Neurological Emergencies

INTRODUCTION

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Neurological problems represent a wide range of presentations. The complaint may be as vague as confusion or lethargy or as specific as hemiparesis or aphasia. The underlying pathologies are numerous and encompass primary neurologic disorders as well as sequelae of metabolic, infectious, and toxic causes. Psychiatric disorders are complex and may also masquerade as a neurological issue. In the prehospital setting, it is very challenging and can be very difficult to elicit the etiology of the neurologic presentation. Historical information from the patient if possible, family, and bystanders is important for the early differentiation and treatment of these patients (Table 38-1).

TABLE 38-1

Neurological Problems in EMS

Common complaints:

Altered mental status

Confusion

Unresponsiveness

Hemiparesis

Seizure

Dizziness

Underlying pathology:

Cerebrovascular accident and transient ischemic attack

Intracranial hemorrhage

Migraine

Todd paralysis

Seizure

Hypertensive encephalopathy

Pharmacology

Toxins

Metabolic derangements

Neurological emergencies require transport to hospitals for definitive care. Depending on the region and hospital system in the area, undifferentiated neurologic presentations should ideally be sent to the hospital system with stroke care. Protocols and interfaculty agreements are important for efficient, quality transports. Delays in transport can be deleterious. In events where delays occur, medical control should be involved to assist with timely and appropriate patient care.

ISCHEMIA STROKE

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The incidence of stroke in the United States is 178,000 strokes per year.¹ Stroke affects about 3% of adults² and is the third leading cause of death in the United States, accounting for 137,000 deaths annually.³ Approximately 29% to 65% of stroke patients utilize EMS systems,⁴ and the EMS system is integral to care for stroke patients. The American Heart Association recognizes the chain of survival for stroke treatment (Table 38-2). In cases of alteration in mental status, the diagnosis may be difficult to make in the field. One study showed a correlation with elevated blood pressure in altered mental status patients in the field and an increased risk of stroke.⁵

TABLE 38-2

Stroke Chain of Survival

Detection recognition of stroke signs and symptoms

Dispatch call 9-1-1 and priority EMS dispatch

Delivery prompt transport and prehospital notification to hospital

Door immediate ED triage

Data ED evaluation, prompt laboratory studies, and CT imaging

Decision diagnosis and decision about appropriate therapy

Drug administration of appropriate drugs or other interventions

In December 1995, The NINDS trial⁶ was published in the New England Journal of Medicine. This study was a randomized, double-blind trial of intravenous recombinant tissue plasminogen activator (t-PA). This study suggested that t-PA was beneficial when given within 3 hours of onset of the ischemic stroke. This study established the commonly accepted protocol for administration of tape, and subsequent trials and analysis indicate the importance of adhering to the NINDS protocol. Significant controversy exists regarding the risks and benefits of systemic thrombolytic therapy for stroke. The International Stroke Trial 3 (IST-3) data seem to show lack of benefit and presence of harm; however, the conclusions support the use of thrombolytics in the appropriate setting.⁷ Medical directors and EMS physicians must develop protocols and have CQI that enable this type of high acuity care. Several considerations must be addressed from having the appropriate critical care prehospital team, well-established protocols for patients on t-PA drips, and the plan of care in the event the patient decompensates. The appropriate receiving hospitals need to be identified. Criteria for consideration of t-PA therapy are listed in Table 38-3.

TABLE 38-3

Inclusion/Exclusion Criteria for tPA

Inclusion Criteria

Onset of symptoms <3 hours before beginning treatment (Onset time is defined as either the witnessed onset of symptoms or the time last known normal if symptom onset was not witnessed.)
Diagnosis of ischemic stroke causing measurable neurological deficit
Aged ≥18 years
Potential risks and benefits of IV tPA treatment discussed with the patient and/or family members and they have verbalized understanding (to be documented in the patient’s record). If the patient unable to give verbal consent and no family available, IV tPA can be given under Emergency Doctrine. Written informed consent not required for IV tPA when given within 3 hours of symptom onset

Exclusion Criteria

Significant head trauma or prior stroke in previous 3 months
Symptoms suggest subarachnoid hemorrhage
History of previous intracranial hemorrhage
Intracranial neoplasm, arteriovenous malformation, or aneurysm
Recent intracranial or intraspinal surgery
Arterial puncture at noncompressible site in previous 7 days
Elevated blood pressure (systolic >185 mm Hg or diastolic >110 mm Hg)
Active internal bleeding
Blood glucose concentration <50mg/dL (2.7mmol/L)
Acute bleeding diathesis, including but not limited to: platelet count <100 000/mm³
(In patients without history of thrombocytopenia, treatment with
IV rtPA can be initiated before availability of platelet count but should be discontinued if platelet count is <100,000/mm³.)
Heparin received within 48 hours, resulting in abnormally elevated aPTT greater than the upper limit of normal
Current use of anticoagulant with INR >1.7 or PT >15 seconds (In patients without recent use of oral anticoagulants or heparin, treatment with IV rtPA can be initiated before availability of coagulation test results but should be discontinued if INR is >1.7 or PT is abnormally elevated by local laboratory standards.)
Current use of direct thrombin inhibitors or direct factor Xa inhibitors with elevated sensitive laboratory tests (such as aPTT, INR, platelet count, and ECT; TT; or appropriate factor Xa activity assays)
CT demonstrates multilobar infarction (hypodensity >1/3 cerebral hemisphere)

Relative Exclusion Criteria

Recent experience suggests that under some circumstances—with careful consideration and weighting of risk to benefit—patients may receive fibrinolytic therapy despite one or more relative contraindications. Consider risk to benefit of IV rtPA administration carefully if any of these relative contraindications are present:

Only minor or rapidly improving stroke symptoms (clearing spontaneously)
Seizure at onset with postictal residual neurological impairments
Major surgery or serious trauma within previous 14 days
Recent gastrointestinal or urinary tract hemorrhage (within previous 21 days)
Pregnancy

To extend IV tPA to 4.5 hours from symptom onset/last known normal, the following additional criteria must be met:

The patient is <80 years of age
The patient does not have a history of both diabetes and stroke
The patient is not taking warfarin (Coumadin) or any other anticoagulant regardless of INR/coagulation results
NIHSS is <25
Written informed consent obtained from the patient and/or family–required when IV tPA given within the 3- to 4.5-hour window