A nephrologist is a physician who has been trained in the diagnosis and management of kidney disease, mainly by treating risk-factors for kidney disease such as high blood pressure and diabetes, balancing fluids in the body, and providing dialysis transplant treatment when the kidneys fail.
In general, patients are referred to nephrologists for various reasons, such as :
- Acute kidney injury, a sudden loss of renal function
- Chronic kidney disease (CKD), declining renal function
- Hematuria, blood in the urine
- Proteinuria, the loss of protein especially albumin in the urine
- Kidney stones, usually only recurrent stone formers.
- Chronic or recurrent urinary tract infections
- Hypertension that has failed to respond to multiple forms of anti-hypertensive medication or could have a secondary cause
- Electrolyte disorders or acid/base imbalance
In Malaysian Clinical Practice Guideline (CPG) 2004, most patients with CKD stage 4-5 (GFR <30ml/min/1.73m2) or with CKD stage 3 and rapidly deteriorating renal function should be referred for assessment by a nephrologist. An earlier referral to a nephrologist may also be indicated if:
- the diagnosis of diabetic nephropathy is in doubt e.g. proteinuria occurs in the absence of retinopathy, renal failure occurs without proteinuria
- nephrotic syndrome or unexplained hematuria occurs
- a sudden worsening of renal function occurs
- blood pressure is difficult to control
- hyperkalaemia arises
- renal artery stenosis is suspected
With regards to the diabetic nephropathy, it is a clinical syndrome characterised by :
- Persistent albuminuria (>300 mg/d or >200 µg/min) that is confirmed on at least 2 occasions 3-6 months apart
- Progressive decline in the glomerular filtration rate (GFR)
- Elevated arterial blood pressure
Diabetic nephropathy rarely develops before 10 years’ duration of type 1 Diabetes Mellitus (DM). Approximately 3% of newly diagnosed patients with type 2 DM have overt nephropathy. The peak incidence (3%/year) is usually found in persons who have had diabetes for 10-20 years, after which the rate progressively declines. A nephrologist will try to retard the progression of the disease to End Stage Renal Disease (ESRD) using medications, strict advices and follow up, and later prepared the patients for renal replacement therapy if the disease is advance.
Signs & Symptoms
The diagnosis of diabetic nephropathy is usually made clinically. Other target organ involvement is often present. 90-95% of type 1 diabetics and about 70% of type 2 diabetics with nephropathy will have retinopathy as well. In the absence of retinopathy, non-diabetic renal disease may need to be excluded. Most of the time the disease is detected by the primary care physician before being referred to the respective nephrologist. The symptoms are usually related to the advancement of the disease; the higher the CKD stage the more symptomatic the patients. The patients can be asymptomatic, experiencing lethargy, poor appetite, feeling nauseated or severely uraemic and fluid overloaded as the CKD is approaching the ESRD.
Diabetic nephropathy accounts for significant morbidity and mortality. Proteinuria is a predictor of morbidity and mortality. The overall prevalence of microalbuminuria and macroalbuminuria in both types of diabetes is approximately 30-35%. Microalbuminuria independently predicts cardiovascular morbidity, and microalbuminuria and macroalbuminuria increase mortality from any cause in diabetes mellitus. Microalbuminuria is also associated with increased risk of coronary and peripheral vascular disease and death from cardiovascular disease in the general non-diabetic population.
Several studies have shown that late referral leads to increased morbidity, prolonged hospital stay and early mortality on dialysis. Uraemic symptoms and complications often occur earlier in diabetics compared to non-diabetics and dialysis may be required once GFR falls to 10 to 15mls/min. Diabetic patients on renal replacement therapy (i.e. dialysis or transplant) have a 2 to 4 times higher mortality risk than non-diabetic patients, mainly from cardiovascular disease. Coronary artery revascularisation may reduce this complication especially in type 1 diabetics.
Treatment & Management
As primary physician, several issues are keys in the medical care of patients with diabetic nephropathy. These include glycaemic control, management of hypertension, and reducing dietary salt intake and phosphorus and potassium restriction in advanced cases. Major therapeutic interventions include near-normal blood glucose control, antihypertensive treatment, and restriction of dietary proteins. Drug classes employed include hormones (ie, insulin), sulfonylureas, biguanides, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta-adrenergic blocking agents, calcium channel blockers, and diuretics. The role of nephrologist is similar but the monitoring is far more aggressive and the patients are made aware of the RRT preparation if the progression of the disease is inevitable. Once the patients end up as ESRD, the nephrologists will guide the patients to choose the mode of renal replacement therapy that suits them.
Patient education is the key in trying to prevent diabetic nephropathy. Appropriate education, follow-up, and regular doctor visits are important in prevention and early recognition and management of diabetic nephropathy. Good evidence suggests that early treatment delays or prevents the onset of diabetic nephropathy or diabetic kidney disease.
- Malaysian CPG for Diabetes Nephropathy 2004
- Malaysian Society of Nephrology
- NADI (National Diabetes Institute)