<P> A number of health issues, some of them hereditary, have been found in individual Shih Tzu, and are listed below . </P> <P> Hypothyroidism occurs when the thyroid gland malfunctions and stops producing a hormone responsible for proper metabolism . This malfunction is commonly attributed to immune system problems . It usually affects middle - aged dogs and is seen in all breeds . Symptoms include hair loss, weight gain, muscle loss, and lethargy . This disease is usually diagnosed through blood tests . It can be effectively treated with drug therapy . </P> <P> Intervertebral disk disease in the dog is a common chondrodystrophic disorder manifested by acute back pain, loss of coordination, paresis, and loss of the ability to feel deep pain sensations . IVDD commonly occurs in certain toy breeds, such as Dachshund, Pekingese, French Bulldog, Beagle, Basset Hound, American Cocker spaniel, Shih Tzu, Lhasa Apso, and Welsh Corgi . </P> <P> Shih Tzu have a number of respiratory problems related to the shape of their face and head . Brachycephalic airway obstructive syndrome is a common problem and mostly affects dogs with short noses (brachycephalic breeds). An obstruction in the upper airways causes the dog to have laboured breathing . Not every brachycephalic dog will develop respiratory problems, but most will to some degree . Severe problems may require surgery . </P>

What is the origin of the shih tzu