Atheroembolic renal disease

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Atheroembolic renal disease is kidney injury caused by cholesterol crystals released from ulcerated aortic or major-artery plaque. Crystals lodge in small renal arteries, arterioles and glomerular capillaries, creating mechanical obstruction followed by inflammation, vasospasm and fibrosis. The same shower can affect skin, retina, brain and gastrointestinal tract. It commonly follows angiography, cardiac catheterisation, aortic surgery or another arterial procedure, but can occur spontaneously; anticoagulation or thrombolysis is an uncommon association rather than proof of causation.

Recognition depends on the pattern. Creatinine rises subacutely or in steps over days to weeks; livedo reticularis, blue or purple toes with palpable pulses, Hollenhorst plaques, eosinophilia and low complement are clues. None is individually diagnostic. Contrast-associated AKI usually begins within 24–72 hours and does not cause systemic small-artery signs. Biopsy may show empty biconvex cholesterol clefts because crystals dissolve during processing, but patchy embolisation limits sensitivity. There is no established lesion-reversing therapy: supportive nephrology care and prevention of further atherosclerotic events are central.

Key points

Think AERD when AKI appears days to weeks after aortic or arterial instrumentation and is accompanied by livedo, blue toes or retinal cholesterol emboli despite preserved distal pulses.
The renal trajectory is often delayed and staircase-like, unlike the earlier creatinine rise typical of uncomplicated contrast-associated AKI.
Treatment is supportive—manage volume, electrolytes, blood pressure and dialysis indications, avoid unnecessary further arterial manipulation, and use atorvastatin for cardiovascular prevention rather than crystal removal. Do not give corticosteroids routinely or reflexively stop essential antithrombotics; evidence for steroids is unconfirmed and antithrombotic indications require specialist reconciliation. Eosinophilia, low complement and inflammatory markers remain supportive, not diagnostic.
Urine is often bland or shows modest haematuria and proteinuria; an active glomerular sediment argues for an alternative or coexisting diagnosis.
Skin or renal biopsy can demonstrate cholesterol clefts, but lesions are patchy and a classic iatrogenic presentation may not need tissue confirmation.
Treatment is supportive: manage volume, electrolytes, blood pressure and dialysis indications, minimise new plaque manipulation and address cardiovascular risk.
Do not start corticosteroids routinely: published regimens are heterogeneous, observational and have not established a reliable renal or survival benefit.
Do not reflexively stop essential anticoagulation or antiplatelet therapy; review its indication and embolic/bleeding balance with the relevant specialist.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Iatrogenic plaque disruption

Catheters, wires, aortic surgery and other arterial interventions can disrupt ulcerated plaque and release cholesterol crystals into downstream renal and systemic arteries.

Spontaneous or drug associated

Advanced aortic atherosclerosis can embolise spontaneously; anticoagulation or thrombolysis is an uncommon association and should not be assumed causal without the clinical pattern.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Crystal shower
Cholesterol crystals travel distally and wedge in arcuate, interlobular and glomerular vessels while larger renal and peripheral pulses can remain patent.
2
Inflammatory amplification
Crystal surfaces trigger eosinophilic and neutrophilic inflammation, complement activation and vasospasm, extending injury beyond the initial mechanical obstruction.
3
Fibrotic loss
Persistent arteriolar inflammation progresses to intimal proliferation and fibrosis, explaining delayed staircase deterioration and incomplete renal recovery after the shower stops.
4
Systemic distribution
Emboli from the thoracic or abdominal aorta reach kidneys, skin, retina, gut and brain according to plaque location and downstream flow.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Delayed staircase AKI

Renal function worsens over days or weeks after an arterial trigger, sometimes with successive deteriorations as crystals shower intermittently and inflammation evolves.

Blue toes with pulses

Painful cyanotic digits, nail-bed infarcts or livedo occur despite palpable proximal pulses because cholesterol crystals obstruct small arteries rather than the main limb vessel.

Inflammatory clues

Eosinophilia, low C3, fever and raised CRP or ESR can accompany the acute inflammatory response but are transient and nonspecific.

Multiorgan diseaseRed flag

Retinal plaques, neurological events, myalgia, abdominal pain or gastrointestinal bleeding alongside AKI strengthen the diagnosis and indicate a larger embolic burden.

Severe renal presentationRed flag

Oliguria, pulmonary oedema, resistant hypertension, hyperkalaemia, acidosis or uraemia signals advanced injury and requires urgent nephrology support.

Red flags requiring action

Oliguria, refractory hyperkalaemia, acidosis, pulmonary oedema or uraemic complications require immediate nephrology and critical-care discussion of renal replacement therapy.
Severe abdominal pain, gastrointestinal bleeding or peritonism may represent mesenteric cholesterol embolisation and requires urgent imaging and surgical assessment.
New focal neurology, retinal ischaemia or rapidly progressive gangrene indicates a systemic embolic shower rather than isolated kidney injury.
Fever, a murmur and positive blood cultures raise infective endocarditis with septic emboli, which must be distinguished before immunosuppression.
Purpura with glomerular urine sediment, major proteinuria or disease-specific serology should prompt assessment for vasculitis or glomerulonephritis.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Serial creatinine, urine output and electrolytesFirst step
Why
Define timing, severity and renal-support needs rather than relying on one creatinine.
Interpretation and limitations
A delayed or stepwise trajectory supports AERD; hyperkalaemia, acidosis, pulmonary oedema and uraemic complications determine urgent treatment.
02
Urinalysis and protein quantification
Why
Characterise renal injury and identify a glomerular alternative.
Interpretation and limitations
A bland sediment, mild haematuria and modest proteinuria fit AERD. Red-cell casts or heavy proteinuria should reopen vasculitis and glomerulonephritis.
03
Full blood count, complement and inflammatory markers
Why
Look for eosinophilia and complement consumption while assessing mimics.
Interpretation and limitations
Abnormalities are supportive only and may disappear. Marked sepsis or cytopenias suggests infection, thrombotic microangiopathy or another process.
04
Skin, retinal and pulse examination
Why
Find accessible evidence of systemic small-artery embolisation.
Interpretation and limitations
Livedo or blue toes with preserved pulses is characteristic; fundoscopy may reveal a cholesterol plaque but a normal examination does not exclude renal disease.
05
Selective skin or renal biopsy
Why
Secure diagnosis when uncertainty changes treatment, especially against vasculitis or interstitial nephritis.
Interpretation and limitations
Needle-shaped clefts in small arteries with inflammation support cholesterol emboli. Focal distribution creates sampling error, so a negative specimen is not definitive.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Contrast-associated AKI

Creatinine usually rises earlier after contrast and lacks livedo, blue toes, retinal plaques and other evidence of systemic arteriolar embolisation.

Small-vessel vasculitis

Purpura, systemic inflammation and AKI overlap, but active urine sediment, disease-specific serology and biopsy show inflammatory vessel destruction rather than cholesterol clefts.

Infective endocarditis

Fever, murmur, positive cultures and septic emboli can produce renal and skin lesions; infection must be excluded before any steroid decision.

Renal artery occlusion

Acute flank pain, haematuria and wedge infarction suggest a large embolus or thrombosis rather than diffuse delayed small-artery crystal disease.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Worked caseAKI after coronary angiographyFirst stepCreatinine rises ten days after angiography and the patient has livedo, blue toes and preserved pedal pulses.

1Plot creatinine and procedures over time, assess urine output and emergencies, and examine skin, pulses, retina, abdomen and neurology for a systemic shower.
2Compare alternatives: early contrast-associated AKI, pre-renal injury, renal infarction, vasculitis and infective emboli; send urine, blood count, complement, inflammatory markers and cultures when infection is plausible.
3The delayed staircase course plus small-vessel skin signs with intact pulses makes AERD the leading diagnosis; involve nephrology and avoid unnecessary repeat arterial manipulation.
4Provide supportive AKI care, correct volume and electrolytes, control blood pressure, review every antithrombotic indication and apply CKD-appropriate cardiovascular prevention.
5Verify the working diagnosis through trajectory and multisystem findings; reserve biopsy for consequential uncertainty because patchy disease can be missed.

02Diagnostic boundaryWhen biopsy adds valueThe presentation is incomplete or vasculitis, endocarditis, interstitial nephritis or another treatable disease remains credible.

1Identify whether tissue would change immunosuppression, antimicrobial or antithrombotic decisions and select an affected accessible skin site when possible.
2Discuss renal-biopsy bleeding risk and patchy sampling with nephrology; do not pursue tissue merely to decorate an already classic diagnosis.
3AlternativeInterpret a negative biopsy alongside pre-test probability and reconsider alternative diagnoses rather than declaring AERD impossible.

03Supportive pathwayRenal and vascular protectionAERD is the leading diagnosis and immediate organ-threatening alternatives have been addressed.

1Optimise haemodynamics without overload, stop nephrotoxins where possible, dose medicines to current renal function and monitor potassium, bicarbonate, fluid balance and nutrition.
2Discuss dialysis urgently for refractory hyperkalaemia, acidosis, fluid overload or uraemic complications; use the whole clinical state rather than an isolated laboratory threshold.
3Avoid elective arterial instrumentation when benefit is marginal, manage smoking, blood pressure, diabetes and lipids, and arrange renal and cardiovascular follow-up.

Key medicines and prescribing safety1 treatment · regimens, roles and cautions

Stabilises systemic atherosclerotic risk and prevents cardiovascular events; it is supportive secondary prevention, not a proven way to remove lodged cholesterol crystals.

Atorvastatin

For a person with CKD, offer atorvastatin 20 mg orally once daily for primary or secondary cardiovascular prevention; if the lipid target is unmet, increase when eGFR is at least 30 mL/min/1.73 m², but agree higher doses with a renal specialist when eGFR is below 30. Outside CKD, NICE offers 80 mg once daily for secondary prevention unless modification criteria apply.

The product SmPC requires no pharmacokinetic renal adjustment, but NICE still supplies a CKD-specific starting and escalation regimen. Check liver enzymes, CYP3A4 interactions and muscle symptoms; active liver disease and pregnancy are contraindications. Continue long term while indicated and tolerated.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Kidney failure

Progressive loss of perfusion and inflammatory fibrosis can require temporary or permanent dialysis and may leave chronic kidney disease even after partial recovery.

Bowel ischaemia

Mesenteric arteriolar embolisation can cause severe abdominal pain, gastrointestinal bleeding, intestinal infarction and perforation with high mortality.

Skin necrosis

Livedo and blue toes may progress to ulceration or gangrene while proximal pulses remain present, creating pain and infection risk.

Neurological or retinal injury

Cerebral and retinal emboli can produce acute confusion, focal neurological deficit, transient visual symptoms or permanent tissue infarction.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Measure creatinine, eGFR, urine output, potassium, bicarbonate and fluid balance according to AKI severity; the direction and pace matter more than one value.
Monitor skin lesions, pulses, abdominal symptoms, neurological status and vision because new organ involvement may require urgent specialist action.
Review blood pressure frequently; severe or labile hypertension can accompany renal microvascular injury and fluid disturbance.
Assess dialysis indications clinically and biochemically, and document renal recovery or transition to chronic kidney disease after discharge.
Reconcile antiplatelet and anticoagulant indications rather than stopping automatically; document the specialist risk-benefit decision.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Time course discriminates

Contrast and cholesterol embolisation can follow the same procedure. Earlier isolated AKI suggests contrast or haemodynamics; delayed multisystem decline points toward AERD.

Pulses can stay normal

Large-vessel patency does not protect arterioles. Blue toes with palpable pulses is therefore a positive small-vessel clue, not a contradiction.

Eosinophils are witnesses

Eosinophilia reflects inflammatory reaction to crystals but is neither required nor exclusive; a normal count later in the course is weak negative evidence.

Biopsy can miss

Cholesterol emboli lodge focally. A skin lesion may be safer and more fruitful than kidney tissue, while a negative specimen cannot erase a strong pattern.

Steroids remain uncertain

Reports use varied doses, combinations and endpoints, with confounding by indication. No stable regimen can be presented as established AERD care.

11Common pitfallsFrequent interpretation and management errors.

01
Calling every post-angiography creatinine rise contrast nephropathy misses the delayed systemic pattern of cholesterol embolisation.
02
Excluding AERD because eosinophils or complement are normal gives excessive weight to transient nonspecific markers.
03
Repeating angiography solely to diagnose AERD risks another plaque shower and rarely answers the small-vessel question.
04
Starting empirical steroids without excluding infection or appreciating uncertain evidence can create avoidable harm.
05
Stopping essential anticoagulation automatically ignores competing embolic indications; the decision needs specialist reconciliation.

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