Amyloidosis (systemic)

Systemic amyloidosis is a serious and progressive condition in cats characterized by the abnormal deposition of amyloid proteins in various organs throughout the body. Amyloid is an insoluble fibrous protein that accumulates in tissues when the body produces certain proteins in excess or when normal proteins misfold and aggregate. This condition can affect multiple organ systems simultaneously, with the kidneys and liver being the most commonly impacted organs in felines. While systemic amyloidosis can occur in any cat, certain breeds demonstrate a significantly higher predisposition to developing this disease, making it an important consideration for breeders and owners of susceptible breeds.

The underlying cause of systemic amyloidosis involves the overproduction or abnormal processing of specific proteins that then aggregate and deposit in organ tissues. In cats, the most common form involves the deposition of amyloid A protein, which is derived from serum amyloid A, an acute phase protein produced during inflammatory responses. Chronic inflammation, infections, or neoplastic conditions can trigger increased production of these proteins, leading to their eventual accumulation in organs. The genetic predisposition seen in certain breeds suggests that inherited factors play a significant role in determining which cats develop clinical disease.

The impact of systemic amyloidosis on a cat's health can be devastating as the accumulated amyloid proteins progressively damage organ function. When amyloid deposits in the kidneys, it leads to chronic kidney disease and eventual renal failure, which is the most common presentation in affected cats. Liver involvement can result in hepatic dysfunction and potentially liver rupture, a particularly serious complication seen in some breeds. The progressive nature of this disease means that organ function deteriorates over time, significantly affecting the cat's quality of life and overall health status.

Treatment for systemic amyloidosis focuses on supportive care and managing the complications associated with organ dysfunction, as there is currently no cure for this condition. Early detection through regular health monitoring is crucial for cats at risk, allowing for intervention before significant organ damage occurs. The prognosis for cats with systemic amyloidosis varies depending on which organs are affected and the extent of amyloid deposition at the time of diagnosis. Veterinary care is essential for managing this condition, providing supportive treatments that can help maintain quality of life and potentially slow disease progression in affected cats.

The primary cause of systemic amyloidosis in cats involves the abnormal production, processing, or clearance of specific proteins that subsequently misfold and aggregate into insoluble amyloid fibrils. The most common form seen in felines is reactive or secondary amyloidosis, where amyloid A protein derived from serum amyloid A accumulates in tissues. This acute phase protein is normally produced by the liver in response to inflammation, infection, or tissue damage. When inflammatory conditions persist chronically, continuous production of serum amyloid A can overwhelm the body's ability to process and clear this protein, leading to its deposition in organs as amyloid fibrils.

Genetic and hereditary factors play a crucial role in feline systemic amyloidosis, particularly in certain predisposed breeds. Abyssinian and Siamese cats have well-documented hereditary forms of the disease that appear to follow familial patterns. In Abyssinians, the condition typically affects the kidneys and follows an autosomal dominant inheritance pattern with variable penetrance, meaning not all cats carrying the genetic mutation will develop clinical disease. The specific genetic mutations responsible for familial amyloidosis in cats are still being researched, but the strong breed predisposition clearly indicates inherited susceptibility to abnormal amyloid protein processing.

Environmental and lifestyle factors can contribute to the development of systemic amyloidosis, particularly conditions that cause chronic inflammation. Persistent infections, including chronic dental disease, ongoing urinary tract infections, or other long-standing inflammatory conditions can trigger sustained production of acute phase proteins. Cats with chronic inflammatory bowel disease, neoplastic conditions producing inflammatory mediators, or immune-mediated diseases may be at increased risk. The cumulative effect of chronic inflammation over time can eventually lead to sufficient amyloid accumulation to cause organ dysfunction.

Risk factors for developing systemic amyloidosis include advancing age, breed predisposition, and the presence of chronic inflammatory conditions. Middle-aged to older cats are more commonly affected, likely reflecting the time required for sufficient amyloid to accumulate and cause clinical signs. Cats with recurring infections or chronic diseases that stimulate ongoing inflammatory responses face elevated risk. Additionally, cats from breeding lines known to be affected by familial amyloidosis carry inherited susceptibility regardless of other risk factors.

The mechanism of amyloid formation involves a complex process where normally soluble proteins undergo conformational changes that cause them to aggregate into beta-pleated sheet structures characteristic of amyloid fibrils. Once formed, these fibrils are highly stable and resistant to normal protein degradation processes. The deposited amyloid progressively replaces normal tissue architecture, disrupting organ function through both mechanical interference and cellular toxicity. In the kidneys, amyloid typically deposits in the glomeruli and interstitium, impairing filtration and leading to protein loss and eventual renal failure. Hepatic deposition can weaken blood vessel walls, predisposing to potentially fatal hemorrhage.

Early warning signs of systemic amyloidosis in cats are often subtle and easily overlooked, as the condition develops gradually over time. Initial symptoms may include mild lethargy, slightly decreased appetite, or subtle weight loss that owners might attribute to normal aging or minor illnesses. Cats are notoriously skilled at hiding signs of illness, which means early-stage amyloidosis frequently goes undetected until significant organ damage has occurred. Some cats may show increased thirst and urination as early kidney involvement affects their ability to concentrate urine, though these changes may be mild initially. Regular wellness examinations and blood work in at-risk breeds are crucial for catching the disease before obvious symptoms develop.

Common symptoms of systemic amyloidosis reflect the organs most significantly affected by amyloid deposition. The majority of cats with this condition present with signs of kidney disease, including increased thirst and urination, decreased appetite, weight loss, and vomiting. As kidney function declines, cats may develop poor coat quality, bad breath with a uremic odor, and general malaise. When the liver is primarily affected, symptoms may include decreased appetite, lethargy, and occasionally jaundice if hepatic function is significantly compromised. Some cats may present with a combination of symptoms reflecting multi-organ involvement.

Behavioral changes in cats with systemic amyloidosis often reflect their declining health status and discomfort. Affected cats typically become less active and may spend more time sleeping or hiding. Changes in appetite are common, with many cats becoming increasingly picky about food or refusing to eat altogether as the disease progresses. Litter box habits may change, with increased frequency of urination or accidents outside the box as kidney function deteriorates. Social cats may become more withdrawn, while previously independent cats might seek more comfort and attention from their owners.

Physical signs observable in cats with systemic amyloidosis include progressive weight loss and muscle wasting, particularly noticeable over the spine and hindquarters. The coat may become dull, dry, and unkempt as the cat feels too unwell for normal grooming. Dehydration may be evident through decreased skin elasticity and tacky gums. In cases with significant kidney involvement, small and irregular kidneys may be palpable during physical examination. Cats with hepatic amyloidosis may develop abdominal distension due to fluid accumulation or an enlarged liver. Pale gums may indicate anemia, which commonly develops secondary to chronic kidney disease.

Symptom progression in systemic amyloidosis typically follows a gradual but relentless course as organ damage accumulates. Initial mild symptoms become more pronounced over weeks to months, with increasing weight loss, declining appetite, and worsening lethargy. Kidney function progressively deteriorates, leading to accumulation of toxins in the bloodstream and associated nausea, vomiting, and malaise. Some cats experience periods of relative stability followed by acute declines, particularly if complications such as infections or dehydration occur. The rate of progression varies considerably between individual cats and may depend on the extent and location of amyloid deposits.

Emergency symptoms requiring immediate veterinary attention include sudden collapse, severe weakness, pale or white gums, distended abdomen, or signs of internal bleeding. In Abyssinian and Siamese cats with hepatic amyloidosis, spontaneous liver rupture can occur, causing acute internal hemorrhage that presents as sudden collapse, rapid breathing, weakness, and pale gums. This is a life-threatening emergency requiring immediate intervention. Severe dehydration, complete refusal to eat or drink, uncontrolled vomiting, seizures, or loss of consciousness also warrant emergency care. Any rapid deterioration in a cat known to have or suspected of having amyloidosis should prompt urgent veterinary evaluation.

The initial veterinary examination for a cat suspected of having systemic amyloidosis involves a comprehensive physical assessment and detailed history taking. The veterinarian will inquire about the cat's breed, age, family history if known, duration and progression of symptoms, and any previous health issues. Physical examination includes assessment of hydration status, body condition, kidney size and texture through palpation, liver assessment, and evaluation for fluid accumulation in the abdomen. The veterinarian will also examine the coat quality, check mucous membrane color, and assess overall demeanor. For breeds predisposed to amyloidosis, particularly Abyssinians and Siamese, the possibility of this condition will be considered even with relatively nonspecific symptoms.

Diagnostic testing for systemic amyloidosis typically begins with routine blood work and urinalysis to assess organ function. A complete blood count may reveal anemia associated with chronic kidney disease or inflammation. Serum biochemistry evaluates kidney function markers such as blood urea nitrogen, creatinine, and SDMA, which are elevated when kidneys are damaged. Liver enzymes and bilirubin levels help assess hepatic involvement. Urinalysis commonly shows protein in the urine, sometimes in significant quantities, reflecting glomerular damage from amyloid deposition. Additional testing may include measurement of urine protein-to-creatinine ratio to quantify protein loss and blood pressure measurement, as hypertension often accompanies kidney disease.

Differentiating systemic amyloidosis from other conditions causing similar symptoms requires careful evaluation and sometimes advanced diagnostics. Chronic kidney disease from other causes, including chronic interstitial nephritis, polycystic kidney disease, or nephrotoxin exposure, can present similarly. Liver diseases such as hepatic lipidosis, cholangitis, or neoplasia may cause comparable hepatic symptoms. Inflammatory conditions, infections, and cancer can all produce chronic inflammation with weight loss and organ dysfunction. The veterinarian considers the cat's breed predisposition, pattern of organ involvement, and response to treatment when developing a differential diagnosis list. Imaging studies including abdominal ultrasound help evaluate organ size, architecture, and identify any masses or abnormalities.

Definitive diagnosis of systemic amyloidosis requires histopathological examination of affected tissue, typically obtained through biopsy. Kidney or liver biopsies can be performed surgically, laparoscopically, or through ultrasound-guided needle techniques, though the procedure carries some risk, particularly in cats with compromised organ function. The tissue samples are stained with Congo red dye, which causes amyloid deposits to display characteristic apple-green birefringence when viewed under polarized light microscopy. This remains the gold standard for confirming amyloid deposition. In some cases, diagnosis is made presumptively based on signalment, clinical signs, and laboratory findings in breeds known to be affected, particularly when biopsy risks outweigh benefits. Post-mortem examination provides definitive diagnosis in cats that succumb to the disease.

Emergency treatment for cats presenting with acute complications of systemic amyloidosis focuses on immediate stabilization and supportive care. Cats experiencing hemorrhage from hepatic amyloidosis require aggressive fluid therapy, blood transfusions if severe anemia is present, and potentially emergency surgery to control bleeding. Those presenting in uremic crisis due to kidney failure need intravenous fluid therapy to correct dehydration and help flush toxins from the bloodstream. Anti-nausea medications help control vomiting, while gastroprotectants protect the stomach lining. Pain management is provided as needed. The immediate goal is to stabilize the patient before addressing long-term management strategies.

Medical management of systemic amyloidosis in cats centers on treating the complications and supporting affected organ function, as no medication effectively removes established amyloid deposits. For cats with kidney involvement, treatment mirrors that for chronic kidney disease and includes dietary management with phosphorus-restricted, moderate-protein renal diets. Phosphate binders help control elevated blood phosphorus levels. Potassium supplementation addresses losses through diseased kidneys. Medications to control blood pressure may be necessary, as hypertension commonly accompanies kidney disease. Anti-nausea medications and appetite stimulants help maintain nutrition. Erythropoietin-stimulating agents may be used if anemia becomes severe. Regular monitoring of kidney values guides treatment adjustments.

Surgical intervention in systemic amyloidosis is generally limited, as the condition is not surgically correctable. However, surgery may be required in emergency situations such as hepatic rupture with internal bleeding, where surgical exploration and hemostasis may be life-saving. Biopsy procedures for diagnosis may be performed surgically if ultrasound-guided techniques are not feasible. In rare cases where amyloidosis is secondary to a chronic inflammatory focus that can be surgically addressed, such as a chronically infected organ, removal of the inciting cause might slow disease progression, though established amyloid deposits will remain.

Supportive care forms the cornerstone of managing cats with systemic amyloidosis and focuses on maintaining quality of life. Fluid therapy, either intravenous during hospitalization or subcutaneous fluids administered at home by owners, helps maintain hydration and support kidney function. Nutritional support ensures adequate caloric intake, with appetite stimulants, warming food to enhance aroma, or feeding tubes in severe cases. Pain management addresses any discomfort from organ dysfunction. Environmental modifications help affected cats rest comfortably. Regular monitoring allows for early intervention when complications arise.

Alternative and complementary approaches for cats with systemic amyloidosis aim to reduce inflammation and support overall health, though none have proven ability to reverse amyloid deposits. Omega-3 fatty acid supplementation may help reduce inflammation and slow kidney disease progression. Some practitioners recommend antioxidant supplements to combat oxidative stress. Acupuncture may help manage nausea and improve appetite in some cats. Colchicine, a medication used in humans with familial Mediterranean fever to prevent amyloidosis, has been tried in cats with variable results and significant side effects, limiting its usefulness. Any complementary therapies should be discussed with the veterinarian to ensure they do not interfere with conventional treatment.

Treatment decisions for cats with systemic amyloidosis depend on multiple factors including the extent of organ damage, the cat's overall condition, available resources, and quality of life considerations. The progressive and incurable nature of the disease means that treatment goals focus on maintaining comfort and quality of life rather than achieving cure. Cost considerations are significant, as ongoing management including medications, therapeutic diets, fluid therapy, and regular monitoring represents a substantial commitment. Owners must balance the intensity of treatment against the cat's quality of life and understand that eventual decline is expected despite best efforts. Hospice and palliative care approaches become important as the disease advances.

Recovery from acute episodes related to systemic amyloidosis, such as uremic crisis or hemorrhagic events, varies depending on severity and promptness of treatment. Cats that survive acute hepatic rupture and hemorrhage may recover from the immediate crisis with aggressive supportive care, though the underlying amyloidosis remains. Those hospitalized for severe dehydration or uremic crisis typically show improvement within days of initiating intravenous fluid therapy and supportive care. However, it is important to understand that recovery from these acute episodes does not indicate recovery from the underlying condition. Systemic amyloidosis is a progressive disease, and while cats may stabilize and return to reasonable function after acute events, the disease continues to advance.

Post-treatment care for cats with systemic amyloidosis involves ongoing management that becomes part of daily life. Owners learn to administer subcutaneous fluids at home if prescribed, typically several times weekly. Medications must be given as directed, which may include phosphate binders with meals, anti-nausea medications, and other supportive drugs. Special renal diets require consistent feeding and may need adjustments if the cat's appetite changes. Regular monitoring of weight, appetite, water intake, and general demeanor helps track the cat's status between veterinary visits. Follow-up blood work and examinations are scheduled at intervals determined by disease severity and stability.

Prognosis for cats with systemic amyloidosis depends on which organs are affected and the degree of damage at diagnosis. Cats with renal amyloidosis may survive months to a few years with appropriate management, though progression to end-stage kidney failure is expected. Those with hepatic involvement, particularly Abyssinian cats prone to liver rupture, face a more guarded prognosis due to the risk of fatal hemorrhage. Cats diagnosed early with mild organ involvement generally have longer survival times than those presenting with advanced disease. Individual variation is significant, and some cats maintain reasonable quality of life longer than initially expected while others decline rapidly.

Long-term outlook for cats with systemic amyloidosis requires honest acknowledgment that this is a terminal condition with no cure currently available. The focus shifts to quality of life rather than quantity, ensuring that affected cats remain comfortable and experience good days for as long as possible. Some cats stabilize for extended periods with consistent management, enjoying reasonable quality of life despite their diagnosis. Regular reassessment helps determine when the disease has progressed to the point where quality of life is significantly compromised. Ongoing research into amyloidosis offers hope for future treatment advances, but currently, owners should be prepared for eventual progression of the disease.

Primary prevention of systemic amyloidosis focuses heavily on responsible breeding practices in predisposed breeds. Breeders of Abyssinian, Siamese, and Oriental Shorthair cats should be aware of familial amyloidosis in their lines and work to reduce its prevalence. Affected cats and known carriers should be removed from breeding programs. Pedigree research helps identify lines with higher incidence of the disease. Potential buyers of predisposed breeds should inquire about amyloidosis history in the breeding line and request health testing documentation. While genetic testing for feline amyloidosis is not widely available, careful record-keeping of family health history helps breeders make informed decisions.

Environmental prevention strategies aim to reduce chronic inflammation that may trigger or accelerate amyloidosis development. Maintaining excellent dental health through regular veterinary cleanings and home dental care reduces chronic oral inflammation. Prompt treatment of infections prevents them from becoming chronic inflammatory foci. Minimizing stress through environmental enrichment, stable routines, and appropriate resources helps maintain immune balance. Indoor housing protects cats from infectious diseases and injuries that could trigger inflammatory responses. A clean, comfortable living environment supports overall health.

Dietary considerations for cats at risk of amyloidosis center on supporting overall health and reducing inflammatory burden. High-quality, species-appropriate nutrition provides essential nutrients without unnecessary additives that might contribute to inflammation. Omega-3 fatty acid supplementation from fish oil may provide anti-inflammatory benefits. Maintaining healthy body weight prevents obesity-related inflammation. For cats already showing early signs of kidney involvement, early transition to renal-supportive diets may slow progression. Clean, fresh water should always be available to maintain hydration and support kidney function. Avoiding foods known to stress the kidneys or liver supports organ health.

Health maintenance through regular veterinary care is essential for early detection and intervention in cats at risk for amyloidosis. Annual or semi-annual wellness examinations allow veterinarians to detect subtle changes that might indicate developing problems. Routine blood work and urinalysis establish baseline values and identify early organ dysfunction before clinical signs appear. For cats in predisposed breeds, screening may begin at a younger age and occur more frequently. Vaccinations appropriate to the cat's lifestyle protect against infectious diseases that could trigger chronic inflammation. Parasite prevention eliminates another potential source of ongoing immune stimulation.

Early intervention when problems are detected offers the best chance for managing amyloidosis effectively. Cats showing early signs of kidney or liver involvement should receive prompt evaluation and treatment initiation. Beginning supportive therapies before severe organ damage develops may slow progression and extend quality life. Regular monitoring of at-risk cats allows detection of protein in urine or subtle changes in kidney values that might indicate early amyloid deposition. Working closely with a veterinarian familiar with the condition ensures appropriate surveillance and timely intervention. For breeders, maintaining relationships with veterinary specialists in internal medicine provides access to the latest information on detection and management strategies.

Daily management of a cat with systemic amyloidosis requires establishing consistent routines that support the cat's health while fitting into the owner's lifestyle. Medication schedules should be regular and timed appropriately, with phosphate binders given with meals and other medications as prescribed. Subcutaneous fluid administration, if recommended, is typically performed every one to three days depending on the cat's needs, and most owners become comfortable with this procedure quickly. Feeding the prescribed diet consistently helps maintain nutrition while supporting affected organs. Fresh water should be available at multiple locations to encourage adequate hydration. Daily observation of appetite, energy level, and litter box habits provides important information about the cat's status.

Home environment modifications help cats with systemic amyloidosis remain comfortable and maintain quality of life. Providing easily accessible resting spots on the ground floor reduces the need for jumping and climbing as the cat's energy declines. Keeping food, water, and litter boxes on the same floor prevents unnecessary stair climbing. Low-sided litter boxes allow easy entry for cats with reduced strength. Warm, soft bedding in quiet areas provides comfortable rest spots. Maintaining consistent temperature and avoiding drafts helps cats with compromised health regulate their body temperature. Minimizing household disruptions reduces stress on the affected cat.

Quality of life assessment becomes central to caring for a cat with systemic amyloidosis, as the goal of treatment is to maintain good quality rather than simply extend life. Cats should still show interest in their surroundings, enjoy interactions with family members, and engage in some normal activities like grooming and playing, even if at reduced levels. Appetite and the ability to eat comfortably indicate reasonable quality of life. Freedom from significant pain or distress is essential. Regular quality of life assessments using tools such as the HHHHHMM scale help owners objectively evaluate their cat's status. Consulting with the veterinarian about quality of life concerns ensures appropriate adjustments to care.

Monitoring and ongoing veterinary care allow for timely adjustments to the management plan as the disease evolves. Regular rechecks, typically every one to three months depending on disease severity, include physical examination, blood work, and urinalysis. Tracking trends in kidney and liver values helps predict disease trajectory and guides treatment modifications. Blood pressure monitoring identifies hypertension requiring treatment. Watching for signs of complications such as urinary tract infections, severe anemia, or dehydration allows prompt intervention. Maintaining open communication with the veterinary team ensures that concerns are addressed quickly and care remains optimal.

Caregiver support is an important but often overlooked aspect of managing a cat with a chronic terminal illness. Caring for a sick cat can be emotionally draining and time-consuming. Owners should recognize that their own wellbeing matters and seek support when needed. Pet loss support groups and counselors can help with anticipatory grief and eventual loss. Financial planning for ongoing care helps reduce stress about treatment costs. Understanding that quality of life takes precedence over quantity helps owners make compassionate decisions when the time comes. Veterinary teams and online communities of others caring for cats with similar conditions provide valuable support and shared experiences.

Abyssinian cats represent the breed most strongly associated with familial systemic amyloidosis, with the condition well-documented in this breed for decades. Studies suggest that a significant percentage of Abyssinians carry genetic susceptibility to the disease, though not all carriers develop clinical illness. The pattern of inheritance appears to be autosomal dominant with variable penetrance, meaning the trait can be passed from an affected parent to offspring but not all cats inheriting the mutation will develop disease. Abyssinians typically develop renal amyloidosis affecting the kidneys, leading to chronic kidney disease, but some also develop hepatic amyloidosis that can cause fatal liver rupture. The average age of onset in Abyssinians is younger than in non-predisposed cats, with many developing disease between one and five years of age.

Siamese and Oriental Shorthair cats also demonstrate increased susceptibility to systemic amyloidosis. In these breeds, hepatic amyloidosis is more commonly reported than renal forms, with the liver being the primary organ affected. Hepatic amyloidosis in Siamese cats carries significant risk of liver rupture and fatal internal hemorrhage, sometimes occurring with little warning. Related breeds including Balinese and Oriental Longhair may share this genetic susceptibility. The familial nature of amyloidosis in Siamese lines has been documented, though the specific genetic basis remains under investigation. Devon Rex cats have also been reported to have higher incidence of amyloidosis compared to the general cat population.

Screening recommendations for cats in predisposed breeds include regular wellness examinations with blood work and urinalysis starting at a young age. For Abyssinians, annual screening beginning at one to two years of age helps detect early kidney involvement before clinical signs develop. Urinalysis should include assessment for proteinuria, which may be an early indicator of glomerular amyloid deposition. Breeders should maintain detailed health records and track occurrence of amyloidosis in their lines over generations. Potential buyers should request documentation of health screening in parent cats and information about amyloidosis in the breeding line. While genetic testing for feline amyloidosis is not yet commercially available, research continues to identify the specific mutations responsible, which may eventually lead to screening tests. Until then, careful breeding practices based on family history remain the primary prevention strategy.

Chronic kidney disease commonly co-occurs with and results from systemic amyloidosis affecting the kidneys. As amyloid deposits in the glomeruli and renal interstitium, normal kidney tissue is progressively replaced, leading to loss of filtration capacity and the clinical syndrome of chronic kidney disease. Cats with renal amyloidosis require management similar to other forms of chronic kidney disease, including dietary modification, fluid support, and medications to control associated complications. However, the underlying cause differs, and renal amyloidosis may progress more rapidly than some other forms of kidney disease. Hypertension and anemia frequently accompany chronic kidney disease regardless of cause and require specific treatment.

Conditions with similar symptoms to systemic amyloidosis include various other causes of chronic kidney disease, liver disease, and systemic illnesses causing weight loss and malaise. Polycystic kidney disease, another genetic condition affecting certain cat breeds, causes progressive kidney failure with similar clinical signs. Chronic interstitial nephritis, glomerulonephritis from other causes, and nephrotoxin exposure all produce kidney disease symptoms. Hepatic lipidosis, inflammatory liver disease, and liver tumors can mimic hepatic amyloidosis. Hyperthyroidism, diabetes mellitus, and cancer are other systemic conditions causing weight loss, increased thirst, and declining health. Differentiating between these conditions requires careful diagnostic evaluation, as treatment approaches and prognoses vary significantly.

Potential complications of systemic amyloidosis include progressive organ failure, life-threatening hemorrhage, and secondary infections. As kidney function declines, cats develop uremia with associated nausea, vomiting, electrolyte imbalances, and eventually neurological signs. Severe protein loss through damaged kidneys can cause hypoalbuminemia with associated edema and pleural effusion. Hepatic amyloidosis predisposes to spontaneous liver rupture and fatal internal bleeding. Cats with compromised organ function are more susceptible to infections, including urinary tract infections and respiratory infections. Thromboembolism may occur in cats with significant proteinuria. These complications often indicate disease progression and may ultimately be the determining factor in end-of-life decisions.