- Email: [email protected]
Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep
Accepted Manuscript Title: Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep Author: P.R. Scott PII: DOI: Reference:
S0921-4488(16)30363-7 http://dx.doi.org/doi:10.1016/j.smallrumres.2016.12.012 RUMIN 5370
To appear in:
Small Ruminant Research
Please cite this article as: Scott, P.R., Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep.Small Ruminant Research http://dx.doi.org/10.1016/j.smallrumres.2016.12.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep
P.R. Scott*
Division of Veterinary Clinical Sciences, R(D)SVS, University of Edinburgh, Easter Bush, Roslin, Midlothian, Scotland, EH25 9RG, United Kingdom. *
Corresponding author: [email protected]
1
ABSTRACT This article presents ultrasonographic and post-mortem findings from a wide range of common ovine diseases, in which provisional veterinary diagnosis was confirmed by using ultrasonography at the time of the first clinical examination and without recourse to additional, potentially expensive, diagnostic facilities. Furthermore, cases studies are presented of conditions and diseases not previously reported in the veterinary literature, where further investigations and the eventual diagnosis was greatly facilitated by ultrasonographic findings. The article seeks to further develop the application of diagnositic ultrasonography in everyday small ruminant practice.
Keywords: clinical case report, liver disease, respiratory disease, sheep, ultrasonography, urinary tract disease, ultrasonography
2
1. Introduction The principles and applications of ultrasonographic examination of the thorax and abdomen have been presented in a previous paper, as part of a detailed examination of sheep with relevant problems (Scott, 2017a,b). Objective of the present paper is to describe clinical cases of respiratory, liver and urinary tract problems in sheep, in which ultrasonographic examination has been employed in the diagnostic process. It is recommended that readers follow the flow of description of each case and take a sequential reading and viewing before reading the conclusion of each case.
2. Case reports 2.1. Case 1
A 4-year old ewe that was bright and alert with a normal appetite, was presented with increased respiratory rate with a marked abdominal component. The ewe was in poorer bodily condition than other sheep in the group, despite an apparently normal appetite. The clinical presentation is shown in Suppl. material 1. The ultrasonographic examination (presented in Suppl. material 2) revealed sharply demarcated area of consolidation representing pulmonary adenocarcinoma tumour, extending for approximately 6 cm into the lung parenchyma (dorsally and to the left) and liver (ventrally and to the right), separated by the diaphragm (broad hyperechoic line); the findings demonstrate the ‘hepatoid’ echogenic nature of the tumour mass. The post-mortem findings are presented in Suppl. material 3. The sharply demarcated pulmonary adenocarcinoma tumour mass in the diaphragmatic lobe explained why it could be imaged in the same field as the liver, with a similar sonographic appearance illustrating the cellular density of the tumour.
2.2. Case 2
Two 4-year old ewes were presented in much poorer bodily condition than other sheep in the group, despite good grazing conditions. Both ewes were found to be bright and alert, but had increased respiratory rate with a marked abdominal component. The clinical presentation is shown in Suppl. material 4. Ultrasonographic examination performed at the farm (presented in Suppl. material 5, 6) revealed a very sharply demarcated area of consolidation ventrally (to the right) representing pulmonary
3
adenocarcinoma tumour, extending for approximately 6 cm into the lung parenchyma; normal lung dorsally (to the left) was represented by the continuous bright hyperechoic visceral pleura. The post-mortem findings are presented in Suppl. material 7. The sharply demarcated tumours were clearly shown in post-mortem examination. This case report illustrated the application of ultrasonography in reaching a specific diagnosis immediately, in this case pulmonary adenocarcinoma, which was then confirmed by the post-mortem findings. Based on the results, a plan can be formulated to control/eliminate this disease, whilst the veterinarian is still on the farm. Crucially, the post-mortem findings in this situation demonstrated to the owner the application and specificity of ultrasonography in the diagnosis of pulmonary adenocarcinoma and the central role of the veterinarian in disease control.
2.3. Case 3
A valuable ram was reported losing body condition (body condition score 1.5 on the scale 1-5), despite an adequate ration; another 25 rams in the same group were in good condition (body condition score 3-3.5). The sheep were housed for four months during the winter. An increased respiratory rate was noted in the animal during clinical examination, but its rectal temperature was normal. Ultrasonographic examination (presented in Suppl. material 8) revealed a sharply demarcated area of consolidation representing pulmonary adenocarcinoma tumour, extending for approximately 3 to 4 cm into the lung parenchyma (cardiac lung lobe); the heart was imaged in the lower right side of the sonogram; there was a 2 cm-diametre abscess within the tumour mass, at the junction with normal lung dorsally (to the left). The post-mortem findings are presented in Suppl. material 9. The sharply demarcated tumour mass was clearly visible at post-mortem examination, with several abscesses within it; the central abscess was probably that imaged in the video recording. The specific diagnosis of pulmonary adenocarcinoma permitted immediate culling, before further spread of the causal virus to other valuable rams in the group.
2.4. Case 4
A 2-year old ewe was presented bright and alert, with a normal appetite, but with a markedly increased respiratory rate with a pronounced abdominal component. The ewe was in poorer bodily condition than other sheep in the group, despite an apparently normal appetite. There were no lung sounds audible on the right side of the chest and the heart sounds were much reduced. Increased audibility of normal breath sounds were heard on the left side of the chest with increased heart sounds. The clinical presentation is shown in Suppl. material 10. 4
Ultrasonographic examination (presented in Suppl. material 11) revealed a unilateral wellencapsulated fibrinous pleurisy, with a hyperechoic lattice-work within a large anechoic area extending to 15 cm from the chest wall; the well-organised appearance of the fibrin clot suggested that it could have developed over several weeks; the lung surface was not imaged dorsally. This ewe failed to respond to antibiotic administration and was euthanised on welfare grounds. On other occasions, sheep with less severe fibrinous pleurisy lesions have responded well to treatment with procaine penicillin.
2.5. Case 5
A 4-year old ewe was presented bright and alert, but in poorer bodily condition than other sheep in the group. During clinical examination, lesions 6 to 8 cm in diametre were observed in the left mammary gland, which resembled strongly to encapsulated abscesses (Suppl. material 12); the respective teat was enlarged and purulent material could be expressed. Ultrasonographic examination (presented in Suppl. material 13) revealed separation of the pleurae by a 5 to 8 mm thick anechoic layer dorsally, which increased in width as the probe head moved ventrally; there was also fibrinous pleurisy (fine hyperchoic strands within the anechoic area) ventrally, which extended to 5 cm and onto the diaphragm; the liver was visible on the other side of the broad convex hyperechoic line representing the diaphragm. Post mortem findings (presented in Suppl. material 14) indicated that the extent of the pleurisy was evident from this image and corresponded well to the sonographic findings. Further, ultrasonographic examination (presented in Suppl. material 15) revealed separation of the pleurae by a 2 to 3 mm thick anechoic layer dorsally, which increased in width as the probe head moved ventrally; there, there were several 2 to 3 cm in diametre anechoic areas, with hyperechoic boundaries typical of abscesses; the fibrinous pleurisy was not nearly as extensive as on the right side of the chest. Mastitis was long-standing and unlikely to have been the cause of weight loss in this ewe; however, the extensive bilateral pleurisy was considered unlikely to respond to antibiotic therapy and, hence, the ewe was culled for welfare reasons. In post-mortem findings (presented in Suppl. material 16), pleurisy, particularly affecting the ventral margins of the left lung, was evident.
2.6. Case 6
A 4-year old ewe was examined for pulmonary adenocarcinoma, as part of a flock investigation for presence of the disease. Ultrasonographic examination (presented in Suppl. material 17, 18) revealed several 5 to 8 mm anechoic areas on the visceral pleura distributed over the lung surface; these areas had an obvious hyperechoic margin, but it was not possible to ascertain nature of these lesions. 5
The post-mortem findings are presented in Suppl. material 19. Lesions at the visceral pleura were found to be small abscesses following bacteraemic spread, which highlighted the difficulty in differentiating sonographic findings smaller than 1 to 2 cm in diametre, which involved the visceral pleura.
2.7. Case 7
A 4-year old ewe was examined for pulmonary adenocarcinoma, as part of a flock investigation for presence of the disease. The animal had no history of illness and was bright and alert; the shepherd reported to have observed nothing untoward with this sheep. Body condition score of the animal was found to be 2.5 (on the 1-5 scale) consistent with that of other animals in the flock. The clinical presentation is shown in Suppl. material 20. Ultrasonographic examination (presented in Suppl. material 21, 22) of the right chest revealed normal lung (Suppl. material 21) with the normal continuous hyperechoic visceral pleura moving in time with respiration; on the left side, there was a well-encapsulated anechoic area extending to 8 cm in diametre, containing broad hyperechoic fibrinous strands moved by the adjacent beating heart; although this sonographic picture was not dissimilar to some cases of septic pericarditis in cattle (Suppl. material 23), the present case was not diagnosed as pericarditis, because the lesion was unilateral and did not surround the heart; the sonographic findings in this animal were consistent with a very large fluid-filled abscess; the well-developed capsule would explain the normal clinical appearance of this sheep. Subsequently, the animal was re-examined two months later, when the lesion had extended to 12 cm in diametre, with large fibrinous clots clearly visible (Suppl. material 24), and had been confirmed at post-mortem examination (Suppl. material 25). The sheep had remained in good health and had shown no signs of illness and was culled for another reason.
2.8. Case 8
Four ewes were presented for investigation of chronic bodyweight loss. The farmer considered that the most likely cause was ovine pulmonary adenocarcinoma; animals had been tested clinically, by use of the ‘wheelbarrow’ and were not found to be affected. The clinical presentation is shown in Suppl. material 26. Two of the sheep were found with no incisor teeth and a third was found lame due to a chronic stifle injury. In utrasonographic examination, three of the sheep (the two with teeth problems and the one with lameness), no abnormal sonographic findings were evident. Post-mortem examination of these animals confirmed that they were free of pulmonary adenocarcinoma. In the fourth animal, the ewe on the far right as shown in Suppl. material 26, abnormal findings in the left side of the chest were recorded (Suppl. material 27 and 28). In Suppl. material 27, a record of 6
half way up the chest wall at the 6th intercostal space is presented; there was a normal lung dorsally (continuous hyperechoic line formed by the visceral pleura), with a very sharply-demarcated hypoechoic area ventrally representing consolidation caused by pulmonary adenocarcinoma tumour, extending for at least 6 cm into the lung parenchyma. Suppl. material 28 presents at the point of the elbow at the 6th intercostal space; there were several, poorly defined, areas 1 to 1.5 cm in diametre, that appeared more hypoechoic than the tumour mass itself and these probably represented abscesses; the heart was clearly visible in the lower field and to the right; presence of abscess(es) within the tumour mass often causes fibrinous/fibrous adhesions and these were likely present in the animal between the adenocarcinomaaffected lung tissue and the pericardial sac. The post-mortem findings are presented in Suppl. material 29-31. The examination indicated the extent of the tumour mass and there a good agreement with the sonographic findings (Suppl. material 27, 28); extensive pleurisy (Suppl. material 30, 31) and secondary formation of abscesses (Suppl. material 30, 32, 33) were observed with adhesions (Suppl. material 30) between the adenocarcinoma tumour-affected lung and the pericardial sac. Further ultrasonographic examination in the right side of the chest (presented in Suppl. material 34-36) showed a well-defined, 1 cm deep, anechoic area in the dorsal lung field representing lung consolidation (Suppl. material 34). This lesion may be indicative of pulmonary adenocarcinoma, but other disorders (e.g., abscesses, lesions of parasitic aetiology) may give a similar presentation. More characteristic adenocarcinoma lesions, extending to approximately 3 cm and involving the ventral margin of the lung lobe, were then observed (Suppl. material 35, 36). Further post-mortem findings are presented in Suppl. material 35 and 36; the lesions in the right lung were smaller than those in the left lung (Suppl. material 29-31). It is noteworthy to comment that the ‘wheelbarrow’ test is not reliable for diagnosis of pulmonary adenocarcinoma in animals in advanced stage of the disease. Further, it fails, in the great majority of cases, to lead to diagnosis of the disease in its early stage.
2.9. Case 9
A 2-year old ram has been presented in poor body condition, 1.5 (on the 1-5 scale), despite receiving an adequate diet. The ram was bright and alert and the rectal temperature was normal, but the animals had received long-acting oxytetracycline on two occasions in the previous three weeks with no apparent improvement. The clinical examination revealed no abnormalities, except for chronic bodyweight loss and absence of normal auscultatory findings in the ventral area of the left chest. The clinical presentation is shown in Suppl. material 39. Blood biochemical examination revealed a marked increase in globulin concentration (65 g L-1) and a decrease in albumin concentration, which were consistent with long-standing bacterial infections. Ultrasonographic examination (presented in Suppl. material 40), undertaken with a 6.5 MHz microconvex probe and a depth of 11 cm, revealed abnormalities only in the left side of the chest at 7th 7
to 8th intercostal spaces; loss of the continuous hyperechoic (white) line formed by the normal lung surface was observed and was seen to be replaced by a poorly-defined anechoic area extending for approximately 6 cm from the chest wall; the diaphragm was imaged ventrally (to the right) as a broad 1 cm thick convex line; occasionally, a thin convex hyperechoic line was visible immediately below the chest wall, which could indicate an abscess capsule; at a depth of 7 to 11 cm, there was a 5 to 6 cm diametre area with multiple 1 to 2 mm hyperechoic dots, consistent with the sonographic appearance of an abscess; the images made possible that the structure was comprised of two smaller abscesses, each 3 to 4 cm in diametre. Most likely, the imaged lesion was an abscess within the pleural space. The protein blood concentrations were consistent with a septic focus, although this might have been located elsewhere in the body. The possibility of a penetrating foreign body could not be dismissed, although such lesions were rare in sheep. Treatment with procaine penicillin, daily for six weeks, was prescribed based on the assumption that the abscess was caused by Trueperella pyogenes, a common aetiological agent of such lesions (Scott 2011). 2.10. Case 10
A six month-old Scottish Blackface ewe-lamb has been presented with a history of four weeklong tenesmus and chronic severe weight loss. The animal was emaciated with poor abdominal fill and almost too weak to stand; it was euthanised immediately for welfare reasons. The clinical presentation is shown in Suppl. material 41. The ultrasonographic recordings (presented in Suppl. material 42, 43) were taken immediately after euthanasia. The bladder wall appeared as a hyperechoic circle in transverse section, extending to 6 cm in diametre, immediately cranial to the pelvis and extending almost to the umbilical region. This indicated that the bladder would be cylindrical in shape and the true size of the bladder was measured by moving the ultrasound probe head cranially along the ventral surface of the abdomen from the pubis. Urine within the bladder was anechoic. Advanced hydronephrosis can be readily identified by the grossly increased renal pelvis, which was represented by the anechoic (fluid-filled) centre of the kidney. The post-mortem examination was undertaken on farm (presented in Suppl. material 44-46). The bladder was distended; there is no evidence of uroperitoneum. Unusually, the omentum and small intestine were firmly adherent to serosal surface of the bladder over a large area. The bladder wall was thickened and there was a large diphtheritic area of the mucosal surface, which corresponded to the adhesions present on the serosal surface. No evidence of urachal infection was found, although the examination was performed in difficult circumstances. The most likely explanation for this clinical presentation would be pelvic nerve paralysis (Scott, 2012). Bladder distension led in pressure necrosis within the bladder wall and secondary bacterial infection. Leakage across the compromised bladder wall caused fibrin deposition on the 8
serosal surface with progression to more fibrous adhesions. Hydronephrosis resulted from a period of high urinary back pressure. There was no evidence of urethral blockage, also noting that this sheep was a ewe-lamb.
2.11. Case 11
During late winter, several purchased adult sheep presented in poor body condition and the farmer suspected pulmonary adenocarcinoma. Ultrasonographic examination revealed no lung pathologies, but trans-abdominal examination of the liver showed loss of normal architecture and multiple hyperechoic dots throughout the liver (presented in Suppl. material 47) consistent with fasciolosis. One ewe died the following day after treatment with a flukicide and the provisional diagnosis of chronic fasciolosis was confirmed at post-mortem examination (presented in Suppl. material 48).
2.12. Case 12
A valuable five year-old Scottish Blackface ram was presented with a history of weight loss and a smaller condition score (1.5 on the 1-5 scale) than other rams in the group (3.0-3.5). The ram was bright and alert, but presented with an increased respiratory rate and abdominal component (presented in Suppl. material 49). Trans-thoracic ultrasonographic examination of the left chest at the 7th and 8th intercostal spaces revealed extensive irregular fibrinous lesions that extended beyond 18 cm from the probe head; the diaphragm was visible to the right of the sonogram as a broad 15 to 20 mm wide hyperechoic band (presented in Suppl. material 50, 51). The heart was imaged on the right hand side of the chest, with 2 to 3 cm of fibrin deposited on the epicardium (presented in Suppl. material 52, 53). The broad semi-circular band extending across the centre of the recording might have been the grossly thickened pericardial sac (presented in Suppl. material 52, 53). The post-mortem findings (presented in Suppl. material 54-59) showed extensive fibrinous pleurisy and pericarditis with considerable fibrin deposition on the epicardium. It is remarkable that the animal showed no gross signs of illness (presented in Suppl. material 49), despite greatly reduced lung volume and very extensive exudation into the pericardium and pleural space.
Conflict of interest statement The author of this paper has no financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. 9
References Scott, P.R. (2011) Treatment and control of respiratory disease in sheep. Vet. Clin. N. Am. Food Anim. Pract. 27, 175-186. Scott, P.R. (2012) Clinical, ultrasonographic and pathological description of bladder distension with consequent hydroureters, severe hydronephrosis and perirenal fluid accumulation in two rams putatively ascribed to pelvic nerve dysfunction. Small Rumin. Res. 107, 45-48. Scott, P.R. (2017a) Abdominal ultrasonography as an adjunct to clinical examination in sheep. Small Rumin. Res. THIS ISSUE. Scott, P.R. (2017b) Thoracic ultrasonography as an adjunct to clinical examination in sheep. Small Rumin. Res. THIS ISSUE.
10
S0921-4488(16)30363-7 http://dx.doi.org/doi:10.1016/j.smallrumres.2016.12.012 RUMIN 5370
To appear in:
Small Ruminant Research
Please cite this article as: Scott, P.R., Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep.Small Ruminant Research http://dx.doi.org/10.1016/j.smallrumres.2016.12.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Description of clinical cases of diseases of the thorax by means of ultrasonographic examination in sheep
P.R. Scott*
Division of Veterinary Clinical Sciences, R(D)SVS, University of Edinburgh, Easter Bush, Roslin, Midlothian, Scotland, EH25 9RG, United Kingdom. *
Corresponding author: [email protected]
1
ABSTRACT This article presents ultrasonographic and post-mortem findings from a wide range of common ovine diseases, in which provisional veterinary diagnosis was confirmed by using ultrasonography at the time of the first clinical examination and without recourse to additional, potentially expensive, diagnostic facilities. Furthermore, cases studies are presented of conditions and diseases not previously reported in the veterinary literature, where further investigations and the eventual diagnosis was greatly facilitated by ultrasonographic findings. The article seeks to further develop the application of diagnositic ultrasonography in everyday small ruminant practice.
Keywords: clinical case report, liver disease, respiratory disease, sheep, ultrasonography, urinary tract disease, ultrasonography
2
1. Introduction The principles and applications of ultrasonographic examination of the thorax and abdomen have been presented in a previous paper, as part of a detailed examination of sheep with relevant problems (Scott, 2017a,b). Objective of the present paper is to describe clinical cases of respiratory, liver and urinary tract problems in sheep, in which ultrasonographic examination has been employed in the diagnostic process. It is recommended that readers follow the flow of description of each case and take a sequential reading and viewing before reading the conclusion of each case.
2. Case reports 2.1. Case 1
A 4-year old ewe that was bright and alert with a normal appetite, was presented with increased respiratory rate with a marked abdominal component. The ewe was in poorer bodily condition than other sheep in the group, despite an apparently normal appetite. The clinical presentation is shown in Suppl. material 1. The ultrasonographic examination (presented in Suppl. material 2) revealed sharply demarcated area of consolidation representing pulmonary adenocarcinoma tumour, extending for approximately 6 cm into the lung parenchyma (dorsally and to the left) and liver (ventrally and to the right), separated by the diaphragm (broad hyperechoic line); the findings demonstrate the ‘hepatoid’ echogenic nature of the tumour mass. The post-mortem findings are presented in Suppl. material 3. The sharply demarcated pulmonary adenocarcinoma tumour mass in the diaphragmatic lobe explained why it could be imaged in the same field as the liver, with a similar sonographic appearance illustrating the cellular density of the tumour.
2.2. Case 2
Two 4-year old ewes were presented in much poorer bodily condition than other sheep in the group, despite good grazing conditions. Both ewes were found to be bright and alert, but had increased respiratory rate with a marked abdominal component. The clinical presentation is shown in Suppl. material 4. Ultrasonographic examination performed at the farm (presented in Suppl. material 5, 6) revealed a very sharply demarcated area of consolidation ventrally (to the right) representing pulmonary
3
adenocarcinoma tumour, extending for approximately 6 cm into the lung parenchyma; normal lung dorsally (to the left) was represented by the continuous bright hyperechoic visceral pleura. The post-mortem findings are presented in Suppl. material 7. The sharply demarcated tumours were clearly shown in post-mortem examination. This case report illustrated the application of ultrasonography in reaching a specific diagnosis immediately, in this case pulmonary adenocarcinoma, which was then confirmed by the post-mortem findings. Based on the results, a plan can be formulated to control/eliminate this disease, whilst the veterinarian is still on the farm. Crucially, the post-mortem findings in this situation demonstrated to the owner the application and specificity of ultrasonography in the diagnosis of pulmonary adenocarcinoma and the central role of the veterinarian in disease control.
2.3. Case 3
A valuable ram was reported losing body condition (body condition score 1.5 on the scale 1-5), despite an adequate ration; another 25 rams in the same group were in good condition (body condition score 3-3.5). The sheep were housed for four months during the winter. An increased respiratory rate was noted in the animal during clinical examination, but its rectal temperature was normal. Ultrasonographic examination (presented in Suppl. material 8) revealed a sharply demarcated area of consolidation representing pulmonary adenocarcinoma tumour, extending for approximately 3 to 4 cm into the lung parenchyma (cardiac lung lobe); the heart was imaged in the lower right side of the sonogram; there was a 2 cm-diametre abscess within the tumour mass, at the junction with normal lung dorsally (to the left). The post-mortem findings are presented in Suppl. material 9. The sharply demarcated tumour mass was clearly visible at post-mortem examination, with several abscesses within it; the central abscess was probably that imaged in the video recording. The specific diagnosis of pulmonary adenocarcinoma permitted immediate culling, before further spread of the causal virus to other valuable rams in the group.
2.4. Case 4
A 2-year old ewe was presented bright and alert, with a normal appetite, but with a markedly increased respiratory rate with a pronounced abdominal component. The ewe was in poorer bodily condition than other sheep in the group, despite an apparently normal appetite. There were no lung sounds audible on the right side of the chest and the heart sounds were much reduced. Increased audibility of normal breath sounds were heard on the left side of the chest with increased heart sounds. The clinical presentation is shown in Suppl. material 10. 4
Ultrasonographic examination (presented in Suppl. material 11) revealed a unilateral wellencapsulated fibrinous pleurisy, with a hyperechoic lattice-work within a large anechoic area extending to 15 cm from the chest wall; the well-organised appearance of the fibrin clot suggested that it could have developed over several weeks; the lung surface was not imaged dorsally. This ewe failed to respond to antibiotic administration and was euthanised on welfare grounds. On other occasions, sheep with less severe fibrinous pleurisy lesions have responded well to treatment with procaine penicillin.
2.5. Case 5
A 4-year old ewe was presented bright and alert, but in poorer bodily condition than other sheep in the group. During clinical examination, lesions 6 to 8 cm in diametre were observed in the left mammary gland, which resembled strongly to encapsulated abscesses (Suppl. material 12); the respective teat was enlarged and purulent material could be expressed. Ultrasonographic examination (presented in Suppl. material 13) revealed separation of the pleurae by a 5 to 8 mm thick anechoic layer dorsally, which increased in width as the probe head moved ventrally; there was also fibrinous pleurisy (fine hyperchoic strands within the anechoic area) ventrally, which extended to 5 cm and onto the diaphragm; the liver was visible on the other side of the broad convex hyperechoic line representing the diaphragm. Post mortem findings (presented in Suppl. material 14) indicated that the extent of the pleurisy was evident from this image and corresponded well to the sonographic findings. Further, ultrasonographic examination (presented in Suppl. material 15) revealed separation of the pleurae by a 2 to 3 mm thick anechoic layer dorsally, which increased in width as the probe head moved ventrally; there, there were several 2 to 3 cm in diametre anechoic areas, with hyperechoic boundaries typical of abscesses; the fibrinous pleurisy was not nearly as extensive as on the right side of the chest. Mastitis was long-standing and unlikely to have been the cause of weight loss in this ewe; however, the extensive bilateral pleurisy was considered unlikely to respond to antibiotic therapy and, hence, the ewe was culled for welfare reasons. In post-mortem findings (presented in Suppl. material 16), pleurisy, particularly affecting the ventral margins of the left lung, was evident.
2.6. Case 6
A 4-year old ewe was examined for pulmonary adenocarcinoma, as part of a flock investigation for presence of the disease. Ultrasonographic examination (presented in Suppl. material 17, 18) revealed several 5 to 8 mm anechoic areas on the visceral pleura distributed over the lung surface; these areas had an obvious hyperechoic margin, but it was not possible to ascertain nature of these lesions. 5
The post-mortem findings are presented in Suppl. material 19. Lesions at the visceral pleura were found to be small abscesses following bacteraemic spread, which highlighted the difficulty in differentiating sonographic findings smaller than 1 to 2 cm in diametre, which involved the visceral pleura.
2.7. Case 7
A 4-year old ewe was examined for pulmonary adenocarcinoma, as part of a flock investigation for presence of the disease. The animal had no history of illness and was bright and alert; the shepherd reported to have observed nothing untoward with this sheep. Body condition score of the animal was found to be 2.5 (on the 1-5 scale) consistent with that of other animals in the flock. The clinical presentation is shown in Suppl. material 20. Ultrasonographic examination (presented in Suppl. material 21, 22) of the right chest revealed normal lung (Suppl. material 21) with the normal continuous hyperechoic visceral pleura moving in time with respiration; on the left side, there was a well-encapsulated anechoic area extending to 8 cm in diametre, containing broad hyperechoic fibrinous strands moved by the adjacent beating heart; although this sonographic picture was not dissimilar to some cases of septic pericarditis in cattle (Suppl. material 23), the present case was not diagnosed as pericarditis, because the lesion was unilateral and did not surround the heart; the sonographic findings in this animal were consistent with a very large fluid-filled abscess; the well-developed capsule would explain the normal clinical appearance of this sheep. Subsequently, the animal was re-examined two months later, when the lesion had extended to 12 cm in diametre, with large fibrinous clots clearly visible (Suppl. material 24), and had been confirmed at post-mortem examination (Suppl. material 25). The sheep had remained in good health and had shown no signs of illness and was culled for another reason.
2.8. Case 8
Four ewes were presented for investigation of chronic bodyweight loss. The farmer considered that the most likely cause was ovine pulmonary adenocarcinoma; animals had been tested clinically, by use of the ‘wheelbarrow’ and were not found to be affected. The clinical presentation is shown in Suppl. material 26. Two of the sheep were found with no incisor teeth and a third was found lame due to a chronic stifle injury. In utrasonographic examination, three of the sheep (the two with teeth problems and the one with lameness), no abnormal sonographic findings were evident. Post-mortem examination of these animals confirmed that they were free of pulmonary adenocarcinoma. In the fourth animal, the ewe on the far right as shown in Suppl. material 26, abnormal findings in the left side of the chest were recorded (Suppl. material 27 and 28). In Suppl. material 27, a record of 6
half way up the chest wall at the 6th intercostal space is presented; there was a normal lung dorsally (continuous hyperechoic line formed by the visceral pleura), with a very sharply-demarcated hypoechoic area ventrally representing consolidation caused by pulmonary adenocarcinoma tumour, extending for at least 6 cm into the lung parenchyma. Suppl. material 28 presents at the point of the elbow at the 6th intercostal space; there were several, poorly defined, areas 1 to 1.5 cm in diametre, that appeared more hypoechoic than the tumour mass itself and these probably represented abscesses; the heart was clearly visible in the lower field and to the right; presence of abscess(es) within the tumour mass often causes fibrinous/fibrous adhesions and these were likely present in the animal between the adenocarcinomaaffected lung tissue and the pericardial sac. The post-mortem findings are presented in Suppl. material 29-31. The examination indicated the extent of the tumour mass and there a good agreement with the sonographic findings (Suppl. material 27, 28); extensive pleurisy (Suppl. material 30, 31) and secondary formation of abscesses (Suppl. material 30, 32, 33) were observed with adhesions (Suppl. material 30) between the adenocarcinoma tumour-affected lung and the pericardial sac. Further ultrasonographic examination in the right side of the chest (presented in Suppl. material 34-36) showed a well-defined, 1 cm deep, anechoic area in the dorsal lung field representing lung consolidation (Suppl. material 34). This lesion may be indicative of pulmonary adenocarcinoma, but other disorders (e.g., abscesses, lesions of parasitic aetiology) may give a similar presentation. More characteristic adenocarcinoma lesions, extending to approximately 3 cm and involving the ventral margin of the lung lobe, were then observed (Suppl. material 35, 36). Further post-mortem findings are presented in Suppl. material 35 and 36; the lesions in the right lung were smaller than those in the left lung (Suppl. material 29-31). It is noteworthy to comment that the ‘wheelbarrow’ test is not reliable for diagnosis of pulmonary adenocarcinoma in animals in advanced stage of the disease. Further, it fails, in the great majority of cases, to lead to diagnosis of the disease in its early stage.
2.9. Case 9
A 2-year old ram has been presented in poor body condition, 1.5 (on the 1-5 scale), despite receiving an adequate diet. The ram was bright and alert and the rectal temperature was normal, but the animals had received long-acting oxytetracycline on two occasions in the previous three weeks with no apparent improvement. The clinical examination revealed no abnormalities, except for chronic bodyweight loss and absence of normal auscultatory findings in the ventral area of the left chest. The clinical presentation is shown in Suppl. material 39. Blood biochemical examination revealed a marked increase in globulin concentration (65 g L-1) and a decrease in albumin concentration, which were consistent with long-standing bacterial infections. Ultrasonographic examination (presented in Suppl. material 40), undertaken with a 6.5 MHz microconvex probe and a depth of 11 cm, revealed abnormalities only in the left side of the chest at 7th 7
to 8th intercostal spaces; loss of the continuous hyperechoic (white) line formed by the normal lung surface was observed and was seen to be replaced by a poorly-defined anechoic area extending for approximately 6 cm from the chest wall; the diaphragm was imaged ventrally (to the right) as a broad 1 cm thick convex line; occasionally, a thin convex hyperechoic line was visible immediately below the chest wall, which could indicate an abscess capsule; at a depth of 7 to 11 cm, there was a 5 to 6 cm diametre area with multiple 1 to 2 mm hyperechoic dots, consistent with the sonographic appearance of an abscess; the images made possible that the structure was comprised of two smaller abscesses, each 3 to 4 cm in diametre. Most likely, the imaged lesion was an abscess within the pleural space. The protein blood concentrations were consistent with a septic focus, although this might have been located elsewhere in the body. The possibility of a penetrating foreign body could not be dismissed, although such lesions were rare in sheep. Treatment with procaine penicillin, daily for six weeks, was prescribed based on the assumption that the abscess was caused by Trueperella pyogenes, a common aetiological agent of such lesions (Scott 2011). 2.10. Case 10
A six month-old Scottish Blackface ewe-lamb has been presented with a history of four weeklong tenesmus and chronic severe weight loss. The animal was emaciated with poor abdominal fill and almost too weak to stand; it was euthanised immediately for welfare reasons. The clinical presentation is shown in Suppl. material 41. The ultrasonographic recordings (presented in Suppl. material 42, 43) were taken immediately after euthanasia. The bladder wall appeared as a hyperechoic circle in transverse section, extending to 6 cm in diametre, immediately cranial to the pelvis and extending almost to the umbilical region. This indicated that the bladder would be cylindrical in shape and the true size of the bladder was measured by moving the ultrasound probe head cranially along the ventral surface of the abdomen from the pubis. Urine within the bladder was anechoic. Advanced hydronephrosis can be readily identified by the grossly increased renal pelvis, which was represented by the anechoic (fluid-filled) centre of the kidney. The post-mortem examination was undertaken on farm (presented in Suppl. material 44-46). The bladder was distended; there is no evidence of uroperitoneum. Unusually, the omentum and small intestine were firmly adherent to serosal surface of the bladder over a large area. The bladder wall was thickened and there was a large diphtheritic area of the mucosal surface, which corresponded to the adhesions present on the serosal surface. No evidence of urachal infection was found, although the examination was performed in difficult circumstances. The most likely explanation for this clinical presentation would be pelvic nerve paralysis (Scott, 2012). Bladder distension led in pressure necrosis within the bladder wall and secondary bacterial infection. Leakage across the compromised bladder wall caused fibrin deposition on the 8
serosal surface with progression to more fibrous adhesions. Hydronephrosis resulted from a period of high urinary back pressure. There was no evidence of urethral blockage, also noting that this sheep was a ewe-lamb.
2.11. Case 11
During late winter, several purchased adult sheep presented in poor body condition and the farmer suspected pulmonary adenocarcinoma. Ultrasonographic examination revealed no lung pathologies, but trans-abdominal examination of the liver showed loss of normal architecture and multiple hyperechoic dots throughout the liver (presented in Suppl. material 47) consistent with fasciolosis. One ewe died the following day after treatment with a flukicide and the provisional diagnosis of chronic fasciolosis was confirmed at post-mortem examination (presented in Suppl. material 48).
2.12. Case 12
A valuable five year-old Scottish Blackface ram was presented with a history of weight loss and a smaller condition score (1.5 on the 1-5 scale) than other rams in the group (3.0-3.5). The ram was bright and alert, but presented with an increased respiratory rate and abdominal component (presented in Suppl. material 49). Trans-thoracic ultrasonographic examination of the left chest at the 7th and 8th intercostal spaces revealed extensive irregular fibrinous lesions that extended beyond 18 cm from the probe head; the diaphragm was visible to the right of the sonogram as a broad 15 to 20 mm wide hyperechoic band (presented in Suppl. material 50, 51). The heart was imaged on the right hand side of the chest, with 2 to 3 cm of fibrin deposited on the epicardium (presented in Suppl. material 52, 53). The broad semi-circular band extending across the centre of the recording might have been the grossly thickened pericardial sac (presented in Suppl. material 52, 53). The post-mortem findings (presented in Suppl. material 54-59) showed extensive fibrinous pleurisy and pericarditis with considerable fibrin deposition on the epicardium. It is remarkable that the animal showed no gross signs of illness (presented in Suppl. material 49), despite greatly reduced lung volume and very extensive exudation into the pericardium and pleural space.
Conflict of interest statement The author of this paper has no financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. 9
References Scott, P.R. (2011) Treatment and control of respiratory disease in sheep. Vet. Clin. N. Am. Food Anim. Pract. 27, 175-186. Scott, P.R. (2012) Clinical, ultrasonographic and pathological description of bladder distension with consequent hydroureters, severe hydronephrosis and perirenal fluid accumulation in two rams putatively ascribed to pelvic nerve dysfunction. Small Rumin. Res. 107, 45-48. Scott, P.R. (2017a) Abdominal ultrasonography as an adjunct to clinical examination in sheep. Small Rumin. Res. THIS ISSUE. Scott, P.R. (2017b) Thoracic ultrasonography as an adjunct to clinical examination in sheep. Small Rumin. Res. THIS ISSUE.
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