Thromboembolism

Introduction

Sarcoma embolus (dog). Courtesy of T. Scase

As the name implies, a thromboembolism is a clot (thrombus) or foreign body that blocks vessels a distance away from its site of origin. The most significant sites of thromboembolic formation are the following: lungs, CNS, terminal aorta, kidneys.

In order for a thromboembolism to occur, some changes in the vasculature need to be present. These include disruption of endothelial integrity, disruption of flow, disruption of blood haemostasis and disruption of fibrinolysis.

The incidence of thromboembolism greatly increases with certain diseases including heart disease, neoplasia, blood disorders, parasitic diseases and hyperadrenocorticism.

Clinical Signs

The '5 P's' are the characteristic clinical signs of thromboembolism. These are pain, paresis, pallor, pulselessness and polar (cold extremities). Long term clinical effects include necrosis of the affected area. Specific clinical signs relating to the thromboembolism being in a particular area include acute onset neurological problems, renal failure if clot in kidneys and dyspnoea if it is in the lungs.

Diagnosis

All findings and diagnostic procedures are heavily dependent on the site affected.

Blood tests may reveal hyperkalemia, acidosis, increased lactate, azotemia and elevated serum creatine phosphokinase. Radiography, echocardiography and angiography may also be used to diagnose a thromboembolism.

Treatment

It is important to treat the underlying conditions. Pain relief is vital and must be very strong, e.g. morphine. I.V. fluids will also need to be given as supportive treatment. Anticoagulants, heparin or aspirin, should also be given.

Prognosis

Prognosis is grave in most cases.

Thromboembolism Learning Resources

References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company

Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2) W.B. Saunders Company

Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.

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