Achieving a Specific Diagnosis

Why: We know birds are ostensibly wild creatures; they have developed in their knowledge that 'If I look sick today, someone is going to come and eat me'. Moreover, they have a faster metabolic rate than mammals, so that once ill, they get sick and die quicker than mammals. It is therefore essential that we teach our clients to recognise the often subtle signs of ill health and to present the 'sick bird' immediately. In turn, the vet must not simply reach for the bottle of enrofloxacin, but instead make every effort to achieve a specific diagnosis, such that the most appropriate therapeutic plan can be developed. If a client ever presents a bird, stating that it is not normal - believe them; do not send it home without a diagnostic work up and appropriate therapy.

How: In order to reach that diagnosis, the clinician must put aside sufficient 'quality time' outside a regular consulting period, to work up the case. Whilst 'clinical pathology' is indeed important, even that remains just 'part of the picture'. All too often, when a clinician is unfamiliar with the species they are presented with, the reaction is to rely on laboratory results in order to hang a diagnosis on the patient. Such an approach (although we have all been guilty of it), is inappropriate. For each sick bird, the following diagnostic tools should be applied (taking into account the species and specific susceptibilities of that species):

Reception patient handling and management must facilitate that the clinician is made aware of the patient species being presented before the patient enters the consulting room. Once species identification is known, then the consulting veterinarian can consider (or research), both the natural husbandry and also the likely captive bird management for this species. Any species or genera, will have diseases which are more or less common and, typically, it is the difference between natural husbandry and captive care which gives rise to the aetiology of the disease presenting.

Full history collection, whilst maintaining visual, auditory, and olfactory observation of the bird and its environment is essential. It is then appropriate to consider physical examination (thorough and systematic, from beak to tail in a systematic manner); the collection of clinical pathology samples (haematology, biochemistry, crop and faecal cytology, relevant aspirates or cytological analysis, serology e.g., Chlamydia spp., radiographs and other specialised tests, e.g., ecg, blood pressure, should be conducted). Such tests (dependent on the patient), are often best carried out under gaseous anaesthesia, or intra nasal midazolam sedation, although some critical birds will benefit from 30 minutes pretreatment with fluid therapy and oxygen. It is vital to appreciate that in avian medicine we use sedation or anaesthesia, to reduce the stress on the bird of what we need to do, rather than as a means of restraint.

So long as correct quality control can be assured, there is great benefit in samples being tested in house (for reasons of expediency).

Initial symptomatic therapy should be provided, pending clinical pathology results; however, it is still essential that appropriate initial fluid therapy and nutritional support be provided, plus symptomatic therapy pending the availability of results. When teaching undergraduates and clinicians respectively, the single most important point to get across, is that the vast majority of diagnosis can be made by companion animal clinicians, so long as they are prepared to apply their basic training to their feathered patient.

As birds are typically small, with a large surface area to body ratio, and have a high metabolic rate, it is vital that any ick bird is provided with a high ambient temperature (80–90°F), appropriate fluid therapy (maintenance at 100 ml/kg, plus replacement of 50% of deficit in day one, 25% in day two, and 25% in day three), together with appropriate nutritional critical care support.

Hospitalisation accommodation should be designed and utilised to provide a stress-free environment where the chances of a positive outcome are optimised. Temperature and humidity should be suitable; visual, auditory and olfactory circumstances should be neutral or positive; the risks of contamination of the environment or infection from the surrounding area must be negated. Each avian patient should ideally be maintained in its own air space, as so many pathogens (especially psittacine) are spread in feather or faecal dust (e.g., Chlamydia spp. and circovirus (the pathogen causing psittacines beak and feather disease) and, hence, may pass between birds who are or have been managed in the same air space). Clinical psittacines air spaces should be cleaned (e.g., by fogging with F10 disinfectant on a regular [weekly] basis) and a log maintained of dates on which this was done).

Sick avian patients require ongoing care 24/7, so day and night nursing staff must be adequately trained to be able to safely provide this, as the typical clinician is too busy to fulfil this requirement.

The carers must be able to visualise the patient without creating stress, catching and handling the patient should be readily achieved and good records of clinical signs and progress (including daily weight record), must be maintained, interpreted and acted upon.

Nutritional support must be appropriate for the patient (carnivore/omnivore/herbivore, etc.); must be readily available when required; must be consumed voluntarily or be administered by gavage or ingluviotomy tube; it must be high in energy (fats and carbohydrates), dietary nucleotides (amino acids), polyunsaturated fatty acids (Omega 3:6), preferably in a semi-elemental form - such that it is more readily absorbed, assimilated and metabolised.

Assessment of progress and response is achieved by monitoring clinical status (weight, response to handling, voluntary feeding), as well as alterations in clinical pathology parameters. This may be easier said than done, as some individuals may not eat whilst in a hospital situation so that timing of discharge is challenging, as one is uncertain whether the patient will self-feed subsequent to returning home.

The potential for post disease persistence of infectivity should be considered; likewise, the potential for reinfection from environment, companions, food or water.

Managing sick birds is not just about treating sick birds; it also involves screening new birds and maintaining them in adequate quarantine, annual/routine health checks, together with recognising all risks of infectious and environmental disease and understanding how these risks may be minimised.

Prevention is the key to managing 'sick birds'.

References

1.  Doneley B, Harrison GJ, Lightfoot TL. Maximising information from the physical examination. In: GJ Harrison, Lightfoot TL, eds. Clinical Avian Medicine. Vol 1. Zoological Education. Spix Publishing; 2006:153–212.

2.  Harris DJ. Avian clinical pathology. In: Scientific Proceedings BSAVA. Congress. Gloucester: BSAVA; 2007:408–410.

3.  Harcourt-Brown N, Chitty J. (2005). BSAVA Manual of Psittacine Birds. 2nd ed. Gloucester: BSAVA; 2005.

4.  Olsen GH, Orosz SE. Manual of Avian Medicine. Missouri: Mosby; 2000.

5.  Samour JH, Naldo JL. Anatomical and Clinical Radiology of Birds of Prey. Elsevier; 2007.