Diagnosis of pericardial effusion in birds by ultrasound

RADIOGRAPHIC EVALUATION OF CARDIAC SILHOUETTE IN CLINICALLY HEALTHY HUMBOLDT PENGUINS ( SPHENISCUS HUMBOLDTI)

Wild populations of Humboldt penguins ( Spheniscus humboldti) on the coasts of Chile and Peru have been declining because of food scarcity caused by the El Niño Southern Oscillation and human interference. Part of conserving this vulnerable and threatened species is maintaining the health of penguins within zoo collections. A variety of cardiovascular diseases has been reported in individuals from the Spheniscidae family including ventricular septal defects, Dirofilaria immitis infection, pulmonary hypertension, and valvular dysplasia, ultimately resulting in congestive heart failure. An accurate clinical picture of cardiovascular disease in Humboldt penguins requires diagnostics tailored to this specific species. The aim of this study was to establish a routine methodology for evaluating the cardiac silhouette of clinically healthy Humboldt penguins using vertebral heart scale (VHS), cardiocoelomic width ratio (CCWR), and a novel cardiac silhouette-to-keel ratio (CKR). Ventrodorsal and right lateral radiographs were taken of 10 mature Humboldt penguins during routine health evaluations. An echocardiographic exam of each penguin was performed to confirm that there was no evidence of cardiac structural remodeling from disease. Two penguins were excluded on the basis of echocardiographic findings; therefore, data from eight penguins were used to calculate objective cardiac measurements for the clinically healthy population. Right lateral radiographs were used to determine VHS (7.4-10.4) and CKR (3.4-4.4). Ventrodorsal radiographs were used for calculating CCWR (0.45-0.59). The excluded penguins had CCWRs that were outside the 95% confidence interval for the range generated by this study. This initial work supports that standardizing radiographic views provides objective measures for cardiac silhouette evaluation in this species. Further research in larger populations and comparison with birds having confirmed cardiac disease is needed to determine the value of these three measurement techniques in Humboldt penguins.

Cardiovascular Drugs in Avian, Small Mammal, and Reptile Medicine

Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds, small mammals, and reptiles. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in exotic species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the exotic cardiac patient.

Pericardial Mesothelioma in a Yellow-naped Amazon Parrot (Amazona auropalliata)

A 37-year-old female yellow-naped Amazon parrot (Amazona auropalliata) was presented with a history of lethargy, inappetence, and decreased vocalizations. On examination, the coelom was moderately distended and palpated fluctuant, and the heart was muffled on auscultation. Coelomic ultrasound, coelomocentesis, and radiographs were performed and revealed an enlarged cardiac silhouette and marked coelomic effusion. Pericardial effusion was confirmed by echocardiography. A well-circumscribed, hyperechoic soft tissue density was observed at the level of the right atrium on initial echocardiography; however, a cardiac mass was not identified by computed tomography scan or repeat echocardiograms. Ultrasound-guided pericardiocentesis was performed under anesthesia, and cytology results were consistent with hemorrhage; no neoplastic cells were identified. A repeat echocardiogram 4 days after pericardiocentesis revealed recurrence of the pericardial effusion. Due to the grave prognosis, the owners declined endoscopic pericardiectomy, and the patient died the following day. On postmortem examination, the pericardial surface of the heart was covered in a white to yellow, multinodular mass layer. Histologic analysis revealed a multinodular mass extending from the atria, running along the epicardium distally, and often extending into the myocardium. Neoplastic cells present in the heart mass and pericardium did not stain with a Churukian-Schenk stain, and thyroglobulin immunohistochemistry was negative. Cytokeratin and vimentin stains showed positive expression in the neoplastic cells within the mass. These results are consistent with a diagnosis of mesothelioma. This is the first report of mesothelioma in a psittacine bird.

Comparative ultrasonographic investigations of the gastrointestinal tract and the liver in healthy and diseased pigeons

The use of ultrasound as a diagnostic tool in birds has been documented for cardiac, urogenital, and liver disease. However, its use in gastrointestinal tract disease is not defined. Therefore, the purpose of this study was to compare the ultrasonographic findings of the intestine and liver of six healthy racing pigeons with those of six racing pigeons with gastrointestinal disease. The echogenicity of the liver was significantly different between the two groups. Pigeons with gastrointestinal disease had less homogeneous liver echogenicity with focal heterogeneous areas and the hepatic blood vessels were visible and dilated. The duodenum was visualized and its mean diameter of 7.2 +/- 0.3 mm in the diseased pigeons was significantly wider (P < or = 0.001) than the 5.7 +/- 0.2 mm in healthy birds. The thickness of the duodenal wall in healthy and diseased pigeons was 1.6 +/- 0.1 and 2.4 +/- 0.1 mm, respectively, and they were significantly different (P < or = 0.001). We defined baseline measurements for the duodenal loop in pigeons and provided evidence that ultrasound can be a useful diagnostic tool for investigating intestinal disease in pigeons.

Development, advances and applications of diagnostic ultrasound in animals

Ultrasound has many industrial applications but it was first introduced as a medical diagnostic aid in the 1940s with its first veterinary application, the detection of ovine pregnancy, being reported in 1966. Since then, improvements in equipment quality combined with an increased awareness of the benefits of ultrasound as an imaging technique have led to its widespread use in the veterinary field. Recent advances in computer technology have significantly influenced equipment design and the miniaturization of transducers allows intra-operative and intra-vascular applications. Software advances have improved the ability to manipulate and process data, leading to an increased amount of information being obtained from each examination and the advent of 'remote diagnosis'. Ultrasound guided interventional techniques can now be used for diagnostic or therapeutic purposes. Many of these developments have been introduced by equipment manufacturers but have found specific applications in the veterinary field. Ultrasound is currently employed in a very diverse range of situations, not just as a diagnostic tool in the routine clinical workup of a range of species, but also for disease screening, conservation projects, commercial services, herd management and clinical research.

Effect of handling-induced stress on the results of spectral Doppler echocardiography in falcons

In order to evaluate the effects of habituation to handling on the Doppler-derived velocity of diastolic ventricular inflow and systolic aortic outflow, falcons that were accustomed to regular handling were compared with falcons that had been handled very little. The mean heart rate of the frequently handled birds was 111 beats per minute less than the non-habituated birds. All the mean blood flow velocities recorded were much higher in the non-habituated birds than those accustomed to handling. Taking into account the difficulty of objectively quantifying the level of stress suffered by any individual bird, the question is, if meaningful clinical or reference values for Doppler-derived blood flow velocities may be obtained in unsedated or non-anaesthetized birds?