Statistically, even laymen know that headaches are rarely serious problems. However, emergency calls in which the Chief Complaint is ‘headache’ cannot be taken lightly.”1 Those are words to the wise in the opening paragraph of Protocol 18: Headache in Principles of Emergency Medical Dispatch, the bible of Protocol application.
In fact, when a caller’s Chief Complaint is a headache, the EMD’s primary objective is not the headache itself. Rather, it is the EMD’s responsibility to understand exactly what happened to help rule out a life-threatening but potentially treatable cause such as stroke, meningitis, or other serious brain condition. And, in case you ask, Protocol 18: Headache is used for the complaint of migraine despite the word’s absence in the script.
A stroke and a migraine are not the same. Some types of migraine, such as hemiplegic migraine, can mimic stroke symptoms. Symptoms of hemiplegic migraine usually come on gradually compared to a stroke or transient ischemic attack (TIA), which happens suddenly. A migraine does not cause a stroke, but a stroke can occur during a migraine attack.2
If the patient is experiencing a stroke—which may cause symptoms similar to a migraine—the Stroke Diagnostic Tool (SDxT) within the Medical Priority Dispatch System™ (MPDS®) is invaluable. A stroke symptom almost always has a sudden onset, and this qualifier accompanies all the STROKE Symptoms listed in Protocol 18. Also, compared to a migraine, stroke numbness or paralysis is almost always unilateral, occurring on one side of the body, and not on a single limb or the surface of the skin. Distinguishing them apart over the phone, however, is not the goal, said Brett Patterson, IAED™ Medical Council of Standards Chair and Academics & Standards Associate.
“The EMD … does not need evaluate to such granularity. Stress ‘sudden onset’ and the goal of the Headache Protocol, which is to rule out serious cause through appropriate questioning and use of the SDxT.” In other words, leave it to the EMD’s interrogation, the Protocol, and the SDxT.
Headache vs. stroke
A headache is not a pain inside the brain. The brain feels like it’s throbbing, but the brain is not the epicenter of pain. Most headaches begin in the nerves of muscles and blood vessels surrounding the head, neck, and face. Once these pain-sensing nerves are activated by muscle tension, enlarged blood vessels, and other triggers, the nerves send messages to the brain, and it can feel like pain is coming from deep within the head.3
Most headaches are not caused by serious problems or health conditions. A headache, in and of itself, is not a diagnosis but a very general symptom of many other low-acuity problems (Axiom 1). Indications of potentially serious underlying conditions include sudden onset of severe pain; sudden visual disturbances such as blurry vision, double vision, or loss of vision; sudden nausea or vomiting; numbness; weakness; dizziness; confusion; or trouble talking. All of these conditions are reasons to suspect the patient’s complaint is something more than a tension or sinus headache.
An ischemic stroke is a medical emergency that occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients.4 A hemorrhagic stroke is caused by the rupture of a blood vessel, or cluster of vessels, in the brain. Hemorrhagic strokes are often fatal and preceded by a sudden onset of severe headache. A TIA is a type of stroke that tends to be mistaken for a migraine.5 This so-called mini-stroke can occur when blood flow to the brain is cut off for a short time, often less than an hour.
Promoting greater awareness
Additional Key Questions, instructions, suffixes, Rules, and Axioms were introduced in MPDS v13.0 to promote greater awareness of the possibility that a patient’s report of a severe headache could be a stroke, meningitis, or other serious brain condition like those listed
in the Additional Information section. A prompt to start the Stroke Diagnostic Tool was added for cases in which stroke symptoms are identified during Key Questions. Asterisks were added to Key Questions 3, 4, 5, and 6 and to Determinant Descriptors for several CHARLIE-level codes (C-3 through C-7) in the cardset to clearly denote possible stroke symptoms (automatically recorded in ProQA®). The “STROKE Symptoms” Additional Information section directs EMDs to Protocol 28: Stroke (CVA)/Transient Ischemic Attack (TIA) “for the conscious and breathing patient when the caller initially reports ‘stroke’ or the sudden onset of one or more of the following symptoms:
• Sudden speech problems
• Sudden weakness, numbness, or paralysis of the face, arm, or leg on one side of the body
• Sudden loss of balance or coordination
• Sudden trouble seeing in one or both eyes
• Sudden, severe headache with no known cause.”
In addition, several portions of Protocol 28 were duplicated and modified for use on Protocol 18. The Key Question “(STROKE Symptoms* identified) Exactly what time did these symptoms (problem) start?” and a new Sub-Key Question (also added to Protocol 28) “(Unknown) When was the last time s/he was seen to be normal?” were added, along with send points to first determine the time frame of symptom onset (if known) and then initiate the response. This time frame is very important to potential treatment qualifications.
Axiom 5 added to v13.0 reinforces the EMD’s role in identifying the possibility of a stroke through use of the SDxT and notifying a stroke center to decrease the time from the patient’s symptom onset to definitive treatment.
Accordingly, stroke must receive an immediate response that is not subject to delay. Lights-and-siren are not recommended (Protocol 18, Rule 2). Complementing the Determinant Levels and Descriptors are additional stroke suffix codes that include a locally defined treatment time window: Less than “T” hrs (since the symptoms started), Greater than “T” hrs (since the symptoms started), and Unknown. Again, these time parameters help to establish various treatment qualification windows.
Stroke Diagnostic Tool (SDxT)
A study that examined the predictive ability of a dispatch-specific stroke diagnostic tool found the tool to have high sensitivity in predicting hospital-confirmed strokes.6
The SDxT within the MPDS contains three tasks for the patient, each designed to assess a specific neurological function. Each task is presented by the EMD as a separate, scripted instruction to the caller, who in turn requests the patient to complete that task. As the caller reports the patient’s actions, the EMD records what the patient was able to do, with five possible outcomes: the patient was able to complete the task, was unable to complete the task, was partially able to complete the task (with two different levels of partial ability for each task), or refused to complete the task. Each of these answers is assigned a point value, and these are added together to calculate the evidence of stroke when the tool is completed.
Once all three task responses are entered by the EMD, the internal SDxT software algorithm uses the point values to compute the level of evidence for stroke, assigning a designation of CLEAR evidence, STRONG evidence, PARTIAL evidence, no test evidence of stroke, or unable to complete the diagnostic. An inability to complete any of the tasks is recorded as the combination (2, 2, 2) because the inability to complete it is actually predictive of stroke, while refusal to complete the task is not weighted at all.
Sources
1. Clawson JJ, Dernocoeur KB, Murray C. Principles of Emergency Medical Dispatch. Sixth Edition. Priority Press; Salt Lake City, Utah, USA. 2015.
2. Sissons B. “What is the relationship between migraine and stroke?” Medical News Today. 2021; Sept.10 medicalnewstoday.com/articles/migraine-stroke#symptoms (accessed July 26, 2022).
3. “Headache Pain: What To Do When Your Head Hurts.” National Institutes of Health. 2014; March. https://newsinhealth.nih.gov/2014/03/headache-pain (accessed July 26, 2022).
4. Brown R. “Stroke.” Mayo Clinic. 2022; Jan. 20. mayoclinic.org/diseases-conditions/stroke/symptoms-causes/syc-20350113 (accessed July 30, 2022).
5. Langmaid S. “Migraine vs. Stroke: How to Tell the Difference.” WebMD. 2021; July 28. webmd.com/migraines-headaches/migraine-and-stroke#:~:text=The%20kind%20of%20stroke%20 that,last%20less%20than%20an%20hour (accessed July 26, 2022).
6. Olola C, Scott G, Gardett I, Clawson J. “Characterization of Hospital-Confirmed Stroke Evidence for Callers Who Were Unable to Complete Stroke Test Requests from the Emergency Medical Dispatcher.” Annals of Emergency Dispatch and Response. 2016. cdn.emergencydispatch.org/AEDR/pdfs/7_Olola-Stroke-Diagnostic-Unable-Result.pdf (accessed July 28, 2022).
