Canis ISSN: 2398-2942

Lung: lobe torsion

Contributor(s): D M Tillson

Introduction

  • Cause: mobility of lung lobes usually due to fluid in thorax.
  • Signs: cough, dyspnea.
  • Diagnosis: radiography, ultrasonography, bronchoscopy.
  • Treatment: symptomatic management, lobectomy if unresolving.
  • Prognosis: guarded.

Pathogenesis

Etiology

  • Primary (spontaneous) without demonstrable cause.
  • Secondary to pre-existing pulmonary or thoracic disease.

Predisposing factors

General
  • Idiopathic - majority of cases have no apparent underlying disease.
  • Pleural effusion Pleural: effusion may be pre-existing or secondary to vascular congestion.
  • Chylothorax Chylothorax.
  • Pneumothorax Pneumothorax.
  • Traumatic diaphragmatic hernia Diaphragm: traumatic hernia.
  • Trauma.
  • Recent abdominal or thoracic surgery.
  • Neoplastic conditions of the thoracic cavity.
  • Chronic parenchymal disease of the lungs.
  • Chronic bronchitis Chronic bronchitis.

Pathophysiology

  • Mechanisms unknown but deep interlobar fissures of dog lung enable freedom of movement of the lung lobe.
  • Lung lobe twists around bronchovascular pedicle.
  • Right middle lobe most commonly cited but recent studies have shown an almost equal frequency of left cranial lobe torsion. Right cranial is third most frequent. Caudal lobe torsions are very uncommon. Partial lung torsions have been reported.
  • Pleural effusion is common finding. Debate exists as to whether the effusion predisposes to lung torsion or whether effusion develops after torsion and vascular compromise.
  • Lobar rotation leads to vascular congestion as a result of blocked venous return.
  • Fluid can extravasate into bronchus and hemoptysis may occur.
  • With chronicity, air within the lung is absorbed. Fluid accumulation results in consolidation of the lung lobe.
  • Venous congestion → formation of pleural fluid.
  • Compromised blood supply can result in pulmonary necrosis.

Timecourse

  • May present with acute onset or signs that have been present for days to weeks.

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.
  • Murphy K A & Brission B A (2006) Evaluation of lung lobe torsion in Pugs: 7 cases (1991-2004). JAVMA 228 (1), 86-90 PubMed.
  • d'Anjou M, Tidwell A S & Hecht S (2005) Radiographic diagnosis of lung lobe torsion. Vet Rad & Ultra 46 (6), 478-484 PubMed.
  • Rooney M B, Lanz O & Monnet E (2001) Spontaneous lung lobe torsion in two pugs. JAAHA 37 (2), 128-130 PubMed.
  • Neath P J, Brockman D J & King L G (2000) Lung lobe torsion in dogs: 22 cases (1981-1999). JAVMA 217 (7), 1041-1044 PubMed.
  • White R N & Corzo-Menendez (2000) Concurrent torsion of the right cranial and right middle lung lobes in a whippet. JSAP 41 (12), 562-565 PubMed.
  • Schwarz L A & Tidwell A S (1999) Alternative imaging of the lung. Clin Tech Small Anim Pract 14 (4), 187-206 PubMed.
  • Lord P F, Greiner T P, Greene R W & Dehoff W D (1973) Lung lobe torsion in the dog. JAAHA 9 (5), 473-482 VetMedResource.

Other sources of information

  • Tidwell A S (1998)Ultrasonography of the thorax (excluding the heart).Vet Clin NA28, 993-1015.


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