I'm new here, so waving to everyone :wave: but this interested me and I thought I would post. I'm in a rescue, a Yorkie rescue and I've heard others talk about this.
I thought I would send you a few links as this could be very serious. Sorry to meet you under these circumstances.
http://www.yorkies.ws/poisons.htm
http://www.canine-epilepsy.com/Why.html Just a few more thoughts on the subject:
Dogs with recurring episodes of shaking, muscle twitches, cramping, or other "atypical" seizure-like activity may have liver malformations - porto-systemic vascular anomalies (PVSA); these include porto-hepatic shunts [blood by-passes the liver] or hepatic microvascular dysplasia (HMVD)[abnormal or no blood flow within the liver]. An episode may present as if the dog has intestinal cramps or is uncoordinated for a brief period. This may progress to what appears to be leg cramps or incoordination, or such dogs may present with typical seizures. Episodes may vary in duration. Episodes may be associated with eating high protein diets. Most episodes from PSVA do not occur in the regular pattern that is often associated with epilepsy. Some of these dogs may drink and urinate excessively as they try to flush "toxins" from their body. Liver biopsies taken from all lobes of the liver, can be done to confirm HMVD in symptomatic dogs, where obvious shunts are not apparent. Invasive surgery for biopsies is NOT recommended in asymptomatic dogs that have abnormally elevated liver function tests (paired bile acids). Affected dogs do not respond to normal seizure drugs, but may do well on specialized vegetable source protein diets (Hills K/D or L/D, the Iams Liver diet, or a home-cooked Tofu and rice diet.).
A single seizure or cramping episode in a dog of any age does not mean the dog is epileptic or has PVSA. Trauma, exposure to toxins that cause liver or kidney damage, hypocalcemia (in a whelping or nursing bitch), hypoglycemia in a severely stressed working animal, fever, or immature liver function have all been implicated in seizure activity. A dog that has one seizure should not be instantly placed on phenobarbital or other anticonvulsants. Most veterinarians wait to see if there is another episode, and meanwhile try to rule out other causes. Many epileptic (regularly recurring) seizures can be controlled with phenobarbital. Where there are recurring episodes some neurologists put the dog on an anticonvulsant to help block the "learning of seizure pathways in the brain." Epileptic seizures that do not respond to phenobarbital can sometimes be controlled with potassium bromide or a combination of potassium bromide and phenobarbital. However, long term use of anticonvulsant therapy is not without risk. Dogs on any medication must be monitored to be sure the medication is at therapeutic levels (different dogs have different metabolisms), as well as to monitor liver and kidney function.