 Hello and welcome to EM Ottawa Toxicology video. This is about the basic approach to the poisoned patient. A 35-year-old comes into your emergency department after a family member found him confused at home with a suicide note. He's taken something, but family is unable to provide any information. How do we go about looking after this patient? This video will take you through the basic approach to the patient with an unknown overdose. If you have not already done so, we suggest you review the Toxidram video prior to this. The general approach of the poisoned patient is a two-armed method. On the left has treatment and the right diagnosis. In real life, these two happen at the same time. We will discuss each component starting with the treatment arm. The first step in the treatment arm consists of the basic approach to any patient in the emergency department, A, B, C. First, airway. As with all emergency patients, we must ensure their airway is patented. This might mean an intubation in the patient with a decreased GCS. Two, breathing. We need to ensure the patient is ventilating and oxygenating properly. If the patient is hypoxic, we will give them supplemental oxygen. Three, circulation. We give fluids to ensure their circulation and end organ perfusion is adequate. We also put patients on a cardiac monitor since different toxins can cause bradycardia, tachycardia, or arrhythmias. And ECG should also be done. Since the poisoned patient can fluctuate quickly, it is important that we reassess them frequently. Next step, D for don't. The don't mnemonic stands for these antidotes, dextrose, oxygen, naloxone, and thiamine. Since many toxins can cause hypoglycemia, every poisoned patient should get a bedside glucose test. If it is low, dextrose is given intravenously. If the patient is hypoxic, oxygen is given. In patients who have a suspected opioid toxodrome and who have respiratory depression, naloxone should be given. Thiamine is given for selected chronic alcoholics with potential bronchies and cephalopathy. However, this antidote is rarely given. D also stands for decontamination. If the patient still has toxin on their skin or clothes, they should remove all clothes and irrigate the skin copiously with water. As a note, as care providers, you should be wearing gloves, goggles, and gowns to prevent contamination. If there is eye involvement, the eye should also be irrigated. What if the toxin is already ingested? The two main methods to remove it from the GI tract are activated charcoal and whole bowel irrigation. Another charcoal can be given for an ingestion that presents within the first one to two hours. The toxin is still in the stomach. We bind to the charcoal and then excrete it. Charcoal will not bind to liquids or metals. It can also cause aspiration in patients with decreased GCS. Whole bowel irrigation is used for specific toxins that do not bind to charcoal. It involves giving large volumes of fluid to flush out the contents of the bowel. Once the toxin is absorbed in the bloodstream, a way of getting rid of it is by dialysis. This method of elimination is used for specific toxins such as aspirin, digoxin, and toxic alcohols. F is for focus therapy or antidotes. There are a small number of specific antidotes for specific toxins. We will discuss a few of these in the antidote video. G is for get tox help. The local poison center always has staff available to answer questions and they should be involved early in the patient's care. Let's go back to our patient. He was able to tell you that he checked something four hours ago and was illiquid. Since he was able to talk to you, his airways patent at this point. His breathing shows a tachypnic respiratory rate at 24, even though his saturation is 100%. His blood pressure is 130 over 80, but his heart rate is 120. His blood glucose is normal. He is quickly put on a cardiac monitor and IV fluids are started. In terms of a universal antidote, since his blood sugar is normal, no dextrose is given. Since his oxygenation is good at this point, no oxygen is given. His presentation really does not look like an opioid, toxidrome, and so no naloxone is given. In terms of decontamination, there is no more of that toxin on his body. Because he's taken this about four hours ago, there's no role for activated charcoal. Because this is illiquid, there's also no role for whole-hour irrigation. You then look up to see if there is a specific antidote for this liquid that he mentioned. Another colleague has already started to call the poison center for advice. We now return to the diagnosis arm of our approach. The diagnosis arm consists of history, physical, toxidrome recognition, and diagnostic tests. History. It is often extremely difficult to get a history from a poisoned patient. They might be confused, sleepy, reluctant to speak, or in some cases, they don't even know what they've taken. Whatever little piece of information you can get, that would be very helpful. Start by asking about what toxins, when the time of exposure, the amount, and why they took the toxin. Ask them and their family member about all possible medication in the house, including over-the-counter medications or any herbal remedies. Have family members go through the pill bottles at home and bring the empty bottles to the emergency department. Ask the paramedics what bottles they have found at home. Next physical. It is tied in with the toxidrome recognition. The physical for the poisoned patient is not overly detailed. The main components include vital signs, neurological examination, and skin examination. The vital signs should include temperature, and the usual heart rate, blood pressure, rest rate, and O2S. And you should refer to the toxidrome video about the specific changes in vital signs that fit with each toxidrome. In terms of neurological examination, toxins should produce a globally decreased level of consciousness rather than a focal deficit. Phenetoxins can also cause seizures. You want to focus on global motor sensory examination and the patient's pupils. The size of the pupils will give you clues about the kind of toxidrome the patient might be in. For skin. Again, specific toxidromes will either cause dry skin or diephoresis. You may also want to look for medications that are still stuck to the skin such as nitro-patch or fentanyl patches. Diagnostic tests. Diagnostic tests can include blood gas, anion gap, osmol gap, specific drug levels, drug screen, and x-ray. Let's see how we can use them. First, blood gas. A lot of toxins create morbidity and mortality by creating metabolic acidosis. Therefore, we often get a blood gas telling us whether the patient is acedotic or not. Getting a venous blood gas will often suffice instead of an arterial one. Let's go back a bit to our patient. In our patient, his blood gas shows a pH of 7.2, which is acedotic. His bicarb is low, pointing towards a metabolic acidosis. In compensating for that acidosis, he's blowing off his CO2, causing a low CO2. Therefore, our patient has a metabolic acidosis, likely because of this toxin. Second, anion gap. Anion gap is calculated this way. A normal gap is about 12. If the patient has an elevated anion gap, there is a list of toxins that can cause an elevated anion gap metabolic acidosis. The mnemonic is mud piles cats. These are the toxins in medical conditions that can cause an anion gap metabolic acidosis. We will go through each letter of the mnemonic. M stands for methanol and metformin. U stands for uremia, really, not a toxin. G stands for DKA, P stands for pereldohyd, I stands for iron and isanizid, a medication used to treat TB, L stands for lactate, E stands for ethylene glycol, S stands for acylicylates, T stands for carbon monoxide and cyanide, and finally T stands for toluene. This is an important list that you'll find you go back and forth during your medical career when a patient presents with an anion gap metabolic acidosis. Let's go back to our patient. A patient's blood work shows a sodium 140 and a chloride of 95. What is the anion gap? Using a formula, the anion gap is 140 minus 95 plus 10, maybe 140 minus 105 equals to 35. There is definitely an anion gap that's elevated. Therefore a patient has an anion gap metabolic acidosis. We know he must have taken one of the toxins on the mud piles cat list. Another question is which one? We now try to narrow it down by doing another calculation called the osmogab. To calculate the osmogab, we first calculate the expecting osmolality. And this is created by 2 times sodium plus glucose plus BUN. Once you have that expected osmolality number, you now compare it with what's measured in this serum. The difference between the two, or the osmogab, can vary from individual to individual. However, an osmogab that's more than 10 is regarded as being abnormal. And there are only a handful of things that can cause an osmogab. A few of them include alcohol, ethylene glycol, and methanol. There are other things that can also cause an osmogab such as mannitol. But that's not usually a medication that people usually take. It is a medication that we often give to patient. And so we should know about the fact that there's mannitol in the system. Let's go back to our patient. He has a sodium of 140, glucose of 10, and BUN of 10. What is the calculated osmolality? That's right. So it should be 2 times 140 plus this 10 and this 10, and therefore gives you 300. If the measured osmolality is 330, what is the osmogab? And hopefully you figure this out, and that's the difference between the calculated osmolality, the 300, and the measured osmolality, giving it a gap of 30. And as you can see, our patient has an anion gap, metabolic acidosis, and also has been exposed to a toxin that also gives you an osmogab. Under those two headings, there are not a lot of medications that do that. And the two that will do both are either ethylene glycol or methanol. And you have just now solved his mystery ingestion just by these very simple blood tests. Sometimes once we have more information, we like to know the specific drug level to confirm how much the patient's serum drug level is, whether it is in the toxic range. These levels can be obtained, such as for acetaminophen, aspirin, digoxin, anti-seizure medications or toxic alcohol such as methanol, ethylene glycol, and just simple alcohol as well. These drug levels give you the amount that's in the body or what's known as a quantitative test. In this case, in order to sort out whether the patient has taken methanol or ethylene glycol, you might want to order methanol and ethylene glycol level to confirm the diagnosis. And then as you draw the ethylene glycol and methanol level, it comes back that there is no methanol in a system but there's lots of ethylene glycol. We call the poison center who suggests a specific antidote, which again we'll talk about in the antidote video. Sometimes tox screen is also being ordered for patients with an unknown overdose. These are screens that we can do in urine or blood to look for the presence or absence of toxins. These are qualitative measures such as whether the drug is in the system or not. It does not give you a level. There are a lot of problems with toxicology screen. A lot of medication will cross-react with the reagent for other drugs and therefore making them very nonspecific when you get the result. Often these results do not come back in a timely fashion for us to decide on treatment and sometimes they're not particularly helpful for us in the emergency department. And therefore, tox screen is really rarely used. And the last for diagnostic are x-rays. Some medications will show up on plain x-rays such as drug packets or heavy metals. In those case, a plain abdominal film can be taken. If the patient has respiratory difficulty, a chest x-ray is done to look for cause of hypoxia. In this video we discuss the simultaneous approach of treatment and diagnosis of the poison patient. In the treatment arm we have ABC, DON'T, enhanced elimination, focus therapy or specific antidote and to get tox help. In the diagnosis arm we have history, physical examination, toxodrome recognition and diagnostic tests. We hope this video will help you look after your next poison patient. In the antidote video we will also be revisiting these concepts as well.