Referral to Nephrology

© Hauora a Toi Bay of Plenty. Te Whatu Ora. December 2023

Please note:
Renal Services are provided through Tauranga Hospital.
Referrals are processed via the BOP Referral Centre

Referrals For Advice Only

• GPs can send ereferrals for non-urgent renal advice.

• Please clearly label these ereferrals as for “Advice Only”

• There is no minimum criteria for this type of referral.

NB: Referrals for advice can also be used to update the renal team on important information for patients currently under active follow up by the BOP renal service.

For urgent renal advice please call the on-call renal physician via the Tauranga Hospital operator (8-4pm weekdays), or the Waikato Hospital on-call renal physician after hours and on public holidays.

Referral For FSA

Category definitions:
These are recommended guidelines for Hauora a Toi Bay of Plenty specialists prioritising referrals from primary care.

Immediate/Urgent Referral (discuss with registrar/SMO re:?acute admission to hospital vs urgent clinic review)

Immediate cases should be discussed with a Specialist or registrar in order to get appropriate prioritisation and then an urgent ereferral also sent if a clinic appointment is required.

• Hyperkalaemia > 6.5 mmol / l
• Acute Kidney Injury - > 1.5 fold increase in sCreat over < 5 days

• NB for AKI with a clear cause (such as dehydration or recent NSAID use) it is often appropriate for the GP to arrange repeat blood and urine tests every 1-2 days and to refer for specialist review only if the AKI is not improving.
• If the GP has access to urgent renal imaging (such as an ultrasound), this is often useful in cases of AKI to rule out obstruction. If obstruction is seen then urgent urology input is required instead.

• Nephrotic syndrome - proteinuria > 3g / 24 hours, serum albumin <30g/L and oedema.
• Malignant hypertension 
• Suspected Multisystem disease with kidney involvement e.g. SLE, myeloma

Routine referral (To be seen within 4 months)

• CKD 3 with progressive fall in eGFR -20% rise in sCreat (or 15% fall in GFR) over 12 months
• Stable CKD 4/5
• Difficult to control hypertension
• >20% rise in sCreat (or 15% fall in GFR) within two weeks of starting ACEI/ARB – (GP to please discontinue ACEi/ARB and repeat kidney function in 1 week)
• Haematuria with proteinuria
• Proteinuria (urine Alb/Cr ratio >75mg/mmol, or urine Prot/Cr ratio >100mg/mmol) - without known diabetic nephropathy
• Isolated persistent haematuria with no proteinuria – NB if age >35 or any smoking history then recommend CT urogram and urology referral for cystoscopy in first instance.
• Recurrent Stone Disease
• 5 year Kidney Failure Risk Equation (4 variable Tangri score)> 20%

• (see https://kidneyfailurerisk.com on how to calculate)

Information Required For Referral

• Relevant medical history and GP concerns
• Medications
• BP – as many historical BP readings as possible is appreciated
• FBC, creatinine, eGFR, Na, K, urea, Alb, Ca, Phos, HbA1c
• Urine microscopy (for haematuria) and urine albumin:creatinine ratio
• Renal Imaging (if available)

Supplementary information

Assessment of Kidney Function

Kidney function should be assessed by Serum creatinine, reported in umol/l and the estimated glomerular filtration rate (eGFR) - reported routinely using the CKD-EPI formula

Drug dosing

The reported eGFR (CKD-EPI) is normalised to body surface area.

In very large or small patients, the reported eGFR (CKD-EPI) should not be normalised to BSA. To calculate this, the eGFR should be multiplied by the estimated BSA (use MD-Calc website) then divided by 1.73.

Alternatively the cockgraft-gault equation can be used (it is not adjusted for BSA).

A further alternative is to measure the 24 hour urine Creatinine clearance however this will only be accurate if the 24 hour urine collection is fully completed.

Kidney Failure Risk Equation (Tangri Score)

A validated 4 variable risk equation score as published by N Tangri can be useful in predicting the risk of progression to ESRF in 2 and 5 years. It requires Age, Sex, eGFR and urine alb/cr ratio.

Identification of Patients with CKD

CKD is defined as an eGFR of <90ml/min/1.73m2 for more than three months, or a normal eGFR with an associated urinary abnormality (haematuria or proteinuria) or abnormal renal imaging.

Management of patients with CKD

CKD stages 1 and 2 (eGFR >60ml/min/1.73m2)

• Identify those at risk for disease progression
• Early detection of CKD is important to prevent further injury and progressive loss of renal function.
• Patients at high risk of developing CKD should have at least annual tests of kidney function
• High risk populations include those with:
  
  • Diabetes
  • Hypertension  - especially those on ACE I / ARBs
  • Coronary, cerebral or peripheral vascular disease
  • Multisystem diseases - SLE, rheumatoid arthritis, myeloma, vasculitis
  • Family History of kidney disease
  • Structural kidney problems  - reflux,  ADPKD, Recurrent stone formers (technically these patients already are classed as having CKD even with normal eGFR)
• Refer if diagnosis unclear
• Assess and manage cardiovascular risk factors aggressively. Check HbA1c, fasting lipids
• Aggressive BP control – encourage home BP monitoring

• First line treatment - ACE I/ARB
  • Monitor creatinine and K within 1-2 weeks of dose adjustments    
• Add in a step-wise approach
  • Calcium channel blocker eg amlodipine
  • Thiazide diuretic eg chlorthalidone (consider switch to frusemide once eGFR<30)
  • Beta blockers/spironolactone/alpha blockers
• Treat hypercholesterolaemia – target total Chol<4.0, LDL <2.0
• Advise on weight loss and smoking cessation
• If diabetic start SGLT-2 refer to diabetic NZ SSD CKD guideline Management of diabetic kidney disease - New Zealand Society for the Study of Diabetes (nzssd.org.nz)

CKD Stage 3 - eGFR 30 - 59 ml/min/1.73m2 as above plus

• Monitor FBC, Electrolytes, Creatinine, eGFR, Calcium, Phosphate, BP - minimum of 6 monthly
• Renal Ultrasound (one-off)
• Refer if progressive rise in serum creatinine
• Anaemia - exclude other causes
  • Target ferritin >200 and Transferrin saturation >20%. Use IV iron to reach target
    • NB special authority criteria for IV iron includes CKD stage 3 and can be completed by GPs
    • IV iron is ideally done by primary care due to patient convenience and limited availability for it to be given in a hospital daystay setting.
  • Refer if Hb < 100g/l despite adequate iron replacement for consideration of erythropoietin (this requires specialist special authority).
• Calcium / Phosphate/PTH   refer if outside normal range. Target levels include:
• Calcium – lower is better
  • Phosphate <1.8mmol/L (using phosphate binders and low P04 diet)
  • PTH – doesn’t need to be checked in CKD3 unless high calcium. Target <50pmol/L using calcitriol
  • (NB oversuppression of PTH leads to adynamic bone disease)
• Review drugs and drug doses

CKD Stages 4 and 5 eGFR <  29 ml/min/1.73m2   - as above plus

• Refer for Nephrology opinion for consideration of Renal Replacement Therapy
• Pre - dialysis education
  • preparation for dialysis / transplantation/ conservative care
• Note: Not all patients are suitable for renal replacement therapy especially those who:
  • are uncooperative / refusing treatment
  • have significant co-morbidities with no prospect of improvement in QoL / life expectancy
  • very elderly – it is rare in NZ for patients >85years old to commence dialysis but can be considered on a case-by-case basis.

Appendix

Classification of CKD

* associated with urinary abnormalities, especially proteinuria, or structural abnormalities; Polycystic Kidneys, reflux nephropathy

Chronic Kidney Disease - New Zealand Management Guidelines