Other complications of diabetes mellitus
Due to their serious consequences and their clear relationship with hyperglycaemia, the best known complications of diabetes are retinopathy, nephropathy, neuropathy and macrovascular disease. However, a great number of less-known complications seriously impede quality of life for diabetes patients. With the use of improved glucose-lowering medications, the risk of infections has dropped but diabetes patients are still about 20% more likely to get an infectious disease compared to healthy individuals. Connective tissue disorders are another main source of discomfort and can lead to prolonged disability. Ultimately, diabetes will lead to dysfunction in almost any tissue, and diabetes patients can be considered at increased risk for almost any disorder that is the result of the chronic wear and tear of daily life.
It was already noted by Joslin and colleagues that 'with proper treatment, the response of the diabetic to infection approaches the normal'. However, hyperglycaemia is a risk factor for infections, and the inflammatory response to an infection decreases insulin sensitivity and aggravates hyperglycaemia. Since many diabetes patients will go through periods of hyperglycaemia, they remain at a slightly increased risk of infection. Some infections are commonly associated with diabetes. The excess sugar in the urine creates a fertile environment for bacteria and yeasts, and therefore urogenital infections occur frequently, also as a presenting symptom of newly diagnosed diabetes. Likewise, superficial skin infections followed by deeper connective tissue and bone infections are a feared complication in the setting of diabetic foot ulcers. However, many other infections threaten the patient with diabetes including rare infections such as mucormycosis.
Connective Tissue disorders
Chronic hyperglycaemia will damage almost any tissue and this is most notable in the myriad of connective tissue disorders that affect diabetes patients. These are frequently attributed to aging rather than to diabetes. Aging is indeed important but diabetes could be said to lead to accelerated aging of these tissues. Clinically, this usually presents as low-grade inflammation or loss of elasticity in the affected tissue.
Diabetes and oral hygiene
Diabetes patients are more prone to have periodontitis, and periodontitis had been associated with poor glycaemic control. Whether improved dental care will improve diabetes control has not been definitively settled, but clearly improved dental care is a worthy goal in itself.
This syndrome, where a patient is unexpectedly found dead in an undisturbed bed at a relatively young age, is fortunately rare, but its cause remains a mystery. Both hypoglycaemia and (pre-existing?) cardiac conduction disturbances have been suggested to play a role, but conclusive evidence is lacking.
Thought to be due to a combination of neuropathy and vasculopathy, sensorineural hearing loss is more frequent in both type 1 and type 2 diabetes.