Diabetic Neuropathy Flashcards
What is lost in diabetic neuropathy
both myelinated and unmyelinated nerve fibres
What are the fibres that are affected in diabetic neuropathy
distal sensory and autonomic fibres
What is likely to contribute to the pathogenesis of diabetic neuropathy
Metabolic and vascular factors and impaired nerve repair mechanisms
what are some of the metabolic risk factors
Advanced glycosylation end products (AGEs)
Sorbitol
Oxidative stress
What is sorbitol
a product that is formed when glucose enters cells and is metabolised by the enzyme aldose reductase
How does sorbitol have an effect on diabetic neuropathy
an accumulation of intracellular sorbitol in tissues such as peripheral nerves results in a rise in cell osmolality, a decrease in intracellular myoinositol and Na-K-ATPase activity and a slowing of nerve conduction velocities
Levels of what are reduced in peripheral micro vessels from diabetic patients
thrombomodulin and tissue plasminogen activator levels
How might diabetic neuropathy manifest as
distal symmetrical polyneuropathy
polyradiculopathy
mononeuropathy
autonomic neuropathy
What is the most common form of diabetic neuropathy
Distal symmetrical polyneuropathy
How do patients present with distal symmetrical polyneuropathy
distal sensory loss or paraesthesia (sensation of numbness, tingling,, burning or sharpen that starts in the fee and spreads proximally
What are the signs of distal symmetrical polyneuropathy
loss of pinprick
termperature
virbation and joint position sensation
diminished ankle reflexes
What is diabetic polyradiculopathy characterised by
severe pain in the distribution of one or more nerve roots
Does diabetic polyradiculopathy ever resolve
yes - usually over 6-12 months
What are the sensory symptoms in polyradiculopathy sometimes accompanied by
Muscle weakness
What is the most common presentation of mononeuropathy
ptosis and ophthalmoplegia due to CNIII palsy
What does autonomic neuropathy usually involve
Multiple systems including:
Cardiovascular: tachycardia, postural hypotension, neuropathic oedema
GI: gastroparesis, anorexia, nausea, vomiting
Genitourinary: bladder dysfunction, erectile dysfunction, retrograde ejaculation, reduced libido
Hypoglycaemia unawareness: reduced adrenaline release results in a loss of the adrenergic symptoms of hypoglycaemia
What must be examined to assess sensory function
Pinprick, temperature, vibration and pressure sensation must be examined
What are the most sensitive tests for the diagnoses of diabetic neuropathy
nerve conducting studies an autonomic testing by using HR change during the Valsalva manoeuvre
How can we control neuropathic pain
tricyclic antidepressents (amitriptyline)
What is a major side effect of amitriptyline
sedation
What can be used to reduced the accumulation of sorbitol in nerve cells
aldose reductase inhibitors
What should be considered for patients with carpal tunnel syndrome
surgical decompression
What is the medical treatment of postural hypotension
increaseing the plasma volume with flrudrocortisone , a high salt diet and adequate hydration
How can we minimise the symptoms of gastroparesis
more frequent, smaller meals that are easier to diegest and are low in fat and fibre
What is the treatment of diabetic autonomic enteropathy
Loperamide (diabetic diarrhoea in acbsence of bacteria) rotating antibiotics (for bacterial overgrowth) stool softeners (constipation)
What is the treatment of bladder dysfunction
Strict voluntary urination schedule
Bethanechol (increases detrusor muscle contraction)
Self catheterisation
Resection of the internal sphincter at the bladder neck
What should be given for diabetic men with erectile dysfunction
oral sildenafil
How can clinically detectable neuropathy be reduced in both type 1 and type 2 diabetics
Tighter glycaemic control
Type1 diabetics are more prone to developing neuropathy. True or False
True
