Renal Function and Kidney Disease Flashcards
Describe the basic unit which makes up the kidney
- Nephron made up of glomerulus and tubules
- Glomeruli filter around 150 litres per day
- Tubules reabsorb most of this filtrate
- Urine excretion usually under 3 litres per day
How much of normal cardiac output do kidneys receive?
25%
Describe how filtration is achieved in the glomerulus
- Blood pressure progressively reduced from renal artery to glomerular capillaries
- Glomerular pressure provides hydraulic force for filtration
Describe the % sodium resorption at different points along the tubules
PCT - 50-60%
TAL - 25-30%
DCT - 5-10%
Collecting Duct - 1-5%
How is normal renal function usually measured?
Assay of serum creatinine (biomarker for kidney function)
What does eGFR stand for?
Estimated glomerular filtration rate
Name 4 things which eGFR is based on
- Age
- Gender
- Ethnicity
- Serum creatinine
What is “normal” GFR?
Around 100 mL/min
How many stages are there in chronic kidney disease (CKD)?
5
Describe stage 1 CKD
- eGFR = 90+
- Normal kidney function
- With urinary structural abnormalities
Describe stage 2 CKD
- eGFR = 60-89
- Mildly reduced kidney function
- With urinary structural abnormalities
Describe stage 3 CKD
- eGFR = 30-59
- Moderately reduced kidney function
- With or without urinary structural abnormalities
Describe stage 4 CKD
- eGFR = 15-29
- Severely reduced kidney function
- With or without urinary structural abnormalities
Describe stage 5 CKD
- eGFR < 15
- Established renal failure
- Very severe or dialysis dependent kidney failure
Name 2 reasons kidneys fail
- Acute Kidney Injury (AKI)
2. Chronic Kidney Disease (CKD)
What is the main issue with acute kidney injury?
- A sudden decrease in kidney function needs urgent assessment as it is usually the setting of another illness
- Primary problem needs addressed ASAP
Describe the 4 stages in the natural history of AKI
- Full recover
- AKI to CKD
- Acute on chronic kidney disease
- AKI to ESRD
Name 3 things which normal kidney function depends on
- Perfusion with adequate pressure and oxygen
- Intact nephrons
- Free urinary drainage
What is the definition of AKI?
A decrease in GFR which occurs within hours to days and is potentially reversible
Name 3 types of AKI
Pre-renal - Disordered perfusion of kidney which is structurally normal
Renal - Damage to nephrons often after prolonged pre renal insults
Post-renal - Urinary drainage obstructed
Name 3 causes of pre-renal AKI
- True Volume Depletion
- Hypotension
- Oedematous States
Name 2 causes of true volume depletion
- Blood loss
2. Gastrointestinal losses
Name 2 causes of hypotension
- Septic shock
2. Cardiogenic shock
Name 2 causes of oedematous states
- Cardiac failure
2. Liver failure
Name 2 major causes of acute tubular necrosis
- Renal ischaemia followed by reperfusion
2. Exposure to nephrotoxins
Name 3 nephrotoxins
- Drugs
- Radiocontrast dye
- Haem pigments
What is the definition of CKD?
A decrease in GFR which occurs over months or years and is usually irreversible
Name 4 common causes of CKD
- Diabetic nephropathy
- Hypertensive renal vascular disease
- Glomerulonephritis
- Polycystic kidney disease
What is the inheritance pattern of polycystic kidney disease?
Autosomal dominant trait
What is the most common cause for patients starting dialysis?
Diabetes
Name 5 major modifiable risk factors of renal disease
- Diabetes
- Hypertension
- Smoking
- Dyslipidaemia
- Cardiac disease
Name 3 major unmodifiable risk factors of renal disease
- Age
- Male > Female
- Family history
What is the principle of dialysis?
Chemical bath which contains appropriate molecules and exchange them with the toxins in the blood
Name 2 types of chronic dialysis
- Haemodialysis
2. Peritoneal dialysis
Describe haemodialysis
- Usually hospital based
- Nurse delivered
- Three times per week
- Very expensive
- Restricted to sites with dialysis machines
Describe peritoneal dialysis
- Home based
- Patient performs dialysis
- Daily administration
- Uses abdominal cavity
- Cheaper
How is the blood stream prepared for haemodialysis?
- Internal arteriovenous fistula
- Surgical connection of vein and artery in fistula
Describe how a kidney transplant is achieved
- Placed ectopically in iliac fossa
- Original kidneys remain in place
- Renal vein anastomosis posterior and lateral to artery
Describe kidney transplants as an alternative to dialysis
- Better quality of life from patient
- Much better survival rate for patients
- Much cheaper than dialysis
- Life long drug treatment to suppress immune system
Describe 4 types of living donors
Living related - Parents, siblings etc
Living unrelated - Partner, spouse
Paired donation - Pair doesn’t match so swap with another pair
Paid donation - Illegal
What is the most common complication of kidney transplant for dentists?
Immunosuppression
Name 2 issues with immunosuppression
- Infections
2. Neoplasia
Name 3 examples of infections which are complications of immunosuppression
- Herpes simplex
- Papillomavirus
- Candidiasis
Name 3 examples of neoplasia which are complications of immunosuppression
- Squamous cell carcinoma
- Basal cell carcinoma
- Non-Hodgkin’s lymphoma
What is the cause of Non-Hodgkin’s lymphoma?
EBV in immunosuppressed patient
Describe the presentation of aphthous ulcers
Round, yellow-grey ulcers present on oral mucosa
Describe the presentation of Herpes Simplex virus
Multiple erosions and vesicular lesions are present in the mouth
Describe the presentation of Herpes Simplex labialis
Grouped vesicles are evident on lower vermilion boarder
Describe the presentation of oral candidasis
White papules and plaques are present on the palate and tongue
Describe the presentation of squamous cell carcinoma on the lip
Erythematous, crusted nodule on the lip
Describe the presentation of nodular basal cell carcinoma
Pearly papule with telangiectasias can be seen
Describe the presentation of infiltrative basal cell carcinoma
Present as indented, scar like lesions
Describe the presentation of Non-Hodgkin’s lymphoma
May present as an intra oral tumour
What is a common side effect of cyclosporin and calcium channel blockers when used in combination?
Gingival enlargement
Briefly describe oral diseases commonly found in patients suffering from CKD
- Edentulism
- Periodontitis
- Oral pain is common
- Xerostomia
