I’ve been on a bit of a kick about altered mental status lately. My reasoning behind this is that determining a patient’s mental status is one of the first things we as medical care providers do when assessing our patient. We discussed assessing mental status in a previous post, and then spent another post discussing the most common causes of AMS, with a little help from Brad Paisley.
Today, I’m going to take us one step further, and discuss caring for patients with AMS in a wilderness setting. The wilderness setting complicates patient care, not so much by changing the way the human body works, but more by reducing the amount of diagnostic equipment available, as well as by making calling for assistance and evacuation more difficulty. Therefore, when dealing with an altered patient, the wilderness medical provider has several priorities:
- Attempt to determine what is causing the patient to be altered.
- Fix the cause of the AMS or, if this isn’t possible, at least stop it from getting worse.
- Make an evacuation determination. Does this patient have to be removed from the mountains? If so, how quickly? What resources will be needed?
The ten million dollar question is, “Does this patient need to be evacuated?” Just like everything else in wilderness medicine and exploration, the answer is, “it depends.” Some general guidelines:
- Patients who lost consciousness due to trauma should be evacuated, even if the actual loss of consciousness was fairly short.
- Patients who became altered with no clear reason should be evacuated, especially when the AMS is a sudden departure from normal.
- Patients who remain altered despite attempts to fix the apparent cause of the AMS (giving the diabetic sugar, etc.).
- Patients showing signs of stroke should be RAPIDLY evacuated.
- In contrast, patients with chronic conditions causing AMS (such as epilepsy) who respond to prescribed treatments or follow the normal course of their condition may not have to be evacuated.
In the previous post, we discussed the mnemonic AEIOU-TIPS, which lays out the most frequently encountered causes of AMS. You may encounter all of these in a wilderness setting; however, you are more likely to encounter some causes more often than others.
When approaching an altered patient, make a list in your head of what you suspect may be causing the problem. This is called a list of differential diagnoses. The keys to determining the cause of a patient’s AMS are doing an excellent patient assessment and obtaining a detailed history. The results of your assessment and history will allow you to either discard differential diagnoses as unlikely, or support other diagnoses as more likely. As part of this assessment process, I perform what I like to call “tests,” which can help me determine if a diagnoses is more or less likely. This is a bit like a treasure hunt or detective story. Common tests include:
- Vital signs (heart rate, respiratory rate, skin color/temp/moisture).
- Blood pressure measurement (equipment dependent).
- Pupillary response.
- Temperature measurement.
- Blood sugar (equipment dependent).
- Oxygen saturation (also equipment dependent).
- Stroke assessment.
After you perform your tests/assessment and discard differential diagnoses, you’re left with the most likely cause of the patient’s AMS. While this may not be definitively the answer, it will give a direction to your treatment plan.
We’ll spend a few paragraphs talking through the most common causes of altered mental status you may encounter in the outdoors, as well as what your exam and your tests may find. Bear in mind, this is by no means an exhaustive list. Also note, this does not totally follow the AEIOU-TIPS mnemonic. I’ve added a few, and dropped out a few you’re less likely to see.
- Alcohol: We all love having that beer at the end of a long mountain bike ride or day at the crag. Many view alcohol as an integral part of enjoying the outdoors. Judging by the volume of beer cans and bottles I find at typical trailhead parking lots in my local area, many others view the outdoors more as a semi-secluded place in which to party. Additionally, alcohol plays a large role in many traumatic injuries, particularly in young men. Patients who are intoxicated on alcohol may smell like alcohol. Look for slurred speech and unsteady gait, but equal strength in extremities. Pupils may be a bit dilated and sluggish. Being drunk causes patients to become a bit dehydrated; this will frequently cause rapid, strong heart rate as the body attempts to compensate for fluid loss. If you’re able to measure blood pressure, you’ll find that the blood pressure will initially be a bit elevated, due to the body attempting to compensate for fluid loss. BP will later drop as the body is less able to compensate.
- Altitude: Those who have been to altitude can attest to the effect altitude has on the brain. Most of these are due to hypoxia, or lack of oxygen. We’ll talk about hypoxia in more detail in a few points. Additionally, look for signs of High Altitude Cerebral Edema, or HACE. Symptoms include confusion, total loss of consciousness, fever, difficulty in walking and speaking, and visual sensitivity to light.
- Environmental Factors, Cold: Hypothermia progresses in stages, with increases in AMS for each stage. Patients who are mildly hypothermic will present as confused and irritable, with loss of fine motor skills and shivering. Look for pale, bluish skin and lowered temperature. Patients who are severely hypothermic may be unresponsive, with weak pulses in extremities, pale, bluish skin, and very low body temperatures. For a great discussion of hypothermia, listen to this podcast!
- Environmental Factors, Heat: Patients also progress through hyperthermia in stages, though a patient may skip stages. Mildly hyperthermic patients will be pale, flushed, and sweaty as the body attempts to dump heat through sweating. Pulse will be slightly elevated; BP may be normal. Patients may be lethargic and tired. We call this heat exhaustion. In contrast, patients who are experiencing heat stroke generally have hot, dry, red skin due to not being able to get rid of heat fast enough. Heart rate is rapid and weak, with low blood pressure, due to the body no longer being able to compensate for dehydration.
- Insulin: When attempting to determine if the cause of a patient’s AMS is low blood sugar (hypoglycemia), the most important questions you can ask is “are you a diabetic?” followed by “when did you last eat?” followed by “when did you last check your blood sugar?” Remember, though, that patients who aren’t diabetic can also get low blood sugar. Look for pale, bluish skin, slurred speech, and confusion; sometimes, patients with low sugar are uncooperative or hostile. They may also have low body temperature; sugar is used to maintain body heat, and if there isn’t enough the body may become hypothermic. Patients who are hypoglycemic may have an odd odor, like ketone or nail-polish remover.
- Hypoxia: The brain does not tolerate lack of oxygen well at all. Hypoxic patients will frequently be cyanotic, or have bluish skin. Patients with darker skin may just show cyanosis on the gums, around the lips, or under the fingernails. The patient may appear confused. Some patients will show air hunger, or panting/gasping. If you have a pulse oximeter, which is a small device which measures the concentration of oxygen in the blood, you will probably find a low reading. Generally speaking, a reading of 94%-100% is considered normal. Less than 94% is usually considered hypoxic.
- Trauma: A strong blow to the head can cause the brain to not work properly; additionally, even if the brain isn’t damaged by the initial blow, bleeding inside the skull and subsequent increase in pressure can damage the brain after the initial injury. Look for a fall or a blow to the head, followed by a period of unresponsiveness. Patients who are dealing with a traumatic brain injury or TBI will show decrease in mental status over time. The patient may also have no short-term recall, and may ask the same questions over and over again. Cushing’s Triad, which is increase in blood pressure, slowing heart rate, and irregular respirations, indicate severe brain injury.
- Infection: Severe, systemic infection is called sepsis. Bacteria which causes infection releases toxins into the blood, and cause dehydration. This is more likely a factor on extended trips. Generally speaking, younger folks have less issues with infection than older folks, children, and immune-compromised individuals. However, it’s still possible. Fever is the major sign to look for, as well as signs of dehydration such as rapid heart rate, rapid respirations, pale skin or flushed skin, and low blood pressure.
- Poisons: This is going to seem like a cop-out; however, so many substances in the natural world can cause altered mental status it would be impossible to list all the symptoms you may see. You’re best bet is to research the various toxic flora and fauna in your area, learn the symptoms, and look for them when dealing with patients. Be extra suspicious of ingested poisons when dealing with children.
- Stroke: A stroke is caused by lack of oxygen-carrying blood flow to brain tissue. Stroke patients will typically have high blood pressure, and weakness on one side of the body. Speech may be slurred. One pupil may react to light, while the other may not. A good test for stroke is called the Cincinnati Pre-Hospital Stroke Assessment.
As mentioned before, this is by no means an exhaustive list of causes of AMS or of the symptoms of each. However, hopefully this gives you enough to be able to discard possible causes as you examine a patient.