Diabetes  |  Type 2 Pathway - Renal/Diabetic Nephropathy




Diabetes

Type 2 Pathway - 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.