Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
Lung Biopsy
Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
Read
Lung tissue can be obtained by transthoracic biopsy or by transbronchial biopsy. These procedures are seldom performed in the horse because transthoracic lung biopsy is considered by many clinicians to be a dangerous procedure and histology of tissue obtained by transbronchial biopsy is poorly described for horses with pulmonary disease.
Transthoracic Lung Biopsy
Indications
- For histological identification of focal pulmonary masses discovered during thoracic radiographic or ultrasonographic examination
- For histological identification of diffuse, interstitial nodular lung disease discovered during thoracic radiographic examination (e.g., for definitive diagnosis of interstitial pneumonia when this disease is suspected)
- When material for fungal or bacterial culture is required
- When less invasive methods have failed to supply a diagnosis, if diagnosis is essential to determine the treatment and prognosis of a horse affected with pulmonary disease
Contraindications
- Rapid and irregular, or labored respiration or violent and uncontrollable coughing increase the risk of lacerating the lung with the biopsy needle
Some clinicians consider the following diseases also to be contraindications of transthoracic lung biopsy: - Pulmonary abscesses, pneumonia, and pleuropneumonia
- Exercise-induced pulmonary hemorrhage
- Recurrent airway obstruction (heaves)
Materials
- #15 blade and sterile gloves
- 3 to 5mL of local anesthetic solution
- A manually operated, Tru-Cut style biopsy needle can be used, but use of an automated, springloaded biopsy device (Bard Monopty Biopsy Instrument, Bard Peripheral Technologies, 1383 Harland Drive N. E., Covington GA. 30014) may increase the safety of the procedure.
- Ultrasonographic equipment for selection of biopsy site (optional)
- Microscope slides, 10% formalin and media for transport of tissue for fungal and bacterial culture if needed
Procedure
- Sedation is optional, but restraint should be such to prevent movement during the procedure.
- When radiographic or ultrasonographic evaluation is not used to determine the optimal site for biopsy, a site commonly used is the 7th or 8th right intercostal space, approximately 8 cm above a horizontal line through the olecranon. The 7th or 8th intercostal space on or above a horizontal line drawn through the scapulohumoral joint is another site recommended for lung biopsy. Lung biopsy can be performed from either side of the chest, but the risk of cardiac or great vessel rupture is claimed to be less if the biopsy is taken from the right side.
- Other intercostal spaces are also used for lung biopsy. The risk of lacerating blood vessels of significant size may decrease if the biopsy is taken superficially and from the caudodorsal lung field (Fig. 13.1).
Figure 13.1. When radiographic or ultrasonographic evaluations are not used to determine the optimal site for biopsy, a site commonly used is the 7th or 8th right intercostal space, approximately 8 cm above a horizontal line through the humeroradial joint.
- After preparing the biopsy site for aseptic insertion of the biopsy needle, the body wall, down to and including parietal pleura, is infiltrated with local anesthetic solution, and the skin is stabbed with a #15 blade near the cranial edge of the neighboring rib. (That site avoids the intercostal vessels located at the caudal edge of each rib.)
- The biopsy needle is placed into the incision and then advanced a small distance through the chest wall and into lung parenchyma. Because of the elastic nature of lung, the specimen notch of the needle often only partially fills with lung tissue (Fig. 13.2). More lung tissue may be obtained by using a spring-loaded, automated biopsy needle rather than a manually operated Tru-Cut style needle. To minimize trauma to the lung that can occur with chest movement, the sample should be taken immediately after insertion of the needle into lung. Several samples of lung should be obtained.
- An impression smear can be made from a sample before it is placed in formalin. Another sample can be placed in a bacterial transport medium.
Figure 13.2. Because of the elastic nature of lung, the specimen notch of the needle only partially fills with lung tissue. More lung tissue may be obtained by using a Biopty® needle rather than a manually operated Tru-Cut style needle.
- The stab incision can be closed with a suture or left to heal by second intention.
- The horse should be closely observed for signs of a complication for several hours after the procedure.
- The horse should not be exercised for at least 48 hours after the procedure.
Interpretation
- A histopathologist should interpret the biopsy, but a brief histological description of some pulmonary diseases is presented.
- Recurrent airway obstruction or heaves is usually diagnosed by means other than lung biopsy, but expected histopathologic lesions include bronchiolar epithelial hyperplasia, goblet cell hyperplasia/ metaplasia, bronchiolar exudates, and peribronchiolar lymphoplasmacytic infiltration.
- When fungal pneumonia is suspected, histological or cytological examination, or culture of a lung biopsy sample may confirm the diagnosis. (Diagnosis of fungal pneumonia based on cytological examination of airway secretions is tenuous because fungal hyphae can be found in airway secretions of normal horses.)
- Definitive diagnosis of interstitial pneumonia requires histological examination of a lung biopsy. Expected lesions include alveolar wall necrosis, hemorrhage or serofibrinous exudates within alveoli, desquamation of pneumocytes, and interstitial inflammation and fibrosis. In some affected foals, a necrotizing bronchiolitis is also seen (bronchointerstitial pneumonia).
- A granulomatous, interstitial pneumonia and, in some cases, small, refractile, crystalline particles within macrophages may be seen during histological examination of lung of horses with silicate pneumoconiosis.
- Pulmonary neoplasia is usually localized, and negative biopsy findings do not rule out this disease.
Complications
The incidence of death of horses after transthoracic lung biopsy was 3% in one survey. Because complications of transthoracic lung biopsy are common and occasionally fatal, this procedure should be performed only after other less hazardous techniques have failed to supply information essential for a diagnosis that may influence treatment. Owners should be informed of potential complications associated with transthoracic lung biopsy.
Reported complications are:
- Clinical signs of pulmonary hemorrhage (coughing, hemoptysis, epistaxis, tachycardia, collapse, and, occasionally, death) (Fig. 13.3). The incidence of this complication is estimated to be 6 to 10%.
- Pneumothorax (clinical signs are tachypnea and dyspnea). This complication is uncommon, and affected horses rarely require treatment.
- Neurogenic shock (sudden collapse). Most horses recover rapidly from this complication.
- Fatal air embolism associated with lung biopsy is reported to occur in people and is a potential complication for horses undergoing lung biopsy.
- Failure to obtain diseased tissue. Unless lung disease is diffuse or can be biopsied using ultrasonic guidance, obtaining tissue of interest is unlikely.
Figure 13.3. Coughing with hemoptysis, epistaxis, tachycardia, collapse, and death is an occasional complication of lung biopsy in the horse.
Transbronchial Lung Biopsy
Although the procedure for transbronchial lung biopsy has been described, we are unaware of any studies that correlate histological findings or culture results with findings using other techniques of diagnosis of pulmonary disease.
Materials
- An 180 cm long (or longer) endoscope for horses and a 150cm long endoscope for ponies
- An endoscopic biopsy forceps. By using a biopsy forceps that has a spike between the biopsy cups to prevent the jaws of the forceps from sliding, full-thickness samples of mucosa can be obtained (Fig. 13.4).
- Sedation (using xylazine or detomidine combined with butorphanol) is advised to inhibit the cough reflex.
- Diluted local anesthetic solution (injection of 25 to 30 mLs of lidocaine diluted with an equal amount of saline)
- 10% formalin and media for bacterial or fungal culture
Figure 13.4. A transbronchial lung biopsy is obtained by using an 180cm (or longer) endoscope for horses and a 150cm endoscope for ponies and an endoscopic biopsy forceps that has spikes within or between the biopsy cups to prevent the forceps jaws from sliding.
Procedure
- Diluted local anesthetic solution instilled is administered though the accessory channel or catheter as the scope or catheter is passed to the region of the carina.
- Rarely, disease of the airway mucosa may be grossly visible, and if so, the endoscopic biopsy forceps is advanced to the lesion for biopsy (Fig. 13.5)
- An endoscope is passed into a bronchus and wedged. An endoscopic biopsy forceps is advanced into a smaller bronchus until resistance is felt, and then, during inspiration, the forceps is further advanced as far as possible. The jaws of the forceps are opened and then closed.
- Samples are placed in formalin and media for bacterial and fungal culture. A good specimen has a white fluffy appearance and floats. Multiple tissue specimens can be obtained.
Figure 13.5. Rarely, disease of the airway mucosa may be grossly visible, and if so, the endoscopic biopsy forceps is advanced to the lesion for biopsy. To view click on figure
Interpretation
A histopathologist should interpret the biopsy, but, to our knowledge, histological descriptions of tissue from horses with pulmonary disease obtained by transbronchial lung biopsy have not been reported.
Complications
We are not aware of any reported complications associated with transbronchial lung biopsy.
Suggested Readings
Raphel CF, Gunson DE. Percutaneous lung biopsy in the horse. Cornell Veterinarian 71:439-448, 1981.
Savage C, Traub-Dargatz JL, Mumford EL. Survey of the large animal Diplomates of the American College of Veterinary Internal Medicine regarding percutaneous lung biopsy in the horse. Journal of Veterinary Internal Medicine 12:456-464, 1998. - PubMed -
Mair T. Diagnostic techniques for lower respiratory tract diseases. In: Robinson, NE ed: Current Therapy in Equine Medicine 3rd Ed. pp.299-303, 1992.
Buechner-Maxwell V, Christman M, Murray M, Ley W, Saunders G, Walton A. Transendoscopic biopsy of the horse’s airway mucosa. Journal of Equine Veterinary Science 16:375-379, 1996.
Get access to all handy features included in the IVIS website
- Get unlimited access to books, proceedings and journals.
- Get access to a global catalogue of meetings, on-site and online courses, webinars and educational videos.
- Bookmark your favorite articles in My Library for future reading.
- Save future meetings and courses in My Calendar and My e-Learning.
- Ask authors questions and read what others have to say.
About
How to reference this publication (Harvard system)?
Affiliation of the authors at the time of publication
1College of Veterinary Medicine Auburn University Auburn, AL, USA and 2Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, USA.
Author(s)
Copyright Statement
© All text and images in this publication are copyright protected and cannot be reproduced or copied in any way.Related Content
Readers also viewed these publications
Buy this book
Buy this book
This book and many other titles are available from Teton Newmedia, your premier source for Veterinary Medicine books. To better serve you, the Teton NewMedia titles are now also available through CRC Press. Teton NewMedia is committed to providing alternative, interactive content including print, CD-ROM, web-based applications and eBooks.
Teton NewMedia
PO Box 4833
Jackson, WY 83001
307.734.0441
Email: sales@tetonnm.com
Comments (0)
Ask the author
0 comments