Mark Nelligan BCS Flashcards
Classification of CKD
see slide 5 of 2- progressive kidney disease lecture
Define rapid deterioration of renal function
Rapid deterioration defined as a fall in GFR of
> 5mLs/min/1.73m2 in 1 year
or
> 10mLs/min/1.73m2 in 5 years
Cause of deterioration of kidneys
- Lose adaptability
- Fail to excrete fluid load promptly
3.Fail to reduce urine volume in hypovolaemia promptly = DEHYDRATION Haemorrhage Hypotension Surgery Reduced Cardiac Output Sepsis
- Nephrotoxicity (NSAID’s, IV Contrast, etc)
- Worse in Diseased Kidneys
- Reduced Ability to Recover
Ist line Mx of HTN to prevent renal failure
- Angiotensin blockade (unless CI) eg. hyperkalaemia
2. Then move to ACE or CCB
1st line Mx of diabetic neuropathy (CHECK THIS WITH GREY BOOK AND NICE)
- Control HTN (130/80)
Tx of acidosis and justification
Sodium biocarbonate
Reduces Hyperkalaemia
Reduces Calcium Loss from Bone
Improves Catabolic State
Tx of hyperphosphatemia and justification
- Deranged Calcium, VitD, PTH
Normal Serum Phosphate
Reduces Renal Osteodystrophy
Reduces Calcium Loss from Bone
Improves Catabolic State
Dietary modifications in renal failure
- Protein Restriction 0.8 g/kg/day
- Avoid Ultra-Low Protein
- Calorie Supplements
No-Added Salt
- Sodium 60-90 mmol/day, Sodium Chloride 3.5-5 g/day
Reduced Protein
- Chronic Renal Failure 0.8 g/day
- Haemodialysis/CAPD 1.2 g/day
Reduced Phosphate
- <1000 mg/day
Low-Potassium Diet
- Potassium 40 mmol/day
Options or end stage renal failure
- End of life care
- Transplanatation
- Haemodialysis
- Peritoneal dialysis
What does dialysis `achieve
- Removes nitrogenous wastes/toxins
- Corrects electrolytes
- Removes water
- Corrects acid base abnormalities
Difference between dialysis and haemofiltration
Haemofiltration Blood is filtered across
a highly permeable membrane, allowing
movement of large and small solutes by
convection at almost the same rate. The
ultrafi ltrate is replaced with an equal volume
of fl uid, so there is less haemodynamic
instability. It is used in critically ill patients
for this reason, but is impractical as longterm
RRT, as it takes much longer than HD to
achieve the same clearance.
Haemodialysis removes solutes by diffusion. As such, it is relatively inefficient for solutes of high molecular weight as clearance by diffusion is inversely related to the molecular weight of the solute.
Haemofiltration removes solutes by convection. As such, efficiency remains more constant for all solutes able to cross the semi-permeable membrane.
The choice between haemodialysis and haemofiltration can be difficult. Points in favour of haemofiltration include:
better control of blood pressure
less risk of hyperlipidaemia
Those in favour of haemodialysis:
less expensive
technically easier
toxicity of molecules of high molecular weight has yet to be demonstrated
haemofiltration can only reduce, not normalise, the concentration of larger solutes
Advantages of haemodialysis
Good Clearance of small molecules
Very Efficient and Adjustable
Patient Freedom between Sessions
Does not cause Domestic Strain (Centre HD)
Acceptable to Patients
Disadvantage of haemodialysis
Expensive, Labour-Intensive, Capital-Intensive
Vascular Access
Intermittent Fluid Overload
Haemodynamic Instability during Dialysis
Restricted Fluid Intake
Poor Clearance of Phosphate
Poor Clearance of Middle Molecules
Malnutrition
Restrictive Diet
Types of peritoneal dialysis
- Diffusion of Chemicals – ‘Dialysis’
- Concentration Gradient In Both Directions - Osmotic Gradient (hypertonic glucose) - Endothelial Membrane with larger pores - ‘Middle Molecules’
- Convection of Chemicals – ‘Ultrafiltration’
- Transmembrane Hydrostatic Pressure does not exist
- Convection - Solvent Drag
- Endothelial Membrane with larger pores
- Middle Molecules’
Advantages of peritoneal dialysis
Preserves Residual Renal Function (8 ml/min virtual GFR)
Haemodynamically Stable, less challenging
Better Clearance of Middle Molecules
No Potassium Restriction
Liberal Diet
Lesser/No Fluid Restriction
Home-Based, No Travelling, More ‘Own’ time
Bloodless, Painless
Disadvantages of peritoneal dialysis
Self-Administered or Dependent on Trained Helper
Peritonitis and its Complications
Sclerosing Peritonitis
Often Chronic Fluid Overload
Poor Clearance of Phosphate
Obesity
Technique Failure after a few years
How is kidney function measured
MDRD equations gives eGFR
Causes of end stage renal failure
Diabetic Nephropathy
Glomerulonephritis
Idiopathic
Systemic (SLE, Vasculitis, Blood Dyscrasia, other)
Hypertension
Adult Polycystic Kidney Disease
Reno-Vascular Disease
Vesico-Ureteric Reflux Nephropathy and Congenital Renal Malformations CAKUT (‘Chronic Pyelonephritis’)
Other Hereditary Renal Diseases
Uremia related CV risk factors
- increased ECF
- Calcification
- PTH
- Anaemia
- ROS
- Malnutrition
- Pulse pressure
- TG’s and LP remnants
- Thrombogenic factors
Haemostatic Fx of the kidney
Fluid Balance & Euvolaemia
Excretion of Metabolic ByProducts
Degradation of Metabolic ByProducts, Peptides
Regulation of Chemical Composition of Plasma/ECF
Maintenance of Normal Osmolality
Acid-Base Balance
Hormonal Fx of the kidney
HORMONAL
- Endocrine
- Renin secretion
- Erythropoietin (HIF, Peritubular Cells)
- 1-α Hydroxylation of 25(OH)VitD3 - Paracrine
- Angiotensin II production
- Prostaglandin (PGI2, PGE2)
Haemostatic pathogenesis in renal failure
Accumulation of ‘Middle Molecules’ – ‘Uraemia’
Accumulation of Metabolic ByProducts (potassium,
phosphate, urate, oxalate, urea, creatinine)
Electrolyte Abnormalities
Acidosis
Oedema (Peripheral/Pulmonary) or Dehydration
Hyperlipidaemia
Compications of chronic renal failure
CKD1
No complications
CKD2
Increased CVD
CKD3
Increased CVD; Bone disease - raised PTH
CKD4
CVD, Anaemia, Bone disease - low Ca, high PO4
CKD5
CVD, Anaemia, Bone disease, Pruritus, Bleeding, Malnutrition
Symptoms of chronic renal failure
- Uraemic Muddy Colour:‘Urochrome’
- Severe Hypertension: Cardiac Failure, Headache, cerebrovascular Events,
- Fluid Overload : Peripheral Oedema, Ascites
- Pulmonary Oedema: Dyspnoea, Orthopnoea
- Hyperkalaemia: Cardiac Arrest, Diarrhoea,Peripheral Paralysis
- Diarrhoea, Vomiting: Gastritis, Hypermotility
- Peripheral Neuropathy :‘Middle Molecules’
- Encephalopathy, Coma: ‘Middle Molecules’, Urea
Cause of failure of hormonal control in CRF
- Hypertension
Renin-Driven - Anaemia
Erythropoietin deficiency
3.Proximal Myopathy
↓ 1,25(OH)2VitaminD3, ↑ PTH
- Pruritus
↑ PTH, ↑ PO4, Iron deficiency
Importance of potassium in CRF
Hyperkalaemia in CRF
- Reduced GFR
- Acidosis (competition with H cations at Collecting Duct)
- Acidosis (competition with H cations as ICF cation)
- Fluid Overload Suppresses Aldosterone Release
- ANP Digitalis-like Effect on the Na/K CounterTransporter
Iatrogenic Hyperkalaemia
- ACE Inhibitors
- Angiotensin II Receptor Blockers
- Aldosterone Antagonists
- β-Blockers
Causes of acidosis in CRF
Reduced GFR
►►Retained Acids (Phosphate)
Low Serum Bicarbonate
- Reduced Renal Mass – Tubular Cells
►►Reduced HCO3 Regeneration in Proximal Tubule
►►Reduced H Cation Secretion in Proximal Tubule
►►Reduced Hydrogen Secretion in Collecting Duct
►►Reduced Ammonia Production
Reduced Buffering
- Reduced Haemoglobin
- `High Phosphate
Consequences of acidosis
Hyperkalaemia
Hydrogen Cations Replace and Expel Calcium from Bone
Protein Catabolic Effect
Dyspnoea
What does the presence of casts in the urine indicate?
Haematuria/pyuria is of glomerular or renal tubular origin
Would bladder cancer or kidney stones have casts?
No cast but would have haematuria
Would acute cystitis have casts?
No casts, but would have pyuria
What do RBC casts indicate?
- Glomerulonephritis
2. Malignant HTN
What do Fatty casts (oval fat bodies) indicate?
Nephrotic syndrome (assoc. with maltese cross sign)
What do WBC casts indicate?
- Tubulointerstitial inflammation
- Acute pyelonephritis
- Transplant rejection
What do brown muddle casts indicate?
Acute tubular necrosis
What do waxy casts indicate?
1.ESRD/CRF
Normal and nephrotic range for 24 hour urinary protein
Normal <150 mg
(pregnancy <300 mg)
Nephrotic range >3g
Treatment of hyperkalemia?
Treatment in non-urgent cases
• Treat the underlying cause; review medications.
• Polystyrene sulfonate resin (eg Calcium Resonium® 15g/8h PO) binds K+ in the gut,
preventing absorption and bringing K+ levels down over a few days. If vomiting
prevents PO administration, give a 30g enema, followed at 9h by colonic irrigation.
If there is evidence of myocardial hyperexcitability, or K+ is >6.5mmol/L, get senior
assistance, and treat as an emergency (see p849).
Treatment for urgent hyperkalaemia:
1 Stabilize cardiac membrane with 10mL 10% calcium gluconate
2 Drive K+ into cells with 10units actrapid in 50mL 20% glucose
- Stop all potassium-retaining/containing drugs where possible and arrange dietary
review of potassium in diet where appropriate.
Treatment for anaemia
EPO and Iron
What are the causes and features of uremic syndrome
Cause:
Accumulated products of protein catabolism, Urea usually excreted from the kidney - in renal failure it is not so builds up in the blood
Features:
- Pruritus
- Peripheral Neuropathy
- Encephalopathy
Cause of platlelet dysfunction and haemorrhage in CRF
Uremia interrupts the binding of platlets resulting in haemorrhagic state
Platelet dysfunction and haemorrhage
Inhibition of platelet adhesion
Defective vWF receptor ligand
Bleeding time is useful
Cause of prothrombotic tendency in CRF
Protein C/S functional deficiency
Increased homocysteine
Inadequate tPA
wHAT TYPE OF CONDITION EFFECTING pth DOES crf LEAD TO?
Secondary hyperparathyroidism
Consequences of calcium dysregulation
Periarticular calcification
Blood vessel wall calcification
Proximal Myopathy
Calciphylaxis
Calcification of the heart
Symptoms of bone changes due to calcium dysregulation
Proximal Myopathy
Bone pain – backs, hips, legs
Joint pain
Fractures
Poor mobility
Growth retardation, deformities, child
Features of osteodystrophy
Osteitis Fibrosa Cystica: increased PTH
Osteomalacia: defective Mineralisation
Adynamic Bone Disease: low bone Turnover (low PTH)
Osteoporosis: defective bone Formation
Aluminium-Induced Calcification Failure (Newcastle
Disease – Pathological Fractures)
Mx of bone disease in CKD 3/4
- High PTH: Start 1a caldiol then repeat Ca2+, phospahte and PTH
- If still high Calcium and Low PTH stop 1a calcidiol
- If High PO4: PO4 restriction or calcium based PO4 binders
- If low Vit D: Start Vit D
What is the vertebral level of the kidneys?
T12 - L3 - they are protected by the thoracic ribs but or not in thoracic cavity as they are below the level of the diaphragm
How many lobes per kidney?
5-11
What are the origins of the renal pelvis?
Superior part of the ureter. Branches to firn two or three major calices - each of which divide again to form minor calices which collect urine from papillae of kidneys
Innervation of the kidney
Vagus (PNS) through coeliac plexus - allows RA and RV dilation
T10-L1 (SNS) - constricts RA and RV
Location of nephrons in the kidney
See slide 12 of renal anatomy lecture
Significance of septum between adrenal gland and kidneys?
Prevents damage to adrenal gland in renal transplantation
Site for transplanting a kidney?
Iliac fossa of the greater renal pelvis
Which structure joins the ext. iliac a.
RA
Which structure joins the ext. iliac vein
RV
What does the ureter pass over anteriorly?
- Psoas major
2. Genitofemoral nerve
Which structures is the left ureter related to?
- sigmoid colon,
gonadal vessels - left colic branches of inferior
mesenteric artery.
What structures is the right ureter related to?
- descending (2nd
part) duodenum, - terminal ileum,
- root of the
mesentery, - gonadal vessels,
- right colic and
ileocolic branches - terminal part of the
superior mesenteric artery.
At which landmark does the ureter cross medially
into the pelvis?
Ext. iliac or common iliac vessels