Basic Approach to the Bird Patient
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

Observation of bird

Advise owners to bring bird in cage, not carry box, where possible to allow assessment of housing conditions and to be able to examine the bird at rest. The owners should be instructed not to clean the cage for 24 hours to allow examination of the volume and quality of the droppings.

 Examine within cage or on perch, not on owners shoulder or in your hand (initially)

 Can bird perch, is it ruffled, assess respiratory rate, is it bright alert and responsive?

 Evidence of feather loss, change colour (fret marks)

 Quality of feathers, beak, nails

 Body posture--standing equally on both legs, wings at equal height

Restraint

This section assumes to some extent that the bird is not used to being handled or restrained. This is unfortunately the case with the majority of pet birds in the UK. Tame birds may allow examination and auscultation with minimal restraint, but it is wise to restrain the head. All the psittacines are able to inflict a painful bite and the claws of the larger parrots can pierce the skin. Adequate restraint of the head and feet is therefore essential.

 Birds have no functional diaphragm; air is drawn into and out of the lungs primarily by sternal movements. Consequently any prevention of these movements will lead to suffocation. Thus when handling a bird, never place the hands around the upper body of the animal.

 Dim the lights and make calm purposeful movements to avoid excess stress to the bird. Avoid chasing the bird as the heat generated will not be dissipated when restrained, leading to panting, hyperthermia and collapse.

 Smaller birds (budgerigars, cockatiels) may be held by the examiner, but a separate handler is required for the larger birds to enable a complete examination to be carried out

 Remove as much cage furniture as possible without stressing the bird.

 Small birds may be picked up from a perch. Bare hands or a cloth enable the tightness of grip to be accurately gauged, gloves are not recommended. The use of a small towel or cloth may be used to cover the bird whilst the head is located. This reduces the chance of being bitten and restrains the bird more adequately as the cloth can be lightly wrapped around the bird to prevent the wings flapping. The bird's head is grasped between first and second fingers, the thumb and little fingers used to restrain the feet. Wings can then be extended and held between the thumb and forefinger or using the free hand.

 The larger psittacines require a two handed approach. Tilt the cage to the side (having first removed all cage furniture), allowing the bird to grip the bars with his beak. Using a towel, grasp the bird around the mandible and neck. The towel can then be wrapped around the bird to prevent wing injury and to restrain the feet. A piece of paper or towel will give the bird something to chew on during the examination. Teasing the bird with such an object often allows visualisation of the oral cavity.

Clinical Examination

The head should be symmetrical, the nares open, dry and of normal size, the beak smooth, shiny and of normal shape, and the ear canals clean with intact tympanic membrane. The eyes should be clear, bright and wide open. Cataracts are common in aged parrots. The iris is under voluntary muscular control and the excited parrot will contract and dilate its pupil rapidly. A rapid PLR indicates CNS damage.

The oral cavity should be even coloured with dry fleshy tongue and moist choanal slit, pharyngeal and laryngeal mucosa. Choanal papilla should be present (especially Amazons and macaws).

The feathers should be well preened, tidy, brightly and evenly coloured according to species.

General

Inspect the feathers for evidence of trauma, self-plucking, cysts, fret marks, preening, ectoparasites, colour breaks, dystrophy (PBFD, polyoma viruses). The skin should be checked especially at propatagium (wingweb), check feathered and non-feathered skin. Observe the bird perching. Perching with one leg is indicative of sciatic paralysis from kidney disease; gripping perch improperly may indicate sore feet (bumblefoot, articular gout).

Specific

Transillumination of the trachea may reveal mites, foreign bodies. The oesophagus and crop on the right side of the neck should be palpated for impaction, dilatation (caused by thyroid hyperplasia in budgerigars), inflammation (sour crop), foreign body, trauma, and burns. Cloacal mucosa used to assess colour, CRT, petechiation, etc.

Auscultation

This is generally only of value in the larger birds. A paediatric or infant head stethoscope is required. Lung fields heard over back where adhere to body wall. Normal respiratory sounds consist of a short, loud inspiratory noise followed by a longer, lower pitch respiratory sound. Abnormal sounds include pleuritic rubs, rales, dull or lack of sounds. Localisation of lesion is difficult (better by radiography).

Diagnostic Techniques

Crop Flush

 Flush out crop with saline. Centrifuge fluid. Examine deposit; unstained (parasites), Diff Quick and Grams Stain

 Crop crystals generally normal findings but can indicate hypovitaminosis A

 Alysiella common in the crop

 A uniform bacterial population usually indicates an abnormality

Cloacal Swab/ Droppings

 Rub a moistened plastic or wire handled swab against mucous membrane of cloaca. Roll onto a glass slide, air dry, stain (Diff Quick, Gram's stain, Modified Ziehl-Nielsen) Examine microscopically normal = 80: 20 Gram positives: negatives in seed eating birds

 Use Gram's stain to detect bacteria, fungi, yeasts

 If only see a few bacteria, smear from fresh droppings

 Check faecal flotation for parasite eggs, oocysts

 The normal pH of the cloaca is 6.5-7.0 A basic pH (>7.5) will encourage the growth of yeasts and Enterobacteriaceae

Blood Sampling

Up to 1% of the body weight can be collected for a blood sample. EDTA is the anticoagulant of choice as heparin can cause cell clumping and alter staining characteristics. However, for small samples, taking 1ml heparin and making a fresh blood smear allows a full haematology and biochemistry.

 Use right jugular, medial metatarsal or cutaneous ulnar vein. Waterfowl--metatarsal vein.

 2ml blood from African Grey sized parrot (1.5ml heparin, 0.5ml EDTA)

 Do not use EDTA for blood from corvids, ratites, crowned cranes, penguins (lyses cells)

 Plasma sample used for; CK, AST, ALT, ALP, LDH, Ca, P, cholesterol, glucose, urea

 Fresh drop of blood for blood smear--intracellular parasites surprisingly common, toxic heterophils indicate septicaemia and/or bacteraemia

Radiography

Ventro-dorsal

Restrain bird in crucifix position using micropore tape

Lateral

Lateral recumbency, legs held back, bird parallel to film

Assess skeletal density, lesions (fractures), and heart normal lies at the second rib to the fifth rib. The lateral margins of the normal heart and liver in psittacine birds create an hourglass shape (there may be a kink between the two in macaws). On the VD view, the heart covers much of the lung field; the abdominal air sacs outline the liver.

Interpretation of Avian Haemogram

Abnormal finding

Differential diagnosis

Regenerative (Blood loss) anaemia

Trauma, parasites, coagulopathy, organic disease

Haemolytic anaemia

Red blood cell parasites, bacterial septicaemia,
toxicity, immune mediated

Non Regenerative anaemia

Chronic disease, hypothyroidism, toxicity,
nutritional deficiencies, leukaemia

Leucocytosis

Infection, trauma, toxicity, haemorrhage,
neoplasm, leukaemia

Heterophilia

Inflammation, stress response

Leucocytosis and heterophilia

Chlamydiosis, avian TB, aspergillosis

Immature heterophils

Severe inflammatory response

Toxic heterophils

Septicaemia, toxaemia

Leucopoenia and heteropaenia

Viral disease, overwhelming bacterial disease

Lymphocytosis

Infections

Monocytosis tissue

Chlamydiosis, granulomas (bacterial, fungal),
massive necrosis

Thrombocytopenia

Severe septicaemias, rebound from blood loss

Heart size at base should equal about 50% of the width of the coelomic cavity at the level of the fifth thoracic vertebra. Cardiomegaly is rare and associated with; endocarditis (often secondary to pododermatitis), chronic anaemia most commonly. Pericardial effusion shown as a large rounded heart is caused by; chlamydiosis, polyoma virus, TB and neoplasia. Microcardia suggests hypovolaemia and an emergency. Atherosclerosis is common in older birds maintained on a high fat diet (oily seeds).

On a good quality radiograph, the para-bronchi can be seen as a honeycomb pattern to the lungs. Pneumonic changes are best appreciated at the caudal edge of the lungs on the VD view. The air sac walls are not readily visible unless they are inflamed when fine lines may be seen on the lateral view.

The crop is on the right side of the distal neck but may appear to extend across the neck, depending upon species and contents.

The liver should not extend beyond the sternum on the lateral view. An enlarged liver is detected by the loss of the 'waist' of the hourglass shape formed with the heart, the loss of abdominal air sac, the presence of liver lobes beyond the scapula/ coracoid line, a cranially displaced heart and dorsal elevation of the proventriculus.

The spleen is a rounded object slightly right of midline at the junction of the ventriculus and proventriculus on the VD view. The gastrointestinal tract is best appreciated radiographically by the use of barium contrast material. Gas is considered abnormal in the avian GIT.

The kidneys are normally made visible by the presence of air around them. The cranial and caudal divisions are best appreciated on the lateral view ventral to the synsacrum. Masses of the spleen, testis, ovary, intestine may appear as renal enlargement.

The active ovary appears as a bunch of grapes cranial to the kidneys. The active testis is large and can be misinterpreted as renal enlargement.

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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