Accurate characterization and diagnosis of generalized tremors is difficult. Discovering the cause requires a thorough history as well as a complete physical, neurological and orthopedic exam. Other diagnostics that may be helpful include a CBC and chemistry panel to evaluate body systems and look for metabolic dysfunctions. An EMG and/or muscle and nerve biopsies may be warranted if a primary muscle disorder is suspected. Collection and analysis of cerebrospinal fluid is useful when looking for inflammation or an infectious cause. Tremors have been associated with congenital disease, chemical/plant intoxication, secondary to drug therapies, and bacterial or viral diseases.
Congenital diseases that cause generalized tremors in dogs, such as insufficient myelination of the CNS, often manifest themselves early in life. The tremors involved with these abnormalities are primarily noticed during goal-oriented activity (intention tremors), seem to lessen with rest and resolve with sleep. The pathogenesis of these tremors is unclear, but spontaneous discharge of the unmyelinated axons, and loss of coordinated muscle control may be the cause.
Ingestion of toxins such as organophosphates, hexachlorophene and bromethalin may result in generalized tremors. Suspected pathogenesis centers around altered nerve impulse conduction brought on by intramyelin edema. Mycotoxins have commonly been associated with tremors in dogs. Tremors resulting from drug therapies have also been documented. The pathogenesis is not always known, but discontinuing drug therapy will also stop the tremors.
Bacterial and viral encephalitis are also rule-outs when presented with a tremoring dog. The agents most frequently associated with tremors are canine distemper virus, adenovirus, parvovirus, herpes virus and tick-borne diseases. An extensive evaluation of cerebrospinal fluid is necessary for diagnosis. This includes cytologic evaluation of, as well as laboratory titers for, the suspected agent in the fluid.
Finally, there are those dogs that are referred to as little white shaker dogs. The syndrome was given this name because it was historically recognized in small breed white dogs such as the Maltese, West Highland White Terrier and poodle, although dogs with all coat colors are susceptible. They are generally young adults, initially showing signs at less than two years of age, and are small to medium sized dogs (<15 kg/33lbs). The generalized head and body tremors can range in severity from mild to incapacitating and tend to worsen with exercise, stress or excitement and lessen or resolve with sleep. Other neurologic signs (deficit in menace, nystagmus) may be present, but are not always noticed. Screening for infectious agents is generally negative. Cerebrospinal fluid analysis often reveals a mild lymphocytic pleocytosis, but may also be normal. Histologic exam of the CNS tissue of affected animals varies. A mild, non-suppurative meningoencephalitis with mild perivascular cuffing, most evident in the cerebellum, may be identified, but normal CNS tissue can also be found. The underlying disease process is still unknown. Some speculate that the tremors are due to an immune reaction targeted against the tyrosine producing cells. Tyrosine is important in the production of melanin as well as the neurotransmitters dopamine and norepinephrine. An imbalance of these neurotransmitters may lead to the clinical signs observed; however, variation in the pathologic changes identified in tissues suggests that inflammation is not the only mechanism involved in the pathogenesis. Diagnosing a white shaker dog is one of exclusion and response to treatment. These dogs respond to an immunosuppressive dose of cortico-steroids (prednisone). Tremors will generally resolve the first week or two after instituting therapy. The dose of steroids can then be tapered to the minimum effective dose, or discontinued completely. If the tremors return, reinstitution of the initial immunosuppressive dose may be necessary. Because of the response to steroids and the recognition of this syndrome in breeds other than those with a white hair coat, this disease is also referred to as steroid responsive tremor syndrome. Dogs that have this disease are subject to tremors that affect their entire body. Stress, handling, and excitement seem to worsen the condition. Occasionally, other neurological abnormalities are seen in association with this condition such as head tilts, limb weakness and seizures. White Shaker Dog Syndrome most commonly is seen in such breeds as West Highland White Terriers, Maltese, Yorkshire Terriers, Australian Silky Terriers, and Miniature Pinschers. While rare, it can also occur in Goldendoodle dogs.
A veterinarian normally will treat this condition with corticosteroids, with some dogs responding quickly and not needing additional treatments. Other dogs will need to have low doses every other day to keep the tremors under control. Again it must be stressed, that treatment must be in conjunction with the directions of a veterinarian. There are no known exact causes for White Shaker Syndrome. Any breed and color of dog may develop this disorder. However, small breeds with white coats are at greater risk of developing it. West Highland white terriers, Maltese terriers and beagles are the breeds most commonly affected. The age of onset typically occurs between one and two years of age. It affects the cerebellum and the cerebellar nerve tracts. There are various theories concerning the cause of shaker dog syndrome. One proposes a disruption in the production of the neurotransmitter substances epinephrine and dopamine. These substances are made from tyrosine, an amino acid, in nerve cells. Theoretically an autoimmune-mediated process, in which the affected animal's body makes antibodies against these nerve cells, could destroy the cells that make these neurotransmitters. A genetic role in the underlying cause has also been proposed. To date, these and other theories concerning the cause have not been proven, nor are there any conclusive tests available to either prove or disprove a genetic link. Some suggest that topical flea treatments can cause many health issues in dogs, especially Goldendoodles. Topical flea treatments can be toxic due to long term usage that can build up in the blood stream. We do not recommend topical flea treatments for the Goldendoodle dog.
FOOTNOTE: Since 1999, none of our created Goldendoodles have ever been diagnosed with "White Shaker's Syndrome. We have only written about this illness because someone who owns a Goldendoodle purchased from a different breeder brought the illness to our attention. This is for general "doodle" info only.
-by Kelly Smith, Class of 2004-edited by Dr. Leon Thacker, ADDL Director
References:
Bagley RS: 1992. Tremor syndromes in dogs: Diagnosis and treatment. J Small An Med 33: 485-589.
Bagley RS, Kornegay J, Wheeler S, et al: 1993. Generalized Tremor in Maltese: clinical findings in seven cases. JAAHA 29: 141-145.
Cuddon P:1990. Tremor syndromes. Progress in Veterinary Neurology. 1:285-298.
Ettinger and Feldman: 2000. Textbook of Veterinary Internal Medicine. WB Saunders, Philadelphia.
Wagner S, Podell M and Fenner WR: 1997. Generalized tremors in dogs: 24 cases. JAVMA 211(6): 731-735.
*Special thanks to Erica for bringing her Goldendoodle's plight to our attention. Although she did not purchase her doodle from us nor does her Goldendoodle share related bloodlines, she contacted us seeking information about a health problem her Goldendoodle dog was experiencing. It is with hope that her Goldendoodle's plight can help other doodles who may experience the same situation. The emails below are actually not posted in the order they were received, but we placed them on here for others in case they ran into a similar issue with their Goldendoodle, regardless of what breeder they may have purchased from:
RE: Goldendoodle
From: Birt and Erica Anderson
Sent: Mon 5/28/07 9:16 PM
To: Goldendoodle World
Thanks Dee! You've been really supportive in this and I really appreciate it - I know your research and help might save another dog down the road. I got great news yesterday that after a couple of days on predneson, she was able to come off the diazepam drip without seizures, but will be taking both drugs still - could be for a while, could be forever. Sunday morning she was able to crawl about 20 feet - sounds horrible but the vet said very encouraging - and then proceeded to drink a bunch of water and eat an entire can of food and kept it down and was able to sit up for the first time, but still has tremors. She actually might get to come home on this week but will be in for some major nursing/lounge time as she can't stand yet. I'm so glad one of our vets attended Kansas State and knew the right person to call there at the vet clinic - either it was a good guess on their part or they know more about the subject than people in WY. Either way, I'm glad my little Bailey will be home soon without brain damage (they're pretty sure). I was really grateful for any information I could find anywhere, and you were a really good start.
thanks again, and hope you're having a nice Memorial Day weekend.
erica
At 06:32 PM 5/27/2007, you wrote:
Maybe it will be of some help.
Thanks.
dee
Date: Thu, 24 May 2007 16:34:32 -0600
To: goldendoodleworld
From: birt and Erica
Subject: Re: Goldendoodle
Thanks for the info - not what I wanted to hear, but it's in my head as well. AFter I sent my note to you, I heard from my vet, who had talked with someone at the Kansas STate University vet school - they suggested "shaker dog syndrome" as a cause which is supposedly treatable with steroids. I've never heard of that before, but will do some checking. They decided that the pancreatitis wasn't to blame, just an unfortunate problem during the same time frame so they were assuming it caused the seizures. However, the seizures have pretty much stopped today, just constant tremors.
I really appreciate your getting back to me so quickly!
Thanks, Erica
At 03:48 PM 5/24/2007, you wrote:
The best thing to do is to have your doodle put to sleep if a canine specialist has not been able to find out what has caused the health issue and if the issue can not be controlled with medications. We have discovered via the internet that topical flea treatments can cause severe health issues with dogs if used for a long period of time.
You may want to DNA your doodle to see if its a genetic issue. Many things can cause pancreatitis in dogs, including people. Such issues are not always genetic. Back in 1999, we had to put our sister's Goldendoodle to sleep because she went into kidney failure due to the medication remidyl that was given to her to treat an inner ear infection. She was good while on IVs, but as soon as she was not on them, she went downhill fast. It was not an easy situation, but we didn't want her to suffer as much as she was. We wish you well.
From: The Frappr Team
To: admin@igoldendoodle.com
Subject: Frappr Admin Message
Date: Thu, 24 May 2007 12:03:53 -0700 (PDT)
Hi Goldendoodle World Admin,
You have received a message regarding your map:
From: Erica
Message: Hi - our golden doodle, Bailey, had what they thought was pancreatitis on Friday, then started having severe seizures Saturday and since Sunday has been on a diazepam drip. When she's taken off, the seizures and tremors start again. Now today (Thursday 5/24/07), we're starting to have to think of putting her down - but she's not even 3 so I'm searching for information everywhere. We did not purchase our Goldendoodle from you but wondered if you had ever experienced this issue or had any customers of yours experience this issue. Any suggestions? Thanks for any information you can give to help.
Sincerely,
Erica
