Poisoning and Drug Overdose

Poisoning refers to the development of dose-related adverse effects after exposure to chemicals, drugs or other xenobiotics. To paraphrase Paracelsus, the dose produces poison. Although most poisons have predictable dose-related effects, individual responses to a given dose may vary due to genetic polymorphism, enzyme induction or inhibition in the presence of other xenobiotics or acquired tolerance

Poisoning can be local (eg skin, eyes or lungs) or systemic depending on the route of exposure, the chemical and physical properties of the poison and its mechanism of action. The severity and reversibility of poisoning is influenced by age and pre-existing disease, which is also depend on the functional reserve of the individual or target organ

Drug overdose occurs when people take drugs at higher doses than recommended. The higher the dose and the greater its exposure in the body, severe poisoning will occur. Different individuals react differently to drug overdoses. And based on individual needs the treatment also differs from person to person. No two individuals react similarly and in such cases they should be treated with professional help. It can happen to anyone of any age

Crawling children can be exposed to the danger of accidentally coming and using any of the medications, as they tend to take everything by mouth. A large overdose can cause you to stop breathing and die if not treated immediately. The person may need to be hospitalized to continue treatment. Depending on the drug or medications taken, multiple organs may be affected. This can affect the person's outcome and survival chances

Managing overdose patients is a stimulating aspect of emergency medicine. Diagnosis can be difficult in the absence of a clear history, so medical personnel should have a high index of suspicion in evaluating patients who may have taken a drug overdose. This is particularly important in patients with a reduced level of consciousness. In addition, many patients are reluctant to cooperate during the initial evaluation. The potentially significant effects of the substances taken may not be immediately evident, but may require emergency intervention to limit morbidity and mortality

General Management Principles

• Revive the patient
• Consider preventing drug absorption
• Activated charcoal (50 g orally) will absorb many medications if administered <1 hour after ingestion
• Gastric lavage may be considered if a substantial overdose of <1 hour before has been ingested. Proof of benefit is weak and is now done less often
• Supportive care (eg airway maintenance, acid-base and electrolyte balance, seizure treatment) is important
• Unstable arrhythmias (TV, rapid SVT> 180 / min) are better treated with cardioversion than drugs

Primary Evaluation and Resuscitation

Airway

An appropriate answer to the question "Okay?",  that confirms by  proving, that the patient has a sufficient respiratory function to speak, and has a patented airway with reasonable laryngeal function, and he is aware of adequate brain perfusion. The doctor must ensure adequate airway and a reduced level of consciousness

Breathing

Since various agents taken in overdose can cause respiratory depression, it is very important to seek adequate respiration. Frequency, depth and respiratory work must be assessed. In the event of signs of respiratory failure, breathing must be supported by the use of a bag-mask valve device connected to high concentrations of inspired oxygen; Consider reversing the cause of inadequate ventilation (eg, Naloxone in case of opioid overdose). Even in the patient who appears to be breathing adequately, high concentrations of inspired oxygen should be administered until deemed unnecessary.
Arterial blood gases should be measured in case of concern about patient ventilation. Remember that unexplained tachypnea may reflect metabolic acidosis resulting from an overdose, e.g. after salicylates

Circulation 

Heart rate, adequacy of peripheral perfusion, heart rate and blood pressure should be assessed. Inadequate circulation in the overdose patient is generally caused by hypotension or cardiac arrhythmia

Hypotension is generally caused by relative hypovolemia secondary to peripheral vasodilation, often aggravated by poor intake during a period of reduced consciousness or by the diuretic effect of alcohol associated with overdose, which responds well to fluid resuscitation

The cause of cardiac arrhythmias differs from those observed in ischemic heart disease, since they are probably due to the toxicity of the drug and therefore require a different approach to treatment. Arrhythmias are often surprisingly well tolerated in the overdose patient and, if possible, specific antiarrhythmic drug therapy should be avoided. Initially, treatment should aim to minimize the effects of the drug that can cause arrhythmia, in particular by correcting abnormalities of electrolytes, calcium and magnesium in the bloodstream. If antiarrhythmic treatment becomes necessary, cardioversion should be considered an alternative to medical treatment to avoid possible drug interactions and side effects
Intravenous access should be established at this stage, providing a way for fluid resuscitation, emergency medications and the opportunity to take blood samples for relevant investigations

Disability

Evaluate the conscious level using the AVPU or the Glasgow Coma Scale and measure the pupil size and the response to light. The latter observations can be helpful in establishing a diagnosis if the agent who was hired is unknown

Exposure

Full exposure is required, looking for signs of injury, skin rashes and possible needle marks. It is very important to evaluate the temperature at this stage, since various drugs can alter the thermoregulatory mechanisms, e.g. Phenothiazines Once patients have been completely exposed and the required exam has been completed, cover them immediately, as many will rapidly lose heat in this situation

Laboratory, Radiographic and Other Tests

An overdose can be mild, moderate or severe. The specific drug involved depend on Symptoms. An examination will be performed in the emergency room. The following tests and treatments may be needed:

• Activated carbon
• Airway support, including oxygen, respiratory tube through mouth (intubation) and respirator (ventilator)
• Blood and urine tests: rapid / bedside glucose test (many toxins can cause hypoglycaemia, so this should be one of the first tests performed; if not available, dextrose IV can be given empirically). and urinalysis
• Chest X-ray
• Computed tomography (computed tomography or advanced imaging)
• ECG (electrocardiogram or cardiac tracing)
• Fluids through a vein (intravenous or IV)
• laxative
• Medicines to treat symptoms, including antidotes (if any) to reverse the effects of overdose

Urgent investigations into poisoning

• Glycemia
• Sodium, potassium and creatinine
• Plasma osmolality : If the substance ingested is not known
• Paracetamol and salicylate levels (since mixed intoxication is common) and plasma levels of other drugs / poisons if indicated
• Account full of blood
• Urinalysis (myoglobinuria due to rhabdomyolysis gives a positive blood test result)
• Arterial blood gas and pH in the following circumstances:

• Chest X-ray if the patient is unconscious, hypotensive, has respiratory symptoms or a reduced arterial oxygen saturation on the pulse oximetry
• If the poison can cause metabolic acidosis
• After an inhalation injury

• ECG in case of hypotension, heart disease, suspected ingestion of cardiotoxic drugs (antiarrhythmic, tricyclic) or age> 60 years
• If the ingested substance is not known, store serum (10 ml), urine (50 ml) and vomiting (50 ml) at 4 ° C in case further analyzes are needed