S2: Overview of Renal Diseases Flashcards
Functions of the Kidney
- Excretes waste substances
- Important for acid base balance
- Vitamin D activation
- Blood pressure control
- Red blood cell production
- Helps regulate water balance
- Regulates minerals in the extracellular fluid
How do we measure kidney function?
- GFR ( creatinine, MDRD)
- Measure urine output
- Measure elimination of radioisotopes
Presentations of kidney disease are by renal syndromes:
Nephrotic syndrome
- CKD
- Acute kidney injury
- Haematuria
- Nephrotic syndrome
- Asymptomatic proteinuria
Describe the pattern seen in serum creatinine in acute and chronic kidney diseases
In acute kidney disease, serum creatinine will rise over days
In chronic disease, the serum creatinine will rise over years.
You can also have acute on chronic
What are the three types of acute kidney injury?
- Blood goes into kidney - is there a problem with this = pre-renal
- Kidney does its thing - problem here = renal factors
- Problem with excreting urine = post-renal factors
List some pre-renal causes of acute kidney injury
- Hypovolemia: May be caused by haemorrhage or diarrhoea/vomiting
- Decreased perfusion: Due to septic shock or cardiac failure
- Drugs:
ACE inhibitors (probs with intraglomerular pressure)
NSAIDs (vasodilation of afferent arteriole is mediated by prostaglandins, we want to keep this open so pressure can reach glomerulus)
Give three examples of intrinsic renal disease
Glomerular :
- Glomerulonephritis
- Systemic disease
Tubular:
- Acute tubular necrosis
Intersitial:
- Interstitial nephritis
What is glomerular disease?
Glomerulus is a filter so when it fails it will start letting things through it shouldn’t such as blood and proteins.
They also start to fail to filter things they should be and retaining certain things.
Glomerular disease can be primary or secondary to systemic disease e.g. Diabetes.
It is a difficult subject as we are ignorant of pathogenesis in many cases, there is difficult terminology and often no good clinicopathological correlation.
How is proteinuria generally quantified?
Proteinuria generally quantified by urine albumin:creatinine ratio or protein:cretinine ratio
How can post renal factors be investigated?
Obstruction between kidney and outside world, generally can be investigated by ultrasound
Consequences of AKI
Immediate problems of AKI are pulmonary oedema (peripheral looks unpleasant but won’t die of it) and hyperkalemia (high potassium can lead to cardiac arrhythmias).
The consequences of AKI:
- Significant impact on outcome e.g. Hospital mortality/post discharge mortality
- Resources e.g. Length of stay, referrals/tests/treatment
Patient morbidity e.g. Acute complications, dysfunction of other organs, risk of CKD
What do renal patients most often die of?
CVS disease
- Multifactorial cause
Treatment and Management of CKD
Treatment Treatment of CKD is dialysis and treatment of underlying condition (but almost by definition CKD is not treatable so we can try stabilise it). The key aspect of management of kidney disease is controlling blood pressure and controlling the diabetes. Supportive care includes general measures, dialysis and transplantation. Management - Conservative (slow progression and minimise symptoms/complications) - Control Na+, water, blood pressure - Diet (K+, phosphate, protein) - Vitamin D (1-alpha) - Erthropoetin
Describe Haemodialysis and Peritoneal Dialysis
Dialysis removes nitrogenous wastes, corrects electrolytes, removes water and corrects acid-base abnormalities.
You connect it to them via a fistula if long term or cather if more short term.
Haemodialysis removes toxins via the blood flow going in the opposite direction and dialysate going in the other direction separated by a semi-permeable membrane. The countercurrent maintains the gradient. Protein remains in the blood.
In peritoneal dialysis there is toxin/fluid removal via osmosis. The peritoneal dialysis fluid contains high glucose load to draw water out.
