29th May 2025

Diabetic neuropathy

Damage to the vessels that supply the nerves in the body, through the same mechanism outlined above, leads to diabetic neuropathy affecting both the somatic and autonomic systems. Damage to sensory nerves can cause problems in the feet, making patients more likely to develop ulcers or Charcot arthropathy, discussed in more detail in the diabetic foot disease section. Patients may experience painful neuropathy, typically in the extremities, which should be managed in the same way as neuropathic pain in non-diabetics. They should be offered one of the following: amitriptyline, gabapentin, pregabalin or duloxetine. If one agent is not effective even when titrated to a maximum dose then it should be substituted for an alternative. Patients with severe pain that limits their daily activities (such as sleep) or that causes a deterioration in a comorbidity should be referred to a specialist pain team.

Autonomic neuropathy can cause a variety of symptoms, which can be managed with specific interventions. Other causes of these symptoms must be ruled out before a diagnosis of diabetic autonomic neuropathy can be made:

• Cardiovascular autonomic dysfunction (CAN) – Causing resting tachycardia, reduced heart rate variability, exercise intolerance, orthostatic hypotension, dizziness and syncope. CAN increases an individual’s risk of developing cardiovascular disease, including silent myocardial infarction. ACE inhibitors and beta-blockers are effective treatment options. 
• Orthostatic hypotension – Medications should be reviewed as many can exacerbate hypotension, including antihypertensive medications, nitrates, diuretics, alpha-adrenergic blockers (such as tamsulosin), levodopa and tricyclic antidepressants. Other medications that increase the risk of falls should also be reviewed such as opioids, benzodiazepines, ‘Z-drugs’ (zopiclone and zolpidem) and anticholinergics. Patients can be encouraged to increase fluid and salt intake to expand their circulating volume. Medications such as fludrocortisone may be used if the hypotension is symptomatic and resistant to non-pharmacological methods.
• Constipation or diarrhoea – May be treated using laxatives and loperamide respectively and where appropriate. 
• Gastroparesis – Causing erratic blood sugars, abdominal bloating and vomiting. There is unfortunately limited evidence for the use of antiemetics for gastroparesis with the most evidence for domperidone. It is recommended that erythromycin and metoclopramide be alternated and domperidone only used in exceptional circumstances given its significant cardiac risk profile and potential interactions with other medications.
• Erectile dysfunction – Men should be offered a phosphodiesterase-5 inhibitor, such as sildenafil, if they have problematic erectile dysfunction. 
• Impaired hypoglycaemic awareness – Hypoglycaemic episodes can disrupt autonomic pathways and thereby inhibit the associated neurogenic symptoms.
• Reduced sweating – This leads to dry skin, which can crack and allow entry of microorganisms, causing infections. 
• Neurogenic bladder – Patients may have difficulty emptying their bladder, which can cause recurrent urinary tract infections or incontinence.