Associate Lecturer Exotic Species, School of Veterinary Medicine, Dublin, Ireland
Introduction
In contrast to cats and dogs, a large proportion of avian patients present to veterinary clinics critically ill and requiring emergency treatment. This occurs because birds have an instinctive preservation reflex where they mask signs of sickness until the illness is very advanced. There is also less tradition of taking pet birds to a vet for routine health checks and disease prevention.
How Does a 'Sick Bird' Present?
A sick bird will often appear sleepy, huddled, have fluffed plumage and be emaciated, inappetant and lethargic. Critically ill signs are tachypnoea, tail bobbing, open mouth breathing, seizures and haemorrhage. Any bird preferring to be on the floor of its cage is seriously or terminally ill. It may be necessary to provide supportive care first and delay clinical examination and diagnostic tests until the patient is out of immediate danger.
Supportive Care
Place the patient in a quiet warm area or incubator at a temperature of 29–32°C.3 Provide wide easy perches or a soft floor covering if non perching. Check the bird has ABC, i.e., airway, breathing and circulation. Critically ill birds or those showing respiratory signs should be given oxygen supplementation immediately.1 Provide familiar foods to encourage feeding behaviour. Non feeding bird will need to be gavage tubed with fluids and /or food when stabilized.
History Taking
The owner needs to be asked about the length of the bird's illness, reproductive status, toxins and fumes, access to other pets and birds, environment and diet. Is the bird from an aviary or a single pet bird? For example birds from aviaries are more likely to succumb to bacterial or viral infectious diseases while a single free flying pet bird could have chewed some lead paint or been attacked by the family dog.
Clinical Examination
Always spend time observing the bird in the cage. Is there tachypnoea, respiratory effort or tail bobbing? Evaluate the droppings looking at faecal, urate and urine component. Don't rush to handle the bird. Many owners are unaware how ill their pet is so always warn them that the bird is critically ill in case it drops dead in your hand! Prepare all the equipment and drugs first. If necessary admit the bird and provide oxygen before and during handling!
When the bird is stable weigh the bird and examines the oropharnyx, nares, vent and pectoral muscles. Gently palpate the abdominal cavity and auscultate the heart, lungs (dorsally) and airsacs (ventrally). Assess hydration status and mucous membrane colour (the cloacal mucosa can be useful). If trauma is suspected check for wounds and examine wings and legs for fractures.
Is the Bird in Shock?
Signs of Shock
Hypothermia (< 40–42°C), cool extremities, tachycardia, pale mucous membranes and dull demeanour. Weak pulses and slow CRT (capillary refill time) can be felt at the basilic or metatarsal artery.
Hypovolemic shock is commonly seen and caused by inadequate blood volume. Absolute hypovolemia occurs due to haemorrhage from trauma, coagulopathies or gastrointestinal tract bleed. Relative hypovolemia occurs with severe dehydration from the GIT or with extreme loss of fluids into a third body space (e.g., abdominal ascites.)Birds tolerate haemorrhage better than mammals but if there is severe ongoing haemorrhage monitor the PCV and give intravenous or intraosseous fluids. Give vitamin K, calcium and antibiotics as necessary. The use of steroids in haemorrhage and hypovolemic shock is not currently recommended.3
A blood transfusion should be considered when the PCV < 20%. Homologous (same species) transfusion is preferred as the red blood cells last longer (9–11 days). Anticoagulant citrate phosphate or a heparinized syringe and a blood filter must be used. A donor bird can safely give 1% of body weight, e.g., 5 ml from healthy 500 g bird.2
Is the Bird Dehydrated?
Skin tenting is not reliable in the avian patient so a more useful guide to hydration status is to press the basilic wing vein. If you press the vein in a normal bird it should refill immediately. If it takes > 2 seconds it means dehydration of over 7%. Raised PCV and TP are also useful guidelines. A quick rule of thumb is that it can be assumed that a very sick bird is about 10% dehydrated.
Fluid Therapy
Birds in shock or with moderate to severe dehydration need intravenous or intraosseous fluids. Intravenous can be given via the basilic, jugular (right jugular is larger) or metatarsal vein. In small avian patients or collapsed birds an intraosseous catheter is placed aseptically in either the distal ulna or the proximal tibiotarsus.4 In large birds use short spinal needles (20–22 g) while injection needles (22–25 g) can be used in small birds. They can be placed under a light general anaesthetic or under lidocaine (0.2 mg/ 100g diluted with saline) on the skin and periosteum.
How Much and What Type?
Birds in shock can be immediately given a slow bolus of warmed crystalloids (lactated ringers (10 ml/kg) combined with either hetastarch or a haemoglobin based oxygen carrier (5 ml /kg) over five minutes. This can be repeated as necessary.3 Fluids for dehydration can then be given IV, Io or orally.
The fluid deficit can be calculated by the formula: Estimated dehydration % x body weight (g) = fluid deficit. Give half the deficit in the first 24hrs. The daily maintenance is then 75–100 ml/kg.3
Nutritional Support
Once hypovolemia has been corrected start enteral feeding to prevent the onset of hypoglycaemia. Anorexic birds should be gavage tubed with warm hand rearing formula or commercial convalescent bird formula 3–4 times daily.4
Venipuncture
The amount of blood collected should never exceed 0.4 ml /100 g for a sick bird. Always get a minimum database of TP, PCV and glucose before initiating fluid therapy. Get electrolytes, Uric acid, and albumin, calcium AST / CK and CBC if possible.
Does the Bird Need Other Medication?
With a critically ill bird there is no time to lose so if indicated, antifungal and bactericidal antibiotics should be started immediately. Penicillin type drugs, like piperacillin, must be given after an animal attack or doxcycline if Chlamydia is suspected. Analgesia is vital after trauma - Buprenorphine or Butorphanol can be given. NSAIDS like Carprofen and Meloxicalm are also useful (avoid if dehydration or renal compromise).
Cardiopulmonary Resuscitation
CPR is rarely successful in the case of chronic disease but can be very successful with respiratory arrests with anaesthetic overdose. Cardiac arrest carries a poorer prognosis because the sternum prevents direct cardiac compression. If an arrest occurs while under anaesthetic turn off the anaesthetic, intubate if necessary and IPPV every 5 seconds with 100% oxygen. If no heart beat is heard compress the sternum, ventilate and give atropine 0.2 mg.kg intravenously and epinephrine 0.01mg.kg diluted in saline via a catheter down the trachea. If there is tracheal obstruction than a sterile endotracheal tube needs to be inserted and stitched into left abdominal air sac.3
Common Avian Emergencies
Respiratory Distress
Causes: Ascites, aspiration pneumonia, Aspergillus, Chlamydia, obesity, tracheal mites, goitre, foreign body (Seeds, fungal granuloma), fumes (smoke, Teflon).1,2
Treatment: Administer oxygen (30–40%) immediately and during examination with nebulising as necessary. Check for abdominal fluids and perform abdominocentesis if necessary. If emergency radiographs are needed isofluorane anaesthesia may be less stressful on the bird. If upper tract obstruction an air sac cannula will be necessary. Birds inhaling toxic fumes may also need steroids, antibiotics, bronchodilators and diuretics.
Coelomic Cavity Disease
These birds often present with acute respiratory distress but have no abnormal respiratory sounds. The coelomic space will be enlarged and either a mass or fluid can be palpated. The commonest cause of this is either ascites or organomegaly.1
Treatment: Supportive therapy. Then radiography / ultrasound under general anaesthetic. Perform fluid aspiration and drainage with cytology and culture of fluid.
Gastrointestinal Signs
Birds often present with regurgitation, vomiting or diarrhea. Regurgitation is the expulsion of food from the crop. This is more common than vomition, i.e., expulsion of food from the proventriculus (stomach).
Crop Problems
Crop stasis is common in young hand reared chicks or adults with impacted food stuffs. Pooled or impacted food can be dissolved by passing a gavage tube and flushing with warm saline. In very severe case ingluviotomy surgery is needed to manually remove the ingesta. Crop tubing may need to be done for a few days to restore motility and metoclopromide can also be given
Vomiting
Common causes include Aspergillus, Chlamydia, liver and renal disease and lead /zinc poison. Birds that are truly vomiting should be fasted. These patients are often quite ill and more likely to be dehydrated so fluid therapy should be instigated.
Diarrhoea
Many owners confuse diarrhea with polyuria so if possible the avian patient should be brought down in their own cage so that the droppings can be evaluated. Patients with severe diarrhea often need fluid therapy (intravenous or po) and parenteral antibiotics (Enrofloxacin, ceftazadine) pending culture results.
Neurological Signs
Signs include seizures, ataxia, tremors, head tilt and blindness. Head trauma is common if the bird is free flying. The commonest cause of seizures is hypocalcaemia, hypoglycemia (neonates and starved raptors), lead poisoning and trauma. Infectious diseases like proventricular dilatation disease can also present with CNS signs.1
Treatment: If seizuring give intravenous midazolam (0.25 mg/kg), Calcium (50–100 mg kg im and an i/v bolus 5% Glucose saline ( 5ml/kg)and lactated ringers (5 ml/kg).1,4 Place the bird on a soft floor if unable to perch with access to food and water. Birds with head trauma should be kept quiet, dark and cool (T 23C) to prevent vasodilatation of the intracranial blood vessels. Steroids are no longer recommended. Avoid over perfusion of fluids. Birds having seizures may need to be wrapped gently in a towel. Lead poisoning cases need chelation therapy with calcium edetate.
Trauma
Traumatic injuries and fractures commonly occur in pet birds. Common injuries are birds flying into windows and cracking their keel bones or birds attacked by the family pet dog. Control any haemorrhage and give fluids for shock. Clean all wounds and give immediate parenteral penicillin type drugs to avoid septicemia–piperacillin (100–200 mg/kg tid) is the drugs of choice. Any fractures should be stabilized with a bandage and analgesia given.1,2
A common and dramatic cause of haemorrhage is from bleeding toe nails and beaks. These can easily be staunched with ferric chloride styptic powder. Beak injuries bleeding extensively may need to be filed or cauterized under general anaesthetic. A broken blood feather will also bleed profusely. Remove the feather and apply pressure for 60–90 seconds. Don't use styptic powder in the feather follicle.20
Reproductive
Cloacal Prolapse
This may originate from the oviduct, intestines or cloacal wall. Once the bird is stabilized give the bird a short acting anaesthetic and identity the prolapse origin. If viable clean with warm saline and sterile lubricating jelly and replace the tissue. Place retention stitches across vent if necessary.
Egg Binding
This is caused by obesity, poor diet (lack of calcium, vitamin a, and protein), old age or oviduct infection. Clinical signs included depression, straining, soiled and swollen vent, anorexia and leg paralysis. Radiography or ultrasound is very useful. Eggs high up the oviduct may not be palpated but can be seen on radiographs. Stabilise the bird first and then give calcium and fluid therapy. Lubricate the tissues. Prostaglandin can be applied to the uterovaginal sphincter to dilate it. If relaxed oxytocin may be used. If the egg cannot be passed than gently collapse the egg under anaesthetic and aspirate contents through the skin
References
1. Bowles, Lichtenberger, Lennox. Emergency and critical care of pet birds. Vet Clin Exot Anim 2007;10:345–394.
2. Jenkins JR. Avian critical care and emergency medicine. Avian Medicine and Surgery. Philadelphia, WB Saunders, 1997:839–63.
3. Lichtenberger M. Shock and cardiopulmonary-cerebral resuscitation in small mammals and birds. Vet Clin Exot Anim 2007;10:275–291.
4. Raftery A. The initial presentation: triage and critical care. BSAVA Manual of Psittacine Birds. 2nd ed. 5, p35–50.