This site tells you exactly what the symptoms are:

lyme.org/otherdis/ld_pets.html

Best of Luck at the Vet’s …. I hope your pooch will be alright!

For a nymph to transmit B. burgdorferi, it must be attached to the host for at least 24-48 hours. if a tick dies or is removed within this 1-2 day period, transmission of the bacteria will not occur. even if a tick is a carrier of B. burgdorferi and it attaches to the dog for more than 48 hours, the dog may not contract the disease. In fact, studies show that only around 10% of dogs that are exposed will contract the disease. there is no evidence to suggest that infected dogs pose a risk to other members of the household except as a reservoir of infected ticks. Once a tick has had a full meal, it will detach and not bite another mammal. the risk comes from ticks that have not gotten a complete meal and are detached. they could possibly seek out a human and bite them causing infection. Other types of ticks and insects have been shown to be infected with B. burgdorferi, but they are considered insignificant spreaders of the disease.

Clinical illness usually occurs 2 to 5 months after initial exposure and the likelihood of disease and the severity of the disease seems to vary with the animal’s age and immune status. Cats can develop Lyme disease, but it occurs rarely in them, even in endemic areas. Other domestic animals such as horses have contracted Lyme disease, but it does not appear to be a significant problem. Dogs show several different forms of the disease, but by far, the most common symptoms are a fever of between 103 and 105°, shifting leg lameness, swelling in the joints, lethargy, inappetence, and maybe most importantly, response to appropriate antibiotics.

Arthritis may be a result of both short- and long-term infections. Most dogs that are promptly diagnosed and treated do not appear to develop arthritis, but a few dogs who do not respond completely to treatment or were not treated will develop progressive degeneration of the infected joints.

A few dogs have developed severe progressive renal disease as sequelae to Lyme disease. this severe kidney failure is non-responsive to treatment and death is often the outcome. Fortunately, this form appears to be rare.

Usually, dogs will not develop any rash or the circular area of redness around the bite (erythema migrans) which is seen in people.

Ten years ago, Lyme disease was often under-diagnosed, but today, the opposite is true. because of the lack of sensitivity of the blood test, many dogs show positive test results, but are not actually infected with the disease. the standard blood test detects antibodies made by the dog in response to infection with B. burgdorferi. the problem is that many animals are exposed to the organism, but fight the infection off on their own. these animals will have antibodies to B. burgdorferi but not have the disease. As we mentioned earlier, only around 10% of the exposed dogs actually contract the infection. at the same time the antibody test cannot distinguish between a dog that has been vaccinated or naturally exposed to Borrelia. therefore, in endemic areas, the test alone is not an accurate way to get a diagnosis. However, the test can be used with several other criteria to gain a positive diagnosis. Suspected animals should have a history of tick exposure, compatible clinical signs, and have a rapid response to antibiotic therapy. In fact, clinical signs and rapid response to doxycycline antibiotic therapy is how I make a diagnosis of Lyme disease. a practitioner in a Lyme endemic area will often be able to diagnose the disease on physical exam. Practitioners in areas that have fewer Lyme cases may have to resort to using the blood test and treatment to confirm the diagnosis. if an animal that is suspected of having Lyme disease does not clinically improve within 48 hours of starting antibiotic therapy, assume that it is not Lyme disease and begin to do other diagnostic tests to find the source of the problem.

Treatment for Lyme disease is very straightforward and consists of using either a tetracycline or penicillin-based antibiotic. the two most commonly used are oral Doxycycline or Amoxicillin. a recent study showed that both antibiotics worked equally well. the antibiotics must be given a minimum of 14 days, but 30 days is recommended. However, some preliminary studies show that some animals may not even clear the organism after 30 days and will relapse once the antibiotic is discontinued. In these cases, the animal may have to be on the antibiotic for much longer. it appears that some animals may never completely rid themselves of B. burgdorferi despite aggressive treatment. these animals may suffer from increased degenerative changes in the joints leading to premature arthritis. Despite the fact that some animals may develop chronic infections, the vast majority of infected dogs respond rapidly and satisfactorily to doxycycline treatment. In some animals with severe arthritis, pain killers such as buffered aspirin (Do NOT give your cat aspirin unless prescribed by your veterinarian.) can also be used in addition to antibiotics. the use of steroids in this disease is definitely contraindicated

The most common visible symptoms of the disease in dogs include recurrent arthritis or lameness that lasts for several days accompanied by a loss of appetite and a sense of depression. Additional signs can include swollen joints, a painful gait, fever, fatigue and swollen lymph nodes. Symptoms can appear and disappear over a period of time, shift in their intensity and often are not apparent until several months after the dog is infected. many of these symptoms are shared by other health problems, which further adds to the confusion about identifying the diseaseFortunately, there are tests that can rapidly diagnose canine Lyme disease, yielding immediate results during a pet’s annual check-up visit. some of these tests also can identify other diseases caused by parasites, such as heartworm disease and ehrlichiosis. the American Lyme Disease Foundation recommends routine checks for dogs living in high-exposure areas, in order to catch problems early. these screenings can be a part of a dog’s annual or semi-annual check-up.

The most common symptom is no symptoms–it is a strange disease.