CHRONIC KIDNEY DISEASE (CKD)

• CKD implies longstanding (more than 3 months), and usually progressive, impairment in renal function. In many instances, no effective means are available to reverse the primary disease process. Exceptions include correction of urinary tract obstruction, immuno suppressive therapy for systemic vasculitis and Goodpasture’s syndrome, treatment of accelerated hypertension, and correction of critical narrowing of renal arteries causing CKD.

• The rate of deterioration in renal function can, however, be slowed.

Congenital and inherited disease

• Polycystickidneydisease(adultandinfantileforms)

• Medullary cystic disease

• Tuberous sclerosis

• Oxalosis

• Cystinosis

• Congenital obstructive uropathy

Glomerular disease

• Primary glomerulonephritides including focal glomerulosclerosis

• Secondary glomerular disease(systemic lupus, polyangiitis,Wegener’s granulomatosis,amyloidosis, diabetic glomerulosclerosis,accelerated hypertension, haemolytic uraemic syndrome,thrombotic thrombocytopenic purpura,systemic sclerosis,sickle cell disease)

Vascular disease

• Hypertensive nephrosclerosis(common in black Africans)

• Renovascular disease

• Small and medium-sized vessel vasculitis

Causes

Tubulointerstitial disease

• Tubulo interstitial nephritis–idiopathic, due to drugs (especially nephrotoxic analgesics),

• immunologically mediated

• Reflux nephropathy

• Tuberculosis

• Schistosomiasis

• Nephrocalcinosis

• Multiplemyeloma (myeloma kidney)

• Balkan nephropathy

• Renal papillary necrosis(diabetes,sickle cell disease and trait, analgesic nephropathy)

• Chinese herb nephropathy

Urinary tract obstruction

• Calculus disease

• Prostatic disease

• Pelvic tumours

• Retroperitoneal fibrosis

• Schistosomiasis

Symptoms• Malaise, loss of energy

• Lossofappetite

• Insomnia

• Nocturia and polyuria due to impaired concentrating ability

• Itching

• Nausea,vomiting and diarrhoea

• Paraesthesiae due to polyneuropathy

• Restlesslegs’syndrome(overwhelming need to frequently alter position of lower limbs)

• Bone pain due to metabolic bone disease

• Paraesthesiae and tetany due to hypocalcaemia

• Symptoms due to salt and water retention–peripheral or pulmonary oedema

• Symptoms due to anaemia • Amenorrhoea in women; erectile

dysfunction in men. • In more advanced uraemia CKD stage

5,these symptoms become more severe and CNS symptoms are common

• Mental slowing,clouding of consciousness and seizures

• Myoclonictwitching.

Signs and symptoms

Investigations• Urinalysis

1. Hematuria

2. proteinuria

3. Urine culture

• Urine microscopy

1. WBC

2. Eosinophiluria

3. Casts

4. Red cells in the urine

• Urine biochemistry

1. Measurements of urinary electrolytes, Urine osmolality, Urine electrophoresis and immunofixation

• Serum biochemistry

1. Ureaandcreatinine

2. CalculationofeGFR

3. Electrophoresis and immunofixation for myeloma

4. Elevations of creatine kinase and a disproportionate elevation in serum creatinine and potassium compared with urea suggest rhabdomyolysis.

• Haematology

1. Eosinophilia

2. Markedly raised blood viscosity

3. Fragmented red cells and/or thrombocytopenia

4. Tests for sickle cell disease

• Immunology

1. Complement components

2. autoantibody Screening

3. Cryoglobulin

4. Antibodies to streptococcal antigens

5. Antibodies to hepatitis B and C

6. Antibodies to HIV

• Radiological investigation

1. Ultra sound

2. CT

3. MRI

4. Renal biopsy

Complications of CKDComplicatiin Causes

Anemia Erythropoietin deficiency, Bone marrow toxins, Bone marrow fibrosis, Haematinic deficiency, Increased red-cell destruction, Abnormal red-cell membranes, Increased blood loss(Hemodialysis), ACE inhibitors.

Bone disease 1α-hydroxylase deficiency, Reduced activation of vitamin D receptors, Phosphate retention.

Skin disease Retention of nitrogenous waste, hypercalcaemia, hyperphosphataemia, hyperparathyroidism.

Gastrointestinal complications continuous ambulatory peritoneal dialysis(CAPD).

Metabolic abnormalities- Gout - Modestly impaired glucose tolerance

Urate retentionend-organ resistance to insulin

Endocrine abnormalities(Anterior pituitary gland) Altered protein binding

Muscle dysfunction Uraemia, Decreased physical fitness

Depressed cerebral functions Severe uraemia.

TreatmentHypocalcaemia and hyperphosphataemia should be treated aggressively, preferably with regular (e.g.3 monthly) measurements of serum PTH to assess how effectively hyperparathyroidism is being suppressed. Suppression of PTH levels to below two or three times the upper limit of ‘normal’ carries a high risk of development of a dynamic bone disease.

Eg:-

• Gut phosphate binders

• Nicotinamide

• Calcitriol (1,25-dihydroxycholecalciferol) or a vitamin D analogue

• Calcimimetic agents

Drug therapy should be minimized in patients with CKD. Tetracyclines (with the possible

exception of doxycycline) should be avoided in view of their anti-anabolic effect and tendency to worsen uraemia. Drugs excreted by the kidneys, such as gentamicin, should be prescribed only in the absence of any alternative and drug levels monitored if feasible. Non-steroidal anti-inflammatory drugs(NSAIDs) should be avoided. Potassium-sparing agents, such as spironolactone and amiloride, pose particular dangers, as do artificial salt substitutes, all of which contain potassium. Bardoxolone,an antioxidant inflammatory modulator, has shown a reduction in GFR in diabetic CKD.

Dialysis• Haemodialysis

• Haemofiltration

• Peritoneal dialysis

This mode of renal replacement therapy has significant survival advantage compared to dialysis patients on transplant waiting lists. It allows freedom from dietary and fluid restriction; anaemia and infertility are corrected; and the need for parathyroidectomy is reduced.

Kidney Transplantation