Dark Urine in Dogs

Summary

Dark urine is commonly observed in dogs, and is often normal. The color of urine varies for healthy pets, but some illnesses and injuries can contribute to a color change in the urine along with other symptoms.

Conditions associated with dark urine include any illness or injury that causes bleeding into the urinary tract, damaged muscle or red blood cells, as well as some types of immune-mediated diseases, diseases affecting the liver or kidneys, and some types of poisoning. Dark urine is classified by the substance present in the urine to cause the color change, such as blood or bile pigments. 

Diagnosis of potential causes for dark urine may include physical examination, bloodwork, urinalysis and diagnostic imaging. Treatment will depend on the nature of the underlying condition.

Guidelines

Healthy urine presents in a spectrum of colors and most of the time color changes are of no significance. It is not common for a dog to have a condition where dark urine is the only observation, as it typically occurs along with other symptoms.

The presence of dark urine is not considered a medical emergency, but if it is accompanied by other symptoms such as straining to urinate, it requires immediate veterinary attention.

Possible Causes

Color changes in urine are a normal indicator of the constantly fluctuating state of a healthy dog’s internal organs throughout the day. For example, the first morning urination is the most concentrated and therefore is often darker in color.

There are some instances where a color change can be directly associated with specific underlying factors, such as dehydration and some types of medication.

More serious conditions associated with dark urine include:

• Any condition that causes pigment to be present in the urine: including heatstroke, excessive exercise, or an electric shock. 

• Any condition that causes blood or traces of blood cells in the urine, such as urinary tract infections, and bladder stones

• Cancer: Some cancers such as prostate or bladder cancer may lead to discoloration of the urine. 

• Heartworm Disease: a dog suffering from severe heartworm disease often has dark brown urine. 

• Immune Mediated Hemolytic Anemia (IMHA): A condition in which a dog's immune system attacks its own red blood cells. 

• Toxins: ingestion of various toxins (including onion, zinc, or acetaminophen) can create dark urine. 

Note that in any case, dark urine in and of itself is not cause for concern. When dark urine is related to a more serious condition, other, more severe symptoms, are expected.

Risk Factors

Dark urine in dogs in dogs may be characterized by:

• Frequency: how often is the dark urine present? Is it regular or occasional?

• Development: did the dark urine suddenly arise (acute) or has it been present long-term (chronic)?

•Specific timing: does it happen throughout the voiding or only at the beginning or end of the stream? 

Dark urine can also be classified upon testing according to the substance in the urine that gives it the dark color: blood, hemoglobin, bilirubin, or myoglobin.

Testing and Diagnosis

The color of urine is not diagnostic itself, so a dog presenting with dark urine and other symptoms will need the some or all of the following diagnostics to determine the root cause and best course of action:

• Physical examination  • Urinalysis • Bloodwork• Diagnostic Imaging

Treatment will depend on the underlying cause. For example a urinary tract infection will be treated with antibiotics, and bladder stones may be treated with either diet or surgery. Some causes of dark urine, like what occurs after a day of extreme exercise, resolve on their own.

Similar symptoms

Dark urine is self-evident and not easily mistaken for other symptoms. The more common mistake to make is assuming dark urine means a dog is sick. The color of urine is highly subjective and varies for completely healthy dogs.

Associated Symptoms

Other urinary symptoms may appear with dark urine like: 

• Straining to urinate (stranguria)

• The presence of blood or hemoglobin in the urine (hematuria or hemoglobinuria)

• Increased frequency of urination (pollakiuria)

• Difficult and painful urination (dysuria)

• Urinating very small amounts (oliguria)