Diabetes  |  Type 2 Pathway - Complications




Diabetes

Type 2 Pathway - Complications

Neuropathy

Involvement of the peripheral and autonomic nervous systems is one of the complications of diabetes. Clinical diabetic neuropathy is categorized into distinct syndromes according to the neurological distribution, although many overlap syndromes occur. Neuropathies severely decrease patients' quality of life and in turn can have adverse psychological effects.  Whilst the primary symptoms of neuropathy can be highly unpleasant, the secondary complications (eg, falls, foot ulcers, cardiac arrhythmias), are even more serious.

Poor glucose control and vascular risk factors appear to be associated with the development of diabetic neuropathy.

Autonomic Neuropathy

Autonomic nephropathy is frequently under diagnosed. It is a common condition with a slow onset and affecting 30% - 40% of people with diabetes. Although many people have mild, sub clinical features, significant functional abnormalities can be present. The autonomic nervous system plays an important part in carbohydrate metabolism and blood glucose regulation and when affected can compromise blood glucose control. Organs commonly affected by autonomic neuropathy include, the gastrointestinal and urinary tract, the cardiovascular system and genitals.


Peripheral neuropathy

In Type 2 diabetes peripheral neuropathy affects approximately 50% of people after 20 years and is present at diagnosis in 10% of people. Neuropathy can affect the sensory nerves giving rise to pain, tingling and numbness. This in turn results in an inability to detect heat, cold, touch and vibration and an increase in the risk of undetected trauma, foot ulcers and burns.


Treatment of Neuropathy pain

First-line pain management

Paracetamol may be trialled as first-line management for neuropathic pain and may be continued throughout any regimen.Second-line pain managementIf paracetamol alone is not adequate for controlling pain, a tricyclic antidepressant (TCA) may be added to the regimen (or paracetamol substituted for a TCA). Nortriptyline is the preferred TCA for neuropathic pain, due to fewer adverse effects than other TCAs. Initiate nortriptyline at 10 mg per day (usually taken at night) and titrate dose upwards until pain is controlled. The dose should not usually exceed 75 mg.Third-line pain management

If second-line pain management is insufficient, an anticonvulsant may be added to the treatment regimen, or the TCA substituted for an anticonvulsant. Referral to, or discussion with, a pain specialist can be considered. Carbamazepine and sodium valproate are both effective for neuropathic pain. Gabapentin has also traditionally been used for neuropathic pain but recent evidence suggests that it has limited effectiveness for this indication For more information see "New evidence shows less benefit of gabapentin for neuropathic pain" . Carbamazepine may be initiated at a dose of 100 mg per day. Increase the dose slowly until pain is controlled, to avoid adverse effects such as nausea, vomiting and dizziness. Regular monitoring is required. Opioids such as methadone or oxycodone may have a limited place in the treatment of neuropathic pain but their use is not advised unless in consultation with a specialist in pain management.

Adjuvants

Capsaicin cream and local anaesthetic gels may be trialled throughout a treatment regimen for neuropathic pain, They should not be applied to broken/ulcerated skin.

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Eyes/Retinopathy


About diabetes retinopathy

  • Classified into non proliferative, proliferative. And macular oedema.
  • About 20% of patients with Type 2 diabetes have retinopathy at diagnosis.
  • After 15 years of diabetes, 80% of Type 2 will have retinopathy.
  • Severe retinopathy may be present with normal vision.

Patients with multiple risk factors should be considered at high risk of developing diabetic retinal disease.

Risk factors

  • Poor glycaemic control (HbA1c > 7% or 53mmol/l)
  • Raised blood Pressure (BP> 130/80mmHg)
  • Longer duration of diabetes
  • Microalbinuria and proteinuria
  • Raised triglycerides and lowered haemaTOPrit
  • Pregnancy
  • Serum cholesterol

Assessment

Arrange regular retinal screening:

  • Start from diagnosis for Type 2
  • If no retinopathy, screen every 2 years.

Check visual acuity. Normal vision does not preclude sight threatening retinopathy.

Look for cataracts- more common in diabetes and seen at a younger age and progress more rapidly.

Management

  • Identify early any visual impairment.
  • Aggressive management of all diabetes risks factors helps prevent the onset and reduce the progression of retinopathy.
  • Warn about being seen urgently if any reduction in visual acuity.

 

Renal / Diabetic Nephropathy

Risk factors

  • Younger patients with type 2 diabetes have a higher lifetime risk of renal complications.
  • Mäori, Pacific Island and South Asian peoples are at a higher risk of renal complications. More frequent monitoring of renal status is indicated.

Investigations

  • Microalbuminuria is the earliest sign of diabetic kidney disease.
  • To test for microalbuminuria this should be an early morning sample.
    Microalbuminuria is confirmed if, in the absence of infection or overt proteinuria, two out of three specimens have an elevated albumin / creatinine ratio.
  • Renal USS not generally required in NIDDM - only if symptoms suggestive of obstruction or haematuria as in other patients.
  • 24 hour urines for protein not done for people with type 2 diabetes.


Management

People with confirmed microalbuminuria should be treated with an ACE inhibitor or an ARB whether or not hypertension is present.

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Image: Further info regarding notes see: Figure 3, page 10, NZGG Type 2 Diabetes Management

  • Any evidence of renal disease based on decreasing eGFR should be treated with urgency.
  • Loop diuretics may be used instead of or in combination with thiazide diuretics in patients with significant renal impairment (eGFR <45 ml/min/1.73m2).
  • Patients with an eGFR < 30ml/min/1.73m2 (or <45 with rapid deterioration - this needs defining further) should be referred to a renal physician.
  • People with type 2 diabetes are more prone to nephrogenic anaemia (from no other cause) and eligible for erythropoiein for eGFR<45. Hb <100. 
  • Opinions vary as to when metformin should be discontinued in the presence of renal impairment but all agree that metformin is contraindicated when eGFR<30.


Peripheral Vascular Disease

Assessment

Assess peripheral circulation with thorough palpation of pedal pulses (dorsalis pedis and posterior tibial). If there are no palpable pulses, and if a Doppler machine is available, calculate ankle brachial index (see below) or consider referral to a vascular specialist. Absent pulses, calf claudication, absence of hair on the feet, altered temperature (a cold foot) and thin, bluish skin are suggestive of peripheral arterial disease.6 A bounding, easily detected pulse in a warm, dry foot is suggestive of autonomic neuropathy, which causes abnormal arterio-venous shunting.

Calculating ankle brachial index

Equipment - Blood pressure cuff and hand-held Doppler machine

1. Take the blood pressure in the arm (brachial pressure)

2. Take the blood pressure in the ankle using the Doppler machine (ankle pressure)

3. Calculate ankle brachial index by dividing systolic ankle pressure by systolic brachial pressure e.g. ankle pressure is 120 mmHg and brachial pressure is 132 mmgHg, ankle brachial index is 120/132 = 0.9

Normal

0.9 - 1.2

Risk of vascular foot ulcer is small

Definite vascular disease

0.6 - 0.9

Risk of vascular ulcer moderate, depending on other risk factors

Severe vascular disease

Less than 0.6 

Risk of vascular foot ulcer very high


Ankle brachial index may not be able to be reliably calculated in some people with diabetes as the arteries in the ankles may be calcified.

Referral for Vascular opinion

Criteria for referral to a vascular surgeon for a patient with a diabetic foot complication includes the following:

  • Foot lesion (ulcer, gangrene) or suggestion of rest pain with peripheral arterial disease
  • Deteriorating ulcer with known peripheral arterial disease or absent pedal pulses
  • Ankle Brachial Index <0.5 or absolute ankle pressure <50 mmHg
  • New foot lesion with previously treated peripheral arterial disease
  • Symptomatic intermittent claudication at <200 m
  • Acute diabetic foot sepsis
  • Osteomyelitis of forefoot or metatarsals
  • Acute osteomyelitis


Feet / Podiatry

Identifying high risk feet

Risk factors for diabetic foot disease include:

  • peripheral vascular disease (PVD)*
  • peripheral neuropathy
  • previous amputation
  • previous ulceration
  • presence of callus
  • joint deformity
  • visual/mobility problems.

* Risk factors for PVD are smoking, hypertension and hypercholesterolaemia.

The cumulative effect of these risk factors for PVD is considered to be at least additive.
Appropriate footwear is recognised in the literature as an important part of management to prevent diabetic foot disease.

Feet should be screened at least annually how to use a 10g monofilament


Further Information BPAC
- Screening and management of the diabetic foot



Last updated : Wednesday, July 26, 2017
Next review date : Thursday, July 26,2018


Disclaimer: This site is intended to be flexible and frequently updated. While every effort has been made to ensure accuracy, all information should be verified.