Suspected panosteitis in a camel

David G. Levine Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by David G. Levine in
Current site
Google Scholar
PubMed
Close
 DVM
,
Jennifer J. Smith Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Jennifer J. Smith in
Current site
Google Scholar
PubMed
Close
 DVM, DACVS
,
Dean W. Richardson Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Dean W. Richardson in
Current site
Google Scholar
PubMed
Close
 DVM, DACVS
,
Valerie Brown Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Valerie Brown in
Current site
Google Scholar
PubMed
Close
 DVM
,
Jill Beech Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Jill Beech in
Current site
Google Scholar
PubMed
Close
 DVM, DACVIM
,
Perry Habecker Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Perry Habecker in
Current site
Google Scholar
PubMed
Close
 VMD, DACVP
, and
Emma Adam Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348-1692.

Search for other papers by Emma Adam in
Current site
Google Scholar
PubMed
Close
 BVetMed

Abstract

Case Description—A 6-month-old male Bactrian camel was examined because of a 3-week history of lameness of the left hind limb.

Clinical Findings—Lameness was initially detected in the left hind limb but resolved and was detected in the right hind limb during treatment. Lameness increased during periods of rapid growth. Radiography revealed multiple small opacities of the medullary cavity of several long bones throughout treatment. Core bone biopsies of lesions in the tibiae revealed lamellar bone with areas of loose connective tissue, osteoblasts in the medullary cavity, and periosteal new bone formation, all which were consistent with panosteitis.

Treatment and Outcome—Palliative treatment was attempted with epidural and transdermal administration of analgesics. Flunixin meglumine was administered PO, which coincided with an abrupt increase in serum creatinine concentration. Performance of multiple diagnostic bone biopsies led to remission of clinical signs of pain.

Clinical Relevance—Panosteitis should be a differential diagnosis for shifting limb lameness in young camels. Bone biopsies can be useful for diagnosis of panosteitis and possible relief of pain associated with the disease. Bactrian camels may be susceptible to the renal toxicity of flunixin meglumine, especially when dehydrated.

Abstract

Case Description—A 6-month-old male Bactrian camel was examined because of a 3-week history of lameness of the left hind limb.

Clinical Findings—Lameness was initially detected in the left hind limb but resolved and was detected in the right hind limb during treatment. Lameness increased during periods of rapid growth. Radiography revealed multiple small opacities of the medullary cavity of several long bones throughout treatment. Core bone biopsies of lesions in the tibiae revealed lamellar bone with areas of loose connective tissue, osteoblasts in the medullary cavity, and periosteal new bone formation, all which were consistent with panosteitis.

Treatment and Outcome—Palliative treatment was attempted with epidural and transdermal administration of analgesics. Flunixin meglumine was administered PO, which coincided with an abrupt increase in serum creatinine concentration. Performance of multiple diagnostic bone biopsies led to remission of clinical signs of pain.

Clinical Relevance—Panosteitis should be a differential diagnosis for shifting limb lameness in young camels. Bone biopsies can be useful for diagnosis of panosteitis and possible relief of pain associated with the disease. Bactrian camels may be susceptible to the renal toxicity of flunixin meglumine, especially when dehydrated.

A6-month-old male Bactrian camel (Camelus bactrianus) was examined during winter at the George D. Widener Hospital for Large Animals at the University of Pennsylvania's New Bolton Center because of a 3-week history of lameness of the left hind limb. The captiveborn camel had been acquired by the owner at 1 month of age from a local breeder. Diet consisted of goat's milk with vitamin C until 5 months of age, at which time diet was changed to a commercial lactating alpaca feed, grass hay grown on the property, and pasture. Prior to indoor confinement for the recent onset of lameness, the camel was allowed free access to pasture and water. The camel was pastured with several other healthy Bactrian camels. Initially, the left hind limb lameness was localized to the pastern region, and the camel was treated by the owner with orally administered ibuprofen (unknown dose) for its anti-inflammatory and analgesic effects. However, 1 week prior to evaluation, a large firm mass appeared on the dorsal aspect of the proximal third of the left metatarsus. As a result of the persistent lameness and the appearance of the mass, the camel was referred to New Bolton Center for further evaluation and treatment.

On physical examination, the camel appeared to be in poor body condition and weighed 195 kg (429 lb). Warm, firm, 3 × 4 × 3-cm oval swellings were on the dorsal aspect of the proximal third of the left metatarsus and on the lateral aspect of the mid-diaphyseal region of the left tibia. Deep palpation of both areas elicited signs of pain or discomfort. Digital radiography of the left metatarsus was performed and revealed diffuse, patchy, intramedullary opacities in the diaphyseal and metaphyseal regions and endosteal thickening and periosteal proliferation (Figure 1). A similar radiographic finding was observed in the medullary cavity of the left tibia. Digital radiography of the right metatarsus (Figure 2), tibia, and thorax did not reveal abnormalities.

Figure 1—
Figure 1—

Dorsoplantar radiographic view of the left metatarsal region of a camel with suspected panosteitis. Notice increased opacity in the medullary cavity (arrows).

Citation: Journal of the American Veterinary Medical Association 231, 3; 10.2460/javma.231.3.437

Figure 2—
Figure 2—

Dorsoplantar radiographic view of the right metatarsal region of the camel in Figure 1. Notice the normal appearance of the medullary cavity.

Citation: Journal of the American Veterinary Medical Association 231, 3; 10.2460/javma.231.3.437

Differential diagnoses for the clinical signs and radiographic findings included panosteitis, nutritional osteopathy, metabolic bone disease, endocrinopathy, neoplasia, and fungal or bacterial osteomyelitis. Hematologic analysis revealed no abnormalities other than hyperfibrinogenemia (1,000 mg/dL; reference range, 100 to 500 mg/dL). No abnormalities were detected via serum biochemical analyses; however, the serum creatinine (1.7 mg/dL; reference range, 1.4 to 1.7 mg/dL) concentration was at the upper limit of the reference range. Both serum calcium (9.93 mg/dL [reference range, 7.88 to 10.04 mg/dL]) and phosphorus (6.53 mg/dL [reference range, 6.22 to 7.89 mg/dL]) concentrations were within Bactrian camel reference ranges,1 which made metabolic disorders less likely. Nutritional disorders were unlikely because other healthy Bactrian camels were located and raised on the property. To assist in further defining the osseous lesion, core biopsy of the left metatarsus was recommended.

The camel was placed in standing stocks, and the subcutaneous tissue on the dorsal, mid-diaphyseal region of the left metatarsus was infiltrated with 10 mL of 2% mepivacaine hydrochloride. An 8-gauge bone marrow biopsy needlea was used to obtain a core bone specimen through the area of greatest radiopacity in the medullary cavity. The bone specimen was submitted for aerobic and anaerobic bacterial and fungal cultures as well as histologic examination. A bone marrow aspirate was submitted for cytologic examination.

Until results of the bone specimen tests were available, treatment consisted of administration of flunixin meglumine (0.5 mg/kg [0.23 mg/lb], PO, q 24 h) for its anti-inflammatory and analgesic properties. Although the camel's lameness improved substantially (noted by increased time standing and decreased reluctance to ambulate) following administration of the initial dose of flunixin meglumine, within 24 hours, the serum creatinine concentration was increased (2.67 mg/dL), and after 72 hours, the camel became moderately azotemic (5.84 mg/dL). Free catch urinalysis revealed proteinuria and occasional granular casts. Treatment with flunixin meglumine was discontinued after a second dose, and a balanced electrolyte fluidb was administered IV (20-L bolus followed by 0.05 mL/kg/min [0.023 mL/lb/min]).

Histologic examination of the core biopsy specimen of the left metatarsus revealed marked periosteal new bone formation. Normal bone architecture was difficult to detect in the cortical and medullary regions. Cytologic examination of the bone marrow aspirate revealed few progenitor cells and was reported as a hemodiluted sample. No neoplastic cells or infectious organisms were observed, and the bacterial and fungal cultures yielded no growth.

Three days after the bone biopsy was performed, the camel became less lame in the left hind limb and serum fibrinogen concentration began to decrease (657 mg/dL). Serial creatinine concentrations remained high (mean, 5.40 mg/dL) during hospitalization. Repeat urinalysis samples yielded no abnormal findings. Despite recommendations for further fluid therapy, the owner chose to have the camel discharged with additional instructions for continued rest and periodic monitoring of fibrinogen and creatinine concentrations. Two weeks after discharge, the owner reported that the camel was gaining weight and bearing more weight on the left hind limb, and the serum creatinine concentration had decreased (1.8 mg/dL) to near reference range.

The camel was readmitted to the hospital 3 weeks after discharge because of acute onset of lameness in the right hind limb, anorexia, and signs of depression. The camel had lost weight (190 kg [418 lb]), was non-weight bearing on the right hind limb, and had evidence of discomfort with deep palpation over the middiaphyseal region of the right tibia. Hematologic and serum biochemical analysis indicated azotemia (serum creatinine concentration, 3.0 mg/dL) and hyperfibrinogenemia (972 mg/dL). Blood samples were submitted for determinations of parathyroid hormone, vitamin D, 1,25-hydroxycholecalciferol, and ionized calcium concentrations. Results of these tests were considered within reference ranges, compared with reported values for Bactrian camels,1 although no reference ranges for Bactrian camels were available in this laboratory. Digital radiographic examination of both tibiae revealed changes similar to those previously seen in the left tibia, with multiple intramedullary opacities localized to the middiaphyseal regions of both tibiae with overlying periosteal proliferation (Figure 3).

Figure 3—
Figure 3—

Lateral radiographic views of the left (left image) and the right (right image) tibiae of the camel in Figure 1. Notice increased opacity in the medullary cavities of both tibiae (arrows). LH = Left hind. RH = Right hind.

Citation: Journal of the American Veterinary Medical Association 231, 3; 10.2460/javma.231.3.437

Treatment for the camel at this time consisted of a continuous rate infusion of lidocaine (1.5 mg/kg [0.68 mg/lb], IV, loading dose; 0.05 mg/kg/min [0.02 mg/ lb/min], maintenance), butorphanol (0.05 mg/kg, IV, q 3 h), and a continuous rate IV infusion of a balanced electrolyte solution (150 mL/h). Despite this treatment, the camel remained lame and anorectic. An epidural catheterc was placed for instillation of morphine sulfate (0.1 mg/kg [0.045 mg/lb], q 6 h) with bupivacaine (0.1%), with minimal improvement in the lameness. The camel received transfaunation with rumen contents from a donor cow. The camel's appetite was mildly improved.

Because of the perceived clinical improvement subsequent to core biopsy of the left metatarsus and reports of decreased lameness after bone biopsies in dogs with panosteitis, and to assist in further definition of the multicentric lesions, a core bone biopsy of the right tibia was recommended. The camel was placed in standing stocks, and the most proximal aspect of the middiaphyseal region of the right tibia was anesthetized via local infiltration with 10 mL of 2% mepivacaine hydrochloride. A 5/16-inch trephined was used to take several larger specimens of bone than were obtained previously by use of the 8-gauge biopsy needle in the left metatarsus. The bone specimens were submitted for histologic examination of calcified and decalcified sections, which revealed periosteal new bone formation with no inflammatory cells. The cortical bone was thicker in the region of the medullary lesions, but within normal limits. The medullary bone contained lamellar bone with areas of loose connective tissue and osteoblasts. These findings were also consistent with a diagnosis of panosteitis.

The epidural catheter was maintained in place for 10 days, during which lameness improved. After removal of the epidural catheter, fentanyle patches (100 μg/h) were used for analgesia for 4 days prior to discharge. Fentanyl patches were changed every 48 hours and were placed on the lateral aspect of the right forelimb. Intravenous administration of fluids was slowly decreased and discontinued once serum creatinine concentration returned to reference range. The camel seemed to be comfortable on all 4 limbs and returned to its previous weight of 195 kg. The camel was discharged from the hospital after 14 days of treatment with recommendations to provide strict stall rest and continued treatment with transdermal fentanyl patches as needed for analgesia. Three months after discharge, the camel was reportedly sound and had gained weight (276 kg [607 lb]).

The camel was evaluated a third time 4 months after the previous discharge with acute onset of lameness in the left hind limb, anorexia, and signs of depression. The owners reported that the camel had recently undergone a large growth spurt (approx 4 inches of height) and had become lame during that accelerated growth period. At the time of readmission, the camel had lost weight (236 kg [519 lb]), and deep palpation over the left tibia caused signs of discomfort. Digital radiographic examination of both tibiae revealed partial resolution of the prior radiographic findings in both tibiae. Nuclear scintigraphic evaluation was performed. On delayed-phase bone images, focal, intense, increased radiopharmaceutical uptake was evident in the medullary cavities of the left tibia and both metatarsi (Figure 4). Because the biopsy procedures seemed to provide some relief of signs of discomfort on prior occasions, the camel was once again placed in standing stocks for a bone biopsy. After local infiltration with 10 mL of 2% mepivacaine hydrochloride, a 5/16-inch trephined was used to take several large specimens of bone from the left tibia, which was the suspected site of discomfort on the basis of physical and nuclear scintigraphic examinations.

Figure 4—
Figure 4—

Lateral delayed-phase nuclear scintigraphic images of the left (left image; cranial is to the left of the image) and right (right image; cranial is to the right of the image) hind limbs. Notice the increased radiopharmaceutical uptake of the left tibia and both metatarsi (arrows). See Figure 3 for key.

Citation: Journal of the American Veterinary Medical Association 231, 3; 10.2460/javma.231.3.437

The camel remained in the hospital for 6 days. Fentanyle patches (100 μg/h) were again used for analgesia. The camel appeared to become comfortable within 24 hours of the biopsy, and its appetite and demeanor improved. Four months after discharge, the camel was reportedly sound and had gained weight (409 kg [900 lb]) despite 2 more reported periods of accelerated growth.

Discussion

Although panosteitis is described in dogs, it has not been previously reported in camelids to our knowledge. The diagnosis in this camel was made on the basis of the close resemblance of the disease process to that described for panosteitis in dogs, as well as by exclusion of other differential diagnoses. The clinical signs and radiographic findings did not support a diagnosis of nutritional or metabolic disease, and the serum calcium, phosphorus, vitamin D, and intact parathyroid hormone concentrations were within reference ranges. Neoplasia was excluded by the absence of neoplastic cells in the biopsy and aspirate specimens and by the camel's recovery.

Panosteitis in dogs typically occurs in young, largebreed, or giant-breed dogs.2-5 Dogs affected with panosteitis usually have acute, intermittent, shifting-limb lameness, and signs of pain on deep palpation are often detected via physical examination. Radiographic findings consist of 3 phases. The first phase consists of increased opacity of the medullary cavity and accentuated trabecular pattern around the nutrient foramen in long bones.2,3 As the disease progresses, further mottling and increased opacity are seen in the medullary cavity, as well as cortical and periosteal thickening.3 As the disease resolves, the radiographic appearance of the bone gradually returns to normal, although some abnormalities can be detected for months after clinical signs have abated.2,4 The disease is spontaneous and self-limiting with no definitive etiology. Treatment consists of exercise restriction and anti-inflammatory drugs to help control pain. Remission is usually complete by 2 years of age or less. Vascular abnormalities, viral disease, and genetic factors have been suggested as potential causes of the disease.2-5

A similar radiographic disease has been reported in horses. Lesions described as enostosis-like have been described and are similar to those of panosteitis in dogs.6-9 Enostosis-like lesions are commonly found in adult horses with or without clinical evidence of lameness. The etiology of this process is also unknown. These lesions are often detected via delayedphase nuclear scintigraphic examination.7 The disease has a similar radiographic appearance to panosteitis in dogs, although horses rarely have cortical or periosteal involvement.6 Thus, without cortical or periosteal involvement, the term enostosis, which is defined as any mass of proliferating bone in the medullary cavity,10 is used to describe the disease. Enostosis is also self-limiting when lameness is associated, because this usually resolves with stall rest and administration of nonsteroidal anti-inflammatory drugs.

The clinical disease process described in the camel of this report more closely resembled panosteitis in dogs than enostosis-like lesions. The camel was a young, fast-growing animal with severe shifting-limb lameness. Radiographic lesions were similar to those described for dogs with medullary, cortical, and periosteal involvement. The camel had signs of depression, weight loss, and anorexia, all of which have been seen in dogs with panosteitis. Histopathologic findings in the camel's bones were consistent with those described for dogs, with increased osteoblast numbers and fibrosis and lamellar bone in the medullary cavity.2-4 The cortical thickening and periosteal reaction with new bone formation in the camel's bones closely resembled histopathologic descriptions in canine panosteitis. However, the scintigraphic findings in this camel were similar to those typically seen in horses with enostosis-like lesions, with the most intense areas of increased radio-pharmaceutical uptake localized to the medullary cavities of the long bones of the appendicular skeleton.

Anecdotally, camels are extremely susceptible to nephrotoxic drugs.11,12 A notion that camels recirculate blood more than other species to allow better conservation of water has been proposed but has no supportive scientific evidence.11 In this case, because of reports of susceptibility to nephrotoxic drugs, the camel initially received a low dose of flunixin meglumine. After 2 doses, the camel became azotemic and proteinuric, and casts were detected on urinalysis. The camel was administered balanced electrolyte solution IV when the serum creatinine concentration did not rapidly decrease after administration of flunixin meglumine was discontinued. Although no further evidence of renal damage was detected and the serum creatinine returned to reference range over time, this response to this medication may provide some supportive evidence that Bactrian camels are susceptible to the nephrotoxic effect of flunixin meglumine.13 Camels are adapted to dehydration and subclinical dehydration, and renal hypoperfusion can be easily missed. It is possible that the camel in this report was subclinically dehydrated and not truly susceptible to the nephrotoxicity of flunixin meglumine. Administration of flunixin meglumine to camels should be avoided if subclinical dehydration or cachexia may exist. If this medication is indicated, careful monitoring of serum creatinine concentration and urinalysis are advised.

a.

TrapLok bone marrow aspiration needle, Jorgensen Laboratory Inc, Loveland, Colo.

b

Normosol-R, Abbott Laboratories, Abbott Park, Ill.

c

Perifex epidural anesthesia set, Braun, Bethlehem, Pa.

d

Michele trephine 5/16, Miltex Instrument Co Inc, Bethpage, NY.

e

Fentanyl transdermal system, Mylan, Morgantown, WV.

References

  • 1

    Zongping L. Studies on rickets and osteomalacia in Bactrian camels. Vet J 2005;169:444453.

  • 2

    Bohning R, Suter P & Hohn R, et al. Clinical and radiologic survey of canine panosteitis. J Am Vet Med Assoc 1970;156:870883.

  • 3

    Lenehan TM, VanSickle DC, Biery DN. Canine panosteitis. In:Newton DN, Nunamaker DM, ed.Textbook of small animal orthopaedics. Philadelphia: JB Lippincott Co, 1985;591596.

    • Search Google Scholar
    • Export Citation
  • 4

    Turnier J, Silverman S. A case study of canine panosteitis: comparison of radiographic and radioisotopic studies. Am J Vet Res 1978;39:15501552.

    • Search Google Scholar
    • Export Citation
  • 5

    Johnson K, Allan G. Panosteitis in a cocker spaniel dog. Aust Vet J 1982;58:153155.

  • 6

    Bassage LH, Ross MW. Enostosis-like lesions in the long bones of 10 horses: scintigraphic and radiographic features. Equine Vet J 1998;30:3542.

    • Search Google Scholar
    • Export Citation
  • 7

    Dyson SJ. Radiography and radiology. In:Ross MW, Dyson SJ, ed.Diagnosis and management of lameness in the horse. Philadelphia: WB Saunders Co, 2003;153166.

    • Search Google Scholar
    • Export Citation
  • 8

    Jones E, McDiarmid A. Multiple enostosis-like lesions in a racing Thoroughbred. Equine Vet Educ 2005;17:9295.

  • 9

    Ramzan P. Equine enostosis-like lesions: 12 cases. Equine Vet Educ 2002;14:143148.

  • 10

    Dorland WA. Dorland's illustrated medical dictionary. 28th ed. Philadelphia: WB Saunders Co, 1994;1994

  • 11

    Basic camel medicine tips. Available at: www.allcamels.com/articles/basiccamelmedicinetips.html. Accessed Dec 3, 2006.

  • 12

    Goumi B, Robins SP & De LaFarge F, et al. Water restriction and bone metabolism in camels. Reprod Nutr Dev 1996;36:545554.

  • 13

    Wasfi I, Boni N & AbdelHadi A, et al. Pharmacokinetics, metabolism and urinary detection time of flunixin after intravenous administration in camels. J Vet Pharmacol Ther 1998;21:203208.

    • Search Google Scholar
    • Export Citation
  • Figure 1—

    Dorsoplantar radiographic view of the left metatarsal region of a camel with suspected panosteitis. Notice increased opacity in the medullary cavity (arrows).

  • Figure 2—

    Dorsoplantar radiographic view of the right metatarsal region of the camel in Figure 1. Notice the normal appearance of the medullary cavity.

  • Figure 3—

    Lateral radiographic views of the left (left image) and the right (right image) tibiae of the camel in Figure 1. Notice increased opacity in the medullary cavities of both tibiae (arrows). LH = Left hind. RH = Right hind.

  • Figure 4—

    Lateral delayed-phase nuclear scintigraphic images of the left (left image; cranial is to the left of the image) and right (right image; cranial is to the right of the image) hind limbs. Notice the increased radiopharmaceutical uptake of the left tibia and both metatarsi (arrows). See Figure 3 for key.

  • 1

    Zongping L. Studies on rickets and osteomalacia in Bactrian camels. Vet J 2005;169:444453.

  • 2

    Bohning R, Suter P & Hohn R, et al. Clinical and radiologic survey of canine panosteitis. J Am Vet Med Assoc 1970;156:870883.

  • 3

    Lenehan TM, VanSickle DC, Biery DN. Canine panosteitis. In:Newton DN, Nunamaker DM, ed.Textbook of small animal orthopaedics. Philadelphia: JB Lippincott Co, 1985;591596.

    • Search Google Scholar
    • Export Citation
  • 4

    Turnier J, Silverman S. A case study of canine panosteitis: comparison of radiographic and radioisotopic studies. Am J Vet Res 1978;39:15501552.

    • Search Google Scholar
    • Export Citation
  • 5

    Johnson K, Allan G. Panosteitis in a cocker spaniel dog. Aust Vet J 1982;58:153155.

  • 6

    Bassage LH, Ross MW. Enostosis-like lesions in the long bones of 10 horses: scintigraphic and radiographic features. Equine Vet J 1998;30:3542.

    • Search Google Scholar
    • Export Citation
  • 7

    Dyson SJ. Radiography and radiology. In:Ross MW, Dyson SJ, ed.Diagnosis and management of lameness in the horse. Philadelphia: WB Saunders Co, 2003;153166.

    • Search Google Scholar
    • Export Citation
  • 8

    Jones E, McDiarmid A. Multiple enostosis-like lesions in a racing Thoroughbred. Equine Vet Educ 2005;17:9295.

  • 9

    Ramzan P. Equine enostosis-like lesions: 12 cases. Equine Vet Educ 2002;14:143148.

  • 10

    Dorland WA. Dorland's illustrated medical dictionary. 28th ed. Philadelphia: WB Saunders Co, 1994;1994

  • 11

    Basic camel medicine tips. Available at: www.allcamels.com/articles/basiccamelmedicinetips.html. Accessed Dec 3, 2006.

  • 12

    Goumi B, Robins SP & De LaFarge F, et al. Water restriction and bone metabolism in camels. Reprod Nutr Dev 1996;36:545554.

  • 13

    Wasfi I, Boni N & AbdelHadi A, et al. Pharmacokinetics, metabolism and urinary detection time of flunixin after intravenous administration in camels. J Vet Pharmacol Ther 1998;21:203208.

    • Search Google Scholar
    • Export Citation

Advertisement