Thyroid disorders and driving
Hyperthyroidism
The increased activity of the thyroid gland is frequently evidenced as goiter, hot fine and moist skin, tachycardia, tremor, ocular signs and atrial fibrillation.
The most frequent types of hyperthyroidism are Graves’ disease or diffuse toxic goiter, toxic multinodular goiter, and toxic adenoma.
The most characteristic manifestations are nervousness and increased activity, palpitations, fatigue, hypersensitivity to heat, increased appetite, weight loss, tachycardia, insomnia, weakness and diarrhea.
The ocular signs seen in patients with thyrotoxicosis consist of gaze with increased eye opening and eyelid retraction, bloodshot eyes, orbital pain, lacrimation, irritation, and photophobia.
Infiltrative eye disease is a more serious complication, specific of Graves’ disease, that causes exophthalmos and weakness in the extraocular muscles with blurred vision or diplopia.
Infiltrative skin disease, mainly located in the pretibial area, causes in the initial stages significant pruritus and erythema, and is typical of Graves’ disease.
Thyroid crisis or storm is an emergency requiring immediate specific treatment, and is characterized by the sudden onset of fever, weakness, extreme agitation with significant emotional oscillations, confusion, psychosis, or even coma. The patient can show cardiovascular collapse and shock.
Treatment of hyperthyroidism
Antithyroid drugs, such as propylthiouracil and metamizol, achieve euthyroidism in a large number of patients.
Beta-adrenergic blockers such as propanolol improve tachycardia, tremor, mental symptoms, intolerance to heat and sometimes diarrhea and proximal myopathy.
In cases where drug therapy does not control hyperthyroidism, thyroidectomy will be indicated.
The administration of radioactive iodine and surgery are reserved to selected cases, usually obtaining satisfactory results.
The treatment of the eye disease is aimed at preventing corneal dryness. In progressive exophthalmos, corticoids are administered and, in selected cases, decompression surgery is indicated.
Advice on hyperthyroidism
- Ocular symptoms of hyperthyroids prevent from seeing properly when driving, so the physician will advise against driving while symptoms persist.
- Advanced infiltrating ophthalmic disease preventions from driving. The favorable outcome with medical or interventionist therapy will allow the specialist for reporting on the visual capacity of the patient in each review.
- The patient should be warned about the possible side effects of beta-blockers, such as bronchospasm, CHF, TO-V blockade, bradycardia, depression, hyperglycemia, peripheral vascular insufficiency, etc.
- The patient cannot drive with symptoms reducing the psychophysical capacity. This must be notified to the physician administering the medication so that he make the dose adjustment or drug switching.
- Thyroid crisis or storm is incompatible with driving until the problem is definitively solved, ensuring the absence of this possibility.
- After the surgical approach for performing a thyroidectomy, the patient cannot drive for approximately three weeks, and always following the surgeon’s criterion based on the clinical recovery of the patient.
Hypothyroidism
The symptoms can be mild and of insidious onset.
Intolerance to cold is usually very severe, facial expression is rough, the voice hoarse, and speech slow. It is usually associated with swelling and periorbital tumefaction, and palpebral ptosis is seen.
Patients are forgetful and show some signs of cognitive and motor slowness, with a gradual personality change, that can reach frank psychosis.
Bradycardia and sometimes pericardial effusion occur, generally without symptoms. Constipation is more significant and eventually becomes serious, and paresthesia of the hands and feet are common.
Obstructive sleep apnea can occur with daytime somnolence, which, added to the lethargy caused by hypothyroidism, leads to an increased risk when driving.
The disease can progress to a stuporous hypothermic state, predisposing to coma, enhanced by exposure to cold, infections, injuries, and administration of narcotics.
The complete recovery of the clinical condition with thyroid hormone replacement is a process that takes months, during which a strict control of the patient is critical.
Treatment
Hormone replacement therapy with levothyroxine can result in side effects at therapeutic doses, including angina, palpitations, tachycardia, diarrhea, insomnia, tremor, excitability, arrhythmia, muscle weakness, headache, intolerance to heat, and fever.
It can also cause cardiac and anticoagulation decompensation.
Advice on hypothyroidism
- Hypothyroid drivers with symptoms interfering with driving are recommended not to drive transiently until the complete recovery of the clinical condition returns to him the capacity to do it safely.
- Hormone replacement therapy requires a more or less prolonged period of adaptation to the drug and dose adjustment, where side effects can arrive that limit driving seriously.
- Until the treatment with thyroid hormone is not adjusted and while the patient shows adverse events, he may not drive.