Avian Medicine Flashcards
Describe how to take a good history in avian medicine
For how long have you had this bird? where did you get it from? is it living with other birds? when was the last introduction of birds? has this or any of your other birds been sick in the past? has it been tested for circovirus, chlamydia or other diseases? has the sex been confirmed by PCR? Describe the cage, situation and temperature of the rom, describe diet offered and diet consumed, including mineral /vitamin supplements and brand names, how much time does the bird spend outside its cage, is it allowed free flight, does anyone in the house smoke, is the bird location in or near the kitchen, what is the hunting and feeding schedule for raptors? what is the weight before hunting?
What diseases can be diagnosed by tests such as PCR and Serology?
Chlamydia, psittacine beak and feather disease virus, polyomavirus or proventricular dilatation disease (caused by a bornavirus. The possibility of becoming infected after having been tested exists.
Describe what may be seen on visual examination of a bird
may be fluffed up feathers - sick birds conserve energy and will fluff out feathers to conserve heat. Respiratory rate and effort should be noted, and dyspnoeic birds may be tail bobbing. A voice change is indicative of obstruction or infection of the syrinx. Severe dyspnoea together with a voice change is an emergency presentation, generally linked to aspergillosis or tracheal foreign bodies. Birds are experts at hiding illness so subtle changes in behaviour or weight are important observations which require immediate veterinary attention. Droppings should be examined to detect abnormalities such as diarrhoea, melena or biliverdinuria. Stressed birds usually produce watery droppings. Seed eating birds will have a darker central faecal component with small amounts of urates and minimal urine. Birds on extruded diets will have more voluminous faeces and higher moisture content.
Describe what parts of the bird should be examined in the clinical exam
The birds weight should be determined to the nearest 1g for small birds. This is critical for drug, fluid and food calculations. comparing with previous weights form the same animal, comparing to reference weights for the species and assessing the response to therapy. Parts of the body that should be examined include the eyes, for swelling, discharge, cataracts, corneal ulcers. Nostrils - for secretion, assymetry, rhinoliths, Beak for symmetry, fractures, overgrowth. Cere- check colour and overgrowth, Oral cavity - check tongue, mucosae, choanae and papillae. Palpate the crop (full crop in a very sick bird may indicate acute presentation). Ears - otitis are a common cause of neurological signs. Feathers - presence/absence of and pattern of loss, abnormal growth, wear, stress lines, moult, ectoparasites, blood feathers. Pectoral muscle - palpate to assess body condition score, consider birds lifestyle to interpret. auscultate with paediatric stethoscope over sternum, dorsum and vetntrum caudal to sternum. Feet for pododermatitis, overgrown nails, missing toes, excessive faecal build up. Check grip by using a pen or finger and manipulate the legs NOT IN RAPTORS. Palpate the coelomic cavity and check for enlargement, masses, fluid retention, egg binding, hepatomegaly do not misidentify the normal gizzard for an egg or a mass. Check uropygial gland for impaction - not present in amazons and some macaws. Check pericloacal region for faecal build up on feathers. Cloacal mucosa - check for colour, presence of papillomas or prolapse. Examine the wings and check for feather damage, fractures, xanthomas and range of movement. Basillic vein - check for volume and refill, particularly when there is a suspision of dehydration or blood loss.
What are the DDx for regurgitation?
Behavioural/sexual (male budgies), thyroid hyperplasia (budgies), crop burn (hand fet psittacines), crop candidiases, trichomoniasis.
What are the DDx for Vomiting?
Gastric foreign body, gastric impaction or tumour, gastric ulcer, intestinal obstruction, peritonitis, liver disease, heavy metal toxicity, administration of some drugs (itraconazole, doxycyline)
What are the DDx for crop stasis?
Crop infection or unspecific disease in neonates
What are the ddx for diarrhoea in birds?
Infectious parasitic gastroenteritis, proventricular dilatation disease, intestinal intussusception, diet change with increased fruit content, liver disease, antibiotic therapy, heavy metal toxicity.
What are the ddx for melena?
Gastroenteritis, cloacal papilloma, cloacal prolapse, egg binding
What are the ddx for undigested food in faeces?
Proventricular dilatation disease, enteritis, exocrine pancreatic insufficiency.
What are the differential diagnosis for Tenesmus in birds?
Egg binding, cloacal prolapse, cloacolith, GI parasitism, Organomegaly
What are the differentials for abdominal distension?
organomegaly, abdominal hernia, obesity, ascites
What are the differentials for biliverdinuria?
Hepatic disease, hamolysis
What are the differentials for polyuria?
Kidney failure, psychogenic polydipsia, increased water content of food
What are the differentials of dyspnoea?
Pneumonia/air sacculitis, organomegaly, tracheal obstruction
What are the differentials for feather loss?
Self mutilation, PBDF, Nutritional deficiencies, folliculitis
what are the differential diagnosis for neurological signs in birds?
Heavy metal toxicity, gypocalcaemia, trauma, newcastle disease, Hepatic encephalopathy, compression of leg nerves (dystocia)
What is ring compression?
Rings can compress the leg and compromise its viability. Causes include small rings placed in growing animals, accumulation of debris and dead skin the space between leg and ring, inflammation of the tarsometatarsal area and psittacine birds crushing rings with their beaks. In addition the ring can be caught on wire and produce fractures, luxations or inflammation. under anaesthesia the ring should be removed with bold croppers. PRovide analgesia antibiosis and dress wounds. Amputation is needed when distal leg is not viable.
What is a wing clip?
Done to prevent escape or to provide help short term with training. Clipping wings should not be performed on welfare grounds. In addition, birds can develop other problems such as psychological problems by avoiding the flight response, keel damage from falling from a height this can lead to osteomyelitis and self mutilation on that area, poor moulting because of the weight of a feather is a trigger factor for the molt, feather picking of old splintered feathers which can lead to more generalised plucking.
What is imping?
A traditional falconry technique used to replace a damage feather using another feather as a graft. Keep a store of frozen feathers. not as useful to solve a wing clip as in most cases the rachis is damaged making imping impossible. in these cases, feather stumps should be removed under anaesthesia and analgesia (primary feathers are attached to the periosteum)
Describe what may lead to excessive claw overgrowth? When should the claws be trimmed?
The vet meeds to assess the need for this procedure as many owners request it when the nails of their bird are actually normal. Perch design and nutrition can be a cause of claw abrnormalities. Perches should be of variable diameter along their legnth with a rough surface. Malnutrition, high protein diets and in particular liver disease should be suspected in any bird with overgrowht claws as they lead to abnormal keratin metabolism. Use canine nail clippers or dremel. Anaesthesia / sedation may be used. Haemorrhage control with silver nitrate. Corn flour or cotton soaked with peroxide if emergency phonecall.
When is a beak trim needed in birds?
Similar to claw trim, many times the owner requests beak trim and this is not actually needed for the bird. Information about normal beak length in parrots should be provided to the client. when there is a true overgrown, underlying problems include: congenital malocclusion or damage during the hand rearing process with syringe or spoon, distorting beak when still malleable, trauma liver disease or malnutrition in adults. dietary correction leads to an increase in the time between reshapes. The procedure should be done under anaesthesia and with a dremel. These rotary tools generate heat and a damp cotton bud or guaze should be used to cool the beak. Aggressive bak trims also need analgesia
How can temperature be controlled in birds under anaesthesia?
Hypothermia is the mainc ause of anaesthetic deaths and complications. Body temperature of most birds is 40-42C. Birds under anaesthesia lose temperature very quick, and this is ven more pronounced in small birds. Whent he feathers are plucked from large areas of teh body, feathers are used by the bird to regulate its temperature, when the skin becomes wet e.g with the excessive use of disinfectants such as alcohol or when the procedures such as coelitomies are done. fluids should be warmed up to birds body temperature before administration. Temperature control suing a rectal thermometer is mandatory. Temperature setup in small animal surgical theatre is too cold for birds and a room temperature around 22-25C is recommended. Other ways to avoid hypothermia are the use of heat mats, heat lamps, hot air, heated sandbags or gloved filled with hot water.
How can the respiratory system be controlled in a bird during anaesthesia?
Intubation and assisted ventilation is the best way to avoid respiratoy complications such as apnoea, hypoventilation, atelectasis or blockage of the endotracheal tube with secretions. Birds are easy to intubate, and lubricated uncuffed tubes are used as tracheal rings are closed (complete). Very small birds can also be intubated but the chances of obstructing the endotracheal tube with secretions increase. Open anaesthetic circuits are used because birds do not have the strength to move air through a close circuit. Birds in sternal recumbence breath better but this can be correcetd in other positions using assisted ventilation. A pre anaesthetic respiratory rate should be taken with the animal free of stress and that rate should be applied during anaesthesia. Or 10-20 breaths/ min can be used in those birds not breathing by themselves and 2breaths/2 min in those breathing spontaneously. The use of a capnograph is useful to monitor efficacy of ventilation. Should be kept at 30-4g mmHg. Ventilation using an ambubag or mechanical ventilator should not exceed 10-20cm H2o to avoid trauma to lungs and air sacs.
How can cardiac system be maintained during anaesthesia?
Cardiac output should be monitored with the use of a doppler generally over the cubital artery (radial). The presence and intensity of the pulse can also be appreciated placing a finger over the cubital artery. Pulsoximeters are not calibrated for avian haemoglobin and therefore do not provide reliable results. Heart arrests are usually fatal in birds and therefore the cardiovascular function should be supported using an intravenous or intra osseous catheter and fluid therapy. blood pressure can be obtained using a doppler and placing a small cuff in the proximal humerus or tibiotarsus.
Should food be withheld from birds before surgery?
Witholding foot not necessary for passerines and parrots although it is always recomended to have an empty crop before surgery. Carnivore and psicivore birds easily vomit under anaesthesia and food should be withheld for 4-12 hours depending on the size of the bird. For raptors it is worth checking that a cast has been produced after the last meal. Quick intubation reduces the chances of tracheal aspiration.
How is induction done with birds?
With gaseous agents with a face mask and the bird is ready of intubation in 1-2 minutes when using 1L/min o2 and the gas at maximum concentration. Isoflurane is the anaesthetic agent of choice. Sevoflurane can also be used, but it is more expensive and the efficacy is very similar. Injectable agents are rarely used, although there are also effective and safe protocols; alfaxalone, propofol or combination of ketamine with alpha 2 agonists can be used in birds both IV and IM.
How should a bird be intubated?
The tongue should be pulled forwards with atraumatic forceps. The glottis will be seen at the base of the tongue as birds do not have epiglottis. the lubricated tube is placed and secured and anaesthesia is maintained with oxygen and gas. An air sac tube placement can help relieving respiratory distress associated to partial or total blockage of the trachea and gas anaesthesia can also be delivered through the air sac tube when a tracheoscopy or surgical procedure in the trachea needs to be performed. Organomegaly, ascites or severe lung/air sac pathology may complicate the placement of an air sac tube and previous radiographs may help detect those complications.
Which reflexes should be present in a bird during surgery?
During surgical anaesthesia, palpebral reflex should be absent but corneal reflex should be present. The loss of corneal reflex indicates an excessively deep plane of anaesthesia.
What are the possible side effects of NSAIds in birds?
eg meloxicam, carprofen, celecoxib. Generally safe but watch renal and GI effects, particularly with high doses and long therapy. Can be given parenterally or orally. Ideal for short treatments given by the owner at home.
What suture materials are commonly used in birds?
Should be absorbable, synthetic, monofilament and degraded by hydrolysis. In a study, polydioxanone produced the least amount of tissue reaction and took more than 120 days degradation (PDS) while polyglactin 910 ( vicryl) produced more reaction but was degraded in less than 60 days. Cyanoacrylate tissue glue can also be used but may delay healing if it runs between the apposed tissues, creating a physical barrier for healing.
What may be the cause for a toe amputation?
Due to avascular necrosis (circumferential constriction by fibers or scrans) or trauma (aggression, open fractures). less common causes include frostbite, lymphoma, mineralisation of vessels, knemidocoptes infection. Place a tourniquet higher up in the leg and allow extra skin on incision to close up.
What is a feather cyst?
Common genetical condition in canaries. Also seen in psittacines. the feather cannot erupt and the cyst keeps growing. Multiple cysts may be affecting the same bird. Surgery is done for large cysts but other cysts will continue growing in other feathers. Most commonly found affecting the wings. A tourniquet is placed, the cysts is opened and emptied and the follicle is removed with scalpel or cauterised with radiosurgery. Bleeding should be controlled. Skin closure may not be possible and the area may need to heal by second intention with or without the use of bandages.
How can a cranial skin defect be corrected?
Trauma can produce loss of skin on teh dorsal area of the head. A pedicle advancing flap is recommended for these wounds. Two parallel incisions are done on the skin of the dorsal aspect of the neck between the defect and the shoulder area and the flap created is advanced to cover the skull defect. The skin edges are opposed with an interrupted suture pattern.
Why might crop surgery be performed? how is this approached?
Performed to take a biopsy or to resolve a crop burn. For biopsy an area on the lower right side of the crop is prepared for surgery. some feathers may need to be removed. the skin is incised taking care not to reach the crop which is right under the skin and attached to it. The crop is dissected away from the skin and then two stay sutures are placed to exteriorise a section of the crop. Using scissors, a piece of crop ideally 1x1cm is removed and the defect is closed with an apposing pattern, which can be reinforced with an inverting pattern on top of it. For crop burns it is advisable to wait a few days after the injury to better see the difference between dead and viable tissue, following the same technique as for biopsy the dead crop wall is removed.
When is a coeliotomy performed?
Performed in cases of dystocia, prolapse, neoplasia, peritonitis, gastrointestinal foreign body, abdominal hernias or reproductive disease. It should be avoided when the same procedure can be performed using endoscopy. Coeliotomy carries a bad prognosis in very small patients such as canaries and budgies. Depending on the organ affected, a lateral or ventral approach can be performed.
How can fractures be managed in birds?
Fractures of the long bones (humerus, ulna, radius, femur, tibiotarsus and tarsometatarsus) are resolved using external fixation or a combination of an intramedullary pin and external fixation. Fractures of the tibiotarsus and tarsometatarsus in very small patients can be managed with a tape splint i.e compressing the leg between layers of tape. Fractures of the metatarsus in smalla nd medium birds can be managed with a shroeder thomas splint. the humerus and femur are pneumatic bones. In fracturesinvolving the radius and ulna, if one of those bones is intact, then an IM pin can be used to stabilise the fractured bone using the intact bone as an external stabilisation.
How can bandages be used for injuries in birds?
Bandages can be used to treat fractures, stabilise fractures before orthopaedic surgery or treat other conditions such as luxations or wounds. Performing physiotherapy in between banage changes can help limit complications. Som efractures like those affecting the coracoid bone are beter managed with bandages. Two bandaging techniques are used for the immobilisation of the wing;; figure of eight bandage (does not stabilise the humerus) and full wing bandage (stabilises the humerus). A ball bandage is commonly used to treat foot problems such as fractures, luxations and pododermatitis.
Which diagnostic imaging techniques can be used in birds?
Radiology is most commonly used. Ct and MRI are also useful but less availablt. Ultrasound has limited use due to the presence of air sacs. Endoscopy is also very useful for imaging, sample collection and resolution of some problems. The high avian respiratory rate requires very short exposure times usually between 0.01-0.05 seconds. Two views are required generally VD and LL. Contrast studies can be used and 1-2% barium sulphate can be given by crop tube. Iodine compounds should be used if a perforating ulcer is suspected. Transit time in psittacines is about 3h. Radiographs are commonly taken immediately after barium administration and at 30,60,90,120 and 180 minutes. CARE should be taken to avoid aspiration in anaesthetised patients.
Why may enlargement of the upper hourglass silhouette be seen in radiograph?
Due to cardiomegaly or hydropericardium
