Classic symptoms of polyuria or polydipsia are rarely present. Glucose is not spilled into the urine until the plasma glucose is markedly elevated because the renal threshold for glucose increases with age. Polydipsia is also less common, because thirst is impaired. When symptoms are present, they are generally atypical (falls, failure to thrive, urinary incontinence, or delirium).
Diabetes may present for the first time in elderly individuals as a result of a fasting screening glucose level or be concurrent with the presentation at the time of illness with a complication of illness, such as a myocardial infarction or stroke. Finally, nonketotic hyperosmolar coma may be the first sign of diabetes in older individuals, particularly in older nursing home patients; this results from decreased access to water associated with osmotic diuresis, impaired thirst, and cognitive dysfunction.
Unusual clinical findings also develop in older patients with established diabetes. Intradermal bullae of the feet that resolve spontaneously have been described. Painful limitation of the shoulder joints occurs frequently and may be related to nonenzymatic glycation of proteins. Diabetes increases the risk for accidental hypothermia in older individuals. Malignant otitis externa is a necrotizing infection caused by Pseudomonas, occurring almost exclusively in elderly patients with diabetes. Renal papillary necrosis can occur in association with urinary tract infections.
Diabetic amyotrophy causes asymmetric and painful weakness of the muscles of the pelvic girdle and thigh, and usually resolves spontaneously in a few months. It is most prevalent in older males. Diabetic neuropathic cachexia occurs in older patients with diabetes, causing weight loss, depression, and painful peripheral neuropathy.