De Quervain syndrome

Symptoms are pain and tenderness at the radial side of the wrist, fullness or thickening over the thumb side of the wrist, painful radial abduction of the thumb, and difficulty gripping with the affected side of the hand.[2] Pain is made worse by movement of the thumb and wrist and may radiate to the thumb or the forearm.[2] The onset is often gradual, but sometimes the symptoms seem to come on suddenly and the problem is often misinterpreted as an injury.[2]

The cause of de Quervain syndrome is not established. Evidence regarding a possible relation with activity and occupation is debated.[8][9] A systematic review of potential risk factors did not find any evidence of a causal relationship with activity or occupation.[10] One study found that personal and work-related factors were associated with de Quervain syndrome in the working population; wrist bending and movements associated with the twisting or driving of screws were the most significant of the work-related factors.[11] Proponents of the view that de Quervain syndrome is a repetitive strain injury[12] consider postures where the thumb is held in abduction and extension to be predisposing factors.[8] Workers who perform rapid repetitive activities involving pinching, grasping, pulling or pushing have been considered at increased risk.[9] These movements are associated with many types of repetitive housework such as chopping vegetables, stirring and scrubbing pots, vacuuming, cleaning surfaces, drying dishes, pegging out washing, mending clothes, gardening, harvesting, and weeding. Specific activities that have been postulated as potential risk factors include intensive computer mouse use, trackball use,[8] and typing, as well as some pastimes, including bowling, golf, fly-fishing, piano-playing, sewing, and knitting.[9]

Women are diagnosed more often than men.[9] The syndrome commonly occurs during and, even more so, after pregnancy.[13] Contributory factors may include hormonal changes, fluid retention and—again, more debatably—increased housework and lifting.[13][14]

The extensor tendon sheaths on the back of the wrist.

De Quervain syndrome involves noninflammatory thickening of the tendons and the synovial sheaths that the tendons run through. The two tendons concerned are those of the extensor pollicis brevis and abductor pollicis longus muscles. These two muscles run side by side and function to bring the thumb away from the hand (radial abduction). De Quervain tendinopathy affects the tendons of these muscles as they pass from the forearm into the hand via a fibro-osseous tunnel (the first dorsal compartment). Evaluation of histopathological specimens shows a thickening and myxoid degeneration consistent with a chronic degenerative process, as opposed to inflammation or injury.[15] The pathology is identical in de Quervain seen in new mothers.[16]

De Quervain syndrome is diagnosed clinically based on patient history and physical examination, though diagnostic imaging may be used to rule out fracture, arthritis, or other causes. The modified Eichoff maneuver, commonly referred to as the Finkelstein test, is a physical exam maneuver used to diagnose de Quervain syndrome.[2] To perform the test, the examiner grasps and ulnar deviates the hand when the person has their thumb held within their fist.[1][2] If sharp pain occurs along the distal radius (top of forearm, about an inch below the wrist), de Quervain syndrome is likely. While a positive Finkelstein test is often considered pathognomonic for de Quervain syndrome, the maneuver can also cause some pain in those with osteoarthritis at the base of the thumb.[2]

Most tendinoses and enthesopathies are self-limiting and the same is likely to be true of de Quervain syndrome, although further study is needed.

The mainstay of symptom alleviation (palliative treatment) is a splint that immobilizes the wrist and the thumb to the interphalangeal joint. Activities are more comfortable with such a splint in place. Anti-inflammatory medication or acetaminophen may also alleviate symptoms. [17]

As with many musculoskeletal conditions, the management of de Quervain disease is determined more by convention than scientific data. A systematic review and meta-analysis published in 2013 found that corticosteroid injection seems to be an effective form of conservative management of de Quervain syndrome in approximately 50% of patients, although they have not been well tested against placebo injection.[18] Consequently it remains uncertain whether or not injections are palliative and whether they can alter the natural history of the illness. One of the most common causes of corticosteroid injection failure is the presence of subcompartments of the extensor pollicis brevis tendon.[19]

Surgery (in which the sheath of the first dorsal compartment is opened longitudinally) is documented to provide relief in most patients.[20] The most important risk is to the radial sensory nerve. A small incision is made and the dorsal extensor retinaculum is identified. Once it has been identified, the release is performed longitudinally along the tendon. This is done to prevent potential subluxation of the first compartment tendons. Next the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) are identified and the compartments are released.[19]

Some occupational and physical therapists suggest alternative lifting mechanics based on the theory that the condition is due to repetitive use of the thumbs during lifting. In addition, physical/occupational therapists can suggest activities to avoid (based on the theory that certain activities might exacerbate the condition) and can introduce strengthening exercises (based on the theory that this will contribute to better form and promote the use of other muscle groups, which might limit irritation of the tendons).

Some occupational and physical therapists use other treatments in conjunction with therapeutic exercises, based on the rationale that they reduce pain and promote healing: ultrasound, short-wave diathermy, or other deep heat treatments, as well as TENS, acupuncture, infrared light therapy, and cold laser treatments.

From the original description of the illness in 1895 until the first description of corticosteroid injection by Jarrod Ismond in 1955,[21] it appears that the only treatment offered was surgery.[21][22][23] Since approximately 1972, the prevailing opinion has been that of McKenzie (1972) who suggested that corticosteroid injection was the first line of treatment and surgery should be reserved for unsuccessful injections.[24]

BlackBerry thumb is a neologism that refers to a form of repetitive strain injury (RSI) caused by the frequent use of the thumbs to press buttons on PDAs, smartphones, or other mobile devices. The name of the condition comes from the BlackBerry, a brand of smartphone that debuted in 1999,[26] although there are numerous other similar eponymous conditions that exist such as "Wiiitis",[27] "Nintendinitis",[28] "Playstation thumb", "texting thumb",[29] "cellphone thumb",[30] "smartphone thumb", "Android thumb", and "iPhone thumb". The medical name for the condition is De Quervain syndrome and is associated with the tendons connected to the thumb through the wrist. Causes for the condition extend beyond smartphones and gaming consoles to include activities like golf, racket sports, and lifting.[31]

Symptoms of BlackBerry thumb include aching and throbbing pain in the thumb and wrist.[32] In severe cases, it can lead to temporary disability of the affected hand, particularly the ability to grip objects.[33]

One hypothesis is that the thumb does not have the dexterity the other four fingers have and is therefore not well-suited to high speed touch typing.[34]

• Mobile phone overuse
• Nomophobia