Old Dog Peeing Blood: 7 Causes + Treatments  

Hematuria, or blood in the urine, is a symptom that indicates something is wrong in our dogs’ urinary tract system. Age is one of the main factors that contribute to this condition. 

There are two types of hematuria:

  • gross 
  • microscopic 

Gross hematuria is when the urine appears to be reddish or brownish in color, while microscopic hematuria is when blood in the urine can only be detected under a microscope.

Gross hematuria is often more noticeable to dog owners, as the urine may have a distinct color or odor. However, microscopic hematuria can also be a cause for concern, as it may indicate a problem that is not visible to the naked eye.

In this article, we’ll discuss what causes old dogs to pee blood, underlying medical issues that cause this symptom, how the diagnostic test may look, and treatment options.

Causes of Hematuria [Old dog peeing blood]

  • Urinary tract infections 
  • Bladder or kidney stones
  • Tumors or growths in the urinary tract
  • Blood Clotting Disorders
  • Trauma or injury to the urinary system
  • Age-related changes to the urinary system
  • Diabetes

1. Urinary Tract Infections (UTIs)

UTIs are the most common cause of hematuria in dogs, especially in older dogs. 

UTIs occur when bacteria enter the urinary tract and begin to multiply, causing inflammation and irritation in the urinary tract. 

Senior dogs’ urinary tract system becomes weaker and more susceptible to infections. UTIs can cause discomfort, pain, and frequent urination, along with the presence of blood in the urine. 

If left untreated, UTIs can lead to more severe conditions such as kidney infections, which can be life-threatening.

2. Bladder or Kidney Stones

Bladder or kidney stones are formed when minerals and other substances in the urine crystallize and stick together, forming small, hard stones. These stones can obstruct the urinary tract, leading to discomfort and bleeding. 

The most common treatments for these stones are surgery and interventional radiology.

Some kidney stones can be left untreated if they do not obstruct urine flow. However, if the stones get very large or little pieces break off and lodge in the ureter, the condition becomes very painful.

Symptoms of bladder and kidney stones in dogs may include: 

  • difficulty urinating 
  • blood in the urine 
  • frequent urination 
  • straining to urinate 
  • pain

In senior dogs, these symptoms may be mistaken for other health problems, such as incontinence or arthritis. 

Hemodialysis for pets with acute and chronic kidney disease, as well as those who have ingested toxins, is a blood purification that removes toxic metabolites, balances electrolytes, and removes excess water that builds up when the kidneys are unable to excrete it.

During hemodialysis, a venous catheter is placed in the jugular vein of the animal to allow for repeat treatments if necessary. Blood is then pumped through a machine and cleared by a special filter called an artificial kidney or dialyzer. 

Hemodialysis is effective for managing life-threatening uremia in dogs and cats and is indispensable for animals with refractory acute renal failure.

Early initiation of hemodialysis, prior to the development of hyperkalemia, fluid overload, and severe acidemia, is crucial for superior outcomes such as survival and renal recovery. 

The survival rates of dogs and cats undergoing hemodialysis are about 50%, which is similar to overall survival rates in patients with acute kidney injury.

Hemodialysis is a technically sophisticated therapy and is not available at all veterinary hospitals. You may want to check with veterinary hospitals in your area that provide advanced kidney and urinary therapies for animals.

3. Tumors or Growths

Tumors or growths in the urinary tract, bladder, or prostate can cause hematuria in old dogs. These growths can be either benign or malignant, and they can cause pain, discomfort, and bleeding. 

Some tumors or growths can be treated with surgery or medications, while others may require more aggressive treatment such as chemotherapy or radiation therapy.

Prostate Issues

Older male dogs may develop prostate issues such as inflammation, infection, or even cancer. These conditions can lead to hematuria and other urinary-related problems. 

Prostate issues can cause discomfort, difficulty urinating, and blood in the urine. Treatment for prostate issues depends on the severity of the condition and may include medications, surgery, or other medical interventions.

4. Blood Clotting Disorders

Blood clotting disorders can be genetic or acquired, and they can be life-threatening if left untreated. 

Blood clotting disorders refer to a group of conditions that can lead to excessive bleeding or the inability of blood to clot properly. These conditions can be congenital (present at birth) or acquired (developed later in life).

In senior dogs, there are several blood clotting disorders that may occur:

  • Factor II (prothrombin) disorders: This is a rare inherited disorder that results in a mild bleeding problem such as nosebleeds. However, injury or surgery can lead to life-threatening bleeding. Treatment involves intravenous transfusion with fresh or fresh-frozen plasma.
  • Von Willebrand’s disease (vWD): This is a genetic disorder that affects platelet function and can cause excessive bleeding. It is commonly seen in certain breeds, such as Doberman Pinschers, German Shepherds, and Golden Retrievers. Treatment involves transfusing fresh or fresh-frozen plasma.
  • Hemophilia A: This is another rare genetic disorder that affects blood clotting factor VIII. It is commonly seen in certain breeds, such as German Shepherds and Golden Retrievers. Treatment involves transfusing fresh or fresh-frozen plasma.
  • Immune-mediated thrombocytopenia: This is a condition where the dog’s immune system destroys its own platelets, leading to excessive bleeding. Treatment involves immunosuppressive drugs, blood transfusions, and supportive care.

Your veterinarian may perform coagulation tests, such as the ACT (activated clotting time) test, to diagnose the disorder. 

Treatment will depend on the specific disorder and its severity. With proper management and treatment, many dogs with blood clotting disorders can lead happy and healthy lives.

Treatment for blood clotting disorders may include medications or blood transfusions.

5. Trauma or Injury

If a dog experiences trauma or injury to their urinary tract, bladder, or kidneys, they may experience hematuria. This can happen if a dog is hit by a car or falls from a high place, causing damage to their organs. 

Trauma or injury can cause severe bleeding, pain, and discomfort, and it requires immediate medical attention.

These changes may lead to decreased bladder control and increased susceptibility to urinary tract infections (UTIs).

Common age-related changes are: 

  • decrease in the number of cells within the kidney  
  • thickening of the connective tissue capsule surrounding the organ 
  • decrease in the thickness of the cortical region
  • decreased  ability of the bladder to contract effectively
  • age-related decrease in the urethral sphincter tone

These changes can lead to: 

  • decreased kidney function, which can result in a decreased ability to clear wastes from the body and a decreased ability to conserve fluids when needed
  • incomplete emptying of the bladder and increased risk of UTIs,  urinary incontinence 

To address these age-related changes a complete blood count, biochemistry profile, urinalysis, and thyroid hormone testing should be checked regularly. 

If urinary incontinence or UTIs are present, medications and lifestyle changes may be recommended to manage symptoms.

7. Diabetes

When dogs have diabetes, their bodies can’t properly regulate blood sugar levels, which can lead to damage to the kidneys and urinary tract. 

This damage can cause urinary tract infections, inflammation, and other issues that can lead to hematuria.

To diagnose diabetes, a veterinarian can perform simple blood tests to check for elevated glucose levels. 

If your dog is diagnosed with diabetes, they will need a specific diet and feeding regimen that will enhance the effectiveness of insulin. 

Overweight dogs may need to be placed on a weight-reducing diet, and it’s important that dogs with diabetes stick to their diet. Heavy exercise can reduce the amount of insulin needed, but exercise should always be approached with caution in dogs with diabetes.

You can monitor your dog’s glucose levels with a portable glucometer and blood test strips, either at the veterinarian clinic or at home. 

A veterinarian may recommend neutering if intact dogs have a history of hematuria and an enlarged prostate.

Diabetes is not technically preventable in dogs, pet parents can help by taking their dogs to the vet for routine exams and blood work, particularly for senior dogs over the age of 6 who should be taken to the vet every six months.

Symptoms to Watch For

If you suspect that your old dog is experiencing hematuria, you should watch out for the following symptoms:

Frequent Urination

If your dog is urinating more often than usual, it may indicate a problem with its urinary tract system. This can be a sign of a urinary tract infection, bladder stones, or cancer. It is important to monitor your dog’s urination habits and report any changes to your veterinarian.

Straining to Urinate

If your dog seems to be having difficulty urinating or is straining to go, it could be a sign of hematuria or another urinary tract issue. This can be caused by a blockage in the urinary tract, inflammation, or infection. If left untreated, this can lead to serious health problems for your dog.

Lethargy or Weakness

If your dog is experiencing hematuria, it may feel weak or lethargic due to pain or discomfort. This can be a sign of a more serious underlying health problem, such as kidney disease or cancer. It is important to take your dog to the vet if they are showing signs of lethargy or weakness.

Loss of Appetite

If your dog is not eating or drinking normally, it could be a sign of hematuria or another underlying health problem. This can be caused by pain or discomfort, as well as a loss of interest in food due to illness. It is important to monitor your dog’s eating habits and report any changes to your veterinarian.

Abdominal Pain or Discomfort

If your dog is experiencing hematuria, it may show signs of abdominal pain or discomfort when trying to urinate. This can be caused by inflammation or infection in the urinary tract, as well as other health problems such as bladder stones or cancer. 

Diagnosing and Treating Hematuria (Old dog peeing blood)


Urinalysis is a diagnostic test for evaluating the health of a dog‘s kidneys and urinary system, and metabolic diseases such as diabetes mellitus. It shows parameters for physical and chemical properties of urine, including color, clarity, pH, glucose, ketones, BUN, Serum Creatinine test, etc.

The test can be minimally invasive if you can collect the urine sample, or more invasive – catheterization or cystocentesis.

Catheterization –urine sample is collected via catheter. 

Cystocentesis – urine sample is collected via syringe directly from the bladder. 

X-rays and ultrasound

When a senior dog presents with blood in their urine X-rays help evaluate their internal organs and urinary tract. 

X-rays use electromagnetic radiation to create images of the inside of the body to detect bladder stones, tumors, or other abnormalities in the urinary tract. 

Ultrasound, on the other hand, uses high-frequency sound waves to create real-time images of internal organs and blood flow. Ultrasound can be particularly helpful in detecting kidney or liver disease, tumors, or other abnormalities in the urinary tract or surrounding organs.

Diagnosing cancer

If cancer is suspected, further diagnostic tests such as chest X-rays, abdominal ultrasound, CT scans, or MRIs can help determine the presence and location of tumors in the body. 

Veterinary Bladder Tumor Antigen (VBTA) test is a screening test that is run on urine to check for bladder cancer in dogs. 

This test is used to detect transitional cell carcinoma (TCC) of the lower urinary tract in dogs.

The VBTA test is 85% sensitive to TCC, meaning that it is able to detect the presence of TCC in 85% of dogs with the disease. However, the test is only 45% specific in the presence of other urinary tract diseases such as hematuria and pyuria. 

Therefore, a positive result does not always equal TCC. False positives have been recorded in dogs with bladder infections.

VBTA test is only a screening test and a negative result is 85% reliable. If the VBTA test results are positive, further testing may be necessary to confirm the diagnosis of TCC

In some cases, a biopsy of the affected tissue may also be necessary for a definitive diagnosis.

Identifying prostate problems

Prostatic diseases can include benign prostatic hyperplasia (BPH), prostatitis, and prostate cancer

Common clinical signs of the prostatic disease include blood-tinged fluid on the bedding, changes in urination such as increased frequency, straining, interrupted streams of urine or blood, constipation, or straining to defecate.

Paraprostatic cysts, which are cysts that form outside the prostate, can be spotted via ultrasound or X-rays. 

Another diagnostic test is a rectal exam to evaluate if a dog’s prostate has shrunk, which can indicate BPH as the underlying cause of prostate growth

Blood Pressure Measurement 

Measuring blood pressure in senior dogs that have blood in urine is an important step in identifying potential underlying cardiovascular problems. 

Hypertension, or high blood pressure, can cause damage to the kidneys and can lead to blood appearing in the urine.

Methods for measuring blood pressure in dogs: 

  • Direct arterial monitoring 
  • Doppler ultrasound
  • Oscillometric devices

While direct arterial monitoring is the most accurate, it is invasive and requires anesthesia, making it less suitable for routine monitoring. 

Doppler ultrasound is a non-invasive method that uses a handheld probe to listen for blood flow, but it can be less accurate in dogs with irregular heart rhythms. 

Oscillometric devices are the most commonly used non-invasive method and measure blood pressure using a cuff around the dog’s leg or tail.

Blood Tests 

A comprehensive senior blood panel shows overall health and helps detect underlying conditions. 

This panel typically includes a complete blood count (CBC), biochemistry profile, urinalysis, and thyroid hormone testing.

The CBC measures the number and types of blood cells, while the biochemistry profile assesses organ function and metabolic status. 

The urinalysis helps evaluate kidney function and can detect urinary tract infections or other conditions causing blood in the urine. 

Specialized tests BUN and Creatinine tests, and electrolyte levels are performed when kidney problems are suspected. 


Fine-needle aspiration biopsy, which involves inserting a thin needle into the mass to extract cells for examination is often performed if the mass is easily accessible and visible.

Incisional biopsy, which involves making a small incision into the mass to extract a tissue sample. This type of biopsy is performed if the mass is too large for a fine-needle aspiration biopsy or if the mass is not visible.

Excisional biopsy, which involves removing the entire mass and sending it for analysis. This type of biopsy is often performed if the mass is small and accessible.

Liquid biopsies are non-invasive procedures for detection at early stages. 

Treatment for Hematuria in Old Dogs

If your dog has a urinary tract infection, they will likely be prescribed antibiotics to clear up the infection. It’s important to give your dog the full course of antibiotics as prescribed, even if their symptoms improve before the medication is finished.

If bladder or kidney stones are the cause of the hematuria, surgery may be necessary to remove them. Your veterinarian will discuss the risks and benefits of surgery with you and help you make an informed decision about your dog’s care.

In cases where tumors or growths are the cause of hematuria, your veterinarian may need to perform surgery or recommend chemotherapy. It’s important to discuss all treatment options with your veterinarian and to make the best decision for your dog’s individual needs.

In addition to medical treatment, supportive care may be necessary to help your dog recover from hematuria. This might include medications to relieve pain and discomfort, as well as a special diet that is low in protein and sodium to help prevent further damage to their urinary tract system.

Old dog peeing blood – takeaways

As owners, it’s our responsibility to keep a close eye on our old dogs and respond quickly when we notice any signs of hematuria. 

While it can be scary to think about your dog experiencing blood in their urine, remember that there are many treatment options available to help your dog recover. With the right care and attention, you can help your furry friend feel better and enjoy a happy, healthy life.

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