Updated on Dec. 7, 2017
Finding a patient unresponsive with no identification and no obvious medical history puts an EMS provider in a situation of having an extensive list of differential diagnoses to rule out. Traumatic, neurologic and metabolic causes should all be considered at the beginning of the patient assessment.
In the instance of the patient working out in the hotel, trauma was ruled out by surveying the scene around the patient and performing a physical assessment. Metabolic issues, like diabetes, can be excluded through evaluation of medical history, if available, and assessment findings, like blood glucose.
One additional differential diagnosis to consider for an unresponsive patient is narcotic overdose. With the broad adoption of naloxone administered by BLS providers, police officers and lay people, these rescuers now have a treatment option that does not require ALS to be on scene.
While naloxone is generally regarded as safe, administering it is not without consequence. As a result, providers should still make a specific decision to administer naloxone due to a suspicion of overdose rather than simply giving it to every unresponsive patient.
In this scenario, the patient has irregular respirations with periods of tachypnea and is hypertensive. Neither patient assessment finding is particularly associated with narcotic use and the scene size-up is not suggestive of overdose so naloxone should not be given in this case.
With trauma and metabolic concerns initially ruled out, providers can begin to evaluate neurologic causes. The patient’s symptoms are suspicious for hemorrhagic stroke; for instance posture – arms flexed and held tight against the body – and pupillary findings of dilated and minimally responsive to light.
Brain anatomy
The brain is the chief organ of the central nervous system and resides inside the cranium. The brain itself is covered by a series of membranes called meningeal layers. Immediately on top of the brain is the pia mater, then the arachnoid mater and finally the dura mater. The spaces between these layers contain cerebrospinal fluid or blood vessels.
Types of stroke
Strokes, or cerebrovascular accidents, fall into one of two categories. When a stroke is caused by a clot in the blood supply to the brain it is referred to as an occlusive stroke. Risk factors for occlusive stroke include atrial fibrillation and recent travel, surgery or pregnancy.
A stroke caused by bleeding in the brain is call a hemorrhagic stroke. These strokes can result from traumatic injury or rupture of a blood vessel in the brain. Risk factors for hemorrhagic stroke include a history of aneurysm – an out-pouching of an artery where the wall has weakened – and hypertension. Activities like weight lifting, which can cause blood pressure to spike during episodes of straining, can also cause a rupture of an existing aneurysm.
Pathophysiology of hemorrhagic stroke
There are essentially three varieties of hemorrhagic stroke depending on where in the brain the bleeding is located.
A subarachnoid hemorrhage occurs in the space below the arachnoid layer and may be the result of a traumatic injury or a spontaneous rupture of a blood vessel. A subdural hematoma is the collection of blood between the dura and arachnoid layers. Subdural bleeding is generally the result of tearing of the veins which bridge the space between the two layers and is often the result of a traumatic mechanism. An epidural hematoma occurs between the dura mater and the skull and can result from either a spontaneous rupture or from trauma.
In any case, as the amount of bleeding increases, more and more pressure is placed on the brain. Since the skull is an enclosed space, blood loss into that space increases the amount of pressure and can begin to press against the brain.
Arterial bleeding, since it comes from the high-pressure side of the circulatory system, will fill that space faster than venous bleeding. The measurement of pressure within the skull is called intracranial pressure.
Effects of increased ICP on the life support chain
As ICP increases, the pressure against the brain increases as well. The cranium is an entirely closed space with the exception of the foramen magnum (large opening) at the bottom where the brainstem connects to the spinal cord.
Given enough increase in ICP, the brain can begin to push – or herniate – through the foramen magnum. Obviously the brain will not fit through this space and the increase in ICP creates pressure on the brainstem as the brain presses downward. The pressure, aside from exerting physical stress on the brainstem, may also collapse the blood vessels which supply parts of the brain.
The brainstem is responsible in part for regulating heart rate and breathing. As the pressure on the brainstem increases, patients will begin to exhibit symptoms consistent with Cushing reflex. These symptoms include increased systolic blood pressure, decreased heart rate and irregular respirations. These changes in both respiratory control and circulation can have an impact on the body’s ability to maintain the life support chain and, ultimately, homeostasis.
Time of Stroke onset
One final assessment finding which may have an impact on a stroke patient’s course of treatment is the time last know well. Particularly in the case of occlusive strokes, this time frame, along with severity of symptoms, will guide the decisions about which treatment modalities to consider.
While “time last known well” is often used interchangeably with “time of onset” this may not always be the case. In many cases of stroke the time of onset of symptoms is actually unknown. Additionally, symptoms may gradually begin and increase in severity over time. As a result, understanding when the patient was last at his baseline is of the upmost importance.
In the case of the patient who was working out, EMS providers have a reliable time last known well from the housekeeper who witnessed him working out. You should make careful notes about the timeline she helps to establish and obtain contact information for her in case the physician at the hospital has other questions.
Conclusion
Based on your patient’s vital signs, his posture and the relative speed of onset of his symptoms, you suspect he is suffering from increased ICP due to a hemorrhagic stroke. With manual airway positioning you are able to maintain an adequate airway and are assisting his ventilations with a BVM. You check a blood glucose and obtain a reading of 88 mg/dL. You alert the ALS unit responding and advise of your differential diagnosis.
The ALS truck arrives and concurs with your assessment of the patient. You assist in packaging the patient for transport taking care to elevate the head of the stretcher. The ALS unit leaves for the nearest stroke center.
