Acute compartment syndrome complicating an intramuscular haemangiosarcoma in a dog

Compartment syndrome of the muscles of mastication in a working dog following a traumatic training incident

OBJECTIVE

To describe acute compartment syndrome (CS) of the muscles of mastication in a working dog associated with a traumatic training event.

CASE SUMMARY

A 2.5-year-old male Belgian Malinois was evaluated for acute blindness, severe diffuse swelling of the head, and inability to close the jaw following a traumatic incident during a bite training drill. During the exercise, the maxillary canine teeth were locked on a bite sleeve. Magnetic resonance imaging of the head and ocular system identified diffuse muscle swelling and hyperintensity, most severe in the muscles of mastication. Ocular abnormalities were not identified. Rhabdomyolysis, CS, and indirect optic nerve injury were supported by measurement of increased intramuscular pressure. Bilateral decompressive fasciotomies over the masseter and temporalis muscles resulted in immediate and marked resolution of the swelling and jaw movement. Blindness, however, did not resolve.

NEW OR UNIQUE INFORMATION PROVIDED

CS involving the muscles of mastication may occur as a complication of bite training and may result in irreversible and even life-threatening complications. Emergent decompressive fasciotomy is indicated to reverse swelling; however, visual deficits may not resolve.

Suspected Compartment Syndrome, Consumptive Thrombocytopenia, and Anemia Secondary to a Ruptured Arterial Aneurysm or Pseudoaneurysm Following Multiple Stifle Surgeries

A 12 yr old male neutered beagle was presented on transfer to the intensive care unit with severe anemia, thrombocytopenia, and bruising detected 1 day after undergoing tibial plateau leveling osteotomy surgery. The patient had undergone extra-capsular stifle stabilization surgery 14 wk prior to treat ligament disease in the same knee. Laboratory testing and treatment for anemia, presumptive immune-mediated thrombocytopenia, and possible hemostatic disorder was initiated. A persistent anemia, progressive thrombocytopenia, and the development of a firm swelling and neurologic impairment in the limb raised concerns for compartment syndrome (CS). A musculoskeletal ultrasound revealed a large aneurysm in the caudal thigh surrounded by abnormal muscle tissue. The patient underwent amputation of the limb and recovered without further complication. Pathology findings were consistent with the development of femoral CS secondary to a ruptured peripheral arterial aneurysm or a pseudoaneurysm. A consumptive thrombocytopenia and regenerative anemia were attributed to periodic or progressive thrombosis of the vessel and regional hemorrhage. Postoperative CS can develop in combination with peripheral arterial aneurysm or pseudoaneurysm, and screening for vascular abnormalities as well as CS should be considered in complicated recovery from orthopedic surgery with compatible clinical signs including progressive soft tissue swelling, persistent anemia, and thrombocytopenia.

Acute masticatory muscle compartmental syndrome in a dog

CASE DESCRIPTION A5.5-year-old sexually intact male Bull Terrier was referred for evaluation because of sudden facial swelling and an inability to close its mouth. CLINICAL FINDINGS Physical examination revealed bilaterally elevated nictitating membranes, an inability to adduct the mandible without assistance, and severe, diffuse, firm masticatory muscle swelling. Computed tomographic examination of the head revealed symmetric bilateral enlargement of the temporalis, masseter, and pterygoid muscles with heterogeneous contrast enhancement. Intracompartmental pressures in the left and right temporalis muscles as measured with an invasive arterial blood pressure transducer were 72 and 96 mm Hg, respectively. TREATMENT AND OUTCOME Emergent fasciotomy of the temporalis and masseter muscles was performed, followed by medical management with corticosteroids and analgesics. The diffuse facial swelling resolved within 1 week after surgery. Results of serologic testing for antibody against masticatory 2M muscle fibers were negative. Results of histologic examination of temporalis muscle specimens were consistent with mild to moderate multifocal neutrophilic and histiocytic myositis with myofiber degeneration and necrosis. CLINICAL RELEVANCE Acute compartmental syndrome should be considered as a differential diagnosis for dogs with a sudden onset of severe skeletal muscle swelling, signs of pain, and dysfunction. Findings for this dog with acute compartmental syndrome isolated to the masticatory muscles suggested that emergent fasciotomy followed by medical management may be an effective technique for treatment of this rare disease in dogs.

Compartment syndrome associated with expansile antebrachial tumors in two dogs

CASE DESCRIPTION

A 10-year-old spayed female Jack Russell Terrier and a 7-year-old neutered male mixed-breed dog were evaluated because of acute, progressive, unilateral forelimb lameness associated with signs of pain and turgid antebrachial swelling.

CLINICAL FINDINGS

For either dog, there were no salient pathological or diagnostic imaging abnormalities. A diagnosis of compartment syndrome was confirmed on the basis of high caudal antebrachial compartmental pressure in the affected forelimb.

TREATMENT AND OUTCOME

Both dogs underwent surgical exploration of the affected forelimb. In each case, an intramuscular tumor (mast cell tumor in the Jack Russell Terrier and suspected sarcoma in the mixed-breed dog) was detected and presumed to be the cause of the high compartmental pressure. At 6 months following tumor excision, the dog with the mast cell tumor did not have any clinical signs of disease. The dog with a suspected sarcoma underwent tumor excision and forelimb amputation at the proximal portion of the humerus followed by chemotherapy; the dog was euthanized approximately 1 year following treatment because of pulmonary metastasis.

CLINICAL RELEVANCE

Compartment syndrome is a serious but rarely reported condition in dogs and is typically ascribed to intracompartmental hemorrhage. These 2 cases illustrate the potential for expansile intramuscular antebrachial tumors to cause compartment syndrome in dogs.

Bilateral obturator neuropathy caused by an intrapelvic fibrosarcoma with myofibroblastic features in a dog

A nine-year-old female Rottweiler presented with a 6-week history of progressive impairment of hindlimb adduction. Clinical examination showed abduction of both hind legs when walking on a smooth surface, pain at the medial surface of the left thigh, and an intrarectal palpable mass at the pelvic floor. Electromyography demonstrated fibrillation potentials in the adductor muscles on both sides. Pelvic radiographs showed severe osteolysis of the ischium. Gross post-mortem examination following euthanasia disclosed a large retroperitoneal mass, invading the obturator foramina and compressing both obturator nerves. Histopathological examination revealed a high-grade anaplastic sarcoma. Immunohistochemically, the tumour cells labelled positively for vimentin and alpha-smooth muscle actin, hence the tumour was considered a "myofibroblastic fibrosarcoma". This unique case report describes a novel cause of obturator neuropathy in veterinary medicine. To date, clinical descriptions of obturator nerve lesions have been limited to pelvic fractures in small animals and following difficult labour in large animals.

Compartment syndrome: pathophysiology, clinical presentations, treatment, and prevention in human and veterinary medicine

OBJECTIVE

To review the human and veterinary literature pertaining to all forms of compartment syndrome (CS).

DATA SOURCES

Data sources included scientific reviews and original research publications from the human and veterinary literature.

HUMAN DATA SYNTHESIS

While CS affecting the extremities has been recognized in people for decades, other forms of CS in the abdominal and thoracic cavities are recently gaining more attention. The role of CS in critically ill people is a rapidly growing area of interest. More research on prevention and treatment of CS is being conducted in people because some studies have found mortality rates as high as 80% for those suffering from these conditions.

VETERINARY DATA SYNTHESIS

While a significant amount of experimental studies of CS have been performed on small animals, there is a marked lack of primary veterinary studies. The majority of the veterinary literature includes case reports and series, and many of these studies were published over a decade ago. However, the increased recognition of CS in people has sparked an interest in veterinary critical care medicine and this has been demonstrated by the recent increased evaluation of compartment pressures in veterinary patients.

CONCLUSIONS

CS is a complex clinical condition where increased pressure within a compartment can cause significant adverse effects within the compartment as well as throughout the body. Systemic inflammatory responses and local ischemia-reperfusion elements can contribute to the detrimental effects seen in CS. This cascade of events results in increased mortality rates and contributes to the development of CS elsewhere. A better understanding of CS will help veterinarians improve patient care and outcome. Future studies on incidence, prevention, and treatment of CSs in the critical care patient are needed in veterinary medicine.

Acute compartment syndrome in the pelvic limb of a cow following biopsy of a skeletal muscle-associated hemangiosarcoma

CASE DESCRIPTION

A 6-year-old Holstein cow was examined because of chronic lameness and swelling near the stifle joint of the left pelvic limb.

CLINICAL FINDINGS

A mass was palpated in the soft tissues lateral to the proximal aspect of the left tibia. Multiple attempts to obtain a biopsy specimen of the mass resulted in acute compartment syndrome of the femoral compartment (tensor fasciae latae and biceps femoris muscles) and lateral tibial compartment (cranial tibial and peroneus tertius muscles) with associated sciatic nerve paralysis.

TREATMENT AND OUTCOME

Surgical decompression via tensor fasciae latae and biceps femoris incision resolved the sciatic nerve paralysis. On the fifth day following surgery, the cow began to develop signs of increased respiratory effort. Thoracic radiography revealed a pulmonary metastatic micronodular pattern. The cow was euthanized because its condition deteriorated. Metastatic hemangiosarcoma was confirmed at necropsy, and the primary tumor was the mass that was lateral to the tibia and within the biceps femoris muscle.

CLINICAL RELEVANCE

Hemangiosarcoma should be considered a differential diagnosis for lameness in cattle when no orthopedic cause can be identified. Close patient surveillance is strongly recommended in the event that a vascular tumor is present because catastrophic consequences are possible. To our knowledge, this is the first report of acute compartment syndrome in a pelvic limb of a bovine patient and the only report of hemangiosarcoma in the skeletal muscle of cattle.

Massive haematoma formation associated with proximal popliteal artery haemangioendothelioma in a dog

A mixed breed dog presented with diffuse unilateral hind limb swelling, which ultrasound and cytology confirmed to be caused by severe haematoma formation. Multi-detector computed tomography (MDCT) angiography allowed distinct visualisation of an anomalous segment of the proximal popliteal artery, the presumed origin of the self-sustaining haematoma. Histopathology classified the malformed vessel as a haemangioendothelioma, a neoplasia of intermediate malignancy. Considering this as differential diagnosis to a neoplastic vascular alteration of high malignancy (such as haemangiosarcoma) might alter choice of treatment in future cases with similar clinical and imaging findings.

A rabbit model of peripheral compartment syndrome with associated rhabdomyolysis and a regenerative medicine approach for treatment

Peripheral compartment syndrome (PCS) has a complex etiology, with limited treatment options and high patient morbidity. Animal models of PCS have been hampered by differences in cross-species anatomy, physiology, and the relative rarity of the naturally occurring syndrome in animals. In the present study, the combination of saline infusion with intermittent crushing of skeletal muscle consistently caused increased intracompartmental pressure, hypocalemia, and hypercreatinine-phophokinasemia, signs diagnostic of PCS. This method was used to evaluate both the standard PCS treatment, specifically a fasciotomy, and a regenerative medicine approach for treatment-consisting of a fasciotomy with local administration of a biologic scaffold material composed of porcine small intestinal submucosa extracellular matrix (SIS-ECM). The use of this SIS-ECM scaffold in conjunction with a fasciotomy was associated with myogenesis and constructive tissue remodeling in the SIS-ECM-treated animals. At 1 and 3 months after treatment innervated muscle tissue was present at the site of injury. No myogenesis was present in the fasciotomy only treated animals. RAM11+ macrophages, which are associated with constructive tissue remodeling, were present within the injury site in the SIS-ECM-treated animals at 1 month. The present study provides a reproducible animal model with which to study PCS, and shows the potential of a regenerative medicine approach to PCS treatment.

Efficacy of doxorubicin-based chemotherapy for non-resectable canine subcutaneous haemangiosarcoma

Eighteen dogs with measurable subcutaneous haemangiosarcoma (SQHSA) were treated with doxorubicin-based chemotherapy. Response assessment was evaluated and compared using World Health Organization (WHO), Response Evaluation Criteria in Solid Tumours (RECIST) and tumour volume criteria. The overall response rate for all dogs was 38.8% using WHO criteria, 38.8% using RECIST criteria and 44% using tumour volume criteria. One dog had a complete response. The median response duration for all dogs was 53 days (range 13-190 days). Four dogs had complete surgical excision after neoadjuvant chemotherapy. The median progression-free interval for dogs with complete surgical excision after neoadjuvant chemotherapy was significantly longer than those not having surgical excision (207 days versus 83 days, respectively) (P = 0.003). No significant difference in metastasis-free interval or survival time was found between the groups. Doxorubicin-based chemotherapy appears to be effective for non-resectable canine SQHSA, although the response duration is relatively short.