Chronic Complications of Diabetes Mellitus

There are three primary microvascular targets:

1. Diabetic Retinopathy: This involves microvascular damage to the retina. It is the most common cause of new cases of blindness in individuals aged 20 to 74 years.
2. Diabetic Nephropathy: This is characterized by damage to the small blood vessels that supply the glomeruli of the kidney. It stands as the leading cause of end-stage renal disease.
3. Diabetic Neuropathy: This refers to nerve damage resulting from the metabolic derangements of diabetes.

Diabetic Neuropathy

Neuropathy is a complex complication that can be classified into two main types: sensory and autonomic.

Sensory Neuropathy

Sensory neuropathy, specifically the distal symmetric type, typically affects the hands and feet bilaterally. Patients often experience a loss of sensation, abnormal sensations, pain, and paresthesias.

A significant clinical danger of sensory neuropathy is that foot injuries and ulcerations can occur without the patient feeling any pain, which significantly increases the risk of severe complications.

Autonomic Neuropathy

Autonomic neuropathy is more widespread and can affect nearly all body systems. Because it affects involuntary functions, the symptoms can be diverse and sometimes subtle. Common complications include:

• Gastrointestinal: Gastroparesis, which is characterized by delayed gastric emptying.
• Cardiovascular: Postural hypotension, resting tachycardia, and even painless myocardial infarctions.
• Genitourinary: Sexual dysfunction and neurogenic bladder.

Exam Tip: Be aware of "Hypoglycemic Unawareness." This is a condition where a patient does not experience the typical warning signs of low blood sugar (like tremors or sweating) due to autonomic neuropathy, making them highly susceptible to severe hypoglycemic events.

Foot Complications and Care

Foot complications are the most common cause of hospitalization for individuals with diabetes. These complications are rarely caused by a single issue; rather, they result from a combination of both microvascular and macrovascular diseases.

Risk Factors and Infection

Several factors increase the risk of foot issues, including sensory neuropathy, peripheral arterial disease, smoking, clotting abnormalities, and autonomic neuropathy. Furthermore, diabetic individuals are more susceptible to infections due to defects in the mobilization of inflammatory cells and impaired phagocytosis by neutrophils and monocytes.

Essential Foot Care Protocol

To prevent ulceration and infection, patients must adhere to a strict foot care regimen:

• Daily Inspection: Check feet every day for any wounds or changes. If a wound is detected, it must be monitored daily.
• Hygiene: Wash feet daily with soap and warm water. Gently dry between the toes and ensure the feet are kept dry.
• Moisturizing: Apply an unscented moisturizer to the feet, but never apply it between the toes.
• Nail Care: Shorten nails with an emery board. Never use nail clippers or scissors, and never cut below the tip of the toe.
• Footwear: Wear natural fiber socks that are not too tight (to avoid impeding circulation) and choose leather or canvas shoes of the correct size. Avoid walking barefoot.
• Temperature Safety: Never use heating pads or place feet near a fire to warm them, as the lack of sensation can lead to burns.

Clinical Note: When assessing a patient's risk for limb loss, look for trends in blood glucose levels. Persistent hyperglycemia is a major driver of the vascular and nerve damage that leads to necrosis.