Renal medicine Flashcards
Where would calyces be found
Within the kidney branching off the renal pelvis
What percentage of the cardiac output do they kidneys receive
20%
What does Renin do
Renin is the enzyme that converts angiotensinogen to angiotensin I, which is then converted to angiotensin II in the lungs by ACE
What is the renin angiotensin aldosterone system
Angiotensin II has four main effects:
-Generalised vasoconstriction → ↑ SVR ↑ BP
-Vasoconstriction of efferent arterioles to a greater extent than afferent arterioles in the kidney → ↑ GFR
-Release of aldosterone by adrenal → ↑ sodium and water retention
-Stimulates thirst by action on hypothalamus
What is the glomerulus
Fenustrated capillary network allowing passage of water solutes and protein
What are the role of the tubules
Reabsorption, secretion, and excretion occurs in tubules
What determines the filtration rate in the glomerulus
Filtration dependent on the balance between hydrostatic and colloid osmotic pressure
GFR - 125ml/min
How much more permeable are glomerular capillaries than normal capillaries
100x times
What is clearance
The volume of plasma that iscleared of the substance in unit time
What is resorbed in the PCT
100% of glucose and amino acids
90% of bicarbonate
80-90% of inorganic phosphate and water
40-50% of urea
What are the roles of the loop of hemle, DCT and collecting duct
Loop of Henle
-Concentrating urine
Distal convoluted tubule
-Fine tuning
-Reabsorption of ions
Collecting duct
-Variable permeability to water
-Antidiuretic hormone (ADH) dependent
-Achieves the final urine concentration
What are the functions of the kidney
Salt and water homeostasis
Acid-base homeostasis
Excretion of waste products
Retention of vital substances
Endocrine functions (produce erythropoietin)
Where is ADH released from
Posterior pituitary
What stimulates ADH release
Increased osmolality in the hypothalamus
Decreased plasma volume
Angiotensin II
What does ADH do
Determines the permeability of collecting ducts
How is calcium homeostasis acheived
Parathyroid hormone (PTH) and vitamin D.
PTH is released in response to low plasma calcium levels
PTH acts on the kidney to increase calcium reabsorption in the distal convoluted tubule
The kidney also converts 25-hydroxyvitamin D to its active form, 1,25-dihydroxyvitamin D, which increases intestinal calcium absorption and renal calcium reabsorption
What is the process of phophate homeostasis
PTH and vitamin D, plus , fibroblast growth factor 23 (FGF23)
PTH decreases phosphate reabsorption in the proximal tubule
FGF23, produced by osteocytes, further enhances phosphate excretion
What is the function of calcitriol
Crucial for calcium and phosphate homeostasis
Whereis renin secreted
Juxtaglomerular cells
How is the estimated glomerular filtration rate used to ‘stage’ the chronic kidney disease
Stage 1: eGFR >90 (normal), with other tests showing signs of kidney damage (e.g. proteinuria)
Stage 2: eGFR of 60 to 89 ml/min, with other tests showing signs of kidney damage (e.g. proteinuria)
Stage 3a: eGFR of 45 to 59 ml/min
Stage 3b: eGFR of 30 to 44 ml/min
Stage 4: eGFR of 15 to 29 ml/min
Stage 5: eGFR <15 ml/min
What are the subtypes of acute kidney injury
Pre-renal
Renal
Post-renal
What causes pre-renal acute kidney injury
Decreased perfusion of kidneys
Hypovolaemia
Hypotension
What is acute kidney injury
Sudden decline in renal function
Typically identified by a rapid increase in serum creatinine levels and/or a decrease in urine output
What could result in renal acute kidney injury
Direct damage to renal parenchyma e.g. acute tubular necrosis, glomerular nephritis
What would cause post-renal acute kidney injury
Obstruction
What is glomerulonephritis
Immune-mediated disorders
IgA nephropathy being the most common type
Inflammation of the glomeruli
How is glomerulonephritis diagnosed and treated
Diagnosis via biopsy
Treatment immunosuppressive & supportive
What are the management options for acute tubular necrosis
Avoid
Supportive care ( fluid management)
Renal Replacement Therapy
What is pyelonephritis
UTI - bacterial infection (Relatively common)
E.Coli most commonly organism
infection typically ascends from the lower urinary tract, facilitated by factors such as vesicoureteral reflux, urinary obstruction, and instrumentation
What are the risk factors for renal cancer
smoking,
obesity,
Hypertension
certain hereditary conditions like von Hippel-Lindau disease
What are the most common causes of chronic kidney disease
HYPERTENSION and DIABETES
Diabetic nephropathy
Hypertensive nephrosclerosis
What is diabetic nephropathy
Prolonged hyperglycaemia causes cellular damage & inflammation
-overproduction of advanced glycation end product
-activation of protein kinase C
-increased oxidative stress
What are signs of diabetic nephropathy
glomerular hyperfiltration and microalbuminuria,
Progressing to macroalbuminuria & ↓ eGFR
What is hypertensive nephrosclerosis
Structural changes in the kidneys as a result of sustained high blood pressure
Changes lead to progressive renal damage and eventual decline in kidney function.
What are the types of polycystic kidney disease
Autosomal dominant - presents in adulthood, more common, mutations in PKD1 PKD2 genes
Autosomal recessive - presents in childhood, rarer, mutation in PKHD1 gene
What is dialysis
Remove metabolic waste products, excess body water, and rebalancing electrolytes
What are the types of dialysis
Haemodialysis
-Fistula or dialysis line
Peritoneal dialysis
What are dental impacts of dialysis
Increased Risk of Oral Diseases
-Higher prevalence of periodontal disease, dental caries, and oral Candida colonization
-This is due to factors such as impaired immunity, altered salivary flow, and poor oral hygiene
Management of Bleeding Risks
-Anticoagulant therapy
Timing of Dental Procedures
-Schedule dental treatments on non-dialysis days to minimize the risk of bleeding and infection.
Infection Control
-Compromised immune systems
-At higher risk for infections.
Impact on Survival
-Proper dental care associated with improved survival rates in dialysis patients.
Oral Health and Systemic Complications:
-Poor oral health in dialysis patients has been linked to systemic complications such as cardiovascular disease and pneumonia.
What factors should dentists be aware of when treating patients with transplants
Post-transplant immunosuppressive therapy
-susceptible to infections
-can causes gingival overgrowth which may need surgery
-can cause oral ulcerations
Dental caries more prevelant until oral pH is normalised after transplant
Why are platelets affected with kidney disease
Primarily due to the accumulation of uremic toxins, which impair platelet aggregation and adhesion.
This results in prolonged bleeding times and reduced platelet reactivity to agonists such as adenosine diphosphate (ADP) and collagen
Patients on hemodialysis (HD), the interaction of blood with the dialysis membrane can activate platelets, leading to a paradoxical state of both increased platelet activation and impaired function.
What drugs should be avoided in patients with renal disease
Probenecid
Tetracyclines
Aspirin
Ibuprofen ( avoid where possible )
Ephedrine
Povidone-iodine
All increase in toxicity without normal renal function
