Several hand conditions have been associated with diabetes, collectively called Diabetic Hand Syndrome. The most common hand conditions associated with diabetics are carpal tunnel syndrome, trigger finger, limited joint mobility, and Dupuytren’s contracture. Diabetics also tend to be more susceptible to hand infections compared to non-diabetics.
Carpal tunnel syndrome (CTS)
The incidence of CTS in the diabetic population is between 11% and 21%. The mechanism is due to glycosylation of soft tissue, causing collagen cross-linking, and leading to thickening and stiffening of the transverse carpal ligament and peritendinous tissue. Furthermore, diabetic microvascular angiopathy of the nerve leads to polyneuropathy and increases the susceptibility of the median nerve to compression in the carpal tunnel. CTS presents with similar symptoms in diabetic and non-diabetic patients.
These include tingling in the hand, which affects the thumb, and index, middle and ring fingers. Tingling is often worse at night or in the early morning. It may be triggered by activities that involve strenuous or repetitive gripping.
When the condition worsens, tingling and numbness become continuous, with weakness and wasting of muscles at the base of the thumb. Patients may drop objects unknowingly and experience pain. If the condition is detected early, medications, avoiding aggravating activities, and a wrist splint can relieve symptoms. Surgery is recommended if the symptoms are severe or do not respond to other treatments. Symptoms are expected to alleviate after surgery but the improvement may not be as great in diabetics due to poorer nerve regeneration. Diabetic patients undergo carpal tunnel release surgery four to 14 times more than the general population.
The prevalence of trigger finger in the diabetic population is 20%. Trigger finger in diabetic patients is more often bilateral and affects multiple digits, responds less well to corticosteroid injections, and more commonly requires surgery. Symptoms include painful swelling, stiffness, and triggering or locking of the affected finger. While trigger finger can be treated with medication, rest, finger splint or steroid injections, those with diabetes are more likely to require surgery.
Limited joint mobility (LJM)
The prevalence of LJM in the diabetic population is 30%. Patients with LJM are unable to fully straighten the finger joints. It usually starts in the little finger and extends to the other digits. Patients are unable to place their palms flat — e.g. on the table (table top test) or together (preacher’s sign). LJM is related to the patient’s age as well as the duration of diabetes. Some studies show that LJM is associated with microvascular complications such as diabetic retinopathy.
Diabetic patients have an increased risk of infection because hyperglycaemia depresses cell-mediated immunity and white blood cell function. Peripheral neuropathy numbs the extremity to pain and sores, and injuries may be left untreated, leading to infection and complications. Furthermore, poor blood flow in diabetics impedes healing and may result in amputation or even death. In one study, diabetic hand infection was caused by several bacteria (polymicrobial), Gram-negative bacteria, and the usually common Staphylococcus aureus bacteria in 55%, 73% and 36% of the specimen respectively.