Canis ISSN: 2398-2942

Caval Syndrome

Synonym(s): Dirofilarial hemoglobinuria, liver failure syndrome, acute hepatic syndrome, vena cava syndrome, vena cava embolism, postcaval syndrome

Contributor(s): Barrett Bulmer, David D Sisson, Mike Stafford Johnson

Introduction

  • Cause:retrograde migration of adult heartworms from the pulmonary artery into the right ventricle, right atrium and vena cava.
  • Signs:acute onset weakness, lethargy, inappetence, respiratory distress and commonly hemoglobinuria.
  • Diagnosis:echocardiography, thoracic radiographs, electrocardiography.
  • Treatment:surgical removal of the obstructive mass of heartworms.
  • Prognosis:guarded to poor, even with surgical removal reported mortality ranges from 14% to 42%.

Pathogenesis

Etiology

Pathophysiology

  • Adult heartworms move in a retrograde fashion from the pulmonary artery into the right ventricle, right atrium and vena cava.
  • The obstructive worm mass results in an acute onset of tricuspid insufficiency. This, in combination with concurrent pulmonary hypertension Cor pulmonale from chronic heartworm disease, results in signs of low cardiac output and right sided congestive heart failure Heart: congestive heart failure.
  • RBC hemolysis ensues as the cells pass through the enmeshed heartworms. Low grade disseminated intravascular coagulation (DIC) Disseminated intravascular coagulation may contribute to schistocytosis.
  • Hepatotoxicity Liver: acute disease and nephrotoxicity Nephrotoxicosis may result from a combination of low cardiac output and passive congestion.

Timecourse

  • Experimentally, inoculation of 16 dogs with 200 infective L3 larvae yielded caval syndrome in a total of 9 dogs after a mean of 12.3 months post-infection (range 7-17 months).

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.
  • Kitagawa H, Kitoh K, Ohba Y, Kuwahara Y, Iwasaki T & Sasaki Y (1998) Comparison of laboratory test results before and after surgical removal of heartworms in dogs with vena caval syndrome. J Am Vet Med Assoc 213 (8), 1134-1136 PubMed.
  • Strickland K N (1998) Canine and feline caval syndrome. Clin Tech Small Anim Pract 13 (2), 88-95 PubMed.
  • Kitagawa H, Sasaki Y, Ishihara K & Kawakami M (1991) Cardiopulmonary function values before and after heartworm removal in dogs with caval syndromeAm J Vet Res 52 (1), 126-132 PubMed.
  • Atkins C E, Keene B W & McGuirk S M (1988) Investigation of caval syndrome in dogs experimentally infected with Dirofilaria immitisJ Vet Intern Med 2 (1), 36-40 PubMed.
  • Atkins C E, Keene B W & McGuirk S M (1988) Pathophysiologic mechanism of cardiac dysfunction in experimentally induced heartworm caval syndrome in dogs: an echocardiographic studyAm J Vet Res 49 (3), 403-410 PubMed.
  • Atkins C E (1987) Caval syndrome in the dogSemin Vet Med Surg (Small Anim) 2 (1), 64-71 PubMed.
  • Jackson R F, Seymour W G, Growney P J & Otto G F (1977) Surgical treatment of the caval syndrome of canine heartworm disease. J Am Vet Med Assoc 171 (10), 1065-1069 PubMed.

Other sources of information

  • Atkins C E (1992) Heartworm Caval Syndrome. In:Current Veterinary Therapy XI, Philadelphia. Eds R W Kirk and J D Bonagura. W B Saunders Company.


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