The physical cause of De Quervain's syndrome may be a number of things. The medical term is idiopathic, or of unknown cause, but some theories do exist.
Repetitive stress may be a cause of De Quervain's syndrome. As a repetitive stress injury, De Quervain's syndrome may propagate from a stressful rubbing of the tendons and their covering, the synovial sheaths, as they slide back and forth through a small opening in the wrist as you move your thumb back and forth across your palm in the plain of your hand. Repetitive rubbing can cause irritation. Irritation can lead to swelling. And once things have swollen it is all downhill from there.
If the tendon gets irritated and swells it can bulge up making it difficult for the tendon to fit through the narrow passageway within the wrist. On top of that every time the swelled portion of the tendon is rubbed it causes pain.
If the synovial sheaths get irritated they can swell as well. If they are chronically inflamed they will start to thicken making them harder and giving the tendon less room to pass through the wrist. After time the synovial sheaths can start to degenerate as well.
The other area that can get inflamed in De Quervain's syndrome is the surface of the bones through which the tendons pass through the wrist. These surfaces are covered with a slippery membrane called a tenosynium. The tenosynium can be irritated by repetitive rubbing and swell with inflammation.
If any one of these anatomical features gets inflamed it will hurt. The more they swell the harder it is for the tendons to slide back and forth through the wrist passage as the fit gets tighter. The tighter the fit the more pressure is placed on the other anatomical features with harder rubbing leading them to get irritated and inflamed.
The irritation and inflammation may be caused by a cumulative trauma, such as a repetitive wrist motion, or it may be caused by a discreet trauma, such as a fall that sprains your thumb. Past injuries may lead to De Quervain's syndrome as a buildup of scar tissue can restrict movements, enclose the passage way in the wrist or put pressure on the tendons leading to irritation.
Other inflammatory conditions may be to blame for De Quervain's syndrome such as rheumatoid arthritis, chronic inflammation or even obesity. Still others may suffer do to a genetic disposition or anatomical features that can worsen the conditions required for De Quervain's syndrome, such as small wrists.
Certain activities may be the discreet cause of your De Quervain's syndrome. It may be impossible to know for sure but these activities may as well be a likely contributor to your injury if not the discreet cause and should be considered and evaluated carefully when trying to determine your specific cause or what activities to monitor when treating and recovering from De Quervain's syndrome.
Activities that that cause an impact to your thumb, cause your thumb move back and forth repetitively, cause an awkward wrist motion, or require continual or repetitive grasping, especially when lifting may cause, contribute or aggravate your De Quervain's syndrome. Some examples of such activities are:
- Gardening, with small hand tools or larger tools
- Playing golf often
- Going bowling a lot
- Playing any racket sport, such as tennis or racket ball
- Repetitive lifting, especially lifting your baby
- Counting money or sorting paperwork
- Playing video games
Though the cause may be ambiguous, and amalgam of a number of things or a complete unknown treatment for De Quervain's syndrome is the same. And even if these element are not the root cause they can certainly exacerbate the condition and should be considered during any treatment or prevention regiment.