Endoscopy Brief: Identifying the cause of acute cough and respiratory distress in a toy poodle - Veterinary Medicine
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Endoscopy Brief: Identifying the cause of acute cough and respiratory distress in a toy poodle

Specific indications for bronchoscopy include chronic coughing, hemoptysis, unexplained pulmonary infiltrates, and suspicion of an airway mass or foreign body. Bronchoscopy allows visualization of dynamic airway changes such as tracheal or bronchial collapse6 and foreign body retrieval. Also, lower airway samples for cytologic examination and culture can be obtained by brush cytology or by performing a bronchoalveolar lavage. Samples collected by bronchoscopy for cytologic examination and culture consistently have a greater diagnostic sensitivity than those obtained with a transtracheal wash.7,8

Since bronchoscopy requires general anesthesia, patients with respiratory distress often cannot safely undergo the procedure. Patients with advanced cardiopulmonary disease or marked metabolic derangements are also at higher risk during any procedure that involves general anesthesia.


Figure 10. A guarded culturette (Boston Scientific Microvasive microbiology specimen brush) with a carbon wax plug (arrow) that expels just before sampling to help reduce the risk of contamination.
Bronchoscopy is best performed by using a flexible fiberoptic endoscope or videoendoscope. Most bronchoscopy procedures in dogs and cats can be performed with a 5-mm-diameter, 55-mm-long endoscope; however, small patients may require a 3.7-mm-diameter endoscope. A three-dimensional map of the endobronchial anatomy of the veterinary patient is especially helpful in navigating the bronchoscope.9,10 Bronchoscopy can be performed with inhalation anesthesia if the endotracheal tube lumen is large enough to allow passage of the bronchoscope without occluding gas flow through the endotracheal tube. For smaller endotracheal tubes, injectable anesthesia or repeated temporary intubation must be used. The biopsy channel of the bronchoscope can be used to deliver oxygen during the procedure, pass biopsy forceps or cytology brushes, and perform bronchoalveolar lavage.6 Culture samples can be obtained from the bronchoalveolar lavage fluid or by using a guarded culturette, which can be passed through the biopsy channel (Figure 10).9

"Endoscopy Brief" was contributed by William R. Lee, DVM; John W. Tyler, DVM, DACVIM; and H. Dan Cantwell, DVM, MS, DACVR, Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762. Dr. Lee's current address is College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27695-8401.

REFERENCES

1. Hawkins EC. Pulmonary parenchymal diseases. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. 5th ed. Philadelphia, Pa: WB Saunders Co, 2000;1061-1089.

2. Hawkins EC. Disorders of the pulmonary parenchyma. In: Nelson RW, Couto CG, eds. Small animal internal medicine. 2nd ed. St. Louis, Mo: Mosby-Year Book, 1998;125.

3. Angus JC, Jang SS, Hirsh DC. Microbiological study of transtracheal aspirates from dogs with suspected lower respiratory tract disease: 264 cases. J Am Vet Med Assoc 1997;210:55-58.

4. Thayer GW, Robinson S. Bacterial bronchopneumonia in the dog: A review of 42 cases. J Am Anim Hosp Assoc 1984;20:731.

5. Ford RB. Bacterial pneumonia. In: Bonagura JD, ed. Kirk's current veterinary therapy XIII small animal practice. Philadelphia, Pa: WB Saunders Co, 2000;812-815.

6. Johnson LJ. Small animal bronchoscopy. Vet Clin North Am Small Anim Pract 2001;31:691-705.

7. Hawkins EC, DeNicola DB. Cytologic analysis of tracheal wash specimens and bronchoalveolar lavage fluid in the diagnosis of mycotic infection in dogs. J Am Vet Med Assoc 1990;197:79-83.

8. Hawkins EC, Morrison WB, DeNicola DB, et al. Cytologic analysis of bronchoalveolar lavage fluid from 47 dogs with multicentric malignant lymphoma. J Am Vet Med Assoc 1993;203:1418-1425.

9. McKiernan BC. Bronchoscopy. In: McCarthy TC, ed. Veterinary endoscopy for the small animal practitioner. Philadelphia, Pa: WB Saunders Co, 2005;201-227.

10. Amis TC, McKiernan BC. Systematic identification of endobronchial anatomy during bronchoscopy in the dog. Am J Vet Res 1986;47:2649-2657.


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