Insulinoma In Ferrets – Under the MICROSCOPE

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What is Insulinoma in Ferrets?

Insulinoma in ferrets is surprisingly common. This condition affects the beta cells in the pancreas that produce insulin. Insulin is an important hormone that regulates blood glucose levels. 

Glucose is the main form of energy in the body and is crucial for maintaining homeostasis. If insulin levels are too high, they can dangerously low blood sugar levels. 

Ferret looking up

Ferret Insulinoma – Symptoms and Signs

An insulinoma can either be a benign adenoma or a malignant adenocarcinoma. Affected ferrets are usually between two and seven, but the average ferret afflicted with an insulinoma is around five years of age.

Ferret insulinoma symptoms can start gradually and worsen if left undiagnosed and untreated. Intermittent periods of hypoglycemia may go unnoticed by some owners. This tumor can cause a variety of clinical signs that depend on the severity of hypoglycemia. The symptoms will also wax and wane after the ferret has eaten. 

Signs to look out for include:

  • Gradual weakness and lethargy worsen over a few weeks. Owners often see their ferret shaking and weak. 
  • Weight loss over a short time.
  • Chronic intermittent nausea, gagging, vomiting, or a ferret drooling and pawing at its mouth.
  • Hind limb weakness, a “stargazing” stance, or ataxia can make the ferret appear uncoordinated and impaired in their regular movements and routine.
  • A rapid heart rate, tremors, and irritability can indicate chronically low blood glucose levels. The adrenal gland responds to hypoglycemia by increasing adrenaline levels to help release more glucose. 
  • A  ferret seizure can link to episodes of collapse, disorientation, depression, and unresponsiveness. In addition, it may sound like a ferret screaming in pain or other disturbing noises during a seizure. 

The signs of an insulinoma are subtle, so owners need to be very attentive if they suspect their ferret is unwell. Prolonged episodes of hypoglycemia can lead to life-threatening convulsions, brain damage, or even death. 

Owners need to monitor their ferrets for signs of depression or sluggishness in the morning. The ferret may even appear better after eating, and then they dip again just before their next meal. 

A healthy ferret can normally regulate blood sugar levels through several pathways. Therefore, if their glucose levels are stable, there should not be extreme peaks and throughs in your pet’s activity levels.

A vet may carry out a physical exam and notice that the patient is subdued but alert. The patient may be bradycardic, hypothermic, lethargic, twitching, or even actively seizing in severe cases. Most patients presenting with subclinical insulinomas will have clinical parameters within normal limits.

It is important to note that an underlying issue such as adrenal problems or other illnesses can destabilize an afflicted ferret and exaggerate subtle signs.

How are Ferret Seizures Diagnosed?

An entire clinical history taken by the attending veterinarian includes diet, behavioral changes, and symptoms noticed. The key to diagnosing an insulinoma depends on how observant and forthcoming an owner is.

If the patient’s history or clinical symptoms concern a vet, they may perform a thorough physical exam, a total blood count, and blood chemistry panels. Doctors will include insulin testing if it is available.

Blood glucose levels need to be measured three to four hours after the patient has fasted, but only if stable. It is dangerous to fast a patient that has not yet achieved euglycemia. Glucose levels below 60 mg/dL are considered diagnostic, but individual variation may occur.

During an insulinoma workup, clinicians do not usually use diagnostic imaging such as x-rays or ultrasonography. It is challenging to locate the pancreas on an ultrasound. Rarely a highly-skilled ultrasonographer with an advanced ultrasound machine can detect subtle changes.   

Clinical symptoms paired with corresponding blood results and response to treatment allow a clinician to make a confident diagnosis.

Treating Insulinoma in Ferrets

Emergency treatment of a moribund or seizing ferret requires immediate hospitalization to stabilize the blood glucose levels. Low-dose intravenous dextrose should only be administered at low concentrations to avoid increased insulin secretion. Oral sugars are dangerous as they cause a sudden insulin release that exacerbates hypoglycemia. 

Once the patient is stable, owners need to decide on either medical, surgical, or complementary management options.

Medical Management 

Long-term medical management is only effective in a stable patient. Treatment doses of prednisone or prednisolone for ferrets affected by insulinomas can range from 1,1 to 3,3 mg/lb (0.5 to 1.5 mg/kg) per os twice daily. The steroids need to be gradually tapered down to the lowest effective dose to achieve a state of euglycemia. 

Ferrets have a keen sense of smell and taste that can affect medication palatability. Therefore, it is essential to use alcohol-free steroid formulations to avoid medication aversion. 

Once on the medication for three weeks, a three-hour fasting period will be required to test the ferret’s glucose levels. This will help determine if the patient is stable and on the correct dose of cortisone.

A follow-up blood glucose test will be required every three months to monitor a patient’s progress. If the clinical symptoms recur, it is essential to see a vet as soon as possible. 

Some researchers theorize that insulinomas increase gastric acid production. This issue, coupled with a ferret’s predisposition to stomach ulcers caused by the Helicobacter mustelae, requires prophylactic gastroprotectant medications. 

Famotidine is an adjunctive gastroprotectant medication used during chronic cortisone treatment to prevent stomach ulcers.      

Prednisone alone may fail to maintain glycemic control, requiring additional medications. It is necessary to closely monitor a patient when using Diazoxide combined with cortisone. Medical therapy does not decrease the size of the tumor. The medication usually only controls clinical symptoms for 6 to 18 months.

Ferret in Nature

Surgical Management 

Surgical management is the ideal treatment option because it enables the removal of the visible tumor nodules. But unfortunately, doctors must discuss with owners that multiple microscopic lesions can still be present in the pancreas. Surgery is therefore not curative; it only slows the progression of the disease. 

Some studies indicate that 50% of patients that underwent either nodulectomies or partial pancreatectomies have recurring clinical symptoms within a year. In addition, a few patients may not stabilize after surgery, indicating a concomitant adrenal gland disease. 

Ideally, surgical and medical management combinations offer the best prognosis. In addition, the variety of treatments enables pets to remain symptom-free for about one to three years. 

Additional Treatment Options

Recently developed chemotherapeutic protocols to treat insulinomas are available. Doxorubicin is administered intravenously every three weeks for 12 weeks. Recommendations for combining chemotherapy, surgical or medical therapy offer the best results. However, the protocols are still undergoing trials, and there is no data on the mean survival time yet. 

Researchers say that patients cope well with the protocols and considerably improve their quality of life.

Dietary changes are also significant. Ferrets prefer to eat small, frequent meals. Four to six small meals a day should provide a consistent food intake. In addition, the implementation of dietary changes helps to stabilize blood glucose levels throughout the day. 

If a ferret is ill and not eating frequent small meals throughout the day, then high protein fluids should be syringe-fed to avoid hypoglycemia.

The Prognosis and Outcome of Ferret Insulinoma

The severity of the disease and the chosen treatment will determine the prognosis of a ferret insulinoma. Many patients respond well to dietary management and medical therapy. Some ferrets can live on for several months or several years. Surgically treated patients have a mean survival time of approximately 500 days. 

A strong genetic predisposition to insulinomas is highly likely, which means affected individuals can pass the genes on to their young. Therefore, it is best to avoid breeding with these individuals as they may pass those genes on. 

Try to avoid high carbohydrate diets in ferrets as they can overstimulate the pancreas and possibly increase the risk of developing insulinomas. 

Home Care and Management of Ferret Seizures

Home care includes a few minor changes to improve your ferret’s quality of life after being diagnosed with an insulinoma. In cases of ferret insulinoma, diet is crucial. Here are a few tips to help manage your ferret’s seizures:

  • Try to eliminate any high carbohydrate or high sugar food or treats.
  • Instead, provide high-quality protein and nutritionally balanced ferret food. 
  • Do not let your pet fast over long periods, and do not feed them erratically. 
  • Try to achieve a feeding schedule that provides frequent, small meals.
  • During a hypoglycemic episode, use honey or corn syrup in a small syringe and administer it in small amounts orally or onto the gums. Be careful not to get bitten as the ferret is seizing and unaware of its actions. Get your ferret to a vet as soon as possible if this occurs.

Managing your pet’s condition requires routine blood glucose monitoring. First, try to invest in an over-the-counter glucometer for at-home use: most pharmacies stock glucometers and glucose strips. Try to measure your ferret’s blood glucose between meal times, usually 3-4 hours after eating. If your ferret’s blood sugar levels are low, contact the vet immediately.

Two Ferrets


If closely monitored, ferrets with insulinomas can have a good quality of life. However, their pet owners need to give extra attention and dedication to ensure their diet and glucose remain stable. Establish a good relationship with your vet to ensure your pet gets consistent and thorough patient monitoring.

Ferrets over the age of three years and older should have their blood glucose levels checked every six months by a veterinarian. Early detection could save your ferret’s life.

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Dr. Kaylee Ferreira, a South African vet from Johannesburg, excels in diverse veterinary roles. Founder of Kubuntu Veterinary Services, she's a dedicated animal lover and adventurer.