Antithrombin III Deficiency Follow-up

Updated: Jan 10, 2022
  • Author: James L Harper, MD; Chief Editor: Hassan M Yaish, MD  more...
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Further Outpatient Care

Consultation with a coagulation-focused hematologist needs to be done both with the child's parents and the child. Repeat consultation should be undertaken later in adolescence for those children diagnosed early in life.



See the list below:

  • Most thrombotic complications involve the venous circulation; venous insufficiency is a common complication.

  • In children more than in adults, antithrombin III (ATIII) deficiency may cause arterial occlusion resulting in stroke or other ischemic injury.



Prognosis depends on 3 variables: the degree of the deficiency, the nature of the observed clot, and the number of clots seen.

  • Prognosis for homozygous-deficient antithrombin III deficiency is grim. Typically, severe thrombotic complications arise in neonates. Prognosis for survival into adulthood is good for patients who are heterozygous deficient. The peak risk for thrombotic complications does not arise until the third and fourth decades of life.

  • The nature of the observed clot is an important variable. A clot that occurs in the mesenteric circulation or other central vein carries a more ominous prognosis than clots in the peripheral circulation. Patients with clots in the mesenteric circulation are often best treated with indefinite anticoagulation, even after a single episode.

  • Clots that recur, particularly those that recur either in the central or mesenteric circulation, are of important prognostic significance. Patients with such clots are much more likely to continue to experience thrombotic episodes and eventually to suffer either a life-threatening clot or suffer needlessly from the complications of the thrombi. One thrombotic event may be treated successfully with limited warfarin therapy, particularly if no other prothrombotic condition is present. Patients who experience multiple thrombi are often best treated with indefinite warfarin therapy.


Patient Education

See the list below:

  • Education regarding signs and symptoms of thrombi, as well as the risks associated with warfarin therapy, is the cornerstone of management.

  • Given the teratogenic potential of warfarin, carefully instruct female patients on the importance of avoiding pregnancy. These patients should alert their hematology team regarding any pregnancy or intention to become pregnant so that alternative anticoagulation strategies may be explored in a timely manner.

  • For excellent patient education resources, see eMedicineHealth's patient education article Blood Clot in the Legs.

  • has a continually updated listing of patient information for antithrombin deficiency.