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594 Lung Lobe Torsion

○ May be associated with chylothorax in Differential Diagnosis Chronic Treatment
this breed • Other causes of pleural effusion: hydrothorax, Lobectomy of the affected lobe is the treatment
VetBooks.ir • Also occurs in small-breed dogs (pugs, • Pneumothorax Behavior/Exercise
○ Right middle lung lobe or left cranial lung
of choice; spontaneous resolution is rare.
hemothorax, chylothorax, pyothorax
lobe are commonly affected.
• Pneumonia
miniature poodles, miniature dachshund)
• Pugs are overrepresented. • Pulmonary thromboembolism Restrict exercise for 2-4 weeks after thoracotomy.
• Pulmonary contusion
○ Commonly affects the left cranial lobe • Pulmonary neoplasia Possible Complications
• Pulmonary atelectasis • Torsion of another lung lobe is possible.
RISK FACTORS • Diaphragmatic hernia • LLT may lead to chylothorax.
Pre-existing conditions leading to atelectasis
of lung lobes: Initial Database Recommended Monitoring
• Pleural effusion • Results of CBC, biochemistry panel, and • Vital signs
• Pneumothorax urinalysis vary. • Respiratory pattern/rate
• Trauma ○ Stress or inflammatory leukogram • Resolution of pleural effusion
• Surgical manipulation common ○ Thoracic radiographs
• Pleural fluid may be a sterile, inflammatory ○ Diminished fluid volume aspirated from
ASSOCIATED DISORDERS serosanguineous effusion or chylous. chest tube in the postoperative period;
Usually associated with marked pleural effusion • Thoracic radiographs: findings vary with 1 mL/kg/day of fluid production is
(sometimes chylous) degree of effusion expected from the presence of the chest
○ Pleural effusion and lung consolidation tube alone.
Clinical Presentation (common) • Postoperative pain
HISTORY, CHIEF COMPLAINT ■ Repeat radiographs after thoracocentesis
Signs may be acute (more common) or (important) PROGNOSIS & OUTCOME
insidious: ○ Vesicular emphysema (pulmonary
• Dyspnea (most common) pattern with small, scattered gas bubbles) Good prognosis if lung lobectomy is performed
• History of pneumothorax, pneumonia, or can occasionally be seen in the affected
trauma lobe on radiographs (CT is more PEARLS & CONSIDERATIONS
• Cough sensitive)
• Hemoptysis • Thoracic ultrasound reveals hepatization of Comments
• Anorexia ± weight loss the torsed lung lobe (fluid-filled bronchi • Any lobe can torse, but the left cranial and
• Exercise intolerance appear similar to hepatic vessels and fluid- right middle lung lobes are more frequently
• Vomiting/hematemesis filled pulmonary parenchyma resembling affected. LLT can occur in the mid-lobar
• Depression normal liver) region of the lung (partial lung lobectomy
indicated).
PHYSICAL EXAM FINDINGS Advanced or Confirmatory Testing • Air bronchograms can be seen for affected
• Muffled heart and lung sounds (ventral Rarely needed or used lobes early in the process, but bronchial air
with effusion or in area of affected lung • Bronchoscopy (p. 1074) may demonstrate is absorbed and replaced by fluid within 2-3
lobe) an obstructed orifice of the main bronchus days.
• Crackles supplying the affected lobe. • During lobectomy, clamp the affected pedicle
• Coughing, hemoptysis ○ Bronchial mucosa may appear folded and with noncrushing forceps before derotation
• Dyspnea (inspiratory or paradoxical with edematous. to help prevent release of toxins into the
pleural effusion) • Thoracic CT may demonstrate anatomic bloodstream.
• Pyrexia alterations of the affected bronchus, such • Automated stapling devices (TA-30 V3)
as narrow, collapsed, or occluded bronchi simplify surgery and decrease surgery time.
Etiology and Pathophysiology with abrupt terminations. • Submit excised lung for culture and histologic
• Spontaneous LLT can occur. ○ Contrast-enhanced ultrasonography exam.
• Any mechanism that increases the mobility (CEUS) may improve the accuracy of • Thoracoscopy-assisted procedures have
of a lung lobe (e.g., pleural effusion, surgical conventional ultrasonography for detec- been described. This procedure, although
manipulation) can lead to torsion. tion of pulmonary blood flow compromise more technically challenging, may decrease
• LLT leads to venous congestion from in dogs with LLT. morbidities associated with a conventional
twisting/occlusion of pulmonary veins of • For some patients, the diagnosis is confirmed thoracotomy approach.
the affected lobe and lung consolidation. at thoracotomy.
Persistent venous congestion causes pleural Technician Tips
effusion. TREATMENT To stabilize the patient while prepping for
• Often associated with pleural effusion surgery, evacuate pleural fluid just after anes-
though the primary lesion is not always Treatment Overview thetic induction (p. 1164).
clear. Improve respiratory function, and stabilize
patient before surgical removal of the affected Client Education
DIAGNOSIS lobe. Animals with concurrent chylothorax may have
a poorer prognosis.
Diagnostic Overview Acute General Treatment
The diagnosis should be considered for any • Thoracocentesis (p. 1164) SUGGESTED READING
patient with pleural effusion. Suspicion is • Oxygen by face mask, nasal cannula, or Monnet E: Lungs. In Johnston SA, et al, editors:
increased in an at-risk breed or by abnormalities oxygen cage (p. 1146) Veterinary surgery: small animal, ed 2, St Louis,
(e.g., atelectasis) found on thoracic imaging • Fluid therapy as needed based on patient 2018, Elsevier.
(plain radiographs, ultrasonography, CT scans) status, physical exam, and laboratory AUTHOR: Michael B. Mison, DVM, DACVS
or bronchoscopy. parameters EDITOR: Megan Grobman, DVM, MS, DACVIM

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