CPT2: Renal Flashcards
What are the three classifcations of renal diseases?
- Pre-renal
- Renal
- Post-renal
What is pre-renal disease?
- Reduction in CO or Blood volume
- Problems occuring before the renal e.g. CO problems or ability to perfuse the kidneys
What is renal disease?
- Occurs in the renal structure e.g. Vascular, endothelial, glomerular dysfunction or necrosis
- May be problems with glomerular leaking, scarring, damage to tubing due to abnormal growth/ cells dying
What is post-renal disease?
- Blockage of ureter - kidney stones, infiltrating tumour, prostate
- Can directly or indirectly block. Blockage of tubing leaving the Renal can lead to build up of pressure and damage e.g. unrine infection
What are the 2 classifications based on time periods for kidney diseases?
- Acute kidney injury
- Chronic kidney disease
What is Acute kidney disease?
- Covers a variety of injuries to kidneys from a range of causes
- Often classified by decline in renal excretory function over hours or days
- Rapid change but short time period
- Failure to maintain electolyte, fluid, acid-base homeostasis
What is Chronic kidney disease?
Abnormal kidney function or structure present for more than 3 months, with health implications
What are examples of pre-renal causes and there resepecable causes
- Decreased CO
- Heart failure
- Hypotension
- Myocardial infraction
- operative (operation theatre CO dcr)
- Hypovolemia (loss of volume)
- Sweating
- Haemorrahge - leakage leads to loss of fluid
- Diuretics - dcr fluid volume
- Burns - loss of insulation layer which helps keeps fluid in
- Systemic Dilation
- pharmacological vasodilation - drugs which cause peripheral vasodilartion to CVS effect blood supply tothe kidney
- Sepsis
What is pre-renal damage to the kidney usually caused by? what is this called?
Lack of perfusion (ischaemia) / ocygen to maintain tissues
What are examples of causes of renal failure?
- Afferent/ efferent arterioles
- Tubules
- Glomerulus
What are types of diagnostic imaging and what do these show?
- X-ray and Ultrasound
- Kidney stones
- Cancer
- Kidney size
- Intravenous excretory urogram
- Contrast media to show perfusion
- Structure
- Voiding
- Renal angiogram
- Confirm diagnosis and/ or check renal vascular anatomy
- Biopsies
- Taking renal samples
- Diagnose cause of kidney disease
- GFR/ eGFR
What is the most frequent test for renal function?
GFR
What is clearance?
The volume of plasma cleared of a substance by glomerular filtration through the kidney
What is the equation for clearance? what are each of the parameters?
Cl = (U x V)/ P
CL = clearance
U= Conc of drug/metabolite in urine
V= Rate of urine formation of drug/ metabolite (ml/min)
P= conc of drug/ metabolite in plasma
- How does GFR tend to be measure?
- What is used and why?
- What else can be used?
- What are the disadvantages?
- What are these techniques generally used for?
- Inject inulin
- Inulin isn’t absobed, metabolised, secreted in the renal system
- Radio isotopes and radio-contrast agents
- Time consuming and costly
- Monitoring chemotherapy and evaluation of renal function in living poteital kidney donors
- What is eGFR?
- What substance is used instead and how is it synthesised?
- How is it done
- Disadvantages
- Estinated GFR
- Creatinine - produced by skeletal muscle at rough;y a constant rate so plasma conc depends on rate of excretion by the kidneys
- 2hr urine collection (measures creatinine in urine. Blood samples taken to measure creatinine in plasma. Then equation used.
- Usually Over estimation, time consuming
- What is the name of the equation used to calculate GFR?
- What is the equation?
- Cockcroft and Gault equation
- GFR = (((140-Age) x wt x 1.2)/CrSr (x0.85 if female)))
CrSr = micromol/l
What is creatinine levels effected by?
- Age
- Gender
- Ethnic group
- Muscle bulk
- Diet (protein)
- Maluntrition
- Pharmacology
These variables need to be accounted for so the eqaution altered
What is pratical advice on GRF?
- People from African- Carabean or African backgrounds need a correction factor
- Amputees, body builders (muscle mass extremites), muscle wasting disorders need to interpretate eGFR creatinine with caution
- Don’t eat meat 12hours before
- Blood samples need to be recieved and processed within 12 hours of venepuncutre
What can be used as an alternative to Creatinine?
What/ where is it from?
Cystatin C - peptide syntheises in nucleated cells
What biochemical tests can be carried out and why is this done?
Not enough just to use GFR to determine renal efficacy - need other markers.
- Urea
- Results from protein/ AA breakdown in liver
- Cleared by GFR
- When filtred rates drop, high urea levels rapidly seen in serum
- Electrolytes
- K - Hyperkalemia and hypokalemia
- Ca - Hypercalcaemia
- Na - Hypernatraemia
What can urine results show?
- Protein:
- Bladder infection or kidnehy disease
- less than 150mg/ day
- Haematuria (blood trace)
- White - INfection
- Red - glomerulo-nephritis
- Use reagent strips rather than urine microscopy
- Glucose
- Diabeties
- High due to dietary intake
- Is it normal to find protein in the urine?
- What can be used to meausre protein in urine?
- Only very small amounts of protein are filtered by the glomerulus and are present in the kidney, therefore large amounts of protein found in the urine is a sign of renal disease
- The Alumbin:Creatinine Ratio or the Protein:Creatine Ratio. ACR is prefered and is more accurate/ sensitive in comparision to PCR
Both eGFR and ACR can be used together to analysis renal status
What are the symptoms of CKD?
- If mild to moderate CKD no symptoms normally present
- Usually CKD is diagnosed by eGFR before any sympyoms experienced
- Initally sympyoms are non-specific and vague e.g. tired,lack of energy, just feeling unwell
- Symptoms tends to arise in serve CKD (stage4), e.g.:
- Nausea
- Paleness
- Fluid retention
- Loss of appitite
- Puffiness around eyes
- Need to pass urine more often
- dry and itching skin
- Weight los
- Difficulty thinking
- Muscle cramps
- Also anaemia and imbalance of phosphate, calcium and other electrolytes and pH leading to tiredness and anaemia; bone thining and bone fractures due to calcium and phosphate imbalance
- Stage 5 - end stage is renal failure which is eventually fatal unless treated


