A17. Mental disorders, drug overdosed patients (the unconscious patient and toxins)

From greek.doctor

Disorders of consciousness

The disorders of consciousness are, in Hungarian literature, usually separated into hypnoid and non-hypnoid types. The hypnoid ones are the most important. They are:

  • Somnolence – patient is sleepy but can be aroused by voice
  • Sopor – patient is unconscious and can only be aroused by pain
  • Coma – patient is unconscious and cannot be aroused

Evaluation

Consciousness is usually evaluated by the Glasgow coma scale, which scores the consciousness from 3 – 15, based on the motor response, verbal response, and eye response to commands or stimuli. A score of 8 or less is an indication for intubation, as the person is no longer able to protect their airway.

It can also be evaluated by the much simpler AVPU scale, where the patient is marked as either:

  • A – alert
  • V – responds to verbal stimulus
  • P – responds to pain
  • U – unresponsive

Etiology

The possible causes of disordered consciousness are endless but can be remembered by the mnemonic ATOMIC:

Delirium

Delirium is an acute state of confusion or otherwise disorder mental state caused by somatic (non-psychiatric) illness. It is characterised by lack of the attention and awareness of the environment, and disordered stream of thought. Patients are usually disorientated, confused, have amnesia, are agitated, and have hallucinations (most commonly visual). It usually worsens at night, and develops over a short period of time. The patient may be hypoactive or hyperactive.

Delirium mostly affects elderly (> 65 years), due to their reduced physiological reserves. It's a very common condition, affecting almost 30% of elderly patients at some point during hospitalisation; in addition to this, it's probably underdiagnosed. It’s clinically relevant because it increases mortality, prolongs the hospital stay, and increases reintubation rate. It usually occurs during acute illness and is therefore common in the hospital, especially the ICU. It’s especially common in the ICU because many of the patients are elderly and because there is a lot happening at night in the ICU, so sleep withdrawal is common.

It's one of the neurocognitive or organic mental disorders, disorders characterising reduced brain function due to non-psychiatric illness.

Etiology

Delirium can be caused by many disorders. The mnemonic I WATCH DEATH can be used to remember them:

Clinical features

Delirium develops over a short period of time and fluctuates during the course of a day, usually worsening during the night. Characteristic for delirium is:

  • Disturbed attention (e.g. unable to name months of the year backwards)
  • Disturbed awareness (e.g. not oriented to time and space)
  • Disturbed memory, language, perception, or visuospatial ability

Delirium may manifest as psychosis, with hallucinations, delusions, or thought disorder.

We distinguish two major types of delirium based on the clinical presentation, hyperactive delirium and hypoactive delirium.

Hyperactive delirium

The hyperactive delirium is the most commonly diagnosed form, characterised by restlessness, agitation, trembling,

Hypoactive delirium

Hypoactive delirium is probably under-diagnosed as it's easier to miss than the hyperactive form. It's characterised by increased drowsiness, lethargy, and inactivity.

Hypoactive delirium likely has a worse prognosis than the hyperactive form.

Diagnosis and evaluation

The diagnosis is clinical, and should be suspected in all elderly with an altered mental status. Determining and treating the underlying cause is essential. Labs, medication review, and medical history may provide clues to the etiology.

Screening

The patients can be screened with the intensive care delirium screening checklist (ICDSC) or confusion assessment method in the ICU (CAM-ICU).

Management

There is no causative treatment for delirium; treating the underlying cause is the aim.

Environmental and interpersonal measures are essential in symptomatically managing delirium. The hospital environment itself, with all its noises and busy personell, worsens the confusion. One must try to avoid these worsening factors. Frequent reassurance, verbal orientation, pain management, maintainance of hydration, and mobilisation are all helpful in improving the symptoms of delirium.

Agitated patients

In some cases of hyperactive delirium, patient behaviour may interfere with patient care or safety. Physical restraint should be avoided if possible, but may sometimes be necessary.

If all else fails, low-dose antipsychotics can be used to treat severe agitation in delirium. Haloperidol is often used. It can be administered intramuscularly if necessary. Benzodiazepines should be avoided as they may worsen the condition.

Drug intoxication

Drug intoxication, the acute overuse of a drug (pharmacological or otherwise), is a common cause of admission to hospitals. Many are voluntary but some are accidental.

Specific types

Sympathomimetic (amphetamine, MDMA, cocaine) overdose presents with mydriasis, hyperthermia, tachyarrhythmia, hypertension, seizures, altered mental status. There is no specific treatment.

Opioid intoxication presents with respiratory depression, pinpoint pupils (myosis), and altered mental status. Naloxone is the specific antidote. On my exam I said shallow breathing, but the examiner said that it’s rather deep breathing but bradypnoea. That doesn’t match up with other sources, though.

Benzodiazepine overdose presents with weak pulse, respiratory depression, and altered mental status. Flumazenil is the specific antidote, but it has a short duration of action and is therefore used for diagnosis rather than treatment.

Clinical evaluation

Toxicology does not give an immediate answer, so the suspected toxin should be identified based on lab results, history, and clinical features.

Management

In a patient with suspected drug intoxication, the following general steps are necessary:

  • Ensuring stability (ABC)
  • Give oxygen
  • Apply monitoring
  • Obtain venous access
  • Assess GCS and intubate if < 8
  • ABG
  • Decontamination

In any kind of intoxication, the following are options:

  • Gastric lavage or activated charcoal – not effective in all intoxications, only effective in ingestion was recent
  • Loop diuretics + fluids – to increase renal excretion
  • Renal replacement therapy – haemodialysis or haemofiltration