Chronic Kidney Disease

Chronic Kidney Disease

summary

Overview

Overview CKD is responsible for a substantial burden of illness and premature death. The kidneys are basically not working as good.

Remember Always assume a ↓ eGFR represents acute kidney injury until proven otherwise
Definition
Acute Kidney Injury: Rapid reduction in kidney function over hours to days, as measured by serum urea and creatinine and leading to a failure to maintain fluid, electrolyte and acid-base homeostasis.
Acute Kidney Failure:
Chronic Kidney Disease: Impaired renal function >3months based on abnormal structure or function, or GFR <60 for >3months with evidence of kidney dysfunction

overview

Kidney Physiology eGFR

More to come...

Limitations to eGFR
Accurate to +/- 30%
Not for use in children, pregnancy, dialysis
Extremes of body composition and size
Vegetarian diets
Rapidly changing renal function
Interferences with creatinine assays

 

Think If eGFR is < 60 mL/min/1.73 m2, consider clinical situations where eGFR results may be unreliable and/or misleading and retest within 14 days

GFR (mL/min) = GFR (mL/min/1.73m²) x BSA / 1.73

Risk Factors

RF

Remember Proteinuria, which is a clinical marker for CKD, is also indicative of an increased risk of cardiovascular disease

Signs and Symptoms

sands

Patients with CKD are often asymptomatic until the advanced stages

  • Fatigue (Anaemia)
  • Breathlessness (fluid overload/acidosis)
  • Pruritis (itching)
  • Restless legs
  • Bone pain
  • Leg swelling

Severe Chronic Kidney Disease (GFR <20mL/min)

  • Pericarditis
  • Serositis
  • Encephalopathy
  • Gastrointestinal bleeding
  • Uraemic neuropathy

Examination

  • Pallor
  • Lemon tinge skin (Uremia)
  • Scratch marks from pruritis
  • Pericardial rub (Uraemic complication)
  • Pleural effusions
  • Palpable kidneys (Polycystic Kidney Disease or hydronephrosis)
  • Peripheral Oedema
sandsofeskd

Differential Diagnosis

Common causes of Chronic Kidney Disease

Investigations

Ix

Determining Renal Function

  • GFR - creatinine clearance and plasma creatinine/urea level
  • Tubular function - glucosuria, EUC, CMP, plasma albumin
  • Urine analysis
  • CT scan - for renal artery stenosis or Urinary tract obstruction

Determine renal structure

  • Ultrasound - small kidneys suggest chronic disease
  • CT scan
  • Cystoscopy

Assess effects of Chronic Kidney Disease on body

  • FBC
  • Serum ferritin and iron
  • CMP
  • LFT
  • parathyroid hormone level
  • Nerve conduction studies
  • Arterial Doppler studies

Aetiology

cause

Aetiology 

Diabetic Nephropathy

Overview Type II diabetes Mellitus is the leading cause of Chronic Kidney Disease. It is classified as a secondary nephrotic syndrome. 20% of people with Type II diabetes will develop end stage kidney disease. Everyone with Diabetes should be screened yearly for microalbuminuria.

Clinical features - Nephrotic Syndrome with signs and symptoms of diabetes (hyperglycemia)

Pathological features Diabetic kidney disease is defined by characteristic structural and functional changes. The predominant structural changes include

  • Mesengial expansion
  • Glomerular basement membrane thickening
  • Glomerular sclerosis
Staging
Class I Isolated glomerular basement membrane thickening. There is no evidence of mesangial expansion, increased mesangial matrix, or global glomerulosclerosis involving >50 percent of glomeruli.
Class II Mild (class IIa) or severe (class IIb) mesangial expansion.
Class III At least one Kimmelstiel-Wilson lesion (nodular intercapillary glomerulosclerosis) is observed on biopsy and there is <50 percent global glomerulosclerosis.
Class IV Advanced diabetic sclerosis. There is >50 percent global glomerulosclerosis.
nephropahty

Pathogenesis

Management and Prognosis Microalbuminuria is reversible if caught early and managed vigorously.

  • Tight glycemic control
  • Right BP control with ACE/ARBs
  • Manage CV risk factors

More info on Long-Term Complications of Diabetes Type II

Staging

stage

Staging according to GFR and albuminuria allows for a more complete description of risk for the major adverse outcomes of CKD

Stage eGFR ml/min/1.73m²
Stage 1 >90 (Normal)
Stage 2 60-90 (Mild)
Stage 3a 45-60 (Moderate)
Stage 3b 30-44 (Moderate)
Stage 4 15-29 (Severe)
Stage 5 <16 (End-Stage)

The majority of patients with CKD stages 1–3 do not progress to kidney failure. The risk of death from CV disease is far higher than the risk of progression. Mild to moderate CKD is usually managed in general practice or by other physicians caring for the patient. Referral to nephrologist should be considered if:

  • Proteinuria with haematuria
  • Stage 4-5 CKD
  • Suspected rare cause of CKD
  • Poorly controlled BP
  • Rapidly falling eGFR
Remember Normal GFR is >90mL/min/1.73m² (130L/day)
Think Low eGFR and raised urine albumin are markers for death, CVD, End-Stage Kidney disease, Acute Kidney Injury

Management

General and limit progression/complication of CKD

  • Exclude Acute Kidney injury
  • Education
  • Stop Smoking
  • Weight reduction
  • Encourage exercise
  • Avoid alcohol
  • Vaccination
  • Fluid intake and diet
    • Fluid and salt restriction are often important to prevent volume overload.
    • A low-protein diet has been shown to slow the progression of renal failure in patients with CKD
    • Phosphate restriction
    • Potassium restriction
  • Cardiovascular risk reduction
    • Hypertension - ACE inhibitors or ARBs
    • Hypercholesterolaemia - Statins
    • Aspirin prophylaxis if not contraindicated
Think CKD with hyperkalaemia be careful with using ACE inhibitors or K+ sparing diuretics.

Symptomatic treatment (usually associated with uraemia)

  • Anorexia
  • Taste disturbance
  • Dyspepsia
  • Constipation
  • Dyspnoea
  • Dry skin and pruritus
  • Anxiety and Depression
  • Confusion
  • Restless legs

Treat complications

  •  Anaemia
    • Erythopoesis stimulating agents
    • Oral/intravenous iron
  • Acidosis
  • Phosphate/calcium/bones
    • Hyperphosphataemia - Dietary restriction, phosphate binders (aluminium hydroxide)
    • Vitamin D
    • Hypocalcaemia - calcimimetics
    • Secondart/Tertiary hyperparathyroidism - Parathyroidectomy

Preparation for renal replacement therapy

  • Consider when to start dialysis
  • Consider suitability for transplant

Dialysis

  • Peritoneal dialysis
  • Haemodialysis
Indications for Dialysis (AEIOU)
Acidosis
Electrolytes - refractory hyperkalaemia
Ingestions/intoxication - Barbiturates, lithium, alcohol, salicylates, theophyline
Overload - Pulmonary oedema
Uraemia Complications - pericarditis, refractory pulmonary oedema and encephalopathy

Complications

Complications

  • Hyperkalaemia
  • Sodium and volume overload
  • Metabolic acidosis
  • Hyperphosphataemia
  • Hypocalcaemia
  • Anaemia
Hyperkalaemia on ECG is characterised by Peak T wave and later widened QRS complex
Hypocalcaemia on ECG is charactersied by QT complex prolongation primarily by prolonging the ST segment. No change is T wave

References

UpToDate
Best Practice
Davidson’s Principles and Practices of Medicine