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Drug-Induced Liver Injury
Drug-induced liver injury (DILI) is an underrecognized cause of hepatic disease in dogs and cats. Successful identification of cases requires an initial suspicion by the practitioner, a thorough drug exposure history, and knowledge of the toxic potential ... moreDrug-induced liver injury (DILI) is an underrecognized cause of hepatic disease in dogs and cats. Successful identification of cases requires an initial suspicion by the practitioner, a thorough drug exposure history, and knowledge of the toxic potential for common veterinary drugs. This article reviews the pathogenesis, classification, and diagnosis of DILI in small animals. It also discusses the clinical presentation, prevalence, and outcomes of DILI for several drugs important in veterinary medicine including azathioprine, azole antifungals, carprofen, diazepam, doxycycline, lomustine, methimazole, phenobarbital, rifampin, sulfonamide antibiotics, and zonisamide, as well as the toxic potential for nutraceuticals and herbal preparations. less
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Intrahepatic Congenital Portosystemic Shunts
Patients with a single congenital portosystemic shunt (PSS) often fail to thrive and routinely experience episodes of hepatic encephalopathy. Although medical therapy may mitigate clinical signs, shunt attenuation improves long-term outcomes and allows fo... morePatients with a single congenital portosystemic shunt (PSS) often fail to thrive and routinely experience episodes of hepatic encephalopathy. Although medical therapy may mitigate clinical signs, shunt attenuation improves long-term outcomes and allows for improved liver function. Intrahepatic PSSs are less common than their extrahepatic counterparts and pose some unique challenges. Minimally invasive intravascular approaches are generally recommended to treat IHPSSs with some exeptions including some patients with patent ductus venosus. Outcomes with percutaneous transvenous coil embolization are generally good, with low perioperative mortality rates and clinical improvement reported in greater than 80% of cases. less
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Crystalloids versus Colloids
Intravenous fluid therapy is a regular component of care for cats and dogs with goals of restoring tissue perfusion, preventing organ dysfunction, and maintaining homeostasis. Veterinarians have a plethora of fluid choices, including hypertonic, hypotonic... moreIntravenous fluid therapy is a regular component of care for cats and dogs with goals of restoring tissue perfusion, preventing organ dysfunction, and maintaining homeostasis. Veterinarians have a plethora of fluid choices, including hypertonic, hypotonic, and isotonic crystalloids, as well as synthetic and natural colloids. Studies published in both the human and veterinary medical literature have documented adverse events associated with synthetic and natural colloids. Reports of increased incidences of acute kidney injury, need for renal replacement therapy, and mortality in a variety of patient populations have called into question the use of synthetic colloids in humans and companion animals. less
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Update on Canine Parvoviral Enteritis
Canine parvoviral enteritis is one of the most common causes of morbidity and mortality in young dogs worldwide. The virus is endemic in the environment and can be infective to unvaccinated or poorly vaccinated dogs. Standard in-patient therapies include ... moreCanine parvoviral enteritis is one of the most common causes of morbidity and mortality in young dogs worldwide. The virus is endemic in the environment and can be infective to unvaccinated or poorly vaccinated dogs. Standard in-patient therapies include use of antiemetics, intravenous fluids, antibiotics and provision of enteral nutrition. The use of antiviral drugs, immunomodulators and monoclonal antibody therapy are newer possibilities that may potentially improve outcome. Outpatient therapy also remains a viable possibility for treatment if financial constraints exist. less
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Hot Topics in Emergency and Critical Care
It is such an honor for me that select topics from a recent issue of Advances in Small Animal Care have been chosen for this issue of Hot Topics in Emergency and Critical Care. For some topics, such as Crystalloids versus Colloids, the debate continues; h... moreIt is such an honor for me that select topics from a recent issue of Advances in Small Animal Care have been chosen for this issue of Hot Topics in Emergency and Critical Care. For some topics, such as Crystalloids versus Colloids, the debate continues; however, research has discovered new indications for and against their use under specific circumstances in small animal medicine. The most critically ill septic patients, including those with canine parvoviral enteritis, require antimicrobial, crystalloid, colloid, and sometimes glucocorticoid therapy for survival. less
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Proliferative and Necrotizing Otitis Externa of Cats and Kittens
Proliferative and necrotizing otitis externa (PNOE) is characterized by thick, adherent dark red, brown, or black crusts. It most commonly affects the concave pinnae and vertical ear canals bilaterally. Lesions may also be seen on the face, and it may rar... moreProliferative and necrotizing otitis externa (PNOE) is characterized by thick, adherent dark red, brown, or black crusts. It most commonly affects the concave pinnae and vertical ear canals bilaterally. Lesions may also be seen on the face, and it may rarely present in a generalized form. There is no known cause of PNOE, but it responds to treatment with topical and systemic immunomodulatories and is therefore thought to be immune-mediated. Twenty-one cases have been described in the literature and are summarized here. less
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Feline Aural Inflammatory Polyps
Feline aural inflammatory polyps originate from the tympanic bulla and less frequently from the auditory tube, representing the most common benign tumor of the feline ear. Clinical signs may be compatible with otitis externa, media, and/or interna with ra... moreFeline aural inflammatory polyps originate from the tympanic bulla and less frequently from the auditory tube, representing the most common benign tumor of the feline ear. Clinical signs may be compatible with otitis externa, media, and/or interna with rare occurrences involving meningoencephalitis or abscessation of periauricular tissue. Traction and avulsion is an effective treatment procedure with a relatively low recurrence rate, especially when systemic glucocorticoids are given after polyp removal. Secondary infections should be addressed with topical and systemic antimicrobials along with lavage of the ear. Bulla osteotomy may be recommended in complicated cases. less
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Nasal Planum Dermatoses of the Dog
Nasal planum dermatoses in dogs can be infectious, immune-mediated, allergic, neoplastic, and metabolic in nature. Recognizing key lesions and features and knowing how and when to biopsy can help distinguish between similar diseases. The focus of this art... moreNasal planum dermatoses in dogs can be infectious, immune-mediated, allergic, neoplastic, and metabolic in nature. Recognizing key lesions and features and knowing how and when to biopsy can help distinguish between similar diseases. The focus of this article is to review the most commonly encountered nasal planum dermatoses in dogs and to enable the veterinary practitioner to recognize and differentiate between them to obtain a diagnosis.
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Cutaneous Mycobacterioses of Cats and Dogs
Worldwide, a variety of mycobacterial species have been associated with skin lesions in dogs and cats. Lesions may result from systemic dissemination or local cutaneous inoculation. Only infections with Mycobacterium tuberculosis complex organisms have th... moreWorldwide, a variety of mycobacterial species have been associated with skin lesions in dogs and cats. Lesions may result from systemic dissemination or local cutaneous inoculation. Only infections with Mycobacterium tuberculosis complex organisms have the potential to be transmitted from companion animals to humans, but even then, zoonotic risk is considered low. Diagnosis of mycobacterial infections is based on identification of intralesional acid-fast bacteria using cytology or histopathology, culture at experienced facilities, and use of PCR-sequencing. Treatment typically requires prolonged combination therapy with antimycobacterial drugs, and the prognosis varies depending on the mycobacterial species involved and presence of underlying immunosuppression. less
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Applications for Laser in Veterinary Dermatology
Laser usage in veterinary dermatology has increased in popularity over the last several decades. Carbon dioxide (CO2) laser is the leading modality in surgical laser for veterinary dermatology because of its unmatched performance with soft tissue, particu... moreLaser usage in veterinary dermatology has increased in popularity over the last several decades. Carbon dioxide (CO2) laser is the leading modality in surgical laser for veterinary dermatology because of its unmatched performance with soft tissue, particularly the skin. This laser cuts and coagulates tissue via the photothermal effect of laser energy when interacting with soft tissues with high water content, such as skin. CO2 laser modality has many indications for the diagnosis and treatment of dermatologic conditions in animals. This article will review the basics of CO2 laser and how to utilize it in veterinary dermatology. less
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Therapeutic Exercises for Rehabilitation of Muscle Injury
Successful rehabilitation of muscle injury requires a comprehensive understanding of the injury process, healing phases, and resources to be employed. The initial phase is characterized by acute inflammatory signs, followed by the regenerative and remodel... moreSuccessful rehabilitation of muscle injury requires a comprehensive understanding of the injury process, healing phases, and resources to be employed. The initial phase is characterized by acute inflammatory signs, followed by the regenerative and remodeling phases. Therapeutic exercises can be utilized in all 3 phases, progressing from isometric exercises to aquatic therapies. The classification and phase of injury and the individual response to the applied therapies will guide the progression of the therapeutic exercises through the rehabilitation program. less
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Traumatic Muscle Injuries
Traumatic muscle injuries are likely to be frequent in athletic horses yet are often overlooked. These injuries usually involve internal (intrinsic) trauma, and particularly occur in athletic horses exercising at higher intensities, at unaccustomed worklo... moreTraumatic muscle injuries are likely to be frequent in athletic horses yet are often overlooked. These injuries usually involve internal (intrinsic) trauma, and particularly occur in athletic horses exercising at higher intensities, at unaccustomed workloads, or performing work requiring sudden acceleration, deceleration, and/or direction changes. These injuries can present with signs ranging from acute pain and lameness in a localized region to unexplained elevations of muscle enzymes on routine blood tests with or without poor performance. They include exercise-induced muscle damage such as delayed-onset muscle soreness and muscle injury such as muscle tears. less
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Polysaccharide Storage Myopathy
Type 1 Polysaccharide Storage Myopathy (PSSM1) is an autosomal dominant glycogen storage disorder affecting more than 20 breeds of horses that can present with a variety of signs, including exertional rhabdomyolysis (ER). It is diagnosed by genetic testin... moreType 1 Polysaccharide Storage Myopathy (PSSM1) is an autosomal dominant glycogen storage disorder affecting more than 20 breeds of horses that can present with a variety of signs, including exertional rhabdomyolysis (ER). It is diagnosed by genetic testing or muscle biopsies containing muscle fibers with abnormal amylase-resistant polysaccharide. Type 2 PSSM has recently been subdivided. PSSM2-ER is a glycogen storage disorder identified in Quarter Horses that causes ER and is diagnosed by muscle biopsy as its genetic basis is unknown. Both PSSM1 and PSSM2-ER respond well to a low nonstructural carbohydrate, high fat diet combined with regular exercise. These forms of PSSM are discussed in this article. less
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Nonexertional Rhabdomyolysis
Although horses most commonly develop exertional rhabdomyolysis, there are numerous causes for nonexertional rhabdomyolysis (nonER) that pose a serious health threat to horses. Their etiologies can be broadly categorized as toxic, genetic, inflammatory/in... moreAlthough horses most commonly develop exertional rhabdomyolysis, there are numerous causes for nonexertional rhabdomyolysis (nonER) that pose a serious health threat to horses. Their etiologies can be broadly categorized as toxic, genetic, inflammatory/infectious, nutritional, and traumatic and a variety of diagnostic tests are available to discern among them. This study discusses causes of nonER as well as diagnostics and treatments that are specific to each etiology. General treatment of acute rhabdomyolysis is covered in detail in the study in this issue on sporadic and recurrent exertional rhabdomyolysis. less
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Vitamin E and Selenium-Related Manifestations of Muscle Disease
Nutritional deficiencies of vitamin E and selenium can occur alone or concurrently. Prolonged and sustained deficiency of either or both nutrients can lead to profound clinical disease. Selenium deficiency can also result in signs of cardiac disease, uppe... moreNutritional deficiencies of vitamin E and selenium can occur alone or concurrently. Prolonged and sustained deficiency of either or both nutrients can lead to profound clinical disease. Selenium deficiency can also result in signs of cardiac disease, upper gastrointestinal dysfunction, and abortion or the birth of weak foals. Deficiencies can usually be readily established by evaluating the dietary intake of individuals and by measurement of blood concentrations of these nutrients. Treatment of clinical disease is not always successful and prolonged morbidity and mortality can be encountered; hence, prevention is of the utmost importance. less
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Clinical Examination of the Muscle System
The equine muscle system is complex and prone to a large range of hereditary and acquired diseases that often have overlapping clinical signs with orthopedic, neurologic, and other disorders. Obtaining a clinical history that fully outlines the client con... moreThe equine muscle system is complex and prone to a large range of hereditary and acquired diseases that often have overlapping clinical signs with orthopedic, neurologic, and other disorders. Obtaining a clinical history that fully outlines the client concerns and any known information about the disorder and following with a comprehensive physical examination and screening clinical pathology tests are fundamental to achieve definitive diagnosis. A methodical and comprehensive approach aids accurate diagnosis and development of an optimal treatment and management plan. This article describes the clinical examination approach and clinical pathology relevant to evaluating muscle disease in horses. less
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Myofibrillar Myopathy
Myofibrillar myopathy (MFM) is characterized by segmental disarray of myofibrils and ectopic accumulation of a protein called desmin. Previously thought to be a glycogen storage disease, MFM is now recognized as a stand-alone myopathy. Endurance Arabians ... moreMyofibrillar myopathy (MFM) is characterized by segmental disarray of myofibrils and ectopic accumulation of a protein called desmin. Previously thought to be a glycogen storage disease, MFM is now recognized as a stand-alone myopathy. Endurance Arabians with MFM usually present with exertional rhabdomyolysis (MFM-ER) at the end of races, elevated serum muscle enzymes, and myoglobinuria. Warmblood horses with MFM (MFM-WB) usually present with pain-associated behaviors such as exercise intolerance, reluctance to engage hind quarter muscles, shifting lameness and normal serum muscle enzymes. Both forms have evidence of decreased cysteine-based antioxidants and, additionally, MFM-WB has molecular signatures of a maladaptive training response. less
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Sporadic and Recurrent Exertional Rhabdomyolysis
Horses are particularly susceptible to developing exertional rhabdomyolysis (ER) characterized by muscle stiffness, pain, and reluctance to move. Diagnosis requires establishing abnormal increases in serum creatine kinase activity when horses exhibit clin... moreHorses are particularly susceptible to developing exertional rhabdomyolysis (ER) characterized by muscle stiffness, pain, and reluctance to move. Diagnosis requires establishing abnormal increases in serum creatine kinase activity when horses exhibit clinical signs. The 2 main categories of ER include sporadic ER arising from extrinsic causes and chronic ER that arises from intrinsic continuous or episodic abnormalities in muscle function. This article focuses on treatment of acute ER and causes and management of sporadic ER. Differential diagnoses for chronic ER as well as the pathophysiology, diagnosis, and management of recurrent ER, and malignant hyperthermia are also discussed in this article. less
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Myosin Heavy Chain Myopathy and Immune-Mediated Muscle Disorders
Several inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexer... moreSeveral inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexertional rhabdomyolysis in Quarter Horse-related breeds. An infarctive form of purpura hemorrhagica affects numerous breeds, presenting with focal firm, painful muscle swelling, and subsequent infarction of multiple tissues. While Streptococcus equi equi is often the inciting cause, anaplasmosis, sarcocystis, piroplasmosis, viruses, and vaccines can also be inciting agents. This article describes the diagnosis, pathophysiology, and treatment of these inflammatory myopathies. less
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Disorders of Muscle Mass and Tone
Muscle disease has various clinical manifestations that range from exertional and non-exertional rhabdomyolysis, fasciculations, weakness, rigidity, stiffness, gait abnormalities, poor performance, and alterations in muscle mass and tone. Neurogenic disor... moreMuscle disease has various clinical manifestations that range from exertional and non-exertional rhabdomyolysis, fasciculations, weakness, rigidity, stiffness, gait abnormalities, poor performance, and alterations in muscle mass and tone. Neurogenic disorders and non-neurogenic disorders such as primary muscle disease can cause muscle atrophy and changes in muscle tone. Myotonic disorders can have a genetic (eg, inherited channelopathies) or acquired (eg, electrolyte derangements) origin. Normal muscle enzyme activities do not rule out a myopathic disorder as the underlying cause of muscle atrophy and changes in muscle tone. Genetic testing to facilitate responsible breeding practices is recommended. less
