

There have been multiple studies and discourse on what to do for patients who do not initially seek treatment, as three-quarters will never seize again but one-quarter will. It is generally accepted that treatment following the first seizure decreases the relapse rate, but there is no evidence that this treatment alters the prognosis of epilepsy.

Many neurologists wait until the second seizure before initiating treatment, unless the first seizure has positive EEG or MRI findings. The physician should discuss with the patient the implications of treatment or nontreatment, medicolegal issues, driving laws in the patient’s state, and options for therapy. Different seizures have different therapies. Table 14–2 provides a reasonable guideline for treatment of different seizures.

CASE CORRELATION

• See Case 15 (Absence Versus Complex Partial Seizures) and Case 16 (Cardiogenic Syncope)

COMPREHENSION QUESTIONS

14.1 A 61-year-old woman with a long history of type 2 diabetes is admitted to the hospital because of poorly controlled disease. During her hospitalization, she develops continuous tonic movements of her right arm and hand. Serum glucose is measured as greater than 600 mg/dL. Which of the following is the most appropriate step in management?

A. Noncontrast CT scan of the brain

B. Intravenous (IV) administration of lorazepam

C. Insulin drip and frequent serum glucose monitoring

D. Securing the airway

14.2 A 45-year-old man with history of embolic stroke 1 year ago presents with a generalized seizure. Which of the following is the most accurate regarding this patient?

A. This patient is at risk for recurrent seizures.

B. This patient requires treatment for an acute stroke.

C. Anticonvulsant therapy is not indicated until he has had a second episode.

D. This patient likely had a syncopal episode.

14.3 A 7-year-old girl with a history of muscle jerks in the early morning, and with sleep deprivation, presents with a generalized tonic-clonic seizure after playing video games late at night. Which of the following is the most likely diagnosis?

A. Juvenile myoclonic epilepsy

B. Febrile seizure

C. Benign epilepsy of childhood

D. Lennos Gastaut syndrome

ANSWERS

14.1 D. The ABCs are always the first step. Securing the airway is the first priority. Assessing for possible hypoglycemia, drug effects, alcohol withdrawal, and metabolic disorders is important. Imaging the brain and/or assessing for meningitis/encephalitis should be considered. Simple focal seizures are often caused by focal lesions in the brain; however, physiologic or metabolic insults such as electrolyte imbalances, significant elevated blood glucose, or drugs/toxins can also induce simple or complex seizures and should be evaluated and managed.

14.2 A. Epilepsy is likely to continue in this patient due to prior stroke and related epileptogenic focus. Similar to sleep deprivation, acute alcohol ingestion or intoxication can be associated with a seizure in the absence of preexisting lesions or risk factors.

14.3 A. Juvenile myoclonic epilepsy is one of the most common epilepsy syndromes. It accounts for 7% of all cases of epilepsy and is associated with myoclonic seizures (quick little jerks of the arms, shoulder, or occasionally the legs), usually in the early morning, soon after awakening. The myoclonic jerks sometimes are followed by a tonic-clonic seizure in the context of sleep deprivation or alcohol ingestion.

    CLINICAL PEARLS    

▶ Seizures can be associated with just about any type of intermittent symptom or sign, depending on location of the epileptogenic focus. The diagnosis should be suspected in anyone with stereotyped paroxysmal events with or without loss of consciousness. ▶ In patients who experience a singular seizure without a known antecedent event, 10% to 25% will develop epilepsy (ie, have more seizures). ▶ The classification of epilepsy is based on whether the seizures are focal or generalized as well as their cause (ie, genetic, structural–metabolic, unknown). ▶ In 60% to 70% of patients with epilepsy, no cause can be found.

REFERENCES

Bazil CW, Morrell MJ, Pedley TA. Epilepsy. In: Rowland LP, ed. Merritt’s Neurology. 11th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:990-1014. 

Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organisation of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005-2009. Epilepsia. 2010;51:676-685. 

Engel J Jr. A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: report of the ILAE Task Force on Classification and Terminology. Epilepsia. 2001;42:796-803. 

Engel J Jr. Report of the ILAE classification core group. Epilepsia. 2006;47:1558-1568. 

Jetté N, Wiebe S. Initial evaluation of the patient with suspected epilepsy. Neurol Clin. 2016;34(2): 339-350. 

Schacter SC. Epilepsy. In: Evans RW, ed. Saunders Manual of Neurologic Practice. Philadelphia, PA: Saunders/Elsevier; 2003:244-265.

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