Specific renal referrals

Acute kidney injury

NICE recommend use of the Kidney Disease Improving Global Outcomes (KDIGO) classification of AKICR2:

• Acute kidney injury (AKI) 1: a rise in creatinine of = 26.5 µmol/l OR 1.5-1.9 times baseline
• Acute kidney injury (AKI) 2: a rise in creatinine of = 2.0-2.9 times baseline

AKI 1 may often be managed safely in the community, although close follow up will be required with early repeat of creatinine and monitoring of potassium. 

Admission to general medicine is appropriate for many patients with AKI 2 as intravenous fluid replacement is likely to be needed and the underlying precipitating cause is likely to require inpatient treatment.  Furthermore, admission facilitates close monitoring of renal function.  As management predominantly requires treatment of the underlying disease, not specialist nephrology input, referral directly to the renal unit is most often not required.  

NICE Acute kidney injury (AKI) Clinical Guideline (CG169) suggests discussion of management of AKI with a nephrologist as soon as possible and within 24h of detection when one or more of the following is present:

• a possible diagnosis that may need specialist treatment (for example vasculitis, glomerulonephritis, tubulo-interstitial nephritis or myeloma)
• AKI with no clear cause
• inadequate response to treatment
• complications associated with AKI
• stage three AKI
• a renal transplant
• Chronic kidney disease (CKD) stage four or five and AKI

Acute glomerulonephritis, vasculitis, interstitial nephritis and thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome (TTP/HUS) are ‘must not miss’ diagnoses.  These diagnoses will be suggested by the history and examination findings and will always be associated with abnormal urinalysis.  Thus, dipstick of the urine is mandatory in patients who may have AKI due to intrinsic renal disease, the finding of haematuria and/or proteinuria requiring discussion with a nephrologist within 24 hours.

Chronic kidney disease

Current clinical practice has moved away from absolute measures of renal function with stages of chronic kidney disease (CKD) and towards the risk that an individual has of developing end stage kidney disease in their lifetime. The kidney failure risk equation is valid in patients with chronic kidney disease but should not be used in acute kidney injury. A kidney failure risk equation (KFRE) is required in patients with chronic kidney disease and uses a four variable calculation, a risk calculator can be found at the following link:

• Kidney failure risk calculator

Patients with a KFRE of >five % at five years should be considered for referral. Not all patients will benefit from secondary care. Where benefit is questionable such as in very frail individuals or those with very poor prognosis from an alternative diagnosis advice and guidance may be offered rather than an appointment.

Urinary tract obstruction

All patients with obstructed kidneys on imaging require emergency urology referral for intervention. Patients require referral to both urology and nephrology services only if there is a concern that a patient requires urgent dialysis. This is a medical emergency and requires a phone call to the on-call renal team and urgent admission to a urology bed via an emergency pathway.

Haematuria

The following require two week cancer referrals to urology services:

• age >45 years with unexplained visible haematuria without urinary tract infection
• age >45 years with persistent visible haematuria that persists or recurs after successful treatment of urinary tract infection
• age >60 and unexplained non-visible haematuria and dysuria or raised white cell count on a blood test

Non urgent referral to urology is required for possible bladder cancer in >60 year olds with recurrent or persistent unexplained urinary tract infection.

Patients with isolated persistent microscopic haematuria with stable estimated glomerular filtration rate (eGFR), no evidence of proteinuria and normal blood pressure, require routine urological assessment for potential lower tract bleeding and structural renal abnormalities. Once urological investigations have been completed this group of patients do not require further investigation in nephrology clinic.

Renal cysts

Simple renal cysts do not require follow-up or referral to secondary care unless causing significant pain where surgical de-roofing can be considered and patients can be routinely referred to urology services.

Complex cysts (thick septae, solid component, significant calcification or radiological concern) should be managed as per a renal mass with a two week cancer wait referral to urology.

Polycystic kidneys (hereditary condition causing enlarged cystic kidneys); check estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (ACR). Kidney failure risk equation (KFRE) is not validated in polycystic kidney disease. Optimise BP control (<130/80), check for family history and refer to nephrology.

Multi-cystic, check eGFR and urine ACR, optimise BP to <130/80. Monitor and referral to nephrology as per CKD guidelines (see quick guide above).

Renal stone disease

Nephrology referral (directed to the nephrology stone clinic) is required in the following scenarios:

• Patients with bilateral, multiple or recurrent stones, (two to three) stone episodes per year or ages <25 years require referral to nephrology metabolic stone clinic.
• Pure calcium phosphate stone (?RTA)
• Non-calcium stones (e.g. Cystine or uric acid stone) or elevated urine cysteine
• Previous gastric bypass (?enteric hyperoxaluria)
• Strong family history of stones with symptomatic stones
• Nephrocalcinosis
• Childhood stones
• Complications from stone AKI, solitary kidney/renal impairment

Patients can be referred to via the general nephrology portal and will be booked directly to the metabolic/stone clinic at Queen Elizabeth Hospital Birmingham (QEHB).

Patients are required to complete a 24-hour urine for Ca2+, citrate, oxalate, and cysteine. This will be arranged via our metabolic CNS prior to the first appointment. 

Symptomatic stones require referral to urology services.

Incidental findings of multiple stones or stones >6mm require referral to urology services.

Metabolic renal disorders

The Queen Elizabeth Hospital Birmingham (QEHB) has a specialist metabolic kidney disease clinic for patients with the following conditions:

• Renal tubular acidosis
• Hypokalaemic alkalosis
• Salt wasting nephropathy
• Bartter’s syndrome
• Gittelman’s syndrome

Patients can be referred via the general nephrology portal and will be booked directly to the metabolic/stone clinic at QEHB.

Hypokalaemia

Hypokalaemia may indicate an underlying renal pathology. Most cases are however unrelated to renal disease and require initial investigation in primary care prior to secondary care referral to either nephrology, endocrinology or gastroenterology depending on the underlying disease aetiology.

Patients with severe hypokalaemia OR symptomatic moderate/mild hypokalaemia require urgent admission to the local medical admissions unit via the on-call medical team.

Mild	K = 3.1-3.5 mmol/L
Moderate	K = 2.5-3.0 mmol/L
Severe	K <2.5 mmol/L

Symptoms of low potassium include:

• muscle cramps and pain
• weakness and fatigue
• palpitations and syncope
• cardiac arrhythmias or rhabdomyolysis
• psychological symptoms: delirium/hallucinations

There are many causes for hypokalaemia which may be identified in the patient’s history:

Cause of low potassium
Gastrointestinal loss	Diarrhoea, vomiting, fistulae, villous adenoma, laxative abuse
Increased renal loss	Diuretics Hypomagnesaemia Mineralocorticoid excess (Cushing’s, primary hyperaldosteronism, secondary hyperaldosteronism: e.g. volume depletion and congestive heart failure, congenital adrenal hyperplasia) Exogenous mineralocorticoid excess (steroids, liquorice, renal tubular acidosis I and II) Increased urine flow (osmotic diuresis) Renal tubular transport defects: Bartters, Gitelmans or Liddle syndrome
Redistribution of potassium from extracellular to intracellular space	Treatment for diabetic ketoacidosis Uptake of potassium into cells due to B12 or folate replacement Refeeding: following prolonged starvation, alcoholism, eating disorders Alkalosis Hypokalaemic periodic paralysis and thyrotoxic periodic paralysis
Pseudo hypokalaemia	Seasonal pseudohypokalaemia (delayed analysis of venous samples in warmer weather) Significant leucocytosis due to in vitro uptake of potassium by white blood cells
Medications	Loop or thiazide diuretics Laxatives Insulin or glucose administration Corticosteroids Beta-agonists Xanthines

Investigations for hypokalaemia

In warmer weather delays in a sample reaching lab can lead to spurious (pseudo) hypokalaemia.

First line investigations in a patient with hypokalaemia:

• serum electrolytes and renal function
• magnesium (hypokalaemia is often refractory to treatment unless hypomagnesaemia is corrected) 
• bicarbonate to assess acid-base status (please ensure sample arrives to laboratory within 4 hours)
• full blood count (FBC) (high white blood cell count (WCC) can cause an increase or decrease to potassium in vitro and mask true potassium status)
• serum glucose
• if clinical suggestion of hyperthyroidism consider thyroid function tests (TFTs)
• if myalgia exclude rhabdomyolysis with CK
• electrocardiogram (ECG); if K+ < three mmol/L to look for small p waves, u waves, prolonged QT, ST depression and T wave flattening

Second line investigation for a patient with hypokalaemia:

Persistent hypokalaemia of unknown cause will require further investigation and referral to secondary care. The following tests are required to determine which specialty to refer to initially.

• Plasma renin and aldosterone – (low renin and high aldosterone (raised aldosterone:renin ratio) suggests primary hyperaldosteronism – refer this to endocrine clinic 9.00am cortisol – if raised may suggest Cushing’s – refer this to endocrine clinic
• Urine potassium >20 mmol/L  on spot urine or >20mmol/day on 24 hour urine collection) (without excess GI losses and not raised aldosterone:renin ratio or raised cortisol) – refer this to nephrology  - please send direct referral letter to Dr Lavanya Kamesh or Dr Graham Lipkin for a new patient appointment in the metabolic renal clinic

Specialist renal services

Patients with previously diagnosed specific kidney conditions in the Birmingham and Solihull area can be booked directly into specialist kidney clinics with a referral letter. Patients can be referred directly to individual renal consultants or booked via the GP referral portal andtriaged directly into specific renal clinics.

Specialist renal clinic	Location	Consultant to direct referrals to
Pregnancy and renal disease	BWC BHH SWBH	Dr Graham Lipkin and Dr Nadia Sarween Dr Awais Hameed Dr Fouad Al Baai and Dr Hui Liew
Cystinosis	QEHB	Dr Graham Lipkin
Tuberous sclerosis	QEHB	Dr Graham Lipkin
Glomerulonephritis	QEHB and Smethwick dialysis unit	Dr Stuart Smith Dr Jennifer Pinney Dr Peter Hewins Dr Nadia Sarween Dr Dimtrios Chanouzas
Lupus Nephritis	QEHB	Dr Peter Hewins Dr Ben Rhodes (Rheumatologist) Dr Nadia Sarween
Vasculitis	QEHB	Professor Lorraine Harper Dr Dimitrios Chanouzas
Renal AL amyloidosis and monoclonal renal disease	QEHB	Dr Jennifer Pinney
Genetic kidney disease	QEHB	Dr Lukas Foggensteiner Dr Yuki Heath
ADPKD	QEHB	Dr Lukas Foggensteiner Dr Yuki Heath
Young adult and transition services	QEHB	Dr Tanya Pankhurst Dr Graham Lipkin
Cardio renal disease	BHH	Dr Amar Mahdi
Diabetic renal disease clinic	BHH	Dr Vijayan Suresh