Medical management of an osseous sequestrum in an alpaca cria

Rachel E. Oman From the Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.

Search for other papers by Rachel E. Oman in
Current site
Google Scholar
PubMed
Close
 DVM, MS
,
Pamela R. F. Adkins From the Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.

Search for other papers by Pamela R. F. Adkins in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
, and
Shannon K. Reed From the Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211.

Search for other papers by Shannon K. Reed in
Current site
Google Scholar
PubMed
Close
 DVM, MS

Click on author name to view affiliation information

Abstract

CASE DESCRIPTION

A 2-month-old 12.0-kg (26.4-lb) sexually intact male alpaca was evaluated for a 1-week history of progressive forelimb lameness with no known history of trauma.

CLINICAL FINDINGS

The cria had toe-touching lameness in the right forelimb with a firm swelling at the distal dorsomedial metacarpal region. Signs of pain were elicited on palpation of the swollen region. There was no associated wound or draining tract. Radiographic examination revealed soft tissue swelling and osteomyelitis of the distal portion of the third metacarpal bone with a possible medial cortical sequestrum.

TREATMENT AND OUTCOME

The cria was hospitalized and treated with meloxicam (1 mg/kg [0.45 mg/lb], PO, q 72 h) and ceftiofur sodium administered SC (2.2 mg/kg [1 mg/lb], q 12 h for 8 days) and by means of regional limb perfusion (1.25 mg/kg [0.57 mg/lb], IV, q 48 h for 8 days). Lameness and swelling improved, and the cria was discharged from the hospital with meloxicam (1 mg/kg, PO, q 72 h for 2 weeks) and ceftiofur crystalline free acid (1.5 mg/kg [0.68 mg/kg], SC, q 5 d for 2 weeks). At a recheck examination 17 days later, there was radiographic evidence of a well-defined 3.4 × 0.3-cm osseous sequestrum in the distal aspect of the affected third metacarpal bone. The owner declined further treatment and elected to monitor the cria at home. One year later, radiographic examination revealed nearly complete resolution of the sequestrum.

CLINICAL RELEVANCE

Results for this patient suggested that osseous sequestra in some camelids may resolve following medical treatment without surgical intervention.

Abstract

CASE DESCRIPTION

A 2-month-old 12.0-kg (26.4-lb) sexually intact male alpaca was evaluated for a 1-week history of progressive forelimb lameness with no known history of trauma.

CLINICAL FINDINGS

The cria had toe-touching lameness in the right forelimb with a firm swelling at the distal dorsomedial metacarpal region. Signs of pain were elicited on palpation of the swollen region. There was no associated wound or draining tract. Radiographic examination revealed soft tissue swelling and osteomyelitis of the distal portion of the third metacarpal bone with a possible medial cortical sequestrum.

TREATMENT AND OUTCOME

The cria was hospitalized and treated with meloxicam (1 mg/kg [0.45 mg/lb], PO, q 72 h) and ceftiofur sodium administered SC (2.2 mg/kg [1 mg/lb], q 12 h for 8 days) and by means of regional limb perfusion (1.25 mg/kg [0.57 mg/lb], IV, q 48 h for 8 days). Lameness and swelling improved, and the cria was discharged from the hospital with meloxicam (1 mg/kg, PO, q 72 h for 2 weeks) and ceftiofur crystalline free acid (1.5 mg/kg [0.68 mg/kg], SC, q 5 d for 2 weeks). At a recheck examination 17 days later, there was radiographic evidence of a well-defined 3.4 × 0.3-cm osseous sequestrum in the distal aspect of the affected third metacarpal bone. The owner declined further treatment and elected to monitor the cria at home. One year later, radiographic examination revealed nearly complete resolution of the sequestrum.

CLINICAL RELEVANCE

Results for this patient suggested that osseous sequestra in some camelids may resolve following medical treatment without surgical intervention.

Introduction

A 2-month-old 12.0-kg (26.4-lb) sexually intact male Suri alpaca was evaluated because of a 1-week history of progressive lameness and swelling of the right forelimb. The cria was reported to be otherwise healthy with no history of abnormal behavior or prior illness. The cria's birth was unassisted, but the owner noted that the cria likely did not receive an adequate amount of colostrum. There was no known history of trauma to the limb. On physical examination, the cria was bright and alert with rectal temperature within the reference range and mildly increased heart rate (112 beats/min; reference range, 60 to 90 beats/min) and respiratory rate (36 breaths/min; reference range, 10 to 30 breaths/min). The mucous membranes were pink and moist, and the sclerae appeared normal. The cria had toe-touching lameness of the right forelimb with a firm, warm, apparently painful swelling centered at the distal dorsomedial metacarpal region and no evidence of a wound or draining tract. The limbs were deemed otherwise normal on palpation, with no other swelling and no joint effusion detected.

Radiographic examination of the affected limb revealed severe soft tissue swelling and osteomyelitis at the distal aspect of the third metacarpal bone with a suspected medial cortical sequestrum (Figure 1). The adjacent physis was radiographically normal. Given the absence of a history of trauma and high degree of suspicion for inadequate passive transfer of immunity, hematogenous osteomyelitis with possible osseous sequestration was suspected.

Figure 1
Figure 1

Dorsopalmar (A) and lateral (B) radiographic views of the right carpal, metacarpal, and phalangeal regions of a 2-month-old alpaca cria with toe-touching lameness of the right forelimb and swelling at the distal dorsomedial aspects of the right third and fourth metacarpal bones. Radiographic evidence of soft tissue swelling (white arrows) and osteomyelitis of the third metacarpal bone with a possible osseous sequestrum (black arrows) is present.

Citation: Journal of the American Veterinary Medical Association 258, 12; 10.2460/javma.258.12.1394

The cria was hospitalized, and an IV catheter was placed in the right cephalic vein to facilitate regional limb perfusion with ceftiofur sodiuma (1.25 mg/kg [0.57 mg/lb], IV, q 48 h for 8 days). A tourniquet was placed just distal to the elbow joint, and 15 mg of ceftiofur diluted in saline (0.9% NaCl) solution to a total volume of 5 mL was infused through the IV catheter. The tourniquet was removed after 30 minutes, and the catheter site was wrapped with a light bandage. Additional ceftiofura (2.2 mg/kg [1 mg/lb], SC, q 12 h for 8 days) and meloxicamb (1 mg/kg [0.45 mg/lb], PO, q 72 h) were also administered.

The lameness and swelling progressively improved during hospitalization, and the cria was discharged from the hospital after 8 days. The owner was instructed to continue the meloxicam treatment at the same dosage and administer ceftiofur crystalline free acidc (1.5 mg/kg [0.68 mg/kg], SC, q 5 d) for 2 weeks before returning the cria for recheck examination and radiography to monitor healing or maturation of the suspected sequestrum.

Seventeen days after hospital discharge, the cria was reexamined and found to be systemically healthy and minimally lame in the right forelimb. There was mild swelling over the distal metacarpal region. Radiography revealed mild soft tissue swelling and a well-defined, sharply demarcated 3.4 × 0.3-cm osseous sequestrum in the distal aspect of the third metacarpal bone (Figure 2). Sequestrectomy under general anesthesia was recommended, but the owner declined further treatment and elected to take the cria home for monitoring.

Figure 2
Figure 2

Dorsopalmar (A) and lateral (B) radiographic views of the distal aspect of the affected forelimb of the cria in Figure 1 obtained 25 days after the initial examination. Minimal soft tissue swelling and a well-defined osseous sequestrum (arrows and asterisk) are evident.

Citation: Journal of the American Veterinary Medical Association 258, 12; 10.2460/javma.258.12.1394

Approximately 1 year later, the cria was returned to the clinic as a companion to a sick herd mate. The owner reported the cria had been doing well with no recurrence of the lameness and no further treatment since discharge from the hospital 12 months earlier. No lameness, swelling, or signs of pain were observed on examination, and recheck radiographic findings were consistent with nearly complete resolution of the osseous sequestrum (Figure 3).

Figure 3
Figure 3

Dorsopalmar (A) and lateral (B) radiographic views of the distal aspect of the affected forelimb of the cria in Figure 1 obtained approximately 12 months after treatment. The findings are consistent with nearly complete resolution of the osseous sequestrum.

Citation: Journal of the American Veterinary Medical Association 258, 12; 10.2460/javma.258.12.1394

Discussion

To our knowledge, this is the first report detailing resolution of an osseous sequestrum in an alpaca cria treated with medical management alone. Previous reports1,2 of medical management of this condition without sequestrectomy in camelids are incomplete, with one animal lost to follow-up and the other lost to follow-up after the affected limb destabilized following pasture turnout. Sequestrectomy in conjunction with antimicrobial administration is recommended for treatment of osseous sequestration in camelids and horses.1,2,3,d However, medical management of acute osteomyelitis and small sequestra in cattle and horses has been successful.3,4 The successful outcome for the cria of this report suggested that medical management alone may provide long-term clinical resolution of osseous sequestration in some camelids. Some unique features of this case may have contributed to the overall success; the anatomy of camelids is such that the location of the sequestrum in the distal aspect of the third metacarpal bone allowed the limb to be supported by the fourth metacarpal bone during resorption and renewal of a substantial portion of the bone, minimizing the likelihood of acute catastrophic failure of the limb. Additionally, the lack of a draining tract in this cria negated the effects that can occur from environmental contamination. Environmental contamination can introduce additional bacteria with individual resistance patterns that frequently complicate antimicrobial selection. The early intervention with aggressive antimicrobial treatment may have contributed to the lack of subsequent development of a draining tract.

The findings for the cria of this report highlighted some of the unusual clinical features of osseous sequestration of camelids. Osteomyelitis with osseous sequestration can result from trauma, causing infection and damage to the periosteum, vascular insufficiency, or hematogenous bacterial emboli.5 In cattle and horses, osseous sequestration is commonly attributed to trauma, leading to cortical ischemia and bacterial contamination.4,5 In contrast, young crias frequently develop osseous sequestra in the absence of prior trauma, and localization of bacterial emboli is considered the likely pathogenesis.1,2,6,d Crias with osseous sequestration commonly have a history of illness or a difficult birth, which increases the likelihood of bacteremia.7,8,d Although the underlying cause of the sequestrum in the cria reported here could not be determined, the progressive lameness without trauma in conjunction with suspected failure of passive transfer of immunity from the dam increased our suspicion for prior bacteremia and hematogenous osteomyelitis.

One of the features of the case reported here that may have contributed to resolution with medical management alone was the short duration of clinical signs prior to evaluation. The cria had a 1-week history of progressive lameness prior to presentation. Clinical evaluation is commonly more delayed, with a median duration of clinical signs of 28 days prior to evaluation in a study2 of 36 camelids treated for osseous sequestration and 7.5 weeks in a report3 involving 67 horses with this condition. Owing to prompt evaluation of the cria, the radiographic changes at the onset of treatment were consistent with osteomyelitis and only suggestive of osseous sequestration. Horses in which medical treatment alone resulted in successful treatment of osseous sequestration all had similarly minimal radiographic changes.3 It is possible that early medical intervention and resolution of bacterial infection minimize ischemic damage and promote extraosseous or periosteal revascularization in affected patients.

Antimicrobial administration by means of IV regional limb perfusion may have contributed to treatment success in the cria of the present report. Antimicrobial administration is routinely used during treatment of osteomyelitis and osseous sequestration in camelids, but previous reports1,2,6 do not include regional limb perfusion of antimicrobials by the IV route. Reports of regional limb perfusion in camelids are limited, and dosage is extrapolated from other species.9 Intraosseous perfusion with dilute ceftiofur has been used successfully to treat septic flexor tendonitis and suspensory desmitis in an alpaca.9 In that report, the authors concluded that severe infection of the distal portion of the limb could be successfully treated without the need for surgical debridement. The high local concentration of antimicrobial achieved with IV regional limb perfusion may have allowed for a therapeutic drug concentration in the affected area despite a very limited vascular supply. It is also possible that unidentified differences in the cortical or periosteal circulation of juvenile camelids make medical management alone more successful in some crias. Further investigation is needed to elucidate the utility of regional limb perfusion for the treatment of osteomyelitis and sequestration in camelids.

Ceftiofur sodium was chosen for systemic treatment as well as IV regional limb perfusion because of its broad spectrum of activity against microbes, including anaerobes. Regional limb perfusion with other antimicrobials including amikacin, gentamicin, and imipenem has been described.10 However, consideration was given to the fact that alpacas are considered a minor food-producing species, limiting the choice of antimicrobials. Intravenous administration of ceftiofur was legal in this case because camelids are not considered a major food animal species and are exempt from the restriction on extralabel use of cephalosporins. Bacterial culture was not attempted because the cria never developed a draining tract, and the risk of contamination from a biopsy or aspiration procedure was considered too great. Bacteria cultured from sequestra in horses were all sensitive to broad-spectrum antimicrobials,3 and previously described culture results for camelids have not indicated high levels of antimicrobial resistance.2 Fusobacterium spp have been cultured from sites of sequestration in camelids with no history of trauma, leading to speculation that these infections were hematogenously spread.2 However, Fusobacterium spp were not identified in cultures of blood samples from crias with sepsis in another study.8 For the cria of the present report, blood was not submitted for culture because the animal appeared systemically healthy and we considered that any bacteremia likely preceded the onset of lameness by weeks. Sequestrectomy was recommended for this patient but was declined in part because of the high cost associated with general anesthesia and surgery. The successful result of medical management suggested that antimicrobial administration by means of regional limb perfusion has promise as a less expensive and less invasive treatment, but further investigation is needed to define optimal case selection.

Acknowledgments

No third-party funding was received in association with the case described in this report. The authors declare that there were no conflicts of interest.

Footnotes

a.

Naxcel, Zoetis, Kalamazoo, Mich.

b.

Meloxicam, Zydus Pharmaceuticals Inc, Pennington, NJ.

c.

Excede, Zoetis, Kalamazoo, Mich.

d.

Huber MJ. Bone sequestration in the appendicular skeleton in camelids (abstr), in Proceedings. Am Coll Vet Surg Vet Symp 2011;660–662.

References

  • 1.

    Debney S, Wereska M, Dart CM, et al. Surgical treatment of osteomyelitis and formation of a sequestrum in the distal metaphysis of the humerus in an alpaca cria. N Z Vet J 2011;59:4649.

    • Search Google Scholar
    • Export Citation
  • 2.

    Rousseau M, Anderson DE, Niehaus AJ, et al. Osseous sequestration in alpacas and llamas: 36 cases (1999–2010). J Am Vet Med Assoc 2013;243:430436.

    • Search Google Scholar
    • Export Citation
  • 3.

    Clem MF, DeBowes RM, Yovich JV, et al. Osseous sequestration in the horse. A review of 68 cases. Vet Surg 1988;17:25.

  • 4.

    Valentino LW, St Jean G, Anderson DE, et al. Osseous sequestration in cattle: 110 cases (1987–1997). J Am Vet Med Assoc 2000;217:376383.

  • 5.

    Lew DP, Waldvogel FA. Osteomyelitis. Lancet 2004;364:369379.

  • 6.

    Bischofberger AS, Dart CM, Dart AJ. Surgical treatment of osteomyelitis and sequestration of the ilium by a cranial partial hemipelvectomy in an alpaca cria. Aust Vet J 2010;88:283285.

    • Search Google Scholar
    • Export Citation
  • 7.

    Fowler ME. Medicine and surgery of South American camelids. 2nd ed. Ames, Iowa: Iowa State University Press, 1998;452467.

  • 8.

    Dolente BA, Lindborg S, Palmer JE, et al. Culture-positive sepsis in neonatal camelids: 21 cases. J Vet Intern Med 2007;21:519525.

  • 9.

    Hunter BG, Semevolos SA. Septic flexor tendonitis and suspensory desmitis in an alpaca. J Am Vet Med Assoc 2013;243:136139.

  • 10.

    Reed SK, Semevolos SA, Newman KD, et al. Musculoskeletal surgery. In: Cebra C, Anderson DE, Tibary A, et al., eds. Llama and alpaca care: medicine, surgery, reproduction, nutrition, and herd health. St Louis: Elsevier, 2014;669690.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 567 0 0
Full Text Views 909 573 80
PDF Downloads 603 203 20
Advertisement