COMPLICATIONS OF DIABETES

DIABETIC RENAL DISEASE (DIABETIC NEPHROPATHY)

It is most common in type 1 diabetes. Some 20-30% of patients with type 1 diabetes will develop renal disease (15-25 years after diagnosis). It is less prevalent in type 2 diabetes (only 10-20% lifetime risk).

HYPERFILTRATION AND MICROALBUMINURIA

The earlier symptoms of diabetes includes hyperfiltration (with urine albumin excretion, UAE, <30mg/24 hour or 20µg/min) followed by progression through microalbuminuria to proteinuria (UAE>300 mg/24 h or 200µg/min). After this GFR falls and progress to ESRF. The first and best opportunity to detect the disease clinically is at the stage of microalbuminuria. Dip-stick testing or urine is not usually positive at such concentration of albumin and detection relies on either 24 h quantitation or more conveniently the use of albumin/creatinine ratio (normal <2.5 mg/mmol in men and <3.5 mg/mmol in women) on at least two out of 3 separate urine specimens over a 3-6 month period can be done. Due to day to day variation of UAE rates 2 of 3 samples should be positive for the diagnosis. Microalbuminuria is not just a risk factor of nephropathy but an independent risk factor for CAD (one of the most potent risk factors known), being also associated with dyslipidaemia, hypertension, endothelial dysfunction and diabetic retinopathy.

TYPE 4 RENAL TUBULAR ACIDOSIS

Hyporeninaemic hypoaldosteronism may be a manifestation of diabetic nephropathy. It presents with hyperchloraemic, hyperkalaemic metabolic acidosis. Failure of renin to rise in response to posture or sodium restriction suggest an interstitial (juxtaglomerular) defect. The failure of aldosterone release to be stimulated directly by resulting hyperkalaemia suggest the possibility of dysfunction of adrenal zona glomerulosa.

CHARCOT FOOT

It is a specific foot deformity occurring due to neuropathy and if untreated leads to bone collapse of the foot causing outward bowing.