Coagulation and thrombotic disorders and their interference with driving

Platelet count that may be normal, but these are not able to form normal hemostatic plugs

Blood coagulation disorders

They are characterized by a platelet count that may be normal, but these are not able to form normal hemostatic plugs.

They can be due to a frequently hereditary intrinsic platelet defect, or to an extrinsic factor affecting the function of previously normal platelets.

  • Hemophilia A and B: They can cause bleeding of various severity, so blows, surgical procedures and dental extractions should be avoided. In these patients the prevention of bleeding is essential; therefore, the patients should not take acetyl salicylic acid, and the use of ibuprofen in indispensable cases should be made with utmost care.
  • Von Willebrand’s disease: This platelet dysfunction is characterized by frequent bruising, mild to moderate bleeding evidenced in skin cuts, metrorrhagia, dental extractions and surgical procedures. The treatment indicated to beat bleeding episodes is prescribed on an individual basis by the specialized physician.
  • Acquired coagulation disorders: They are relatively frequent and associated with a broad range of myeloproliferative and myelodysplastic clinical conditions, uremia, macroglobulinemia, and multiple myeloma, cirrhosis and systemic lupus erythematosus.

The drugs can also cause platelet dysfunction, as it is the case of penicillin and its derivatives, and acetyl salicylic acid.

The leading causes of the acquired coagulation disorders are vitamin K deficits and liver diseases.

Liver diseases cause disorders in the synthesis of coagulation factors, increased fibrinolysis, thrombocytopenia and together they can affect hemostasis.

In some cases the manifestations are different, as in the case of some dysfibrinogenemias that can be associated with significant bleeding or with susceptibility to thrombosis.

The thrombotic manifestations occurring in the adult age can be related to surgery or contraceptives, but in many cases no associated cause is identified.

These patients with thrombotic episodes of congenital origin should receive anticoagulation therapy, based on the criterion of the specialist physician in each case.

Advice on Blood coagulation disorders

  • Any bleeding episodes is disabling for driving until the bleeding site is controlled.
  • The replenishment of the factor deficit will be carried out by the specialized physician, who will report on the stabilization of the patient to be able to drive without risk increases.
  • The ability to drive is limited by the dizziness, drowsiness, and lack of attention caused by anemia.
  • The patient should be warned of the greater risk of suffering hemorrhages in case of minor blows, so caution should be exerted when driving.

Advice on Acquired coagulation disorders

  • Patients with advanced liver disease are highly susceptible, not only for the increased risk of hemorrhage, but also for the associated symptoms making driving difficult for him.
  • The physician will inform each patient of his ability to drive, without increasing the risks.
  • Patients at risk of hemorrhage for the disease itself or for the anticoagulation therapy prescribed for the risk of thrombosis, should be closely monitored and warned of the risks of bleeding that can occur.
  • They should be recommended to maximize precautionary measures when driving, since any small blow can be dramatic in them.
  • The physician will advise against driving in the cases of high risk of bleeding or thrombosis.

Thrombotic disorders

The causes are many and varied, including venous stasis post-operatively, pregnancy, immobilization, etc., also vasculitis, myeloproliferative disorders, contraceptives, autoimmune conditions, thrombocytopenia by heparin, endogenous anticoagulation factors deficit, dysfibrinogenemia, etc.

  • Anticoagulant drugs and their complications:
  • Heparin is the agent of choice parenterally and its main complication is bleeding that requires discontinuation and, in serious cases, administration of protamine.
  • Vitamin K antagonists are the treatment of choice by oral route, but require strict, individualized monitoring of doses.

Multiple drugs show pharmacological interactions with oral anticoagulants, due to the clinical importance involved by changes in hemostatic mechanisms.

Its effect is potentiated by chlorpromazine, sulfonamides, chloramphenicol, allopurinol, tricyclic antidepressants, laxatives, salicylates, thyroxin, androgens, antiarrhythmic such as amiodarone and quinidine, clofibrate, H2 antagonists, glucagon, disulfiram and some antibiotics including erythromycin, tetracycline, neomycin and imidazole-derivatives.

Its effect is reduced by vitamin K, barbiturates, rifampicin, cholestyramine, thiazides, carbamazepine, griseofulvin, and some oral contraceptives.

The administration with substances modifying hemostasis such as acetyl salicylic acid, phenylbutazone and pyrazolone derivatives is not recommended.

Vitamin K antagonists can increase hydantoin serum concentration and can also potentiate the hypoglycemic effect of sulfonylurea.

Patients treated with oral anticoagulants are susceptible to hemorrhagic complications, so anticoagulation therapy is adjusted individually for the dose and time.

Patients with chronic disease associated with a high incidence of thromboembolism will possibly require anticoagulation therapy in the long term.

Advice on Thrombotic disorders

  • In the event of any suspect symptom or sign of thrombosis, the patient should be advised against driving, until the etiological diagnosis and the indicated treatment reverse the clinical symptoms.
  • They patient cannot drive until the increased risk of a new episodes of thrombosis or embolism persists.
  • Patients treated with oral anticoagulants should not take drugs containing acetyl salicylic acid.
  • The patient should be warned not to take over-the-counter drugs, or those indicated by a physician who does not know that the patient is receiving anticoagulation therapy.
  • Any new drug can destabilize the patient on anticoagulation therapy.
  • When a drug is added or removed from the therapeutic regimen, prothrombin time should be monitored more frequently.
  • It is advisable that patients treated on an ambulatory basis carry in their car a coagulation control sheet in case they are injured
  • The patient should know his risk and to be responsible for his situation trying to perform a safe driving, that reduces the possibility of blows that, even if minor, can have dramatic consequences in him.