16 - Diabetic Neuropathy Flashcards Preview

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Flashcards in 16 - Diabetic Neuropathy Deck (41):

What percent of diabetic patients have mild to severe forms of nervous system damage?





What does diabetic neuropathy include?

- Impaired sensation or pain in the feet or hands
- Slowed digestion of food in the stomach
- Carpal tunnel syndrome
- Other nerve problems


What is the number 1 cause of amputation in the US?



What is the number 1 non-traumatic cause of amputation?


More than 60% of nontraumatic lower-limb amputations in the United States occur among people with diabetes.


What are the two CRITICAL risk factors for diabetic neuropathy?


- Poor glucose control *****
- Duration of diabetes over 25 years ***** (ANY patient diagnosed early in life has a higher risk)

Poor glucose control = an A1c over 6.5



What are the other risk factors for diabetic neuropathy?

- Damage to blood vessels
- Mechanical injury to nerves (carpal tunnel syndrome)
- Autoimmune factors (inflammation of the nerves due to autoimmune dysfunction can aggravate neuropathy)
- Genetic susceptibility (inherited traits can increase susceptibility to nerve disease)
- Lifestyle factors


Describe the mechanical injury and autoimmune disease

If a diabetic was compliant and well controlled, but had an injury to the nerve (carpal tunnel), then she will be at increased risk of developing diabetic neuropathy

If you have ANY autoimmune disease on top of diabetes, you have a higher risk of neuropathy


What lifestyle factors contribute to diabetic neuropathy?

- Smoking
- Alcohol abuse

These can cause blood vessel damage leading to nerve damage

Can cause diabetic neuropathy or make the diabetic neuropathy worse


Describe the pathogenesis of diabetic neuropathy

The mechanisms by which diabetic neuropathy develops are still being researched.


Describe the flowchart of pathogenesis hypotheses regarding diabetic neuropathy

- If a patient has uncontrolled diabetes for over 25 years, there will be an increase AGE formation
- There is increased glucose in the serum, but also increased glucose inside of the nerve cells
- This can lead to an increased polyol pathway activity
- Further, glucose in the nerves can increase free radical formation
- Once AGEs in the nerves have formed, there are a lot of functions, including cytokine release and promotion of coagulation
- AGEs can also “quench” NO which is critical for muscle relaxation
- After the NO has been quenched, it will cause vasoconstriction
- The polyl pathway increase and will also decrease the generation of NO
- The overall response is a high level of vasoconstrction
- Endothelin is a hormone that will further contribute to vasoconstriction
- Diabetes will decrease GLA, which is Gamma linolenic acid, which are precursors of PG
- Once there is a decrease of GLA, there will be a lesser production PG and a lesser ability for vasodilation, further contributing to vasoconstriction
- If you have diabetes, we know that it can cause microvascular structure damage, including BM thickening and endothelial swelling
- All of these things contribute together to have nerve hypoxia, which is an irreversible step that lowers nerve conduction velocity and causes structural damage to nerves


What pathological changes will you see in diabetic neuropathy?



These are the pathological changes in nerves that cause diabetic neuropathy
- Axonal loss
- Focal demyelination & regeneration

There will be a decreased conduction velocity and a decreased sensory threshold



What are the four different classifications of diabetic neuropathy?


- Symmetric polyneuropathy
- Autonomic neuropathy
- Polyradiculopathy
- Mononeuropathy



Describe symmetric polyneuropathy

Not emphasized for exam, but clinically relevant
- Most common form of diabetic neuropathy
- Affects distal lower extremities and hands (“stocking-glove” sensory loss)


What are the signs and symptoms of symmetric polyneuropathy?

- Pain
- Paresthesia/dysesthesia (“something is wrong with my hands and feet – they don’t feel normal”)
- Loss of vibratory sensation


What are the complications of polyneuropathy?


- Ulcers***
- Charcot arthropathy (joint deterioration)
- Dislocation and stress fractures
- Amputation

Ulcers are a VERY important complication of polyneuropathy***

Even though amputation is very severe, it is less of a common complication, ulcers are the most common***


What are the treatment options for symmetric polyneuropathy?

- Glucose control
- Pain control
- Foot care


How do we control pain in polyneuropathy?

- Tricyclic antidepressants
- Topical creams
- Anticonvulsants


Describe autonomic neuropathy

Affects the autonomic nerves controlling internal organs
- Peripheral
- Genitourinary (GU)
- Gastrointestinal (GI)
- Cardiovascular (CV)



How do we classify autonomic neuropathy?

Clinical or subclinical based on the presence or absence of symptoms
- Clinical = you feel it
- Subclinical = you can't feel it


Describe peripheral autonomic dysfunction

Contributes to the following signs and symptoms
- Neuropathic arthropathy (Charcot foot)
- Aching, pulsation, tightness, cramping, dry skin, pruritus, edema, sweating abnormalities
- Weakening of the bones in the foot leading to fractures

The weird things that cannot be explained by anything else can be explained by autonomic dysfunction


How do you treat peripheral autonomic dysfunction?

- Foot care/elevate feet when sitting
- Eliminate aggravating drugs
- Reduce edema
--> midodrine
--> diuretics
- Support stockings
- Screen for CVD


What are the signs and symptoms of genitourinary autonomic neuropathy?

- Bladder dysfunction
- Retrograde ejaculation
- Erectile dysfunction
- Dyspareunia (pain during intercourse which occurs frequently in elderly women)


What is the treatment for bladder dysfunction due to genitourinary autonomic neuropathy?

Voluntary urination; catheterization


What is the treatment for retrograde ejaculation due to genitourinary autonomic neuropathy?


Retrograde ejaculation patients have infertility because the sperm goes right back into the bladder (urine) – either do in vitro fertilization or antihistamines


What is the treatment for erectile dysfunction due to genitourinary autonomic neuropathy?

Sildenafil, tadalafil


What is the treatment for dyspareunia due to genitourinary autonomic neuropathy?

Lubricants; estrogen creams


What are the signs and symptoms of gastrointestinal autonomic neuropathy?

- Gastroparesis resulting in anorexia, nausea, vomiting and early satiety
- Diabetic enteropathy resulting in diarrhea and constipation


How do you treat gastrointestinal autonomic neuropathy?

- Other causes of gastroparesis or enteropathy should first be ruled out – don’t move on until all other possibilities have been rules out
- Gastroparesis - Small, frequent meals, metoclopramide, erythromycin
- Enteropathy - loperamide, antibiotics (even though it isn’t caused by infection, stool softeners or dietary fiber


What are the signs and symptoms of cardiovascular autonomic neuropathy?

- Exercise intolerance
- Postural hypotension


How do you treat cardiovascular autonomic neuropathy?

- Discontinue aggravating drugs
- Change posture (make postural changes slowly, elevate bed)
- Increase plasma volume (drink water – saline water w/ some salt/sodium/potassium)


What are the two types of polyradiculopathy?

- Lumbar
- Thoracic


Describe lumbar polyradiculopathy

Lumbar polyradiculopathy (AKA diabetic amyotrophy)

You will see thigh pain followed by muscle weakness and atrophy


Describe thoracic polyradiculopathy

Thoracic polyradiculopathy
- Severe pain on one or both sides of the abdomen, possibly in a band-like pattern


Describe diabetic neuropathic cachexia seen in polyradiculopathy

Diabetic neuropathic cachexia
- Polyradiculopathy + peripheral neuropathy
- Associated with weight loss and depression

Cachexia = weakness and wasting of the body due to severe chronic illness


Describe the diagnosis of polyradiculopathies

Polyradiculopathies are diagnosed by electromyographic (EMG) studies


How do you treat polyradiculopathies?

- Foot care
- Glucose control
- Pain control


What is peripheral mononeuropathy?

Not very important, just know what the names means
- Single nerve damage due to compression or ischemia
- Occurs in wrist (carpal tunnel syndrome), elbow, or foot (unilateral foot drop)
- Symptoms/Signs are numbness, edema, pain, prickling


What is cranial mononeuropathy?

Cranial mononeuropathy
- Affects the 12 pairs of nerves that are connected with the brain and control sight, eye movement, hearing, and taste
- Symptoms/Signs
--> unilateral pain near the affected eye
--> paralysis of the eye muscle
--> double vision
- Mononeuropathy multiplex


What is the treatment for mononeuropathy?

- Foot care
- Pain control
- Glucose control


What are other treatment options?

- Aldose reductase inhibitors
- ACE inhibitors
- Weight control
- Exercise

We do have some other treatment options
- With the first two, we can control the neuropathy pretty well
- With the last two, we should always emphasize this in treatment


A 73-year-old female with the diagnosis of type II diabetes for 28 years presents in the clinic accompanied by her husband. She has been smoking for 55 years and has been drinking 4-5 cans (355ml/ can) of beer every day for 50 years. Her husband complains that she forgets to inject insulin often after she is drunk. Her BMI is 41 (normal is 24-28).Her recent Hb1Ac is 16% (normal should be below 6.5%). She is found to have diabetic neuropathy. The MOST two common underlying factors contributing to the development of her diabetic neuropathy are?

A. 28 years of diabetes and 55 years of smoking
B. 28 years of diabetes and poor control of her blood glucose evidenced by her Hb1Ac level.
C. Obesity and alcohol consumption
D. Poor control of her blood glucose evidenced by her Hb1Ac level and Obesity
E. 55 years of smoking and alcohol consumption

B. 28 years of diabetes and poor control of her blood glucose evidenced by her Hb1Ac level.