List I - Core Conditions Flashcards
What are the causes of chronic kidney disease?
- Diabetic neuropathy
- Glomerulonephritis
- Hypertension
- Systemic disease e.g. SLE, vasculitis, amyloid, myeloma
- Renal artery stenosis
- Hereditary e.g. PCKD
- Chronic pyelonephritis
- Nephrotoxic drugs
How might CKD patients present?
- Incidental finding on blood or urine tests in investigation of other condition/routine test
- Hypertension
- Monitoring “at risk” individuals
- Symptoms usually occur later at advanced stage
How is kidney function assessed?
- Serum urea - increased with reduced renal excretion
- Breakdown of amino acids (protein catabolism)
- Disproportionately high serum urea
- Catabolic state, high protein intake, gastrointestinal bleed, glucocorticoids
- Dehydration/cardiac failure
- Disproportionately low serum urea
- Low protein intake, liver failure
- Serum creatinine
What is the problem with creatinine?
- Insensitive marker - can have very impaired kidney function with relatively little creatinine increase
- Related to musculature
How else is kidney function measured?
- eGFR
- Calculated from blood results and demographic data
- Has a degree of error relating to muscle mass - especially extremes
- Racial correction (multiply 1.2 x if Afro Caribbean / Black patient)
What is the classification of eGFR?
- Stage 1 >90 Normal/high
- Stage 2 60-90 Mild decrease
- Stage 3a 45-59 Mild/moderate decrease
- Stage 3b 30-44 Moderate/severe decrease
- Stage 4 15-29 Severe decrease
- Stage <15 Kidney failure
What is an important marker of risk of progression of CKD?
- Proteinuria
* Spot urine sample
How is the cause of CKD investigated?
- Clinical history
- Biochemistry/hameatology
- Urine - dipstick, microscopy (cells, casts)
- Immunology screen (e.g. SLE, vasculitis, myeloma)
- Renal ultrasound - “normal”, obstruction, cystic disease, scarring, renovascular, renal asymmetry, small kidneys
- Renal biopsy/angiography
What is CKD associated with?
- Accelerated cardiovascular disease and mortality
* Significant life-expectancy reduction
What are the normal functions of the kidneys?
- Excretory function
- Homeostasis - fluid balance, BP
- Endocine - bone metabolism, erythropoiesis
What are the metabolic complications of CKD?
- Anaemia - reduced erythropoietin
- Bone mineral disorder - e.g. low serum Ca, high PO4, high PTH
- Lack of vitamin D 1-alpha hydroxylation by kidneys
- Phosphate retention because low GFR
- Metabolic acidosis (low sodium bicarbonate on venous bloods)
- Hyperkalaemia
What are the clinical features of CKD?
- Renal - fluid retention, polyuria, nocturia
- Cardiovascular
- hypertension, pulmonary, oedema
- LVH/dysfunction, vascular disease, dyslipidaemia, vascular calcification
- Gastrointestinal
- Anorexia, nausea, vomiting, malnutrition, peptic ulceration
- Neurological - peripheral neuropathy, restless legs
- Dermatological - pigmentation, pruritis
- Endocrine - erectile dysfunction, oligoammenorrhea, reduced fertility/ability to carry pregnancy
- Musculoskeletal - bone pain, fractures, arthropathy
When should patients be referred to a specialist for renal function?
- eGFR<30
- Progression
- Uncertain cause or suspected systemic disease
- Hereditary
- Significant proteinuria
- Haematuria and proteinuria
- Complications of CKD
What is the management of CKD?
- Treatment of underlying cause of CRF if possible
- Lifestyle
- BP control
- CVS risk reduction
- Diet
- Anaemia - erythropoietin
- Bone disease
- Vitamin D analogues, phosphate control (diet phosphate binders)
- Bicarbonate supplements for acidosis
- Restless legs - sleep hygiene and off licence gabapentin/pregabalin
When should CKD be suspected?
- Incidental finding of:
- Raised serum creatinine and/or serum eGFR of <60mL/min/1.73m2
- Proteinuria (ACR >3mg/mmol)
- Persistent haematuria (2/3 dipstick tests show 1+ or more of blood) after exclusion of UTI
- Urine sediment abnormalities (RBCs, WBCs, granular casts and renal tubular epithelial cells
- Be aware that CKD can be asymptomatic in the early stages
If CKD is suspected, what should be asked about in the history?
- General symptoms - lethargy, itch, breathlessness, cramps, sleep disturbance, bone pain, loss of appetite, vomiting, weight loss, taste disturbance
- Urine output - polyuria, oliguria, nocturia, anuria, obstructive uropathy
- Nephrotoxic drugs
- Risk factors - previous AKI
- Comorbidities or complications
- Polycystic kidney disease
- Associated features of anxiety or depression
What are the examination signs for progression of CKD?
- Uraemic odour (ammonia smell to breath)
- Pallor
- Cachexia and signs of malnutrition
- Cognitive impairment
- Dehydration or hypovolaemia
- Tachypnoea
- Hypertension
- Palpable flank masses with possible hepatomegaly
- Palpable distended bladder (suggests obstructive uropathy)
- Peripheral oedema
- Peripheral neuropathy
- Frothy urine
What are the initial investigations for CKD?
- Arrange blood tests for serum creatinine and eGFR
- Advise the person not to eat red meat for 12 hours before the test
- Arrange early morning urine sample to measure the urine albumin:creatinine ratio(ACR)
- Arrange a urine dipstick to check for haematuria
- Check the persons nutritional status, BMI, BP and serum HbA1c and lipid profile
- Consider arranging a renal tract USS (if indicated)
What is the management of the eGFR result for CKD?
- If eGFR <60mL/min/1.73m2 - repeat the test within 2 weeks
- If eGFR remains <60mL/min/1.73m2 on repeat, repeat the test in 3 months
- NB interpret with caution for extremes of muscle mass, pregnancy, has oedema, malnourished or uses protein supplements, or is Asian or Chinese in origin
What is the management of the ACR result for CKD?
- <3mg/mmol (no proteinuria) no action required
- Between 3 and 70mg/mmol, repeat the test within 3 months
- 70mg/mmol or more, a repeat test is not needed as this indicates significant proteinuria
- NB transient increases in urine ACR may be seen with menstruation, UTI, strenuous exercise and upright posture
What is the management of the urine dipstick to check for haematuria in suspected CKD?
- If 1+ or more of blood on dipstick, arrange a mid-stream (MSU) to exclude a UTI and manage accordingly
- If there is isolated persistent haematuria (2/3 dipstick show 1+ blood or more after exclusion of UTI) with no decrease in eGFR and no proteinuria - see pathway for urological cancer recognition and referral
If the eGFR and the ACR tests are repeated within 3 months, how should the be interpreted?
- Make a diagnosis of CKD if there is persistent reduction in eGFR <60mL/min/1/73m2 and/or proteinuria (ACR >3mg/mmol) lasting for atleast 3 months
- CKD diagnosis can be excluded if eGFR is persistently >60 and/or ACR is persistently <3mg/mmol and there are no other markers of kidney damage
What how is CKD categorised once a diagnosis is made?
- Using eGFR and urinary ACR
- Increased ACR is associated with increased risk of adverse outcomes
- Decreased GFR is associated with increased risk of adverse outcomes
- Combination multiplies the risk of adverse outcomes
How is ACR combined with eGFR to classify CKD?
- ACR 1/2/3
- eGFR G1/G2/G3a/G3b/G4/G5
E.G. G2A2 or G4A3 - A1=<3mg/mmol normal to mild increase
- A2=3-30mg/mmol moderately increased
- A3=>30 Severely increased
See earlier slide or NICE table for details combined with eGFR