6 year old Shih Tzu panic attacks?

Question
Our extremely docile Shih Tzu, Jake - whom we have seldom heard bark
(maybe a dozen times in six years) has suddenly started having what I can
only describe as 'fits of barking.'  The barking comes on suddenly and is very
high-pitched and urgent.  The barking is continuous for a time span of 30
seconds to a minute or two.  During this time, he runs right up to me, frantic,
eyes wide and then runs away from me frantically, barking the entire time.  
He doesn't seem to know where to run and I can't tell if he's running away for
something or trying to lead me to something.  He seems absolutely panicked.
He also urinates a small amount very suddenly during these 'fits.'  I can only
describe the episodes as 'fits' of some kind - can't tell if he is afraid, hurt, or
if he's seeing ghosts!  I don't know what to do to help him.  He seems to be
trying to 'tell' me something - and I do get down at his level and try to calm
him, but his is too agitated to be calmed.  He eventually calms himself, but
then is 'at alert' with tail tucked between his legs and eyes darting around the
room.  

I don't know if it's related, but he also has a distinct odor about him all of a
sudden - rather unpleasant.

Can you help?

Answer
Kirsten -

It seems as though something is frightening your dog or at least startling him.  The odor you smell is probably from the anal sacs; these sacs are expressed as a means of defense when the animal feels threatened.

Have your doctor check his anal sacs.  The anal sacs are two pockets in the dog's anus. They hold a substance that should express when the animal defecates.  Anal sacs that do not express when they should may become impacted and may even become infected.     The anal sacs sometimes fill up and can cause a considerable amount of discomfort to your pet.
Perhaps your pet is reacting to the irritation of full anal sacs. Expressing the sacs can give him comfort and can prevent ailments such as constipation.

Best Regards,

Charlotte Sherrell, DVM