CHRONIC KIDNEY DISEASE

✓ Medically ReviewedDISEASEID: MDBT0074🚨 TRIAGE: ROUTINEICD-10: N18

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Definition

CLINICAL DEFINITION

Chronic Kidney Disease is persistent kidney abnormality beyond 3 months. It means reduced function or markers of kidney damage. Reduced function means estimated glomerular filtration rate (eGFR, blood test estimate of filtering ability) below 60 mL per min per 1.73 sq m. Damage markers include albuminuria (excess albumin protein in urine), abnormal sediment, tubular disorders or imaging changes. Severity uses GFR category (G1 to G5) plus albuminuria category (A1 to A3).

IN PLAIN ENGLISH

Chronic Kidney Disease means kidneys have been weak for months. Kidneys normally clean blood and make urine. In this disease they filter less or leak protein. It often causes no symptoms at first. Over time it can cause tiredness, swelling and heart problems.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Chronic Kidney Disease is not sudden kidney failure lasting only days. It is not brief protein in urine from fever, exercise or infection. It is not mildly low filtering alone in older adults without damage markers. It is not bladder infection or kidney stones alone without persistent loss. Diagnosis needs persistence beyond 3 months.

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Word Breakdown

chronic-

=long standing or over time

nephr-

=kidney, the blood filtering organ

Literal Meaning: long standing disorder of the kidney

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Abbreviations

CKD=Chronic Kidney Disease - kidney damage or low filtering beyond 3 months

ESKD=End-Stage Kidney Disease - advanced CKD needing dialysis (blood filtering treatment) or transplant

eGFR=Estimated Glomerular Filtration Rate - blood test estimate of kidney filtering ability

ACR=Albumin-to-Creatinine Ratio - urine test for protein leakage

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Synonyms & Variants

Chronic renal failure›Chronic renal insufficiency›Chronic kidney failure›

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Category-Specific Context

Chronic Kidney Disease is a Disease because it is a durable organ disorder with causes and complications. It involves persistent structural or functional kidney abnormality. It moves through stages and affects many body systems. It needs long term management rather than a single test. It sits within nephrology (kidney specialty) but spans primary and cardiac care.

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Clinical Context & Usage

CLINICAL SETTINGS

Primary CareNephrology ClinicDiabetes and Hypertension ClinicCardiology ClinicDialysis and Transplant Service

USAGE & DOCUMENTATION NOTES

Use the term only when chronicity beyond 3 months is documented or strongly inferred. Always add cause plus GFR category (G1 to G5) plus albuminuria category (A1 to A3) when known. Track eGFR (filtering estimate) trend rather than one value alone. Repeat albuminuria (urine albumin excess) testing to confirm persistence. Review nephrotoxins (kidney harming drugs), pressure, sugar, smoking and diet at each visit.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

Chronic injury causes nephron (single filtering unit) loss through inflammation, poor flow or pressure injury. Remaining nephrons over-filter and enlarge to compensate. This raises glomerular (filter) pressure and protein leakage. Proteinuria (urine protein excess) drives tubular (urine tube) inflammation and interstitial fibrosis (scarring between tubules). Progressive scarring plus vessel hardening lowers filtering and disturbs salts, acids and minerals.

PRIMARY CAUSES

Diabetic kidney disease

High blood sugar causes filter overwork plus membrane thickening and scarring, with albuminuria (urine albumin excess) and falling filtration

Hypertension related disease and nephrosclerosis

High pressure injures tiny arteries and causes poor flow plus scarring, with slow filtration decline

Glomerulonephritis such as IgA nephropathy

Immune deposits trigger filter inflammation then scarring, with blood plus protein in urine

Autosomal dominant polycystic kidney disease

Growing cysts (fluid sacs) compress nearby tissue and disrupt structure, causing enlarged kidneys and progressive loss

Chronic urinary obstruction from prostate enlargement, stones or reflux

Back pressure causes swelling plus infection and shrinkage, with tubular (tube) injury

Chronic tubulointerstitial disease including chronic pyelonephritis

Repeated infection or toxic injury causes between-tubule inflammation and scarring, with poor concentration and slow decline

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Drug-Induced Causes

💊 Nonsteroidal anti-inflammatory drugs such as ibuprofen and diclofenac ↗

Mechanism: Lower kidney blood flow and can cause between-tubule injury with chronic use

→ Stop drug when feasible, watch creatinine plus eGFR and potassium, ensure hydration, avoid repeat exposure

💊 Aminoglycosides such as gentamicin ↗

Mechanism: Collect in early tubule segments and injure cells through oxidative (chemical stress) damage

→ Use levels with protocol dosing, stop or switch promptly, watch function and salts, correct volume loss

💊 Tenofovir disoproxil fumarate ↗

Mechanism: Causes energy-structure toxicity in tubules with phosphate wasting and gradual filtration fall

→ Watch eGFR plus phosphate plus urine protein, seek specialist review, switch only on specialist advice

💊 Lithium ↗

Mechanism: Causes chronic tube and tissue injury plus tiny cysts with poor concentrating ability

→ Keep levels in range, watch eGFR plus salts plus urine volume, ensure hydration, coordinate changes with psychiatry

💊 Calcineurin inhibitors ciclosporin and tacrolimus ↗

Mechanism: Tighten kidney vessels and promote small artery injury plus scarring with long use

→ Watch drug levels plus pressure plus eGFR, adjust only via transplant team, control pressure and lipids

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Epidemiology

Prevalence:Chronic Kidney Disease affects about 1 in 10 adults worldwide. Prevalence rises sharply with older age and diabetes. Hypertension (high blood pressure) and obesity add large burden. Advanced disease needing dialysis (blood filtering treatment) is much less common. Exact rates vary by definition, testing and population.

Age Group:All ages can develop Chronic Kidney Disease. Risk rises strongly with advancing age. Older adults carry highest burden from vessel and metabolic (chemical balance) causes. Children are affected mainly by birth-related anomalies and inherited diseases. Young adults may present with filter inflammation or polycystic disease.

Geographic Distribution:Chronic Kidney Disease occurs worldwide in all regions. Burden is higher where diabetes, hypertension (high pressure) and obesity are common. Detection and dialysis (blood filtering treatment) access vary widely and shape recorded burden. Agricultural clusters of undetermined cause need further study.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 ROUTINE

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Hyperkalaemia with ECG changes needing urgent treatment
Pulmonary oedema from fluid overload with breathlessness and low oxygen
Uraemic pericarditis or encephalopathy suggesting urgent dialysis review
Obstructive uropathy with loss of urine or infection needing rapid relief
Severe hypertension with visual change, chest pain or neuro deficit

URGENT EVALUATION TRIGGERS

Severe breathlessness, chest pain, very low urine or new swelling with weight gain
Muscle weakness, palpitations or ECG change suggesting high potassium
Fever in dialysis, transplant or immunosuppressed patients
Vomiting, confusion, pericardial pain or bleeding suggesting uraemia
Blood pressure above 180 over 120 with symptoms or organ injury

Contraindications & Precautions

SPECIAL PRECAUTIONS

Avoid chronic NSAIDs and other nephrotoxins when possible
Adjust drug doses for eGFR (filtering estimate) and check interactions
Apply sick-day rules during vomiting, diarrhoea (loose stools) or fever
Watch potassium and kidney function after starting renin-angiotensin blockers
Advise steady hydration with salt control and smoking cessation

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Anaemia (low red cells) from low erythropoietin (red cell hormone) plus iron lack
CKD mineral and bone disorder with high phosphate and vessel calcification
Metabolic acidosis (acid build-up) with muscle and bone loss
Hyperkalaemia (high potassium) with rhythm risk plus fluid imbalance
Hypertension, heart failure, coronary disease and stroke
Uraemia (toxin build-up) with itch, nausea and brain dysfunction
Drug toxicity from reduced clearance (removal)

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Acute kidney injury

Shares kidney injury wording and creatinine rise, but AKI is sudden and often reversible while CKD needs persistence beyond 3 months

Autosomal dominant polycystic kidney disease

Overlaps in kidney disease wording, but it is one specific inherited cause with enlarged cystic kidneys, not the whole CKD syndrome

CKD mineral and bone disorder

Acronym overlap causes confusion, but it is a complication with bone plus vessel effects, not CKD itself

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Acute kidney injury

Key Distinguishing Feature: Sudden creatinine rise within days without 3-month persistence, often with reversible trigger

Acute-on-chronic kidney injury

Key Distinguishing Feature: Abrupt worsening on prior CKD with acute trigger and partial recovery after treatment

Transient albuminuria from fever, exercise or urine infection

Key Distinguishing Feature: Positive urine protein that normalises on repeat testing without persistent eGFR loss

Age-related eGFR decline without damage markers

Key Distinguishing Feature: Mildly low eGFR in older adults without albuminuria or imaging change, needing careful interpretation

Urinary obstruction with acute retention

Key Distinguishing Feature: Sudden low urine plus pain with swelling that improves after relief, unlike steady CKD progression

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Clinical Pearls

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Confirm chronicity by reviewing old creatinine and urine results because a single low eGFR does not prove CKD.

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Quantify albuminuria with first-morning ACR and repeat it because persistent A2 or A3 changes drug and referral choices.

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Apply sick-day rules to pause high-risk drugs during dehydration and restart only after recovery and recheck.

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Check haemoglobin, iron, calcium, phosphate, bicarbonate and parathyroid hormone early because complications precede symptoms.

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Plan dialysis access and transplant referral before crisis using failure risk plus G4 trends and patient goals.

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Example Usage & SOAP

CLINICAL SENTENCE

""62-year-old man with diabetic CKD G3b A2 needs pressure control and sick-day counselling.""

IN A SOAP NOTE

S: 64-year-old with CKD G3b A2 reports fatigue and ankle swelling, no chest pain or breathlessness at rest. O: BP 148/86, HR 78, RR 18, SpO2 97 percent on air, Temp 36.7C, mild ankle oedema, lungs clear. Labs show creatinine 1.6, eGFR 38, potassium 5.1, bicarbonate 20, ACR 45, Hb 10.8. Ultrasound shows normal-sized kidneys without obstruction. A: CKD G3b A2 likely diabetic plus hypertensive, with anaemia and mild acidosis. P: Continue ACE inhibitor with potassium check, add SGLT2 inhibitor per protocol, adjust statin, salt review, nephrology referral, repeat labs in 2 weeks.

DIFFERENTIAL DIAGNOSIS CONTEXT

Prior labs with eGFR near 40 for over a year plus persistent ACR rise favours CKD (chronic loss). Sudden creatinine jump after vomiting plus NSAID (painkiller) use favours acute-on-chronic change. Repeat testing after hydration and drug review clarifies baseline and trigger.

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Classifications & Scoring

STAGING SCALE

KDIGO CKD G and A Categories

Stages CKD by eGFR (filtering estimate) from G1 normal to G5 failure and albuminuria (urine albumin excess) from A1 normal to A3 severe. Combines G plus A into risk map for progression and heart events. Requires persistence beyond 3 months.

SCORING TOOL

Kidney Failure Risk Equation

Predicts 2-year and 5-year risk of kidney failure needing dialysis (blood filtering treatment) or transplant. Uses age plus sex plus eGFR (filtering estimate) plus albuminuria (urine albumin excess). Guides referral plus access plus transplant planning.

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Prognosis

SHORT-TERM OUTCOME

Short term outlook follows stage, albuminuria (urine albumin excess) and triggers. Stable early disease often changes little over months. Acute illness, dehydration or nephrotoxins (kidney harming drugs) can cause sudden worsening. High potassium and fluid overload need rapid care. Admission risk rises with heart failure and infection.

LONG-TERM PROGNOSIS

Long term course is usually slow decline with variable speed. Higher albuminuria (urine albumin excess) and lower eGFR (filtering estimate) predict faster progression. Cardiovascular (heart and vessel) events are the leading threat. Many patients never reach dialysis (blood filtering treatment). Control of pressure, sugar, proteinuria (urine protein excess) and smoking improves outcomes.

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References & Coding

ICD-10 DIAGNOSTIC CODE

N18

LITERATURE CITATIONS & GUIDELINES

[1]WHO ICD-10 N18

[2]KDIGO Chronic Kidney Disease Guideline

[3]NICE Chronic kidney disease guideline

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.