Renal
Referrals and Advice
Indications For Referral
Acute Renal Failure (ARF) :
Rise in sCreatinine by >50% in hours / days
- when an elevated sCreatinine is noted for the first time the serum creatinine and urinalysis must be repeated immediately
Chronic Kidney Disease (CKD):
- eGFR < 60ml/min/1.73m2 with progressive decline in function or complications of CKD
- eGFR < 30ml/min/1.73m2
Hypertension:
- Not controlled on three or more antihypertensives
- More than 20% rise in sCreatinine after starting ACE I /ARB
Proteinuria:
- Urine protein : creatinine ratio > 100mg / mmol or
- Urine albumin: creatinine ratio >100mg / mmol (equivalent to > 1gm / 24hours )
- Haematuria associated with proteinuria - urine albumin : creatinine ratio > 30mg / mmol
- or isolated haematuria with no underlying urological cause
Referral For FSA
Category definitions:
These are recommended guidelines for DHB specialists prioritizing referrals from primary care.
Immediate referral |
within 24 hours |
Urgent referral |
within 2-4 weeks |
Routine referral |
|
Immediate and urgent cases must be discussed with the Specialist or registrar in order to get appropriate prioritization and then a referral letter sent, faxed or emailed. The times to assessment may vary depending on the size and staffing of the hospital.
Immediate Referral:
- Acute Renal Failure - > 1.5 fold increase in sCreat over hrs - 5 days
- Newly detected ESRF - GFR < 15 ml / min
- Malignant hypertension
- Hyperkalaemia > 7 mmol /
Urgent:
- Newly detected CKD 4 GFR 15 - 29ml/min
- Nephrotic syndrome - proteinuria > 3gm / 24 hours
- Multisystem disease e.g.SLE, myeloma with kidney involvement
- Hyperkalaemia 6 - 7 mmol / l
Routine referral:
- Stable CKD 4
- CKD 3 with progressive fall in eGFR - 20% rise in sCreat (or 15% fall in GFR) over 12 months
- Difficult to control hypertension
- 20% rise in sCreat (or 15% fall in GFR) within two weeks of starting ACE I
or ARBs (ACE I / ARBs should be discontinued) - Proteinuria > 1gm / 24 hours (u protein : creat >100mg/ mmol
or u alb:creat >100mg / mmol ) - without known diabetic nephropathy - Haematuria with proteinuria
- Isolated haematuria once urological causes excluded
- Recurrent Stone Disease.
Information Required for Referral:
- Relevant medical history
- Medications
- BP
- FBC, s creatinine, eGFR, Na, K, urea, Alb, Ca, Phos, gluc (HbA1c) Urine microscopy and urine protein : creatinine ratio or albumin:creatinine ratio(urine dipsticks will not detect microalbuminuria)
- Renal Ultrasound (if available)
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 MDRD formula in eGFR may be unreliable or is yet to be validated in ml/min/1.73m2
- those under 18 years
- where the eGFR is > 60ml/min/1.73m2
- pregnancy
- rapidly changing kidney function (do not use in ARF)
- extremes of muscle mass e.g. amputees, high and low BMI
- certain populations - Asian, Polynesian
Where drug dosing according to renal function is important the eGFR needs to be corrected for actual BSA (i.e. eGFR x actual BSA divided by 1.73)
Age adjusted reference ranges not recommended - Complications of reduced eGFR are the same at any age
Urinalysis:
- Urine dipstick for blood and protein.
- If positive for blood, check MSU for culture and urine microscopy.
- If positive for protein, check urinary protein: creat or alb:creat ratio. Urine dipsticks will not detect other proteins such as light chains in myeloma.
- Albuminuria is a marker of risk of progression of kidney disease and increased cardiovascular risk.
Identification of Patients with CKD:
CKD is defined as an eGFR of > 60ml/min/1.73m2 associated with proteinuria with or without haematuria or an eGFR of < 60ml/min/1.73m2 for more than three months.
Early detection of CKD is important to prevent further injury and progressive loss of renal function.
High risk populations, i.e. those with:
- Diabetes
- Hypertension - especially those on ACE I / ARBs
- Coronary, cerebral or peripheral vascular disease
- Structural kidney problems - reflux, ADPKD
- Multisystem diseases - SLE, rheumatoid arthritis, myeloma, vasculitis
- Family History of kidney disease
- Recurrent stone formers
should have annual tests of kidney function.
Management of patients with CKD:
eGFR >60ml/min/1.73m2
- Identify those at risk for disease progression:
- Proteinuria > 1gm / 24 hours
- Proteinuria and haematuria
Polycystic Kidney Disease:
Refer if diagnosis unclear
Assessment and management of cardiovascular risk factors
BP control as below
Monitor Creatinine and Potassium - at least annually
eGFR 30 - 59 ml/min/1.73m2
Monitor FBC, Electrolytes, Creatinine, eGFR, Calcium, Phosphate, PTH, lipids, BP - minimum of 6 monthly
Request Renal Ultrasound
Refer if progressive rise in serum creatinine
BP Control - treat BP if | > 140/90 |
Ideal BP | < 130/80 |
or if U Alb : Creat >100 | < 120/75 |
First line treatment - ACE I
check creatinine and K within 5 days
stop ACE I and refer if > 20 % rise in creatinine.
Treat hypercholesterolaemia
Advise on weight loss and smoking cessation
If diabetic ensure blood sugar control is optimised
Anaemia exclude other cause
refer if Hb < 100gm / l
Calcium / Phosphate refer if outside normal range
Review drugs and drug doses
eGFR 15 - 29 ml/min/1.73m2 - as above plus
Referral for Nephrology opinion is indicated for consideration of Renal Replacement Therapy and :
Treatment of anaemia - Erythropoietin and i.v. Iron
Management of Ca, Phos, PTH
Management CVS risk factors
Dietary advice - Na, K, Phos, Protein
Pre - dialysis education
- preparation for dialysis / transplantation
- for conservative treatment
eGFR < 15ml/min/1.73m2
Immediate referral
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.
Appendix
Classification of CKD
Stage |
GFR ml/min/1.73m2 |
Consequences |
1 - normal |
> 90 |
|
2 - early |
60 - 89* |
Increased PTH |
3 - moderate |
30 - 59 |
Decreased Ca absorption |
4 - severe |
15 - 29 |
High phosphates |
5 - ESRF |
< 15 |
Uraemia |
* associated with urinary abnormalities, especially proteinuria, or structural abnormalities; Polycystic Kidneys, reflux nephropathy.