The kidney in health and disease - for clinical dental trainees Flashcards
Normal kidney functions
- Salt and water homeostasis
- Excretion of waste
- Humoral regulation of other organs
- bone (Vti D)
- RBCs (erythropoietin)
- BVs (renin)
- selectivity barrier
Nephron
Functioning unit of kidney Tubules -proximal (convoluted and straight) -distal -collecting ducts -loop of Henle We have between 500,000 and 2,000,000
Glomerulus
Folded, large surface area
Filters blood that’s passing through
-retains protein and blood cells
-25% of cardiac output goes through here
Creatinine and GFR calculation
GFR calculated (24hr urine/plasma): Creatinine clearance: \_\_\_\_\_\_ml/min
Formulae to estimate GFR (eGFR)
Modification of Diet in Renal Disease (MDRD)
(4) - Plasma creatinine, age, gender, race
Recently switched to CKD-EPI equation
- Performs better at higher eGFR
Formulae to estimate GFR (eGFR)
Modification of Diet in Renal Disease (MDRD)
(4) - Plasma creatinine, age, gender, race
Recently switched to CKD-EPI equation
- Performs better at higher eGFR
Dialysis
2l bags each
120l of fluid processed by kidney each day
Where is vit D made?
Skin
-processed by kidney and liver
Creatinine and GFR relationship
GFR varies inversely with reciprocal of plasma creatinine (1/Pcr)
Kidney dysfunction
- Salt and water homeostasis
- Excretion of waste products
- Humoral disturbance
- Barrier failure
Kidney dysfunction - salt and water homeostasis
- changes in total body water
- changes in BP
- changes in urine volume or concentration
Kidney dysfunction - excretion and waste products
- uraemia
- acidosis e.g. lactic acid, ketoacids
- others: potassium, phosphate, uric acid
- clearance of drugs
Kidney dysfunction - humoral disturbance
- anaemia
- renal bone disease
- hypertension
Kidney dysfunction - barrier failure
Haematuria -red/ blood Proteinuria -frothy urine -precipitates as it cools down Lipiduria
K/DOQI classification
Stages 1-5 GFR decreases as stage increases 1. Kidney damage/ normal GFR >90 2. Mild renal insufficiency GFR 89-60 3. Moderate renal insufficiency GFR 59-30 4. Severe renal insufficiency GFR 29-15 5. Kidney failure GFR <15
Treatment of chronic kidney disease - mild/ moderate
Diet/ fluid balance Supplements -alkali -vitamin D -iron Drugs -phosphate -hypertension -anaemima -specific conditions: immunosuppression
Treatment of chronic kidney disease - severe
Dialysis
Transplantation
Treatment of chronic kidney disease - very severe
Kidney replacement treatment
- peritoneal
- dialysis
Signs of renal disease
Flame shaped haemorrhages in retina Oedema Haemorrhage in heart Rough 'moth-eaten' edges of bone RBCs broken up - schistocytes
Primary cause of ESRF in prevalent patients UK, top 5 causes <65 years
- Glomerulonephritis
- Diabetes
- Pyelonephritis
- Polycystic Kidney Disease
- Hypertension
Fistula
Abnormal connection between artery and vein
Manmade for pts with kidney disease
Why do we avoid using catheters
Inconvenience for patients
Bleeding
Infection
Air embolus
Primary cause of ESRF in prevalent patients UK, top 5 causes >65 years
- Diabetes
- Glomerulonephritis
- Polycystic Kidney Disease
- Pyelonephritis
- Hypertension
Dialysis
3 times a week on average -ideally every day Peritoneal dialysis -not as efficient -cheaper -probably 4x day
Clinical syndromes
Acute renal failure Chronic renal failure Nephrotic syndrome (proteinuria) Nephritic syndrome (haematuria) Malignant (accelerated phase) hypertension
Primary diagnosis in prevalent RRT patients in E&W
- Glomerulonephritis
- Pyelonephritis
- Diabetes
- Polycystic kidney disease
- Hypertension/ renovascular
Splinter haemorrhage cause
Endocarditis
Vasculitis (disease of small BVs)
-renal??
Splinter haemorrhage history
Is it on one or both hands?
Are you right or left handed?
-can be due to gardening or strenuous activity
Blotchy rash on cheeks, woman
Systemic Lupus Erythematosus
-kidney failure
Red swollen hand
Cotton wool spots (retina)
Hands - flexion deformity, swollen, red and shiny
Completely blocked kidney due to excess material
Systemic sclerosis
ESRD complications
Cardiovascular disease -hypertension -K-related arrhythmias -cardiac valvular calcifications Infections Malnutrition Renal osteodystrophy Immunosuppression -infection (atypicals) -cancer (skin, post tx lymphoproliferative) -hypertension, diabetes CVD Recurrent disease
Oropharyngeal candidiasis
Common problem for immunosuppressed pts
Gingival overgrowth associated with which drugs
Cyclosporin
-transplants/ immunosuppression
Antihypertensives
-calcium channel blockers (Amlodipine, Diltiazem, Nifedipine)
Kidney failure and the dentist
The kidney patient, especially patients with stage 4-5 (eGFR<30, Advanced CKD) are: -anaemic -have a bleeding tendency -->Minimise blood loss -->Transfusions (complicates future transplant) -->Maximum homeostasis Has CVD: -hypertensive -fluid overloaded -valvular sclerosis -->prophylactic antibiotics -->may have difficulty lying supine -->likely to have fluid restriction -hyperkalemic or pre-dialysis -->Be careful with GA -->Monitor serum K post-operatively (rebounds)
Chronic kidney disease and drugs
Generally be careful with appropriate dosing of medications commenced
Ensure considered correct dose and frequency for eGFR
Be aware of medication interactions
eg Clarithromycin/erythromycin/fluconazole and Tacrolimus
If in doubt, aim to plan electively or contact the renal unit to query
Creatinine
End product of skeletal muscle catabolism
> by dietary meat intake
Released into circulation at constant rate
Freely filtered at glomerulus
-15% of urinary creatinine secreted by tubules
-used to calculate GFR
