Canis ISSN: 2398-2942

Hyphema

Contributor(s): Dennis E Brooks, David L Williams

Introduction

  • Hemorrhage within anterior segment.
  • May or may not be accompanied by posterior segment hemorrhage.
  • Cause: multiple etiologies, may be primary ocular damage or result of underlying coagulopathy.
  • Signs: blood in anterior chamber, may be diffuse or form discrete clot. If unclotted, may collect ventrally and form fluid line.
  • Diagnosis: examination. Underlying condition may need further investigation.
  • Treatment: aimed at controlling intraocular pressure, preventing posterior synechiae/iris bombe and/or secondary glaucoma. Underlying condition should be determined and treated appropriately.
  • Prognosis: variable, depending on etiology. Loss of eye possible.

Pathogenesis

Pathophysiology

  • Hemorrhage occurs when blood vessels from uveal tract are damaged, disrupted or anomalous.
  • Iris vessels most common source, but retinal, choroidal and ciliary vessels are possible.
  • Disruption of uveal tract vessels results in blood leaking into ocular media (aqueous, vitreous).
  • Anterior uveal tract → anterior segment hemorrhage, possibly some escape into posterior segment through suspensory ligament.
  • Etiology may influence whether clot forms in anterior chamber.
    • Uveitis/trauma: blood usually clots.
    • Blood dyscrasias/coumarin intoxication: usually unclotted, may be diffuse (acutely) or form fluid line (as it resorbs).
    • Neoplasia/congenital anomalies/hypertension: usually recurrent - may or may not clot.
  • Unclotted blood and degradation products may block iridocorneal angle (ICA), reducing aqueous outflow → increase in intraocular pressure → glaucoma if not treated.
  • Always accompanied by uveitis Uveitis , so danger of posterior synechiae formation (adhesions between posterior iris and anterior lens) → iris bombe (360° synechiae) → no aqueous exit through pupil, iris root pushed forward blocking ICA → peripheral anterior synechiae (adhesions between iris root and corneoscleral region) → glaucoma.

Timecourse

  • Following single bleeding episode, resorption occurs within 7-14 days.
  • Acute onset.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Harrus S, Ofri R, Aizenberg I & Warer T (1998) Acute blindness associated with monoclonal gammopathy induced by Ehrlichia canis infection. Vet Parasitol 78 (2), 155-160 PubMed.
  • Habin D J & Else D W (1995) Parotid salivary gland adencarcinoma with bilateral ocular and osseous metastases in a dog. JSAP 36 (10), 445-449 PubMed.

Other sources of information

  • Komaromy A Met al(2000)Hyphema - Part II. Diagnosis and treatment.Comp Contin Educ Pract Vet22(1), 74-79.
  • Komaromy A Met al(1999)Hyphema - Part I. Pathophysiologic considerations.Comp Contin Educ Pract Vet21(11), 1064-1069, 1091, 1999.


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