Treatment of Respiratory Disease in Birds
World Small Animal Veterinary Association World Congress Proceedings, 2004
Sharon Redrobe, BSc (Hons), BVetMed, CertLAS, CertZooMed, MRCVS
Head of Veterinary Services, Bristol Zoo Gardens
Bristol, UK

Clinical Examination of Patient with Respiratory Signs

The bird should be examined within its cage initially and an assessment made of the severity of the respiratory disease. Marked abdominal effort, open-mouthed breathing and cyanosis are signs associated with increased risk with handling and so oxygen therapy and/or placement of an airsac tube may be required to stabilise the patient before further examination. The patient should be examined in a dimly lit room, and quickly but gently restrained to minimise stress. The neck, wings, and feet are restrained leaving the chest unrestricted. This can be achieved with one hand in budgies but larger birds require a two-handed approach using a towel. The towel is used to restrain the wings and is initially placed over the whole animal whilst the neck is located and restrained. The use of thick gloves is to be avoided as it encourages poor handling--the head does not 'need' to be adequately restrained to prevent bites and thick gloves prevent appreciation of the tightness of the grip. Auscultation using a small (paediatric) stethoscope head should be used to assess the position and severity of the condition. The nares should be examined for signs of erosion or discharge. The choana should be free of discharge. Blunting or oedema of the choanal papillae is an indication of chronic change.

Diagnostic Approach

Differentiate between primary respiratory disease and other diseases such as:

Malnutrition, obesity, goitre, abdominal fluid; ascites (liver or renal disease, neoplasia), blood (trauma), neoplasia, systemic viral diseases (herpesviruses, Paramyxovirus)

Cardiac disease (rare). Differentiate between URS and LRS disease.

URS Signs--rhinorrhea, periocular swelling, coughing, sneezing, voice change, dyspnoea

LRS Signs--tail bobbing, open mouthed breathing, easily stressed but lethargic, depressed

Diagnostic Workup

In all cases to include CBC and biochemistry (Chlamydia tests), whole body radiography and faecal examination.

Upper Respiratory System: Examination, palpation, transillumination of URS, Choanal culture (normal flora is Gram positive), Sinus flush and culture

Lower Respiratory System: Auscultation of lungs and air sac areas, endoscopy, culture and biopsy, tracheal / lung wash for culture and cytology

Nebulisation

A 1:10 solution of antibiotics or F10 in a hand sprayer or nebuliser may be used in the treatment of conjunctivitis or URS disease. The plant sprayers generally do not produce fine enough particles to access the lower air sacs however, for that a nebuliser (with particle size <3 um) must be used and the bird placed into a purpose-built nebuliser cage, a glass tank or a plastic bag with holes in is placed over a small cage.

Sinus Flush

The patient must be restrained firmly or anaesthetised. A syringe of warmed saline (1-2ml per 100g bodyweight) is pressed to form a seal against the nares and the volume slowly infused. The fluid will flow freely from the choana and out of the mouth. Do not force the fluid in. Flush both sides alternately.

Sinus Aspiration

The mouth is restrained opened. Needle is passed through the skin at the commissure of the mouth towards a point midway between the nares and the eye. The needle must be kept parallel to the head and directed under the zygomatic arch. Avoid puncturing the globe. This technique should first be practised on cadavers.

Tracheal / Lung Lavage

A sterile catheter is inserted through the glottis into the trachea to the point just cranial to the syrinx. Sterile saline is introduced (0.5-1.0ml per kg bodyweight) and immediately aspirated. Cytology and culture (bacterial/ fungal) may be performed on the sample. The cytology of normal tracheal or airsac lavage has a low cellular content with few pulmonary macrophages or inflammatory cells. The abnormal aspirate may contain large numbers of heterophils, pulmonary macrophages, inflammatory cells, bacteria, yeasts, etc.

Endoscopy

The air sac membranes may be examined for vascularity, opacity, exudate, bacterial/ fungal plaques etc. Swabs for microbiological culture may be taken from the ostium, air sacs and lung tissue. Biopsies of the lung and air sacs may be rewarding.

Air Sac Cannulation

Acute severe dyspnoea caused by tracheal blockage is an avian emergency. A severely dyspnoeic bird may also be stabilised before treatment by the introduction of an air sac cannula if the dyspnoea is caused by a URS problem. The bird is anaesthetised and placed in lateral recumbency. The area caudal to the last rib is surgically prepared. A small skin incision is made just caudal to the last rib and the abdominal muscles dissected. A sterile endotracheal tube or tubing of appropriate size is inserted into the air sac. If anaesthetised using gaseous anaesthesia, the bird may lighten as it breathes room air through the air sac tube. The anaesthetic circuit may now be connected to this tube to maintain anaesthesia. The tube is fixed in place using sutures or glue. An aseptically placed tube may remain patent for 10 days. The tube should be checked frequently to assess patency whilst the patient relies upon this method of ventilation.

Upper Respiratory Tract Diseases

Common aetiologies and treatment(s)

Foreign body in nasal passages

Dx: unilateral nasal discharge, radiography, transillumination of beak/nasal sinus

Tx: culture and sensitivity testing of discharge and appropriate antibiotic, flush infraorbital sinuses

Rhinitis

Bacterial (Gram negatives, chlamydia, Mycoplasmas), fungal (aspergillus). Parenteral antibiotics based on culture and sensitivity, nasal flushes and intranasal antibiotics (use ophthalmic solutions), nebulisation.

Sinusitis

Due to bacteria or Mycoplasmas (differentials; chlamydia, aspergillosis, candidiasis). Treatment based on sensitivity, flush out sinuses, infuse antibiotic. Vitamin A therapy. Improve ventilation and correct temperature/humidity of environment. Doxycycline, enrofloxacin, tylosin are good first line choices.

Rhinoliths

Concretions of dust, dirt, and nasal mucus blocking external nares, sequel of chronic sinusitis/hypovitaminosis A. Remove with a needlepoint, and treat underlying cause.

Abscesses

Lingual, palatine, periocular, submandibular sites. Abscesses of submandibular salivary gland common in birds fed seeds only, as it undergoes squamous metaplasia associated with hypovitaminosis A. Surgical removal of encapsulated abscess. Treat underlying cause (bacterial infection, hypovitaminosis A).

Tracheitis

Fungal, bacterial, parasitic, viral (Amazon Tracheitis Herpesvirus). Tracheal wash and tracheal endoscopy most useful. If acute dyspnoea, cannulate air sac. Remove obstruction by tracheoscopy. Appropriate treatment, supportive care.

Parasites

Trachea; Syngamus trachea. Air sac; Sternostoma tracheacolum. Ivermectin treatment.

Lower Respiratory Tract Diseases

Air Sacculitis

Bacterial or chlamydial aetiology most common. Also aspergillosis, Mycoplasmas, canary pox, Paramyxovirus 1 and 5. Can be asymptomatic. Radiography and endoscopy for diagnosis. Air sac wash / biopsy most useful for accurate culture results. Parenteral antibiotics, nebulisation, surgery for abscess, granuloma removal.

Diagnosis: Radiography, culture, serology, faecal tests to differentiate cause. Laparoscopic examination of the air sacs following radiographic localisation enables visualisation of lesion plus direct culturing.

Pneumonia

Aspiration pneumonia in hand-fed birds. Granulomatous pneumonia caused by Mycoplasmas, fungal, bacterial (Pasteurella). Parenteral and nebulisation therapy required.

Asthma/Allergy

Sneezing, wheezing, eosinophilia in tracheal wash. No other diagnosis!! Rarely reported. Avoid allergen, use antihistamines, bronchodilators.

General Diseases

Hypovitaminosis A

Usually as a result of a seed-only diet. African Greys often present with clinical signs at 3-5years of age. Can be fatal. Squamous metaplasia with increased keratinisation of epithelia of respiratory tract, GIT, renal tubules, etc. Initial signs include swelling and depigmentation of choanal papilla progressing to degeneration and abscessation of mucous glands. Compromised respiratory tract. Correct diet, add avian supplement (probably multiple deficiencies anyway). Parenteral vitamin A.

Psittacosis

Infection with Chlamydophila psittaci; infects birds, cats, dogs, sheep. Difficult to diagnose--affected birds may have marked illness, lameness only or appear clinically well. Latent infection possible--disease appears when stressed. The signs include; listless, dull, respiratory signs (respiratory distress, respiratory clicks, auscultation, air sac infection), enlarged liver and spleen on radiography, elevated white blood cell count (above 25x109 per litre), especially if concurrent heterophilic left shift, conjunctivitis (ducks); turkeys and cockatiels--sinusitis. Warn owners of zoonotic risk, and make informed decision about treatment or euthanasia.

Treatment: It is advisable to include Psittacosis treatment if the disease is suspected, even if not diagnoses; treat under quarantine conditions, with plastic aprons, hats, masks, and gloves for staff. Parenteral: Doxycycline 2% (Vibravenos Steraject, Pfizer), 100mg/kg IM. (Half dose either side of the keel) and vitamin A injections. Treat with 45day course with injections once weekly.

Aspergillosis

Aspergillus fumigatus is the most common species. A. flavus and A. niger less common. Chronic respiratory infection or peracute death. African Grey parrots, Blue-fronted Amazon parrots, and mynah birds are susceptible pet species. Goshawks, Gyr falcons and penguins are also susceptible. As this organism is ubiquitous in the environment, birds generally succumb to infection only when compromised by certain factors. These include stress, malnutrition, age, antibiotic therapy, respiratory irritants, or concurrent disease. Both local and systemic, acute and chronic forms occur. Clinical findings in an affected bird include; emaciation, respiratory distress, neuromuscular disease, abnormal droppings, vocalisation changes. The acute form is common in young or imported birds, severe dyspnoea, anorexia, and cyanosis (death). The chronic form is more common in the older captive birds, characterised by weight loss, intermittent dyspnoea (CNS Signs).

Local forms include:

 Nasal aspergillosis: dry granuloma in one or both nostrils that causes erosion. Birds may present with one very large nares.

 Tracheal or syringeal: severe dyspnoea, whistling sounds as breath

 Air sac form: diagnosis based on endoscopy, radiography--focal granulomas or diffuse fungus seen

 Lung form: granulomatous pneumonia

 Systemic: thrombosis and infarction

Diagnosis: Haematology, serology, radiography, endoscopy (trachea and air sacs), exploratory surgery. Fungal culture and cytology of sinus flush, lung was, air sac flush, air sac and lung biopsy. (Haematology changes = leucocytosis, heterophilia, monocytosis, lymphopaenia, non-regenerative anaemia, hyperproteinaemia, hypergammaglobulinaemia).

Treatment: Surgical debridement and removal of plaques or granulomas if possible. Topical treatment with antifungal, nebulisation, oral therapy. Amphotericin B can be given intratracheally. Itraconazole is the oral therapy of choice due to its low toxicity and high efficacy (10mg/kg). Nebulisation with clotrimazole ('Canesten' in propylene glycol) for 15minutes daily in conjunction with oral itraconazole has been used successfully in a number of parrots by the author.

References

1.  Tully TN, Harrison GJ, 1994, Pneumonology, in 'Avian Medicine: Principles and Application', Ritchie, Harrison and Harrison (Eds), Winders Publishing Inc, pp556-581

2.  Murphy J, 1992, Avian Respiratory System. Proc. AAV 1992. Advanced Avian Seminars. pp398-411

3.  Tully TN, 1995 Avian Respiratory Diseases: A Clinical Overview, Journal of Avian Medicine and Surgery 93, pp162-174

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Sharon Redrobe, BSc (Hons), BVetMed, CertLAS, CertZooMed, MRCVS
Head of Veterinary Services, Bristol Zoo Gardens
Bristol, UK


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