DOGS · Real veterinary cases
Seizures and hypothyroidism
A pet owner asked our search engine this exact question. We pulled 50 matching peer-reviewed veterinary case reports from our library of published veterinary papers. Here's what they say — in plain English, with citations.
Plain-English synthesis
## What these cases have in common The cases highlight a pattern where hypothyroidism is associated with various neurological symptoms, including seizures and other neurologic deficits. In many instances, treating hypothyroidism with thyroid hormone replacement therapy led to improvements in these neurological signs. ## Treatments that worked - **Levothyroxine therapy**: This thyroid hormone replacement was effective in resolving neurological symptoms in 5 of 7 cases where it was used, including seizures and polyneuropathy. - **Calcium supplementation**: In one case, intravenous calcium and subsequent oral supplementation successfully stopped seizure activity related to hypocalcemia, which can occur alongside hypothyroidism. - **Dietary management**: In cases where underlying conditions like inflammatory bowel disease were present, dietary changes combined with medications helped manage seizures and other symptoms. ## Outcomes The treatments, particularly levothyroxine therapy, showed positive outcomes in improving or resolving neurological symptoms in a significant number of cases, although the response time varied. ## Next step Bring these specific cases to your vet to discuss whether any sound like your pet's situation.
Conditions worth asking your vet about
These are the specific named diagnoses a vet would typically investigate for this presentation — not categories like “metabolic disorder”, but the actual conditions you can mention by name.
Idiopathic epilepsy
Idiopathic epilepsy is a common cause of seizures in dogs, especially in young to middle-aged animals without any identifiable underlying cause. It is diagnosed by ruling out other potential causes of seizures through blood tests, imaging, and sometimes spinal fluid analysis.
Hypothyroidism
Hypothyroidism is a condition where the thyroid gland does not produce enough hormones, leading to symptoms like lethargy, weight gain, and sometimes seizures. It is more common in middle-aged to older dogs and can be diagnosed with blood tests measuring thyroid hormone levels.
Hepatic encephalopathy (portosystemic shunt)
A liver shunt allows toxins to bypass the liver and reach the brain, causing neurological signs like seizures. This condition can be congenital or acquired and is diagnosed with blood tests and imaging studies such as ultrasound or CT scan.
Brain tumor (meningioma, glioma)
Brain tumors can cause seizures in older dogs due to the mass effect or inflammation. They are diagnosed through advanced imaging like MRI or CT scans. Meningiomas are the most common type in dogs.
Meningoencephalitis of unknown origin (MUO)
MUO is an inflammatory condition of the brain and meninges that can cause seizures and other neurological signs. It is diagnosed through imaging and cerebrospinal fluid analysis. It can occur in dogs of any age.
Hypoglycemia (insulinoma)
Hypoglycemia, or low blood sugar, can cause seizures and is sometimes due to an insulinoma, a tumor of the pancreas. It is diagnosed with blood glucose tests and imaging to identify the tumor.
Easily confused with: Cardiac syncope · Narcolepsy/cataplexy · Hypocalcemia · Vestibular disease
Real peer-reviewed cases
Each link below opens the full PetCaseFinder write-up of a published case report. Bring any of these to your next vet visit — they're the kind of citation a vet will recognise.
#1 match
Resolution of polyneuropathy in a hypothyroid dog following thyroid supplementation.Journal of the American Animal Hospital Association · 2014 · United States
An 8-year-old male golden retriever was brought in because he was showing signs of multiple nerve problems that were getting worse over time. During the exam, the vet noticed the dog was very overweight and had swelling in his face, which gave him a sad look. Tests showed that he had hypothyroidism (an underactive thyroid), and a nerve biopsy revealed damage to the nerve fibers. The dog was started on a medication called levothyroxine to help with his thyroid levels. Although it took more than six weeks for his symptoms to improve, he eventually made a full recovery within six months. This case shows that while it can take time for dogs with hypothyroid-related nerve issues to get better, treatment can lead to a complete recovery if started early enough.
Read the full case →#2 match
Neurologic manifestations of hypothyroidism in dogs.Compendium (Yardley, PA) · 2013 · United States
Hypothyroidism, which is a common hormone-related condition in dogs, can sometimes lead to unusual problems with the nervous system, although this is not very common. In some cases, the only signs of hypothyroidism might be related to the nervous system, making it tricky for vets to diagnose and treat these issues. This article talks about different ways hypothyroidism can affect a dog's nervous system and explains how these problems happen. It also looks at the research on how low thyroid hormone levels can impact a dog's brain and nerves. Overall, the findings highlight the importance of considering hypothyroidism when a dog shows neurological symptoms.
Read the full case →#3 match
Iatrogenic, sulfonamide-induced hypothyroid crisis in a Labrador Retriever.Australian veterinary journal · 2009 · United States
This case involves a 4-year-old female Labrador Retriever that developed a serious condition called hypothyroid crisis, which means her thyroid gland wasn't working properly, after being treated with a high dose of a medication called trimethoprim-sulfamethoxazole for 10 days. After starting treatment, she showed signs of weakness, trouble walking, and seemed mentally down. Tests confirmed that her symptoms were linked to the thyroid issue affecting her nervous system. Fortunately, a short course of levothyroxine sodium, a medication to help thyroid function, completely resolved her symptoms, and follow-up tests showed no other thyroid problems. This case is important because it highlights a potentially dangerous reaction to this common antibiotic in dogs, emphasizing the need for veterinarians to recognize it early.
Read the full case →#4 match
Neurologic dysfunction in hypothyroid, hyperlipidemic Labrador Retrievers.Journal of veterinary internal medicine · 2007 · United States
This study looked at four Labrador Retrievers, all of whom had hypothyroidism (an underactive thyroid) and very high levels of fats in their blood. They showed various neurologic problems, such as weakness in all four legs, balance issues, and facial paralysis. Two of the dogs had sudden symptoms that seemed to be caused by a blockage in their blood supply, which was confirmed by imaging tests. The other two dogs had ongoing issues with nerve function and weakness, with one showing signs of blood clots and artery disease. Fortunately, all the dogs improved after receiving thyroid hormone treatment.
Read the full case →#5 match
Primary hypothyroidism associated with leishmaniasis in a dog.Journal of the American Animal Hospital Association · 1999 · Italy
A four-year-old male Yorkshire terrier was diagnosed with primary hypothyroidism, which means his thyroid gland wasn't producing enough hormones. This condition was linked to leishmaniasis, a disease caused by a parasite. Tests showed low levels of a thyroid hormone called T4, a poor response to a hormone that stimulates the thyroid, and high levels of another hormone called TSH. A biopsy of the thyroid revealed the presence of the leishmaniasis parasite along with signs of damage to the thyroid tissue. The outcome of the treatment for this condition is not specified in the abstract.
Read the full case →
Your pet's case is probably already published.
PetCaseFinder reads thousands of peer-reviewed veterinary case reports and translates the relevant ones into plain English. Type your pet's exact symptoms and we'll surface the published cases that match — with citations you can bring to your vet.
Run a personalised search →Frequently asked questions
What does Seizures and hypothyroidism usually mean in dogs?
Published veterinary case reports most often link this presentation to: Idiopathic epilepsy, Hypothyroidism, Hepatic encephalopathy (portosystemic shunt). Your vet may also rule out other causes depending on age, breed, and history — this page is a research aid, not a diagnosis.
How many real cases did PetCaseFinder find?
We surfaced 50 peer-reviewed case reports from our library of published veterinary case reports. The top matches are listed above with full citations.
Is this veterinary advice?
No. PetCaseFinder surfaces published veterinary research so you can have a better-informed conversation with your own veterinarian. Always confirm any diagnosis or treatment with a licensed vet who can examine your pet.