Episode 122: Chronic Kidney Disease Overview
Future Dr. Westwood discusses with Dr. Arreaza the evaluation and treatment of CKD before renal replacement therapy. This is a broad overview of CKD.
Written by Daniel Westwood, MSIV, Ross University School of Medicine. Comments and editing by Hector Arreaza, MD.
Definition of CKD:
CKD is defined as abnormal kidney structure or function lasting more than three months with associated health implications. Indicators include albuminuria, urine sediment abnormalities, abnormal renal imaging findings, serum electrolyte or acid-base derangements, and decreased glomerular filtration rate (GFR).
Stages of CKD are based on GFR - CKD1 normal or high >90, CKD2 60-89, CKD3 <60 (3a 45-60), 3b (30-45), CKD4 <30, CKD 5 <15.
CKD can progress to advanced renal failure, end-stage renal disease, and even death; early detection is critical for initiating timely therapeutic interventions, limiting nephrotoxin exposure, preventing further reduction in GFR, and preparing for renal replacement therapy.
Screening guidelines:
- Annual screening for CKD in pts with DM or HTN (AAFP and National Kidney Foundation)
- Other risk factors that may indicate screening: cardiovascular disease, older age, hx of low birth weight, and family hx of CKD.
- USPSTF recommends against screening asymptomatic adults
- American College of Physicians recommends against screening asymptomatic adults without risk factors.
How to screen? Multiple guidelines recommend at least annual screening with serum creatinine, urine albumin/creatinine ratio, and urinalysis (especially in diabetes mellitus, hypertension, and a history of cardiovascular disease).
Assessment of a patient with CKD:
- Full medical history, including:
- Exposure to potential nephrotoxins (NSAIDS, aminoglycosides, amphotericin B, IV contrasts.)
- Review past and present blood pressure.
- Dietary history: Western diet, high in calories, high in animal proteins, and low in fruit and vegetable content.
- Recent weight gain is essential for CKD evaluation because weight gain may be a sign of fluid retention.
- Obesity can be a risk for CKD.
- Review of systems: Generalized weakness, decreased exercise tolerance, impaired cognitive function, decreased urination, foamy urine (proteinuria), anorexia, altered taste (dysgeusia), vomiting, skin changes, lower extremity edema, periorbital edema, shortness of breath, hallucinations (advanced stages).
- Physical examination:
- Clinical findings vary with the severity and chronicity of symptoms. It would be difficult to explain all the physical findings in a short time, but it is important to mention that some signs and symptoms may take years of chronic disease to develop, and sometimes patients may have CKD and not know it.
- General exam: Chronically ill, tired, chronically ill, slow responses due to the accumulation of multiple toxins, including urea. Vitals: BP is elevated, or the patient is currently taking antihypertensives. The skin can be extremely dry, scaly, itchy, pale, or darker than usual for the patient, or you may see a rash.
- Edema: pitting, bilateral, generalized, especially around the eyes.
- Auscultation: Signs of fluid overload (bibasilar crackles, cardiac gallops, murmurs)
- Signs of severe uremia: Uremic fetor (urine smelling), encephalopathy, uremic frost (urea crystals over the skin).
- Laboratory:
- Spot urine for albumin-to-creatinine ratio (ACR) to detect albuminuria
- Serum creatinine to estimate glomerular filtration rate (GFR), serum electrolytes, fasting lipids, hemoglobin A1C
- Urinalysis: High sensitivity for heavy proteinuria (> 300 mg in 24 hours, estimated from the spot urine protein/creatinine ratio) but may not detect clinically significant lower levels (30 to 300 mg).
- 24-hour urine collections are no longer recommended as an initial diagnostic tool because of the potential for inadequate collection, inconvenience to patients, and the lack of diagnostic advantage over the urine albumin/creatinine ratio.
- Imaging: Renal ultrasound to evaluate for structural abnormalities.
Markers of Kidney Damage:
- Proteinuria: Identifies increased risk of cardiovascular disease and mortality
- Albuminuria:
- microalbuminuria and macroalbuminuria have been replaced with
- normal to mildly increased (albumin/creatinine ratio less than 30 mg/g)
- moderately increased (30 to 300 mg/g)
- severely increased (greater than 300 mg/g)
- severe albuminuria independently predicts mortality and end-stage renal disease.
Common etiologies of CKD
- hypertensive kidney disease
- diabetic nephropathy
- primary or secondary glomerulonephritis
Management of CKD
Treat reversible causes of CKD
- Avoid nephrotoxic drugs (NSAIDs)
- Identify and treat urinary tract obstructions
Slow the rate of progression by treating underlying causes:
- Control BP
- Diabetes mellitus
- Obesity
- Autosomal dominant polycystic kidney disease (ADPKD)
- Glomerular disease (steroids)
- Viral infections: Hep B, C, HIV
- Hematologic disorders: Renal amyloidosis
- Cardiac or Hepatic disorders: Cardiorenal and hepatorenal syndromes
For patients with proteinuria: Control blood pressure with ACE inhibitors or ARBs and SGLT-2 inhibitors.
Other renal protection methods: Protein Restriction (≤0.8 g/kg/day, increase plant source), Sodium (<5 g/day of table salt), smoking cessation, treating chronic metabolic acidosis w/bicarbonate (slows progression to ESRD), strict glycemic control.
Medications in CKD: For patients with type 2 diabetes who have estimated albuminuria ≥30 mg/day despite an ACE inhibitor (or ARB) and an SGLT2 inhibitor, it is recommended to treat with a nonsteroidal selective mineralocorticoid receptor antagonist (MRA, specifically finerenone), but avoid in those who have serum potassium >4.8 or eGFR<25.
When to Refer to Nephrology:
Per National Kidney Foundation - Nephrology consultation is indicated for patients with:
- estimated GFR less than 30 mL/minute/1.73 m2
- persistent urine albumin/creatinine ratio greater than 300 mg/g
- urine protein/creatinine ratio greater than 500 mg/g
- if there is evidence of a rapid loss of kidney function
- See Figure 21
Per AAFP – consult a nephrologist when there is AKI on CKD, family history of renal disease, RBC casts in the urine, progression of CKD, resistant anemia, refractory hypertension, serum potassium persistently high, mineral and bone disorders, nephrolithiasis, preparation for hemodialysis.
Bottom line: CKD is a major concern for patients with DM and HTN, but it can have multiple causes. Make sure you screen your patients for CKD and start treatment early to prevent end-stage renal disease.
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Conclusion: Now we conclude episode number 122, “Chronic Kidney Disease Overview.” Future Dr. Westwood and Dr. Arreaza discussed common signs and symptoms of CKD, and how we can evaluate patients with CKD. Remember to screen your patients with diabetes and hypertension for CKD at least once a year. You may opt to order either a serum creatinine, a urine albumin/creatinine ratio, or just a urinalysis. Once CKD has been diagnosed, your main goal is to prevent end-stage renal disease. Keep in mind at least 3 medications from this episode: ACE inhibitors, SGLT-2 inhibitors, and MRAs.
This week we thank Hector Arreaza and Daniel Westwood. Audio edition by Adrianne Silva.
Even without trying, every night you go to bed a little wiser. Thanks for listening to Rio Bravo qWeek Podcast. We want to hear from you, send us an email at RioBravoqWeek@clinicasierravista.org, or visit our website riobravofmrp.org/qweek. See you next week!
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- Gaitonde, D. Y., Cook, D. L., & Rivera, I. M. (2017, December 15). Chronic kidney disease: Detection and evaluation. American Family Physician. Retrieved October 18, 2022, from https://www.aafp.org/pubs/afp/issues/2017/1215/p776.html
- Quick reference guide on Kidney Disease Screening. National Kidney Foundation. (2018, March 1). Retrieved October 15, 2022, from https://www.kidney.org/kidneydisease/siemens_hcp_quickreference
- Rosenberg, M., Curhan, G. C., & Forman, J. P. (2022, April 21). Overview of the management of chronic kidney disease in adults. UpToDate. Retrieved October 13, 2022, from https://www.uptodate.com/contents/overview-of-the-management-of-chronic-kidney-disease-in-adults
- Kramer H. Diet and Chronic Kidney Disease. Adv Nutr. 2019 Nov 1;10(Suppl_4):S367-S379. doi: 10.1093/advances/nmz011. PMID: 31728497; PMCID: PMC6855949. https://pubmed.ncbi.nlm.nih.gov/31728497/.
- Royalty-free music used for this episode: “Keeping Watch,” New Age Landscapes. Downloaded on October 13, 2022, from https://www.videvo.net/royalty-free-music-albums/new-age-landscapes/.