Diabetic Autonomic Neuropathy (DAN) is an advanced medical disorder originating from complications of Diabetes Melitis. Diabetic autonomic neuropathy can create a wide range of abnormalities affecting the peripheral nerves and the autonomic nervous system (ANS). DAN is often misunderstood even though the complications of diabetes can have a significant negative impact on mortality and quality of life in people with diabetes.
DAN Affects the Autonomic Nervous System
Diabetic autonomic neuropathy is a systemic issue as the disorder can affect multiple parts of the autonomic nervous system. Diabetic autonomic neuropathy (DAN) can affect the function of the longer nerves, in particular the vagus nerve. The vagus nerve is the longest of the ANS nerves and responsible or approximately 75% of the parasympathetic nervous system activity. Parasympathetic dysfunction in diabetic autonomic neuropathy can affect several organs (often simulteanously) creating autonomic symptoms affecting function of the cardiovascular system, sweat glands, sexual performance, pupil dilation, gastrointestinal tract systems & the adrenal medullary system.
Autonomic Nervous System testing (ANS Testing) has improved the understanding & prevalence of Diabetic Autonomic Neuropathy. ANS testing is a non-invasive study proven to be sensitive, specific and reproducible. The availability of ANS testing has enhanced clinical understanding of the prevalence, pathophysiology, and clinical manifestations diabetic autonomic neuropathy. In the past, symptoms of autonomic neuropathy would not occur until long after the onset & complications of diabetes. It is now that ANS testing can provide a reliable method to sub clinically detect autonomic dysfunction which helps clinicians guide lifestyle changes, therapy and other forms of intervention.
The prevalence of diabetic autonomic neuropathy in the US & worldwide can vary slightly depending on the source. This is because in the past there has been a lack of standardized testing criteria used to diagnose diabetic autonomic neuropathy. The prevalence of symptoms of autonomic dysfunction and abnormal tests of autonomic nervous system function in diabetic clinic-based populations and tertiary referral centers is considerably higher than in general clinic-based populations. In a study that evaluated the prevalence of cardiovascular autonomic neuropathy in 1171 diabetic patients randomly recruited from 22 diabetic centers in Germany, Austria, and Switzerland, 25.3% of patients with type 1 diabetes and 34.3% of patients with type 2 diabetes had abnormal findings in more than two of six autonomic function tests.
Risk of Complications with DAN
Diabetic autonomic neuropathy represents a significant risk factor for patients. With autonomic function declining, the affects of diabetic autonomic neuropathy can be systemic. Common complications include microvascular circulatory disorders in the peripheral areas which leads to severe nerve damage. This condition is known as peripheral autonomic neuropathy. Peripheral autonomic neuropathy can range in severity with small & large nerve damage. The advancement of peripheral autonomic neuropathy can begin with loss of sensation in the peripheral areas (hands & feet) with the more several cases amputating of the limbs & feet.
Some metabolic liver diseases also lead to neuropathies as a result of chemical imbalances. Endocrine disorders that lead to hormonal imbalances can disturb normal metabolic processes and cause neuropathies. For example, an underproduction of thyroid hormones slows metabolism, leading to fluid retention and swollen tissues that can exert pressure on peripheral nerves.
The progression of nerve damage diabetic autonomic neuropathy can ultimately lead to dinervation of the heart muscle, a condition known as cardiac autonomic neuropathy (CAN). Some studies indicate that CAN is one of the biggest risk factor in patients as it increases mortality risk by as much as 1.6 – 2.4 times greater risk of adverse cardiovascular event. Further, CAN has proven in multiple studies to increase mortality risk by 5 fold over a 5 year period.