History
A 4-year-old nonpregnant Angus cow was evaluated for mastitis, anorexia, weight loss, intermittent fever, and clinical signs of recurring sepsis of 3 months' duration. The referring veterinarian had administered antimicrobials several times via an intramammary route. Abnormal physical examination findings included poor body condition (body condition score, 3/9),1 pyrexia (40°C [104°F]), mild dehydration, prolonged capillary refill time, and pale mucous membrane color. The cow had tachycardia (80 to 90 beats/min), but no heart murmur was detected. Echocardiography was performed (Figure 1).
Long- (A) and short-axis (B) echocardiograms obtained from a 4-year-old cow evaluated for mastitis, anorexia, weight loss, intermittent fever, and clinical signs of recurring sepsis of 3 months' duration. Echocardiograms were obtained from the right cardiac window in the left ventricular outflow tract position at a depth of 24 cm (A) and the left ventricular position at a depth of 22 cm (B), respectively. RV = Right ventricle. LV = Left ventricle.
Citation: Journal of the American Veterinary Medical Association 228, 1; 10.2460/javma.228.1.37
Diagnostic Imaging Findings and Interpretation
The tricuspid valve is thick, and vegetative proliferations are evident (Figure 2). Differential diagnoses for these ultrasonographic findings included any degenerative or inflammatory (bacterial or viral endocarditis, non-septic valvulitis) condition of the tricuspid valve.
Same echocardiograms as in Figure 1. Notice the thick and irregular tricuspid valve with vegetative proliferations (demarcated by the dotted line), compatible with tricuspid valve endocarditis.
Citation: Journal of the American Veterinary Medical Association 228, 1; 10.2460/javma.228.1.37
Comments
Complete echocardiographic examination is extremely useful in the evaluation of cows with suspected cardiovascular disease.2 In the cow of this report, 2-dimensional echocardiography with a 4.0-MHz curved (convex) linear transducer revealed a thick tricuspid valve with vegetative proliferations. However, no other cardiovascular abnormalities such as tricuspid valve regurgitation (assessed via color flow Doppler echocardiography) or clinical signs of congestive heart failure (subcutaneous edema, ascites, systolic jugular venous pulsations, and mammary vein distension) were observed. The tricuspid valve is the most common location of bacterial endocarditis in cows, although other valves may also be affected.3,4 In the cow of this report, abnormalities detected on CBC and serum biochemical analyses included hyperglobulinemia, hyperfibrinogenemia, anemia, and neutrophilia, which also supported a diagnosis of valvular endocarditis.2
The source of infection should be determined in all cattle in which bacterial endocarditis is suspected by obtaining a thorough history and performing a complete physical examination. Chronic mastitis, chronic metritis, traumatic reticuloperitonitis, and musculoskeletal abscess formation or cellulitis are potential sources of bacteremia.3 In the cow of this report, the udder was a likely source of infection.
Bacteriologic culture of blood obtained during febrile episodes confirmed the existence of septicemia caused by Streptococcus spp and Staphylococcus aureus, which was compatible with the diagnosis of endocarditis. Actinomyces pyogenes and α-hemolytic streptococci are the most common organisms identified on bacteriologic culture of blood obtained from cattle with bacterial endocarditis, although various pathogens have been reported.3,5,6
In general, the prognosis for cattle with bacterial endocarditis is guarded to poor. Valvular incompetence, low-grade anemia, and high serum total globulin concentration have been associated with a poor prognosis.3 In the cow of this report, valvular regurgitation was not detected, but the cow was anemic and hyperglobulinemic. A poor prognosis was given; however, because the genetic value of this cow was high, the owner chose to pursue treatment.
Treatment of bacterial endocarditis is aimed at eliminating the infection by use of antimicrobials for a long duration. Intensive antimicrobial treatment was administered on the basis of results of bacteriologic culture of blood and susceptibility testing.
The cow died suddenly after a month of treatment. Necropsy findings included pulmonary thromboembolism and septic shock (widespread hemorrhages compatible with disseminated intravascular coagulation). Necropsy findings also confirmed the diagnosis of tricuspid valve endocarditis.
Echocardiography is the most reliable noninvasive diagnostic technique for cardiac evaluation in cows in which valvular endocarditis is suspected because no other diagnostic imaging techniques such as radiography can evaluate valvular abnormalities. In the cow of this report, it would have been difficult to reach an antemortem diagnosis of tricuspid valve endocarditis without the use of echocardiography.
- 1↑
Tennant CJ, Spitzer JC, Bridges WC, et al. Weight necessary to change body condition scores in Angus cows. J Anim Sci 2002;80:2031–2035.
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Reef VB, McGuirk SM. Diseases of the cardiovascular system. In: Smith BP, ed. Large animal internal medicine. 3rd ed. Philadelphia: CV Mosby Co, 2002;443–478.
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Power HT, Rebhun WC. Bacterial endocarditis in adult dairy cattle. J Am Vet Med Assoc 1983;182:806–808.
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Yamaga Y, Too K. Echocardiographic detection of bovine cardiac diseases. Jpn J Vet Res 1986;34:251–267.
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Dowling PM, Tyler JW. Diagnosis and treatment of bacterial endocarditis in cattle. J Am Vet Med Assoc 1994;204:1013–1016.
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Sailler L, Partensky J, Marchou B, et al. Bovine endocarditis. Rev Med Interne 2000;21:322s–325s.
