343.1 🎓 醫孞生版

343.1.0.1 📌 䞀頁重點

343.1.0.1.1 Renal Artery Stenosis (RAS)

343.1.1 Atherosclerotic Renal Artery Stenosis (ARAS)

Epidemiology: - Most common renovascular disease in adults - Elderly with atherosclerotic risk factors - Often bilateral or with solitary functional kidney

Clinical Clues: - HTN onset > 55 yo or severe - Resistant HTN (≥ 3 drugs) - “Flash” pulmonary edema (Pickering) - AKI on starting ACE/ARB - Abdominal/flank bruit - Asymmetric kidney size

Diagnosis: - Renal duplex ultrasound (PSV > 200 cm/s in renal artery suggests > 60% stenosis) - CT angiography (gold standard for ARAS) - MR angiography (alternative; less if CKD with gadolinium) - Catheter angiography (during intervention) - Captopril renogram (functional, less used)

Treatment: - Optimal Medical Therapy (OMT) first-line: - ACE/ARB (cautious with AKI; allow up to 30% Cr ↑) - Statin - ASA - BP control - Stent for: - Refractory HTN despite OMT - Recurrent flash pulmonary edema - Progressive CKD on OMT - CORAL trial (2014): stent + OMT not superior to OMT alone (mostly) - Bypass surgery rare

343.1.2 Fibromuscular Dysplasia (FMD)

Epidemiology: - Young women (15-50) - 1-3% of all RAS - Bilateral in 35% - Can affect carotids (SCAD association)

Clinical: - New HTN in young woman - “String of beads” on angiography (medial dysplasia) - 80-90% medial type; other types less common - May affect other vessels

Diagnosis: - CTA / MRA shows “string of beads” - Catheter angiography definitive

Treatment: - Balloon angioplasty alone (no stent typically) - Cure rate 50-60% for HTN - ACE/ARB if angioplasty incomplete - Lifelong follow-up

343.1.2.0.1 Renal Vein Thrombosis (RVT)

343.1.3 Causes

  • Nephrotic syndrome (especially MN with albumin < 2.5)
  • Hypercoagulable states (cancer, factor V Leiden, prothrombin, APS)
  • Tumor extension (RCC)
  • Trauma
  • Pregnancy/postpartum
  • Sickle cell

343.1.4 Clinical

  • Flank pain
  • Hematuria
  • New AKI
  • Worsening proteinuria
  • LE edema (bilateral if IVC extension)

343.1.5 Diagnosis

  • CT or MR venography
  • Doppler ultrasound (lower sensitivity)
  • Contrast-enhanced ultrasound

343.1.6 Treatment

  • Anticoagulation: LMWH or DOAC (DOAC OK for non-malignancy; LMWH for malignancy)
  • Thrombolysis for severe (selected)
  • Treat underlying cause
343.1.6.0.1 Thrombotic Microangiopathy (TMA)

343.1.7 Spectrum

  1. TTP (thrombotic thrombocytopenic purpura)
  2. HUS (hemolytic uremic syndrome) — typical (STEC) or atypical (aHUS)
  3. DIC (related but distinct)
  4. Malignant HTN with TMA
  5. Scleroderma renal crisis
  6. HELLP + preeclampsia
  7. Drug-induced TMA (calcineurin inhibitors, ICI, mitomycin, VEGF inhibitors)
  8. TMA in cancer + hematopoietic transplant

343.1.8 TTP

Pathophysiology: - ADAMTS13 deficiency (cleaves von Willebrand factor multimers) - Acquired antibodies to ADAMTS13 (autoimmune) - Microvascular thrombi - Multi-organ ischemia

Clinical: - Microangiopathic hemolytic anemia (MAHA) - Thrombocytopenia - Fever (less common) - Renal involvement (less than HUS) - Neurologic (more than HUS)

Diagnosis: - Peripheral smear: schistocytes - ↑ LDH, ↓ haptoglobin - ADAMTS13 activity (< 10%) — confirmatory - ADAMTS13 inhibitor (autoantibodies) - PLASMIC score for pre-treatment risk stratification

Treatment: - Plasma exchange (PEX) — daily - Corticosteroids - Caplacizumab (anti-vWF; HERCULES trial): reduces relapse + recovery time - Rituximab for relapsing/refractory - Avoid platelets (worsens thrombosis)

343.1.9 HUS (Hemolytic Uremic Syndrome)

Typical (STEC) HUS: - Shiga toxin-producing E. coli (especially O157:H7) - After bloody diarrhea - Children mostly - Renal predominant - Supportive; avoid antibiotics (controversial — may worsen) - Most recover

Atypical HUS (aHUS): - Complement dysregulation (CFH, CFI, CFB, C3, MCP, DGKE mutations) - Sporadic or familial - Triggers: pregnancy, infection, drug - High mortality without treatment

aHUS Treatment: - Eculizumab (Soliris) — anti-C5 - Ravulizumab (Ultomiris) — long-acting anti-C5 - Plasma exchange (older treatment) - Vaccinate against meningococcus (eculizumab risk)

343.1.10 Drug-Induced TMA

  • Calcineurin inhibitors (cyclosporine, tacrolimus)
  • ICI (pembrolizumab, others)
  • VEGF inhibitors (bevacizumab, sunitinib)
  • Quinine
  • Mitomycin
  • Gemcitabine
  • Treatment: stop drug; supportive

343.1.11 Pregnancy-Associated TMA

  • HELLP (Hemolysis, Elevated LFTs, Low Platelets) — preeclampsia variant
  • Acute fatty liver of pregnancy
  • aHUS can present
  • Treatment: delivery; specific therapy
343.1.11.0.1 Atheroembolic Disease (Cholesterol Embolism)

343.1.12 Etiology

  • Cholesterol crystal embolism
  • After arterial procedure (cath, AAA repair, stent)
  • Spontaneous (rare)

343.1.13 Clinical

  • Subacute (weeks)
  • Livedo reticularis
  • Blue toes (atheroemboli to digits)
  • AKI (progressive)
  • Eosinophilia
  • Hypocomplementemia (some)
  • Multi-organ (CNS, mesenteric)

343.1.14 Diagnosis

  • Clinical + temporal association with procedure
  • Skin biopsy (cholesterol clefts)
  • Renal biopsy (cholesterol clefts in arterioles)
  • Fundoscopy (Hollenhorst plaques)

343.1.15 Treatment

  • Supportive (no specific antidote)
  • Statins (may help)
  • Aspirin
  • Avoid further arterial procedures
  • Poor prognosis (50%+ progress to ESKD or die)
343.1.15.0.1 Hypertensive Nephropathy

343.1.16 Pathology

  • Glomerulosclerosis
  • Arteriolar hyalinosis (afferent arterioles)
  • Intimal thickening of small arteries
  • Tubular atrophy + interstitial fibrosis (late)

343.1.17 Clinical

  • HTN
  • Proteinuria (usually < 1-2 g/d)
  • Slow CKD progression
  • May have benign sediment

343.1.18 Treatment

  • BP control < 130/80 (ACC/AHA, KDIGO 2021)
  • ACE/ARB first-line
  • Multi-drug usually
  • Address other CV risk factors
  • Slow progression with SGLT2i emerging
343.1.18.0.1 Malignant Hypertension + Hypertensive Emergencies

343.1.19 Clinical

  • BP > 180/120 + end-organ damage
  • Encephalopathy
  • Renal failure (rapid)
  • Retinal hemorrhages, exudates, papilledema (KWB grade III/IV)
  • TMA features (MAHA, thrombocytopenia)
  • Acute LV failure / MI

343.1.20 Pathophysiology

  • Severe HTN → endothelial dysfunction → activation of coagulation
  • Fibrinoid necrosis of arterioles
  • TMA features

343.1.21 Treatment

  • IV antihypertensives in ICU
  • Labetalol, nicardipine, clevidipine, nitroprusside (with caution)
  • Reduce SBP 20-25% in first hour (then gradual)
  • Watch renal function
  • Some require RRT
343.1.21.0.1 Scleroderma Renal Crisis

343.1.22 Pathophysiology

  • Diffuse cutaneous systemic sclerosis
  • Severe HTN
  • TMA
  • AKI

343.1.23 Clinical

  • Rapid onset
  • Severe HTN
  • AKI + hematuria
  • TMA
  • Sometimes mild proteinuria

343.1.24 Treatment

  • ACE inhibitor (captopril titrated) — lifesaving (improved outcomes dramatically)
  • Avoid prednisone (precipitates renal crisis in some scleroderma)
  • ARB if ACE intolerant
  • Renal recovery often takes months
  • Some require dialysis temporarily
343.1.24.0.1 Vasculitis (Renal)

343.1.25 Large Vessel

  • Takayasu: aorta + main branches; bilateral RAS effect

343.1.26 Medium Vessel

  • Polyarteritis nodosa (PAN): medium-sized renal arteries; aneurysms; HTN

343.1.27 Small Vessel

  • ANCA-associated (Ch339): GPA, MPA, EGPA → glomerular
  • Henoch-Schönlein purpura (IgA vasculitis): pediatric
  • Cryoglobulinemia: hep C; mixed
  • Anti-GBM: Goodpasture; renal-pulmonary

343.1.27.1 🩺 床邊速查

  • ARAS: elderly atherosclerosis; CORAL trial — OMT first-line
  • FMD: young women; “string of beads”; balloon angioplasty
  • RVT: nephrotic (MN) + hypercoagulable; LMWH/DOAC
  • TTP: ADAMTS13 deficiency; plasma exchange + caplacizumab
  • aHUS: complement dysregulation; eculizumab/ravulizumab
  • STEC HUS: E. coli O157:H7; supportive
  • Cholesterol embolism: post-procedure; livedo + blue toes + eosinophilia; supportive
  • HTN nephropathy: chronic; BP < 130/80; ACE/ARB
  • Malignant HTN: IV antihypertensives; reduce 20-25% first hour
  • Scleroderma renal crisis: ACE inhibitor lifesaving