Neurological disorders due to anoxia, respiratory failure, electrolyte imbalance, and impact in driving

Anoxia

Cerebral energy metabolism lies mainly in glucose oxidation.

Anoxia can cause confusion, more or less severe alertness disorders, seizures and sometimes focal signs.

Acute cerebral anoxia leads to coma in a few seconds and causes irreversible brain injury in a few minutes.

The CO increase causes lightheadedness, lack of concentration and attention, headache, dulling and eventually loss of consciousness.

CO causes alertness disorders of highly variable severity according to the duration and severity of the intoxication, from fatal coma to completely resolutive episodes and others with persistent sequels, including cognitive impairment and extrapyramidal signs.

In the recovery of oxycarbonate coma, a confusional state and alertness disorders recur sometimes after a free interval free of 1-2 weeks.

These post-interval comas can progress to regression or death and are consistent with demyelinating injuries of the white substance.

Respiratory encephalopathy

The decompensation of chronic bronchopneumopathies with emphysema is the most common cause of respiratory encephalopathy.

Together with the hypoxia caused by these diseases, there is hypercapnia and subsequent acidosis of the nerve cells.

Hypoxemia can also cause, in addition to dyspnea, confusional state, malaise or even loss of consciousness.

Often, cerebral vasodilatation occurs, associated with intracranial hypertension, and polyglobulia with increased blood viscosity and increased brain distress.

Physical and alertness disorders are the most common. They are frequently associated with abnormal movements of the limbs, including myoclonic shakes or tremor.

The improvement of respiratory failure for the appropriate alveolar ventilation is seen as a reduction of dyspnea and of consciousness disorders.

Most patients with COPD have it for smoking. Smoking is both a physical distraction and reduces the ability to drive due to the high CO levels present inside the car.

Recommendation on anoxia and respiratory encephalopathy

• In addition to recommending our patients with COPD to quit smoking in order not to die from their disease, they should be reminded that they are more susceptible to the CO held inside the car, that is added to the hypoxia they already suffer.
• If they are not going to quit smoking, at least that should ventilate the car space.
• Perhaps, these patients would obtain the greatest benefit from a smoke-free environment at their homes and cars, as if those surrounding them continue smoking they can hardly isolate from smoking.
• The patient who has suffered loss of consciousness for anoxia or poisoning by CO should be assessed by the specialist for the possible neurological sequels that will limit driving.
• Until the patient does not have the medical report that permits him to drive, he cannot do it, even if he feels apparently well.
• The patient with dyspnea, consciousness disorders, lightheadedness, or difficulty in concentration and attention due to hypoxia must not drive.
• The patient with COPD should be warned of the risk of the start of symptoms of hypoxia and CO2 retention in case of a complication of his disease, such as a cold or a respiratory infection.
• The patient with complicated COPD and neurological symptoms cannot drive and should visit his doctor as soon as possible for institution of the appropriate treatment.
• The physician will report the complete improvement of the patient that will permit him driving again.

Electrolyte imbalance

This can lead to brain dysfunction and lead to signs of encephalopathy.

The inappropriate secretion of ADH hormone provokes situations of hypoosmolality with hyponatremia, that cause confusional states, with risk of epileptic crisis and possible coma.

Some diabetic patients treated with chlorpropamide, that has antidiuretic activity, suffer similar situations.

Hypercalcemia can lead to nervous manifestations as depression, cognitive impairment, or cerebral pseudotumoral syndrome.

Hypocalcemia associated with a state of neuromuscular hyperexcitability and tetany crisis can cause signs of brain distress, with slow cognition and often seizures.

Recommendation on electrolyte imbalance

• All electrolyte imbalances causing neurological dysfunction prevent from driving until complete resolution of the clinical symptoms and control of the causal disease.