ANURIA

✓ Medically ReviewedSIGNID: MDBT0083🚨 TRIAGE: EMERGENCYICD-10: R34

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Definition

CLINICAL DEFINITION

Anuria is absence of urine production below 100 mL per day in adults. It reflects severe fall in glomerular filtration (kidney filtering of blood) or complete outflow block. True anuria must be distinguished from retention (bladder storage with no voiding). It meets stage 3 acute kidney injury (sudden severe kidney failure) when lasting 12 hours or more.

IN PLAIN ENGLISH

Anuria means the body makes almost no urine each day. Less than half a cup in a full day counts as anuria. It is not the same as a blocked bladder that still holds urine. It is always an emergency.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Anuria is not oliguria (low but present output of 100 to 400 mL per day). It is not urinary retention (full bladder with kidneys still making urine). It is not missed collection or leaking catheter without true output fall. It is not stable chronic kidney disease (long term loss) without severe output fall.

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Word Breakdown

an-

=without or absence of

ur-

=urine

-ia

=condition or state of

Literal Meaning: condition of being without urine

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Abbreviations

AKI=Acute kidney injury - sudden loss of kidney function over hours to days

ATN=Acute tubular necrosis - injury to kidney tubule cells with low output

RPGN=Rapidly progressive glomerulonephritis - fast kidney failure over days to weeks with crescents (scar arcs on biopsy)

ESKD=End-stage kidney disease - advanced failure needing dialysis (machine filtering) or transplant

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Synonyms & Variants

Absence of urine output›Anuric state›No urine production›

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Category-Specific Context

Anuria is a Symptom because it is absence of output noticed and measured clinically. It signals critical underlying disease rather than being a disease itself. It overlaps with signs because output is measured objectively. It triggers emergency pathways like stage 3 acute kidney injury (sudden severe failure).

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Clinical Context & Usage

CLINICAL SETTINGS

Emergency DepartmentIntensive Care UnitUrology and Nephrology WardPostoperative Recovery UnitOncology and Transplant Unit

USAGE & DOCUMENTATION NOTES

Use anuria only after strict timed collection confirms output below threshold. Perform bladder scan (bedside bladder ultrasound) to exclude retention before diagnosing true anuria. Distinguish true anuria from pseudo-anuria (apparent absence from retention, leak or blockage). Document duration, prior output, fluids, blood pressure and nephrotoxins (kidney harming drugs) clearly.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

Anuria arises when glomerular filtration (kidney filtering) stops. Bilateral obstruction raises intratubular pressure (fluid pressure in tubes) and stops filtration. Severe tubular injury, filter inflammation, cortical necrosis (death of outer kidney tissue) or vascular occlusion (vessel blockage) abolish filtrate (filtered fluid) formation. Loss of perfusion (blood flow) or loss of working nephrons (filtering units) leaves no capacity to make urine.

PRIMARY CAUSES

Bilateral ureteric stones with complete obstruction

Blocks flow from both kidneys raising intratubular pressure which opposes filtration and stops output

Pelvic tumours, clot or retroperitoneal fibrosis compressing both ureters

Extrinsic compression prevents drainage so filtrate cannot reach bladder and filtration then falls

Bilateral renal cortical necrosis after severe ischaemia

Destroys filtering cortex after loss of blood flow so no filtrate is formed

Severe acute tubular necrosis with prolonged ischaemia

Tubule blockage by casts (cell debris plugs) plus backleak and vessel narrowing abolishes effective output

Rapidly progressive glomerulonephritis with crescents

Crescent inflammation fills filter space and stops filtration in most nephrons

Bilateral renal artery occlusion or end-stage kidney failure

Loss of perfusion or loss of working nephrons leaves no capacity to produce filtrate

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Drug-Induced Causes

💊 Nonsteroidal anti-inflammatory drugs ↗

Mechanism: Constrict inflow vessels and reduce perfusion and filtration during volume depletion

→ Stop drug, restore volume, monitor creatinine and output, seek nephrology review

💊 Aminoglycosides ↗

Mechanism: Cause direct tubular toxicity leading to acute tubular necrosis with falling output

→ Stop drug where possible, check levels, ensure hydration, monitor salts and kidney function

💊 Amphotericin B ↗

Mechanism: Causes vessel narrowing plus tubular injury reducing filtration and concentrating ability

→ Stop or switch therapy, give saline loading if safe, correct potassium and magnesium, involve nephrology

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Epidemiology

Prevalence:Anuria is uncommon compared with oliguria (low urine output). It occurs in severe acute kidney injury and obstructive emergencies. It is more frequent in intensive care and advanced chronic kidney disease. Exact population rates are low and vary by setting and cause.

Age Group:Anuria can occur at any age when severe cause is present. Older adults face higher risk from obstruction, vascular disease and comorbidity (other illnesses). Newborns and children rarely develop anuria except with severe illness or birth urinary blockage.

Geographic Distribution:Anuria occurs worldwide wherever severe kidney injury or obstruction occurs. Causes vary by region with stones, infection and toxins differing locally. Access to imaging, dialysis (machine filtering) and urology affects outcomes.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 EMERGENCY

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Bilateral ureteric obstruction needing urgent drainage
High potassium with heart tracing changes needing emergency care
Sepsis with shock causing anuric kidney failure
Complete vascular occlusion needing immediate flow assessment

URGENT EVALUATION TRIGGERS

No urine for 12 hours with empty bladder on scan
Anuria with high potassium, lung fluid or uraemic symptoms
Anuria with flank pain, blood in urine or pelvic mass suggesting blockage
Anuria with low pressure, fever or rash suggesting systemic emergency

Contraindications & Precautions

CONTRAINDICATIONS

Do not delay bladder scan and assessment to exclude retention
Do not give nephrotoxins or potassium load without review
Do not manage new anuria in outpatient setting without emergency workup

SPECIAL PRECAUTIONS

Avoid volume overload while assessing perfusion and obstruction
Monitor potassium, acid base, calcium and fluid status closely
Adjust drug dosing for kidney failure and avoid contrast dye where possible

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Hyperkalaemia with arrhythmia risk (high potassium disturbing heart rhythm)
Pulmonary oedema with hypoxia (lung fluid causing low oxygen)
Uraemia with encephalopathy and pericarditis (waste build-up affecting brain and heart sac)
Metabolic acidosis worsening salt disturbance (acid build-up in blood)

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Reference Ranges

NORMAL RANGENormal adult output is about 800 to 2000 mL per day with adequate fluids. Output varies with intake, diet, climate and diuretics (water pills). Sustained output below 400 mL per day is oliguria, not normal.

CRITICAL (PANIC) VALUELess than 100 mL per day in adults confirms anuria. Anuria lasting 12 hours or more meets stage 3 acute injury criteria. Any new anuria needs emergency bladder scan to exclude retention.

UNIT OF MEASUREMENTmL per day.

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Oliguria

Shares output context but means 100 to 400 mL per day, not absent output

Enuresis

Shares -uria ending but means involuntary voiding, not absent production

Dysuria

Shares -uria ending but means painful voiding, not absent urine

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Oliguria

Key Distinguishing Feature: Produces 100 to 400 mL per day with some urine seen whereas anuria is below 100 mL per day

Urinary retention with bladder outlet obstruction

Key Distinguishing Feature: Full bladder on scan where catheter drains urine whereas true anuria shows empty bladder

Catheter blockage or leak with pseudo-anuria

Key Distinguishing Feature: Kidneys make urine but collection fails where flushing or imaging reveals blockage or leakage

End-stage chronic kidney disease with oliguria

Key Distinguishing Feature: Long gradual loss with small kidneys on imaging versus acute anuric collapse

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Clinical Pearls

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Do a bladder scan first because retention with full bladder mimics anuria. A catheter fixes retention, not dialysis.

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Do not delay CT urography (urinary tract scan) and urology input when both ureters may be blocked. Hours matter for recovery.

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Check potassium and heart tracing at once because high potassium kills silently. Treat above 6 or with tracing change as emergency.

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Track strict fluid balance because both overload with lung fluid and depletion worsen outcomes. Weigh daily.

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Prepare for dialysis when potassium, acid or overload resists care, and arrange drainage in parallel. Do not wait for creatinine alone.

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Example Usage & SOAP

CLINICAL SENTENCE

""70-year-old with no urine for 14 hours and empty bladder has anuria needing urgent drainage review.""

IN A SOAP NOTE

S: 68-year-old with no urine for 16 hours, lower belly pain and nausea. O: BP 168/96, HR 102, RR 24, Temp 38.0C, SpO2 91 percent on air, bladder scan 20 mL, lungs with crackles, leg oedema present. A: Anuria with overload and stage 3 kidney injury. P: Urgent labs and heart tracing, renal ultrasound, nephrology and urology review, prepare for dialysis and possible drainage.

DIFFERENTIAL DIAGNOSIS CONTEXT

No urine with empty bladder on scan favours true anuria over retention. Output of 100 to 400 mL per day favours oliguria (low output). Full bladder draining large volume on catheter favours outlet blockage. Long small kidneys with gradual loss favours end-stage disease over acute anuric collapse.

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Classifications & Scoring

GRADING SYSTEM

KDIGO Acute Kidney Injury Criteria

Defines stage 3 by anuria for 12 hours or more with creatinine and urine thresholds for severity

STAGING SCALE

KDIGO Acute Kidney Injury Staging

Stages injury from 1 to 3 using creatinine rise and duration of oliguria and anuria to guide care

SCORING TOOL

Sequential Organ Failure Assessment Renal Component

Scores kidney dysfunction using creatinine and urine output to track critical illness severity

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Prognosis

SHORT-TERM OUTCOME

Short term risk is very high without urgent relief of cause. High potassium and lung fluid can be rapidly fatal. Obstructive anuria often recovers quickly if relieved within hours to days. Cortical necrosis (outer kidney death) carries poor immediate recovery.

LONG-TERM PROGNOSIS

Long term outcome depends on cause, duration and baseline function. Promptly relieved obstruction may leave normal or near-normal function. Prolonged ischaemia (low blood flow), cortical necrosis or end-stage disease often leads to chronic kidney disease. Many survivors need long term nephrology follow-up and dialysis planning.

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References & Coding

ICD-10 DIAGNOSTIC CODE

R34

LITERATURE CITATIONS & GUIDELINES

[1]WHO ICD-10 R34 Anuria and oliguria

[2]KDIGO Clinical Practice Guideline for Acute Kidney Injury

[3]NICE NG148 Acute kidney injury

[4]Harrisons Principles of Internal Medicine

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.