Hypophyseal disorders and driving
Adult hypopituitarism
It is characterized by the partial or complete loss of the adenohypophyseal function, with signs and symptoms that depend on the underlying cause and on the specific hormones that are lacking.
Its onset is insidious and is difficult to be recognized by the patient, but in other cases it is sudden and striking.
The TSH deficit leads to hypothyroidism and the lack of ACTH to suprarenal hypofunction, with fatigue, hypotension, intolerance to stress and susceptibility to infection.
The lack of LH and FSH is evidenced as sexual disorders, and that of GH causes growth disorders, non-significant in the adult.
Tumors of the sella turcica are often associated with visual field disorders that hinder driving.
Neurosurgery in selected cases attempts tumor removal.
Advice on hypopituitarism of the adult
- Drivers with symptomatic hypopituitarism or visual field disorders from compression should be advised against driving until an established therapy ensures that the patient is asymptomatic and stable.
- The surgical approach of the tumor injuries forces not to drive during a variable time period, as indicated by the specialist, to complete recovery of the patient.
- After surgery, the specialist will report on the evolution of the patient and of the possible transient or definitive sequels, that enable to assess his ability to drive.
Acromegaly
Adult syndrome characterized by an excessive secretion of growth hormone (GH), usually caused by a hypophyseal adenoma of somatotropic cells.
It results in the patient having rough features, and soft tissue swelling of the hands and feet, with growth of acral parts and early joint cartilaginous proliferation, possibly with necrosis and erosion of the joint cartilage.
The articular symptoms are frequent and can be produced an incapacitating degenerative arthritis.
Often, peripheral neuropathies occur by the nervous compression of the adjacent fibrous tissue, and also, by the endoneural fibrous proliferation.
The headache is very habitual and direct consequence of the hypophyseal tumor.
Furthermore, if the optic chiasm is compressed, there can be manifested a bilateral hemianopsia.
Tolerance to glucose impairs in almost half of the cases of acromegaly, though only 10% develop symptomatic diabetes mellitus.
The treatment is aimed at reducing the tumor with surgery/radiation therapy, although in some cases administering bromocryptine to reduce GH levels is required.
Advice on acromegaly
- The driver with advanced acromegaly will have reduced his ability to drive, for the pain and the limited movement, that causes the degenerative arthritis and the nervous compression.
- This patient will be uncomfortable with foot and hand movements, with inappropriate use of the car commands and pedals, as the commands will not be sufficiently separated among themselves to handling them with skill expected in a driver.
- The physician should be alert to the clinical evolution of its patient and the interference of the expression of the disease with driving.
Diabetes insipidus
Temporal or chronic disorder of the neurohypophyseal system due to the reduction of vasopressin (ADH), and characterized by the excretion of excessive quantities of very diluted urine, with strong thirst.
The driver with diabetes insipidus shows polydipsia and polyuria, and must be almost permanently drinking water and voiding.
While driving, a patient with diabetes insipidus has a significant inconvenience, since he does not have the toilet as accessible as he requires.
Frequently, he needs to take bottles inside the car to drink at any time, even when driving.
This activity can disable the patient for the tasks characteristic of driving, as he must be permanently attentive to drinking liquids and to voiding.
Dehydration, hypotension with dizziness and possible loss of consciousness frequently occur, associated with severe electrolyte disorders.
Medical therapy is based on the hormonal replenishment of vasopressin deficit, or on non-hormonal treatment with ADH releasing drugs such as chlorpropamide, carbamazepine, and clofibrate.
Also, some diuretics such as thiazides reduce polyuria.
Chlorpropamide can lead to secondary hypoglycemia that should be warned in order to avoid risks when driving.
Carbamazepine can reduce reactivity provoking dizziness, somnolence, ataxia, fatigue, headache, and blurred vision, particularly at the start of treatment or in the dose readjustments, so the patients should take this into account when driving.
Advice on diabetes insipidus
- The driver with diabetes insipidus is recommended to try to avoid driving long distances.
- He should stop all times he needs for urination, and do it with sufficient advance not to be uncomfortable for the possible waiting for an appropriate place.
- If while driving he notices dizziness he should stop as soon as possible in a safe area and ask for assistance. He cannot go to the physician driving.
- The maneuvers to drink while driving, managing the car and with an urgent need are very dangerous; the physician will explain to the patient this reality, that the driver often despises.
- The water containers could get in the middle of the pedals and provoke an accident. It would be advisable that the physician explained this possibility to the patient.
- The adverse reactions to medical therapy prevent from driving, so the patient should be warned of this eventuality.