You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Continuous, uncontrolled barking in older dogs is a common cause of referral to behavioural specialists in the USA. There are several causes of this type of behaviour including the presence of an insulinoma.

Insulinomas are neoplasms of the beta cells in the pancreas and they occur most commonly in dogs over 6 years of age. They are usually malignant and produce excess pro-insulin or insulin resulting in hypoglycaemia. As well as uncontrolled barking other signs of hypoglycaemia include intermittent, transient :

• Ataxia 
• Collapse
• Confusion 
• Epileptiform seizures
• Hypothermia
• Muscle tremors
• Polyphagia
• Polydipsia and Polyuria (10% of cases)
• Restlessness
• Twitching
• Vision disturbances
• Weakness
• Weight gain (20% of cases)

In advanced cases the dog may go into a coma and die.

Other reported medical causes of excessive barking include :

• Brain disease
• Hormonal disorders
• Infections
• Irritable bowel syndrome
• Metabolic disease

and reported behavioural causes include :

• Anxiety (including separation anxiety)
• Obsessive-compulsive disorders
• Stereotypies
• Hyperactivity (or hyperkinesis)
• Attention seeking
• Inadequate environmental stimulation
• Excessive environmental stimulation

Confirming a diagnosis of insulinoma can be difficult because the hyperinsulinaemia may be transient, and the pancreatic tumour may be very small. Nevertheless in older dogs presenting with uncontrolled barking and other signs an insulinoma should be considered one of the differential diagnosis. Successful treatment involves surgical excision of the tumour.

Updated January 2016