Renal Disease Flashcards
Anatomy of a nephron
- Afferent arteriole enters the glomerulus in the Bowman’s capsule
- Primary convoluted tubule
- Loop of Henle dipping into the renal medulla
- Descending limb and ascending limb of loop of Henle
- Distal convoluted tubule
- Collecting duct leading to the pelvis of the kidney
Functions of the kidney
- Excrete waste including drugs/metabolites
- Regulate fluid volume
- Regulate acid/base
- Maintenance of blood pressure
- Excrete nitrogenous waste
- Synthesis erythropoietin/renin/1,25 cholecalciferol
- Target organ for parathyroid hormone/aldosterone/ADH
Normal kidney functions values
- Filter 100ml/min
- 99% of the 100ml is reabsorbed
- Urine production of 1ml/minute
How is GFR estimated
-Glomerular filtrate rate (GFR) is estimated from blood creatine levels, age, race and sex
Classification of kidney disease
- Acute renal failure (declining over hours/days): unlikely to see this in clinic
- Chronic kidney disease (two samples taken 90 days apart)
- Pre-renal
- Renal
- Post-renal
Kidney disease classification in terms of where the problem is and likely causes of each
1) Pre-renal
Perhaps hypertensive renal artery stenosis
2) Renal
3) Post-renal
Perhaps due to obstruction via a stone
Causes of kidney disease
- Type 2 diabetes (many have associated renal disease)
- Hypertension
- Glomerular nephritis (IgA nephropathy)
- Polycystic kidney disease (1:1500)
- Vasculitic disease of the kidney
- Kidney infection
- Outflow obstruction/reflex
Clinical features of kidney disease
Often insidious (may not notice until the kidney fails)
- Loss of appetite
- Fatigue/lassitude
- Headaches
- Itching
- Nausea
- Weight loss
- Pain in back
Stages of kidney disease and GFRs relating to disease
-A normal GFR is 100
GFR>60 Stage 1 and 2
GFR 30-59 Stage 3
GFR<30 Stage 4 and 5
If less than 10 then look at transplant or dialysis
Stages of increasing severity of kidney disease
- GFR decrease
- Haematurea (blood in urea)
- PRoteinurea (protein in urea)
- Structural abnormalities
- Genetic disorder
Consequences of kidney disease
- Increased cardiovascular risk (often already diabetic/hypertensive)
- Anaemia and reduced immunity as erythropoetin synthesis is affected
- Increased risk of bleeding
- Decreased bone health due to calcium loss
- Build up of toxins
- Reduced drug excretion
Treatment of kidney disease
- Lifestyle treatment
- Stop smoking
- Low fat/cholesterol foods
- Low salt/potassium intake
- Exercise
- Protein restriction
- Fluid restriction
-Treat the underlying cause if possible
- Control blood pressure (ACE inhibitors, Angiotensin II receptor blockers)
- Control anaemia (transfusions/iron supplementary/EPO)
- Control blood glucose
- Maintain bone health (vitamin D/calcium)
- Lower cholesterol (statins)
Dental Implications of people with kidney disease
- Take care with stage 4 and 5 GFR<30
- Increased peridontal disease (may be related to diabetes)
- Oral signs of anaemia
- Bone abnormalities
- Potential increased bleeding tendency
- Avoid NSAIDs/erythromycin
- Reduce dose of renal exreted drugs eg. amoxycillin
- Good oral health supports nutrition/preparation for transplant
Bone changes in chronic kidney disease
- Massive radioleuncy seen on a PA?
- Check PTH levels
- Could be a giant cell carcinoma
- Increase in PTH as more calcium is lost in the urine
- Releases calcium from skeleton by activation of osteoclast
- OCs can group together and begin resorbing bone forming a central giant cell carcinoma
- Often occur on their own but sometimes secondary to renal disease
Common dental drugs and chronic kidney disease affect
Lignocaine- No alteration Articaine- No alteration Amoxycillin- Reduce the dose if GFR <10 NSAIDs- Avoid if GFR <10 or diabetes Erythromycin- Avoid due to drug interactions Midazolam- Use with caution if GFR<30
