Renal disease Flashcards
1. Give an overview of kidney functioning 2. Knowledge of pathogenesis, clinical features and management of the following - Acute renal failure - Chronic renal disease Nephrotic syndrome 3. Knowledge of renal dialysis and transplantation 4. Knowledge of relevance of renal diseases to dentistry
What are the specialised functions of the kidney
- Excretion of metabolites and drugs
- Regulation of body fluid and electrolyte balance
- Regulation of acid-base balance
- Endocrine functions
Important in vitamin D activation
How does the kidney regulate body fluid and electrolyte balance
It is made of nephrons where filtration of small molecules and ions from blood occurs - the useful materials (glucose, amino acids) are selectively reabsorbed
Urine waste is formed which is passed through the ureter to be stored in the bladder before excretion via urethra
What happens in the PCT
- actively reabsorbs glucose, amino acids, uric acid, inorganic salts
- active transports Na controlled by Angiotensin II
- active transports of phosphate surpassed by PTH
- water follows by osmosis
What happens in the LoH
Water continues to leave by osmosis
What happens in the DCT
More Na is reabsorbed by active transport and more water leaves by osmosis
What happens in the CT
Final adjustment of body Na and water content via ADH and aldosterone
Outline how RAAS controls renal endocrine function
Renin-Angiotensin-Aldosterone System
- Drop in BP is detected in kidneys
- Renin is released
- In the liver this converts Angiotensinogen to Angiotensin I
- In the lung Angiotensin I is converted to Angiotensin II by Angiotensin-converting enzyme
- This causes increase in blood pressure and aldosterone release from the adrenal cortex which increases salt retention to further increase blood pressure
Outline how the kidney is involved in the erythropoietin mechanism
Stimulant = hypoxia due to low RBC count, decreased amount of Hb, decreased oxygen availability
- Reduction in blood oxygen levels causes the kidney to release erythropoietin
- This stimulates red bone marrow
- Enhanced erythropoiesis increases RBC count
- This increases the oxygen carrying capacity of blood
- Normal blood oxygen levels maintained
What are the pre-renal factors for renal failure
- Hypotension due to haemorrhage/server burns
- Renal thrombosis
- Sepsis
- Drugs causing renal shutdown (NSAIDs + ACE inhibitors)
What are the renal factors for renal failure
- Antibiotics: gentamicin, amphotericin, streptomycin
- Analgesic overdose: aspirin, NSAIDs, paracetamol
- Multiple organ failures due to trauma/ sepsis
- Interstitial nephritis
What are the post-renal factors for renal failure
Obstructed urine flow
What is acute renal failure
It is a medical emergency that may lead to confusion, seizures and coma which is managed by dialysis
It occurs more commonly in patients that are hospitalised and those in critical care
What is chronic kidney disease
Non specific disease with several causes characterised by kidney damage/reduction in GFR (<90ml/min) for 3 or more months
It results in progressive loss of renal function (early = no symptoms, mild = GFR 60-80), moderate IIIa = GFR 45-59, IIIb = GFR 30-44, severe = GFR 15-29, end-stage = GFR <15ml/min)
What are the common causes of chronic kidney disease
- Long standing hypertension
- Diabetes mellitus
- Chronic pyelonephritis
- Chronic glomerulonephritis
- Polycystic renal disease
- Urinary tract obstruction
- Renal artery stenosis
What are the less common causes of chronic kidney disease
- Systemic Lupus erythematosus
- Amyloid (protein deposition in organs)
- Multiple myeloma
- Gout
- Lead poisoning
- Long term drug use: analgesics, Goldmans penicillamine, cyclosporine