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280 Diabetic Kidney Disease:
When To Refer To A Nephrologist & Why?

Renal Retinal relationship both primary care providers and for nephrologists.
This challenge increases when patients are referred
The renal-retinal relationship is well established for
the clinical diagnosis of diabetic kidney disease in late to a nephrologist, that is, when they require ur-
Type 1 DM. However, renal-retinal relationship re- gent dialysis. Delayed referral leads to emergency
mains poor in predicting DKD in Type 2 DM. Biopsy dialysis with higher morbidity, mortality and exces-
proven DKD have been reported to occur in protein- sive cost.
uric Type 2 diabetic patient in absence of retinop- Recent studies, have found that it is not uncommon
athy. It means that absence of retinopathy cannot for CKD patients to be examined by a nephrologist
exclude the presence of diabetic kidney disease. The for the first time only one month before starting di-
presence of diabetic retinopathy suggests the con- alysis. Many patients with chronic kidney disease
currence of DKD, but does not exclude non diabetic (CKD) are seen by primary care physicians who may
kidney disease. Early diagnosis of NDKD is crucial not be aware of indications or benefits of timely
as appropriate therapy could prolong renal survival in nephrologist referral. Late referral to a nephrologist
this patient population. It is important to mention that may lead to suboptimal pre-end stage renal disease
40% to 60% of ESRD in diabetic patients is associat- care and greater mortality. Late evaluation of patients
ed with non-diabetic primary renal diseases. with CKD by a nephrologist, especially close to the
time of starting dialysis, is associated with subopti-
Pathological features of DKD mal pre-ESRD management and increased mortality
The main glomerular renal lesions in type 1 diabe- risk . A survey of primary care physicians who made
tes include a nodular, classical Kimmelstiel-Wil- late referrals showed that approximately 90% of the
son lesion, a diffuse pattern, and the presence of physicians felt they did not receive adequate training
non-specific exudative lesions. Today, the accumula- regarding timing or indications for referral of patients

tion of extracellular matrix is considered an indication with CKD.In 2002, the National Kidney Foundation
of nephropathological changes. This accumulation (NKF) developed the Kidney Disease Outcomes
may lead to mesangial expansion and reduction of Quality Initiative (KDOQI) clinical practice guidelines
filtration surface area, which is further disrupted by to facilitate primary care physician management of
the thickening of glomerular basement membranes. CKD by early detection, formulation of an action plan
Concomitant changes at the arteriolar level and in the for each stage of CKD, monitoring of CKD progres-
renal interstitium contribute to the overall functional sion, assessment of complications, and timely refer-
impairment. The recent pathologic classification by ral to a nephrologist.
Tervaert and the Renal Pathology Society does not
9
differentiate between type 1 and T2DM, but provides KDIGO Guidelines for Referral
a comprehensive effort to classify renal lesions from Indication for referral to specialist kidney care serves
the mildest to the worst ones. for people of CKD
Pathologic classification 1. Acute Kidney injury or abrupt sustained fall in
Class 1: Isolated glomerular basement membrane GFR
thickening and mild, non-specific changes, observ- 2. GFR <30ml/min/1.73m (Categories) G -G )
2
able by light microscopy, at an extent at which they 4 5
may not be applicable to the criteria of the other 3. Persistent albumineria (ACR≥ 300mg/gm)
classes. 4. Progression of CKD
Class 2: Mesangial expansion, classified as mild or 5. Urinary red cell casts, RBC more than 20 per HPF
severe, but without nodular sclerosis or global glo- sustained & not readily explained.
merulosclerosis in more than 50% of glomeruli (class
2a: mild; class 2b: severe). 6. CKD and hypertension refractory to treatment
with 4 or more anti hypertensive agents.
Class 3: Presence of nodular sclerosis in at least one
glomerulus (Kimmelstiel-Wilson), without changes as 7. Persistent abnormalities of serum potassium.
described in class 4.
Timing of referral of patients with CKD by their prima-
Class 4: Advanced diabetic glomerulosclerosis involv- ry care physician to the nephrologist affects patients’
ing more than 50% of glomeruli. prognosis and clinical outcomes. Patients that are
11
evaluated by a nephrologist less than four months
Nephrology Referral
prior to dialysis would be classified as a late referral;
Caring for patients with CKD is a great challenge for four to twelve months prior to dialysis as intermedi-

GCDC 2017