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Complications of Liver Disease
Hepatobiliary disease in dogs and cats can lead to various complications. Vomiting is a common clinical sign in liver disease, and antiemetic therapy should be considered on a case-by-case basis. Ascites is managed by feeding a moderate sodium diet, thera... moreHepatobiliary disease in dogs and cats can lead to various complications. Vomiting is a common clinical sign in liver disease, and antiemetic therapy should be considered on a case-by-case basis. Ascites is managed by feeding a moderate sodium diet, therapy with spironolactone, and judicious use of furosemide. Hepatic encephalopathy is managed by feeding an appropriate diet and treating with lactulose and possibly an antimicrobial. Because coagulant and anticoagulant factors are affected in patients with hepatic dysfunction, they may be in an altered but balanced hemostatic state. This balance is fragile and bleeding or thrombosis can occur if it is disrupted. less
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Nutritional Management of Hepatobiliary Diseases in Dogs and Cats
Dogs and cats with liver disease often benefit from nutritional modifications. The most important consideration for patients with severe disease is often providing sufficient energy intake to prevent a catabolic state. Additionally, targeted nutritional m... moreDogs and cats with liver disease often benefit from nutritional modifications. The most important consideration for patients with severe disease is often providing sufficient energy intake to prevent a catabolic state. Additionally, targeted nutritional modifications address specific clinical signs and liver disease pathogenesis. For instance, patients with hepatic encephalopathy often benefit from a diet with a reduced amount of protein, or a vegetarian diet as these modifications can help reduce the severity and frequency of clinical signs. This article aims to guide the clinician in understanding the indications and considerations for nutritional intervention in patients with hepatobiliary disease. less
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Emerging Issues of Importance in Canine and Feline Hepatology
We are excited to present a new issue of Veterinary Clinics of North America: Small Animal Practice on canine and feline hepatology. Since the last hepatology issue in 2017, significant advances have been made in understanding the pathophysiology, diagnos... moreWe are excited to present a new issue of Veterinary Clinics of North America: Small Animal Practice on canine and feline hepatology. Since the last hepatology issue in 2017, significant advances have been made in understanding the pathophysiology, diagnosis, and management of many hepatobiliary diseases. Clinicians face many challenges in diagnosing and treating companion animal hepatobiliary disease. However, the veterinary profession is making continuous progress through the tireless efforts of our colleagues, who have dedicated their research careers to better understanding these important diseases. less
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Congenital Intrahepatic Disease
The spectrum of congenital intrahepatic diseases described in canine and feline patients is broad, and the etiopathogenesis is complex. Developmental dysregulation of the intrahepatic biliary tree and vasculature leads to malformations of the ductal plate... moreThe spectrum of congenital intrahepatic diseases described in canine and feline patients is broad, and the etiopathogenesis is complex. Developmental dysregulation of the intrahepatic biliary tree and vasculature leads to malformations of the ductal plate and aberrant vascular connections. Occasionally, intrahepatic congenital disorders occur as a constellation of biliary and vascular anomalies. Diagnosis requires clinical data, advanced diagnostic imaging, and, in the case of hepatic fibropolycystic disease, liver histopathology. Clinical prognosis is variable. less
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Biliary Tract Infections in Dogs
Bacterial biliary tract infections are increasingly recognized in dogs and should be considered in any dog presenting with vomiting, anorexia, and jaundice, particularly if they have abdominal discomfort or pyrexia. Commonly recognized clinicopathologic f... moreBacterial biliary tract infections are increasingly recognized in dogs and should be considered in any dog presenting with vomiting, anorexia, and jaundice, particularly if they have abdominal discomfort or pyrexia. Commonly recognized clinicopathologic findings include increased liver enzyme activities, hyperbilirubinemia, and an inflammatory leucogram. Hepatobiliary ultrasound forms a key component of the diagnostic approach to these cases, aiding the identification of dogs that require urgent surgical management due to biliary tract rupture, or that have another surgical condition. Ultrasound also allows guided percutaneous bile sampling to gain a sample for cytology and culture, guiding rational antimicrobial therapy. less
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Aminoaciduric Canine Hypoaminoacidemic Hepatopathy Syndrome
Aminoaciduric canine hypoaminoacidemic hepatopathy syndrome is a multifaceted clinical condition that remains insufficiently understood, with its pathophysiology not yet fully delineated. Current evidence suggests a link between hypoaminoacidemia and the ... moreAminoaciduric canine hypoaminoacidemic hepatopathy syndrome is a multifaceted clinical condition that remains insufficiently understood, with its pathophysiology not yet fully delineated. Current evidence suggests a link between hypoaminoacidemia and the development of superficial necrolytic dermatitis and hepatocutaneous lesions (hypoaminoacidemia/hepatocutaneous-associated canine hepatopathy), although the underlying mechanisms driving these associations are not clearly defined. The presence of aminoaciduria, along with impaired amino acid transporter function in critical organs such as the skin, liver, and intestines, may play a significant role in the progression of this syndrome. Additionally, elevated glucagon levels may further contribute to the exacerbation of hypoaminoacidemia, worsening clinical signs. less
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Domestic Cat Hepadnavirus, a Hepatitis B-like Virus Associated with Feline Liver Disease
In 2018, a surprising finding was reported; cats are naturally infected with a virus related to hepatitis B virus (HBV), domestic cat hepadnavirus (DCH). HBV causes chronic hepatitis and hepatocellular carcinoma in people, and HBV-like viruses cause simil... moreIn 2018, a surprising finding was reported; cats are naturally infected with a virus related to hepatitis B virus (HBV), domestic cat hepadnavirus (DCH). HBV causes chronic hepatitis and hepatocellular carcinoma in people, and HBV-like viruses cause similar diseases in rodents. If DCH negatively impacts feline health then demand for diagnostics, therapeutics, and vaccination will follow. Hence, understanding pathogenic potential of DCH for cats, and the size of any associated disease burden are critical goals. Here we evaluate progress made towards these goals by reviewing published studies of DCH against the backdrop of our understanding of HBV and HBV-like viruses. less
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Cytologic Evaluation of the Liver
Liver fine needle aspiration (FNA) and bile cytology are valuable diagnostic tools for evaluating various hepatobiliary diseases in veterinary medicine. Although FNA of the liver is less invasive and faster than histopathology, it may not always provide a... moreLiver fine needle aspiration (FNA) and bile cytology are valuable diagnostic tools for evaluating various hepatobiliary diseases in veterinary medicine. Although FNA of the liver is less invasive and faster than histopathology, it may not always provide a definitive diagnosis, but will often provide information regarding pathologic processes occurring in the liver. Cytologic evaluation is most effective when integrated with clinical information including bloodwork, imaging, and results of other diagnostic tests. less
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Granulomatous Hepatitis
Granulomatous hepatitis (GH) is a subset of chronic hepatitis in which the predominant inflammatory infiltrate consists of macrophages. It can be associated with systemic granulomatous disease or confined to the liver. When associated with systemic diseas... moreGranulomatous hepatitis (GH) is a subset of chronic hepatitis in which the predominant inflammatory infiltrate consists of macrophages. It can be associated with systemic granulomatous disease or confined to the liver. When associated with systemic disease, infectious causes (bacterial, fungal, protozoal, or metazoan) are more common, while disease confined to the liver is often idiopathic. Dogs with idiopathic GH most often present acutely ill, with fever, high white blood cell counts, and with ultrasound finding of a large liver often with nodules and characteristic hyperechoic parenchymal bands. less
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Gallbladder Mucocele
Gallbladder mucocele (GBM) formation was rarely reported prior to 20 years ago and has emerged as one of the most common, deadly, and poorly understood causes of gallbladder disease in dogs. Multiple and large retrospective studies inform many aspects of ... moreGallbladder mucocele (GBM) formation was rarely reported prior to 20 years ago and has emerged as one of the most common, deadly, and poorly understood causes of gallbladder disease in dogs. Multiple and large retrospective studies inform many aspects of diagnosis, concurrent diseases, surgical treatment, complications, and prognosis of patients with GBM. Studies of pathogenesis are fewer but are beginning to disclose underlying mechanisms for GBM formation.
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Equine Tendon and Ligament Injuries: Clinical Challenges and Opportunities for Functional Healing
Tendons and ligaments are vital components of the musculoskeletal system in the equine athlete and are highly susceptible to injuries. Clinical success following tendon/ligament injury can be defined not only as return to function but also sustained athle... moreTendons and ligaments are vital components of the musculoskeletal system in the equine athlete and are highly susceptible to injuries. Clinical success following tendon/ligament injury can be defined not only as return to function but also sustained athletic activity without recurrence of injury. To achieve this, a solid grasp of the functional anatomy of the injured tendon and/or ligament, timely diagnosis, and robust injury-specific therapies are essential. Significant progress has been made in equine practice toward accurate diagnosis and implementing tendon/ligament therapeutics given the increasing use of advanced imaging, particularly MRI, and biologic therapies and rehabilitation, respectively. less
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Evidence Related to the Effects of Intralesional/Intrasynovial Corticosteroids on Tendon/Ligament Homeostasis and Healing
Inflammation plays a role in acute and chronic equine tendon/ligament injury; anti-inflammatories are often indicated. Local corticosteroids provide consistent and profound short-term effects on pain and inflammation across species. However, there is no d... moreInflammation plays a role in acute and chronic equine tendon/ligament injury; anti-inflammatories are often indicated. Local corticosteroids provide consistent and profound short-term effects on pain and inflammation across species. However, there is no demonstrated benefit in the long term, and complications can occur. Alternative biologic anti-inflammatory treatments are available and should be used in horses at risk of complications. Nonetheless, corticosteroids remain an affordable and effective anti-inflammatory that, with continued research, may be indicated on a case-by-case basis as part of a multimodal treatment plan. 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
