Identifying Diseases that Mimic Strokes

JEMS Clinical Review Feature

Learning Objectives
>> Describe the key reasons that a rapid and correct diagnosis of stroke is critical for stroke patients and those with diseases that mimic strokes.
>> List four disorders that mimic strokes and are often misdiagnosed as strokes.
>> Describe key indicators that differentiate strokes from diseases that mimic strokes.
>> Describe why migraine headaches, hypoglycemia, multiple sclerosis, conversion disorders and seizures are often misdiagnosed as strokes.

Key Terms

Aphasia: A condition in which language function is disordered or absent because of an injury to certain areas of the cerebral cortex.
Aura: A sensation of light or warmth that often precedes a migraine or seizure.
Choreoathetosis: Irregular involuntary movements that may involve the face, neck, trunk, extremities or respiratory muscles.
Dysmetria: An inability or impaired ability to control the range of muscular movements and from properly measuring distances associated with muscular acts.
Dysphasia: See aphasia.
Epilepsy: A group of neurologic disorders characterized by recurring convulsive seizures, sensory disturbances, abnormal behavior, loss of consciousness or all of these.
Hemiparesis: Muscle numbness or weakness on one side of the body.
Hemiplegia: Paralysis of one side of the body.
Hyperglycemia: An abnormally high blood glucose level.
Hypoglycemia: An abnormally low blood glucose level.
Migraine: A recurring, severe throbbing headache, usually occurring on only one side of the head, often associated with sensitivity to light.
Todd’s paralysis: A temporary paralysis or weakness that infrequently occurs after seizures, particularly partial seizures.

Stroke Mimics Mnemonic
H: Hypoglycemia (and hyperglycemia)
E: Epilepsy
M: Multiple sclerosis (and hemiplegic migraine)
I: Intracranial tumors (or infections, such as meningitis, encephalitis and abscesses)

EMTs and paramedics need to make rapid assessments to provide the best clinical care possible for their patients. With the onus of caring for critically ill patients with limited time and resources, responders run the risk of focusing too narrowly on what appear to be obvious illnesses and subsequently miss an illness that mimics the signs and symptoms of a common disease. To minimize assessment errors when caring for patients who present with a set of signs and symptoms that mimics a common disorder, providers must always seek to validate their assessments by keeping an open mind and a high index of suspicion for alternate disease possibilities.

This can be accomplished by thoroughly reexamining and reevaluating patients with an open mind and performing every routine test and assessment procedure, even after forming a firm impression about the patient’s condition. Some disorders tend to be misdiagnosed more than others, because they present with signs and symptoms that overlap with other common diseases, such as a stroke being mimicked by a seizure, migraine headache or hypoglycemia.

Behind heart disease and cancer, stroke is the third leading cause of death in the U.S. today, and someone dies from a stroke every four minutes. Strokes affect more than 700,000 patients per year in the U.S., with someone experiencing a stroke every 40 seconds.(1) In one study, 2% of 9-1-1 calls were for patients with potential strokes.(2) The critical key to definitive stroke management is early identification and reperfusion therapy, performed before neurologic injury becomes permanent.

With the advent of the use of tissue plasminogen activator (tPA) to treat strokes, there’s great emphasis today on early recognition and transportation to an emergency care facility so that tPA can be administered as soon as possible for maximum effectiveness with minimal side effects. The window for administration is up to 4.5 hours, and because many patients and families don’t recognize the severity of the signs of a stroke, they fail to call 9-1-1 in time to allow for adequate field and hospital clinical assessments.

Further, administration of tPA for a stroke carries with it a much higher risk of intracranial hemorrhage than thrombolytic administration for an acute ST-elevation myocardial infarction(3) (STEMI). Several studies with small sample sizes suggest that the use of tPA in stroke mimics has been safe, with no incidences of intracranial hemorrhage.(4) Patients who present with focal neurologic impairment, aphasia or dysphasia (speech and comprehension communication disorders), altered mental status, seizures and headaches have been shown to be misdiagnosed by paramedics 27% of the time.(2)

Stroke mimics have been shown to be misdiagnosed by physicians in the hospital setting 31% of the time.(2) A prehospital assessment or field diagnosis of stroke is typically derived from the patient history, the physical examination and clinical tests, such as blood glucose level and neurologic tests (right- and left-side strength and compliance).(5) A key differential to distinguish strokes from those disorders that mimic a stroke include the rapidity of onset, which tends to occur with strokes and not with most other mimics.

A mnemonic to help keep stroke mimics in mind is HEMI: hypoglycemia (and hyperglycemia), epilepsy, multiple sclerosis (and hemiplegic migraine) and intracranial tumors (or infections, such as meningitis, encephalitis and abscesses).(6) Most errors in the misdiagnosis of stroke occur when patients can’t provide a past medical history due to impaired speech or altered mental status, or if their past medical history is unreliable (e.g., in the presence of strangers who are unfamiliar with the patient’s past medical history). (See Table 1, pg 80, JEMS March 2011.)

Here, we present four case scenarios in which the patient appears to have had a stroke, but in fact has one of four stroke mimics: hypoglycemia, hyperglycemia, migraine or seizure.

Hypoglycemia: Case Presentation #1
Mrs. Jackson calls EMS because she woke up in the morning to find her 35-year-old husband lying in bed confused, exhibiting a left-side facial droop and not moving his left arm and leg. EMS arrived and see the patient lying in bed confused with slurred speech, left-side facial droop and left side-paralysis. They administer oxygen (O2) via non-rebreather mask at 12 L/min and start an IV of normal saline TKO and transported to the stroke center on the ECG monitor. En route, the crew checks his blood glucose serum level; it’s 35 mg/dL. They administer an amp (50 cc’s) of dextrose 50% D50 in water, and the symptoms cleared. At the hospital, the emergency department (ED) physician consults with the neurology department, and an MRI is performed and found to be negative for stroke.

Hypoglycemia is the most easily detected stroke mimic, because a blood glucose level test is usually reliable and indicates the presence of low blood sugar. Patients typically respond rapidly to the administration of a bolus of D50. Although hypoglycemia sometimes presents with hemiplegia and aphasia, hypoglycemic patients who present with these signs will most often be alert and not also concurrently show the more severe signs of confusion and altered mental status or coma.(7)

Hypoglycemia most often goes undetected as a stroke mimic when the field
provider becomes so convinced by the presenting signs and symptoms that the patient is having as stroke that they fail to follow the standard altered mental status protocol and perform the blood glucose level test.

Hyperglycemia: Case Presentation #2
EMS responds to Mrs. Reynolds, a 50-year-old female with a history of hepatic encephalopathy and end-stage liver disease. Her husband called 9-1-1 because she suddenly began to have jerking movements of her upper left arm and hand. EMS providers check her blood glucose serum level, which reads “high.” They transport her to the ED on O2 and start an IV of normal saline solution en route.

Mrs. Reynolds has intermittent choreo-athetotic movements of her left upper extremities en route. On further examination, there was dysmetria of the left upper extremities and left lower extremities. Her Cincinnati Prehospital Stroke Scale level was 3, and the stroke team at the hospital was activated. A screening MRI rules out stroke. Her blood glucose level came back at 1245 mg/dL. Symptoms were resolved with treatment for hyperglycemia.

Hyperglycemia is most often confused with stroke when it presents with a generalized, global, altered mental status or coma. The lack of a past medical history indicating a long and gradual onset combined with a nonspecific “high” blood glucose level reading leads to a reasonable suspicion of stroke. Assessing the patient with a standardized assessment instrument, such as the Cincinnati Prehospital Stroke Scale is one of the best ways to increase the specificity of assessment for strokes.(2) (See Table 2, pg. 81)

Hemiplegic Migraine: Case Presentation #3
Helen Bradshaw, a 50-year-old female in generally good health suddenly developed paralysis of her upper extremities. Her husband calls 9-1-1, and the EMS crew arrives in seven minutes. They find her lying in bed with bilateral paralysis of her arms and hands. As the paramedics delve deeper with their assessment questions about her medical history, they learn from her husband that she’s had intermittent headaches for most of her life but has never seen a doctor for them.

As they continue to ask pertinent questions to explore any associated symptoms about her headaches, she states that she noticed “squiggly lines” in her visual fields and says it was just after she noticed those that she developed the weakness. As she relates this history, she reports that she was having one of her throbbing, generalized headaches. As the paramedics gather the curious history, signs and symptoms, her weakness begins to resolve, and her headache begins to throb with greater intensity. The ED physician treats Mrs. Bradshaw for her migraine headache, and the symptoms completely resolve.

Familial hemiplegic migraine (FHM) is a rare variant of migraine with an aura. Symptoms include hemiparesis, visual disturbances (aura) and dysphasia. Set criteria exist to establish the diagnosis, but diagnosis at the first attack may be impossible.8 Clues to this disorder are a family history of migraines, in particular FHM and a typical throbbing headache with an aura. Stroke may present with headache, but a prominent headache suggests a diagnosis other than ischemic stroke. Hypertensive intracerebral hemorrhage, subarachnoid hemorrhage and FHM may all present with headache and hemiparesis.

Epilepsy (Todd’s Paralysis): Case Presentation #4
Ralph Morris, a 47-year-old male, planned to go fishing at 5 a.m. with his son, Larry. But when Larry tried to wake up Ralph, he found that his dad was confused and couldn’t move his left arm and leg. Larry calls 9-1-1, and EMS arrives in 12 minutes. The crew starts O2 via non-rebreather mask at 12 L/min. and an IV of normal saline TKO and places ECG leads.

They find Ralph confused, with slurred speech and left-side paralysis, and are certain he had a stroke. As the paramedics continue to ask Larry about what happened prior to their arrival, he mentions his dad’s left hand had been “jerking a little” when he first went in to wake him up. Larry also mentions he’d noticed that his dad’s eyes were slanted to the left and he had drooled a little, as well. The paramedics transport Ralph expeditiously to the closest ED for treatment for a possible stroke.

A routine blood glucose level test in the ED shows 50 mg/dL, and 25 g of D50W is administered. The IV is switched to D10W. Ralph responds quickly to the glucose and can answer questions. He lets them know that he has a past history of epilepsy and hasn’t been taking his medications recently. He also lets them know he’d experienced an episode of hemiparesis in the past following one of his seizures. The ED physician has the nursing staff explain to Ralph the importance of compliance when taking anti-seizure medications, and he’s discharged with no further ED treatment needed.

Robert Bentley Todd (1809—1860) was an anatomist, pathologist and physiologist and the first person to present an electrical theory of epilepsy. He stated, in 1849, that some patients “who recover from a severe fit, or from frequently repeated fits of epilepsy, are often found to labor under hemiplegia, or other modifications of palsy.”

Multiple neurologists subsequently described the same phenomena.(9) The patient presents with a hemiparesis and possibly aphasia after having had a seizure of variable duration. The stroke-like symptoms resolve after a variable amount of time, ranging from a few minutes to several weeks.(10) The key to diagnosis is the history of a seizure or seizures. A clue on physical exam is a bite mark on the lateral side of the tongue, which may be seen in up to 64% of patients who die during a seizure. Another clue to a possible seizure is the presence of a postictal state (i.e., confusion) which is gradually improving.

A definite seizure at the onset of stroke symptoms is a contraindication to thrombolytic therapy.(3) Failing to obtain or report the history of a seizure risks a hospital misdiagnosis of stroke and subsequent thrombolytic therapy and a risk for intracranial hemorrhage.

A number of disorders mimic strokes, and the consequences can be serious for the patient. Conducting a careful, comprehensive history and physical examination, with a thorough scan of the patient’s environment, and diligently performing all appropriate available tests are the surest ways to make a correct assessment and provide a clinically sound assessment to the receiving hospital. Speed is the primary key to getting stroke patients to reperfusion therapy as quickly as possible, although a thorough patient assessment performed with a high index of suspicion for possible mimics is the best way to avoid having a patient receive unnecessary and potentially dangerous thrombolytic therapy. JEMS

1. American Heart Association. Heart Disease and stroke statistics—2010 Update. Dallas, Texas: American Heart Association; 2010)
2. Kothari R, Barsan W, Brott T, et al. Frequency and accuracy of prehospital diagnosis of acute stroke. Stroke; A Journal of Cerebral Circulation. 1995;26:
3. Adams HP, Brott TG, Furlan AJ, et al. Guidelines for thrombolytic therapy for acute stroke: A supplement to the guidelines for the management of patients with acute ischemic stroke. A statement for healthcare professionals from a special writing group of the stroke council, American Heart Association. Circulation. 1996;94:1167—1174.
4. Chernyshev OY, Martin-Schild S, Albright KC, et al: Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia. Neurology. 2010;74:1340—1345.
5. Hand P, Kwan J, Lindley R, et al. Distinguishing between stroke and mimic at the bedside: The brain attack study. Stroke; A Journal Of Cerebral Circulation. 2006;37:769—775.
6. Jamieson D. Diagnosis of ischemic stroke. Am J of Med. 2009;122 (Suppl 2:S14—S20.)
7. Ng C. Diagnostic challenge–is this really a stroke? Australian Family Physician. 2006;35:805—808.
8. Jen JC in Pagon RA, Bird TC, Dolan CR, Stephens K, editors. Familial Hemiplegic Migraine. University of Washington, Seattle. 1993—2001.
9. Binder D. A history of Todd and his paralysis. Neurosurgery. 2004;54:480.
10. Ulrich J, Maxeiner H. Tongue-bite injuries–a diagnostic criterium for death in epileptic seizure? Arch Kriminol. 2003;212:19—29.

This article originally appeared in March 2011 JEMS as “Clandestine Conditions: Know how to identify diseases that mimic strokes.”

Facial Droop
Normal: Both sides of face move equally.
Abnormal: One side of face doesn’t move at all.
Arm Drift
Normal:  Both arms move equally or not at all.
Abnormal: One arm drifts compared to the other.
Normal:  Patient uses correct words with no slurring.
Abnormal: Slurred or inappropriate words or mute.

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