Categories
Renal System

Chronic kidney disease (CKD)

Presence of kidney damage, manifested by abnormal albumin excretion or decreased kidney function, quantified by measured or estimated glomerular filtration rate (GFR), that persists for more than three months

Presence of kidney damage, manifested by abnormal albumin excretion or decreased kidney function, quantified by measured or estimated glomerular filtration rate (GFR), that persists for more than three months


Etiology

  • Congenital and inherited (5%): Polycystic kidney disease, Alport’s syndrome
  • Renovascular disease (5%)
  • Hypertension (5-20%)
  • Glomerular diseases (10-20%): M/C IgA nephropathy
  • Interstitial diseases (20-30%): Often drug-induced
  • Systemic inflammatory diseases (5-10%): Systemic lupus erythematosus (SLE), vasculitis
  • Diabetes mellitus (20-40%)
  • Idiopathic (5-20%)
CKD Pathophysiology
Chaudhry, S. (2017). Chronic kidney disease (CKD) | McMaster Pathophysiology Review. [online] Pathophys.org. Available at: http://www.pathophys.org/ckd/ [Accessed 1 Jun. 2017]

Presentation

Metabolic defects:

  • Hypernatremia: ↓ GFR → ↑ Na + H2O retention → ↑ BP, Oedema
  • Hyperkalemia: ↓ GFR → ↑ K+ → ↑ Muscle weakness, ECG changes, fibrillations
  • Metabolic acidosis: Bone decalcification

Mineral balance & osteodystrophy:

  • Loss of nephron → ↓ Calcitonin → ↓ Ca2+ absorption → Hypocalcemia → Secondary Hyperparathyroidism
  • Loss of nephron → ↓ GFR → ↓ Hyperphosphatemia

Uremia:

  • Neurological
  • GI (nausea, vomiting)
  • Reproductive (↓ Oestrogen, testosterone)
    • Amenorrhoea
    • Impotence
  • Skin changes
CKD Presentation
Webster, A. C., Nagler, E. V, Morton, R. L. and Masson, P. (2017) ‘Chronic Kidney Disease’, The Lancet. Elsevier, 389(10075), pp. 1238–1252. doi: 10.1016/S0140-6736(16)32064-5

Complications

CKD Complications
Chaudhry, S. (2017). Chronic kidney disease (CKD) | McMaster Pathophysiology Review. [online] Pathophys.org. Available at: http://www.pathophys.org/ckd/ [Accessed 1 Jun. 2017]

Chronic kidney disease-associated anaemia (50%):

Tubular atrophy → tubulointerstitial fibrosis → ↓ Erythropoietin  production → normochromic, normocytic anaemia
  • Cardiorenal anaemia syndrome: Anaemia of CKD increases morbidity and mortality from cardiovascular complications (angina, left ventricular hypertrophy (LVH) and worsening heart failure) which may lead to further deterioration of renal function and the establishment of a vicious cycle

CKD-associated mineral and bone disorders (CKD-MBD):

Abnormalities in bone and mineral metabolism and/or extra-skeletal calcification secondary to CKD pathophysiology.
Role of vitamin D in the development of secondary hyperparathyroidism in CKD
Role of vitamin D in the development of secondary hyperparathyroidism in CKD: The kidney is the primary site for phosphate excretion and 1-α-hydroxylation of vitamin D. CKD patients develop hyperphosphatemia as a result of inadequate 1, 25 dihydroxy-vitamin D levels that reflect reduced synthesis from parenchymal scarring. In addition, renal phosphate excretion is reduced. Together both processes cause, serum calcium levels to fall resulting in increased secretion of parathyroid hormone (secondary hyperparathyroidism) which begins to distort bone architecture. Parathyroid hormone has a phosphaturic effect. It also increases the calcium levels by increasing bone resorption and promoting 1-α-hydroxylation of 25-hydroxy vitamin D synthesized by the liver (limited effect because of reduced kidney reserve from scarring). Rising phosphorus levels are almost universally observed in stage 3 CKD patients. | Nigwekar, S. U., Tamez, H., & Thadhani, R. I. (2014). Vitamin D and chronic kidney disease-mineral bone disease (CKD-MBD). BoneKEy reports, 3, 498. doi:10.1038/bonekey.2013.232

Cardiovascular risk:

Interplay of processes secondary to chronic kidney disease leading to cardiovascular disease and death
Interplay of processes secondary to chronic kidney disease leading to cardiovascular disease and death. | Red arrows: Pathogenetic pathways; black arrow: Feedback loop; kidney disease worsened by heart failure | Thomas, R., Kanso, A., & Sedor, J. R. (2008). Chronic kidney disease and its complications. Primary care, 35(2), 329–vii. doi:10.1016/j.pop.2008.01.008

Diagnosis

Diagnostic criteria:

One of the following needs to be present for at least 3 months:
Diagnostic criteria for CKD
Diagnostic criteria for CKD | Chapter 1: Definition and classification of CKD. (2013). Kidney International Supplements, 3(1), 19–62. https://doi.org/10.1038/kisup.2012.64

Lab studies:

  • Urea & creatinine
  • Urinalysis
    • Quantification of proteinuria
  • Electrolytes
  • Calcium, phosphate, parathyroid hormone & 24(OH)D
  • Albumin
  • Full blood count (± Fe, ferritin, folate, B12)
  • Lipids, Glucose ± HbA1c
  • Hepatitis & HIV serology

ECG:

A 12-lead ECG of a person with CKD and a severe electrolyte imbalance: hyperkalemia (7.4 mmol/l) with hypocalcemia (1.6 mmol/l). The T-waves are peaked and the QT interval is prolonged, secondary to long ST-segments
A 12-lead ECG of a person with CKD and a severe electrolyte imbalance: hyperkalemia (7.4 mmol/l) with hypocalcemia (1.6 mmol/l). The T-waves are peaked and the QT interval is prolonged, secondary to long ST-segments | By Jer5150 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19825868

KDIGO “traffic light” staging system:

Kidney Disease Improving Global Outcomes (KDIGO)
  • Estimated glomerular filtration rate (eGFR)
  • Albuminuria (evidence of chronic kidney damage)
Prognosis of CKD by GFR and albuminuria category
Prognosis of CKD by GFR and albuminuria category | Notes: Green: low risk (if no other markers of kidney disease, no CKD); yellow: moderately increased risk; orange: high risk; and red, very high risk. | Kidney International Supplements. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. 2013;3:1–150. © 2013 KDIGO, Macmillan Publishers Ltd

Management

Integrated care continuum for CKD
Integrated care continuum for CKD that is consistent with the chronic care model. | Abbreviations: AVF, arteriovenous fistula; CKD, chronic kidney disease; ESRD, end-stage renal disease; RRT, renal replacement therapy. | Wouters, O. J., O’Donoghue, D. J., Ritchie, J., Kanavos, P. G., & Narva, A. S. (2015). Early chronic kidney disease: diagnosis, management and models of care. Nature reviews. Nephrology, 11(8), 491–502. doi:10.1038/nrneph.2015.85

Renal replacement therapy:

  • Haemodialysis
  • Haemofiltration
  • Peritoneal dialysis
  • Transplantation

Summary

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