History
A 21-month-old neutered male Toy Poodle was evaluated for acute onset of signs of left hind limb lameness and pain upon manipulation of the left hip joint. There was no known incidence of trauma; however, the dog had a history of jumping from high objects.
At 9 months of age, the dog had been evaluated for chronic shifting limb lameness, signs of pain in the cervical and lumbar regions of the vertebral column, and generalized hind limb paresis. Bilateral medial patellar luxation was diagnosed, and panosteitis was suspected. The lameness and orthopedic pain had been responsive to treatment with an NSAID, and the dog received a low dose of meloxicam PO daily. Within the last year, the dog had been evaluated multiple times for lethargy, anorexia, and melena. During these visits, results of diagnostic testing (abdominal ultrasonography, CBC, and serum biochemical analysis) revealed no clinically relevant abnormalities.
Findings on physical examination were unremarkable. The dog was lame on the left hind limb during gait analysis. A pain response was appreciated upon manipulation of the left hip joint. A ventrodorsal radiographic view of the pelvis was obtained (Figure 1). An orthogonal view of the pelvis was not obtained because the dog had signs of pain during manipulation.
Ventrodorsal radiographic view of the pelvis of a 21-month-old neutered male Toy Poodle evaluated because of acute onset of signs of left hind limb lameness and pain upon manipulation of the left hip joint.
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Ventrodorsal radiographic view of the pelvis of a 21-month-old neutered male Toy Poodle evaluated because of acute onset of signs of left hind limb lameness and pain upon manipulation of the left hip joint.
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Ventrodorsal radiographic view of the pelvis of a 21-month-old neutered male Toy Poodle evaluated because of acute onset of signs of left hind limb lameness and pain upon manipulation of the left hip joint.
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Radiographic Findings and Interpretation
Sclerosis is observed within the medullary cavities of the long bones and is silhouetting with the endosteal surfaces of the cortices in some locations (Figure 2). Three pelvic fractures are appreciated. A minimally displaced fracture of the left pubis, a greenstick fracture of the left ischium, and a fracture of the central acetabulum with medial and caudal displacement are observed. There is no appreciable bone remodeling or callus formation associated with the fractures. A supplemental radiographic image of the proximal aspect of the left humerus reveals diffuse sclerosis and increased opacity of the ribs and sternebrae (Figure 3). The proximal physis of the humerus remains open; the importance of this delayed physeal closure is unknown. Radiographic findings are most consistent with osteopetrosis; the fractures are most likely pathological.
Same ventrodorsal radiographic view as in Figure 1. Sclerosis is observed diffusely throughout the pelvis, vertebrae, and long bones (thin arrows). Pelvic fractures of the left ischium, pubis, and acetabulum are also appreciated (wide arrows).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Same ventrodorsal radiographic view as in Figure 1. Sclerosis is observed diffusely throughout the pelvis, vertebrae, and long bones (thin arrows). Pelvic fractures of the left ischium, pubis, and acetabulum are also appreciated (wide arrows).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Same ventrodorsal radiographic view as in Figure 1. Sclerosis is observed diffusely throughout the pelvis, vertebrae, and long bones (thin arrows). Pelvic fractures of the left ischium, pubis, and acetabulum are also appreciated (wide arrows).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Lateral radiographic view of the left humerus of the same dog as in Figure 1. Sclerosis is appreciated within the medullary cavities and throughout the ribs and sternebrae (thin arrows). The proximal humeral physes remain open (wide arrow).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Lateral radiographic view of the left humerus of the same dog as in Figure 1. Sclerosis is appreciated within the medullary cavities and throughout the ribs and sternebrae (thin arrows). The proximal humeral physes remain open (wide arrow).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Lateral radiographic view of the left humerus of the same dog as in Figure 1. Sclerosis is appreciated within the medullary cavities and throughout the ribs and sternebrae (thin arrows). The proximal humeral physes remain open (wide arrow).
Citation: Journal of the American Veterinary Medical Association 236, 3; 10.2460/javma.236.3.287
Comments
Osteopetroses are a heterogeneous collection of skeletal disorders in which abnormal osteoclast function results in decreased bone resorption and increased bone density.1,2 Radiographic abnormalities include osteosclerosis with a classic marbled bone-in-bone appearance, a poorly demarcated marrow cavity, abnormally shaped bones as a result of decreased remodeling ability, and a predisposition to pathological fracture.1,2 In addition, a narrowed marrow cavity, as seen in severely affected individuals, may result in decreased marrow production of all cell lines and extramedullary hematopoiesis.2–4 Less commonly appreciated are renal, neurologic, and ophthalmic abnormalities.2
Osteopetrosis has been rarely reported in domestic veterinary species. The recommended diagnostic tests for suspected osteopetrosis include survey radiography to evaluate bone density, bone biopsy to evaluate histologic structure, CBC to evaluate hematopoiesis, serum biochemical analysis to evaluate renal function, and abdominal ultrasonography to evaluate splenic and renal architecture. There are no proposed treatment recommendations for the osteopetroses of domestic animals. Lifestyle modification to minimize traumatic risk should be attempted. Frequent transfusions and treatment of renal disease may be required in severe disease.3 Periodic reassessment of diagnostic findings may be required, and recommendations should be based on the severity of the disease.3
In the dog of this report, osteopetrosis was diagnosed via single radiographic views of the pelvis and left humerus; these views were obtained at the time of initial evaluation at the emergency service and the owners declined additional diagnostic testing after the initial consultation. Although medullary sclerosis and increased bone density were apparent on these single radiographic views of the pelvis and left humerus, optimal diagnostic testing should normally include orthogonal views. With consideration of the risks of bone biopsy and fracture repair, the owners of the dog of this report elected to address the dog's fractures with cage rest and pain medications. The dog, which had no hematopoietic or visceral abnormalities, has reportedly done well, and additional assessment and further diagnostic testing have not been performed.
- 1.
Johnson KA, Watson ADJ. Skeletal diseases. In: Ettinger S, Feldman EC, eds. The textbook of veterinary internal medicine. 6th ed. St Louis: Elsevier Inc, 2005;1972.
- 4.
Scrugs DW, Fleming SA, Maslin WR, et al. Osteopetrosis, anemia, thrombocytopenia, and marrow necrosis in beef calves naturally infected with bovine virus diarrhea virus. J Vet Diagn Invest 1995;7:555–559.
