Dog Lyme disease life expectancy: what owners should know

Most dogs with Lyme disease have a normal life expectancy. The large majority of dogs that test positive never become ill at all. Most of those that do, with fever, lameness and swollen joints, improve within days of starting antibiotics from their vet and go on to live as long as they otherwise would.

The exception is Lyme nephritis, an uncommon form of kidney damage linked to the infection, and it is what most searches about Lyme disease and life expectancy are really about. Its outlook is much poorer. Dogs already in kidney failure when it is found often live only days to weeks, even with treatment. Dogs caught earlier, when the only change is protein in the urine, can do far better. These are commonly reported patterns, not predictions, and your own vet is the one who can give a prognosis for your dog.

How long can a dog live with Lyme disease?

It depends on which of these four situations your dog is in.

What Lyme disease is and how it usually goes

Lyme disease is caused by a bacterium, Borrelia burgdorferi, carried by blacklegged ticks, often called deer ticks. A tick usually has to stay attached for a day or two to pass it on.

When a dog does become ill, it tends to be weeks to months after the bite. The typical signs are:

• Fever and tiredness
• Lameness, sometimes moving from one leg to another
• Warm, swollen, painful joints
• A poor appetite
• Swollen lymph nodes

The usual in-clinic test looks for antibodies. A positive result means the dog has met the bacterium at some point. It does not show that the dog is ill, or that Lyme is the reason for a limp. In an older dog a limp is far more often arthritis or one of the other causes of limping in old dogs, and a positive Lyme test can sit alongside any of them. Your vet weighs the test against the signs and the examination.

Does treated Lyme disease shorten a dog's life?

Not usually. Vets treat Lyme arthritis with a course of antibiotics, most often doxycycline. The choice of drug, the dose and the length of the course are your vet's decision, based on your dog's weight, age, kidneys, liver and other medicines. Most dogs are noticeably more comfortable within a few days. If yours is not, tell the vet, because that often means something else is causing the lameness.

The antibody test can stay positive for a long time after treatment, which is not a sign that treatment failed. A dog can also be infected again by a new tick bite. Neither, by itself, shortens a dog's life.

If your dog is sore while the antibiotics take effect, ask the vet about pain relief. Do not give human painkillers. Ibuprofen, naproxen, acetaminophen and aspirin can seriously harm or kill dogs, and several of them damage the kidneys.

Lyme disease and kidneys in dogs: life expectancy

Lyme nephritis is the serious form. It is thought to be caused by the immune system's reaction to the infection, which damages the filters of the kidney, more than by the bacteria attacking the kidney directly. The damaged filters leak protein into the urine. In the severe form the kidneys then fail quickly.

It is uncommon, affecting only a small minority of dogs that test positive. It has been reported more often in Labrador and golden retrievers, and it can appear in dogs that never showed lameness. Signs that can point to it include:

• Vomiting and refusing food
• Marked tiredness and weight loss
• Drinking and urinating more, or later, passing very little urine
• Swelling of the legs, face or belly from fluid
• Breath that smells of ammonia

None of these confirms Lyme nephritis. Other kidney diseases look the same, and the diagnosis rests on blood and urine tests.

What is the prognosis when a dog's kidneys are shutting down from Lyme disease?

Poor. In the classic form, a dog that is vomiting, off food, with high kidney values and heavy protein loss, most reported cases died or were euthanized within days to weeks despite hospital care. Some dogs do survive longer with intensive treatment, which at referral hospitals can include immune-suppressing medicines and dialysis. No one can promise that outcome.

The picture is clearly better for a dog found earlier, with protein in the urine but normal kidney blood values, who still feels well. With treatment and regular checks, these dogs can stay stable for months to years. If lasting kidney damage remains, it is staged and managed like other chronic kidney disease, and the figures in dog kidney disease stages and life expectancy become the more useful guide.

How vets treat Lyme nephritis

Treatment usually combines antibiotics, medicines that reduce protein loss and control blood pressure, medicine to lower the risk of blood clots, and a kidney diet (see what to feed a dog with kidney disease). Sick dogs need fluids and anti-nausea treatment in the hospital. Which of these apply, and in what amounts, is for the treating vet to decide.

Why older dogs need a urine protein check after a positive test

Guidance from veterinary internal medicine specialists is that every dog with a positive Lyme test should have its urine checked for protein, whether or not it seems ill, and rechecked from time to time. The usual test is a urine protein to creatinine ratio on a sample you can often collect at home.

This matters most for older dogs and dogs that already have chronic kidney disease. They have less kidney reserve to lose, protein in the urine is linked with faster decline whatever the cause, and a baseline makes later changes easier to read.

Questions worth asking your vet after a positive test:

• Has my dog's urine been checked for protein, and when should it be rechecked?
• Are the kidney values on recent bloodwork normal for my dog's age?
• Does my dog need treatment now, or monitoring?
• Which tick preventive suits my dog, and is a Lyme vaccine worth considering where we live?

What changes the outlook

• Whether the kidneys are involved. This is the dividing line between a normal lifespan and a guarded one.
• Other illnesses. Existing kidney disease, heart disease or a second tick-borne infection make recovery harder, and older dogs recover more slowly.
• Preventing new tick bites. Reliable tick control lowers the chance of reinfection.

Call the vet today if

Call your vet or an emergency clinic now if a dog with a positive Lyme test, or one that lives or travels where ticks are common:

• Is vomiting repeatedly or has stopped eating
• Is suddenly drinking and urinating much more, or is passing little or no urine
• Has swelling of the legs, face or belly
• Is very weak, flat or unwilling to get up
• Has a fever, or lameness that has not improved after a few days of antibiotics
• Has trouble breathing, pale gums, or collapses

This article is general educational information about Lyme disease in dogs and is not veterinary advice. Life expectancy figures are commonly reported ranges that vary widely between dogs, and a positive Lyme test does not by itself mean a dog is ill or has kidney disease. Testing, treatment and prognosis for your dog should be decided with your veterinarian.