NOTES NOTES VASCULAR RENAL DISEASE GENERALLY, WHAT IS IT? PATHOLOGY & CAUSES DIAGNOSIS ▪ Variety of diseases affecting renal arteries, veins → abnormal renal circulation DIAGNOSTIC IMAGING RISK FACTORS CT scan/MRI ▪ Age, atherosclerosis, smoking, diabetes, high cholesterol Doppler ultrasound Renal arteriogram LAB RESULTS COMPLICATIONS ▪ Renal atrophy, kidney failure SIGNS & SYMPTOMS ▪ Impaired renal function → urine output disorders ▪ Blood pressure disorders ▪ Excess nitrogen waste products ▫ Blood urea nitrogen (BUN), creatinine ▪ Proteinuria, hematuria, cell casts ▪ Biopsy ▫ Rare TREATMENT ▪ Conservative, angioplasty, bypass surgery, hemodialysis RENAL ARTERY STENOSIS osms.it/renal-artery-stenosis PATHOLOGY & CAUSES ▪ Progressive narrowing of renal artery → decrease in renal blood ﬂow ▪ Stimulates renin release by juxtaglomerular cells → production of angiotensin II, aldosterone → vasoconstriction, increased reabsorption of sodium, water ▪ Contraction of blood vessels, increase in blood volume → blood pressure (BP) elevation CAUSES ▪ Atherosclerosis (most cases) ▪ Fibromuscular dysplasia (in individuals who are biologically female) COMPLICATIONS ▪ Secondary hypertension, AKA renovascular hypertension ▪ If severe, persistent: renal blood ﬂow decreases → prerenal azotemia ▪ Renal atrophy, ﬁbrosis OSMOSIS.ORG 863
SIGNS & SYMPTOMS ▪ Sudden onset of hypertension ▫ Severe, refractory to medical therapy; headaches, blurry vision ▪ Impaired renal function ▪ Upper abdominal bruit on auscultation, caused by turbulence of blood ﬂow through stenosis DIAGNOSIS DIAGNOSTIC IMAGING Renal arteriogram ▪ Localize stenotic lesion Megnetic resonance angiogram (MRA) ▪ Individuals with impaired renal function, at risk for contrast-induced renal failure Figure 122.1 A 3D-reconstructed CT scan demonstrating the renal vasculature. The left renal artery (on the right of this image) is completely stenosed and the left kidney is poorly perfused as compared to the right. Doppler ultrasound of renal arteries ▪ Initial screening test CT scan with contrast ▪ Alternative LAB RESULTS ▪ High BUN to creatinine ratio TREATMENT MEDICATIONS Antihypertensive medication ▪ Angiotensin converting enzyme (ACE) inhibitors, calcium channel blockers SURGERY ▪ Percutaneous transluminal renal angioplasty (PTRA) ▪ If PTRA not successful ▫ Bypass surgery 864 OSMOSIS.ORG Figure 122.2 A contrast CT scan demonstrating stenosis of the right renal artery. The right kidney is small and shows minimal contrast uptake when compared to the left.
Chapter 122 Vascular Renal Disease RENAL CORTICAL NECROSIS osms.it/renal-cortical-necrosis PATHOLOGY & CAUSES ▪ Rare, irreversible prerenal kidney injury; sudden decrease in blood perfusion to renal cortex ▪ AKA diffuse cortical necrosis ▪ Reduced blood supply to renal tubules → acute tubular necrosis ▪ Lack of anastomoses among cortical radial arteries (end arteries) ▪ High demand for blood of nephron (e.g. proximal tubule, thick ascending loop of Henle) ▪ If ischemia persists → irreversible necrotic injury of renal cortex → renal cortical necrosis CAUSES DIAGNOSIS DIAGNOSTIC IMAGING CT scan with contrast ▪ Non-enhancing renal cortex, thin rim of enhancement may occur (cortical rim sign) Ultrasound ▪ Hypoechoic areas in renal cortex LAB RESULTS ▪ BUN, creatinine ▪ Hyperkalemia, metabolic acidosis ▪ Hematuria, proteinuria, tubular cell casts Biopsy ▪ Patchy necrosis, atrophy of renal cortex ▪ Obstruction of blood ﬂow ▫ Blood clots/vasospasms ▪ Pregnancy complications → disseminated intravascular coagulation → widespread blood clots → renal cortical necrosis ▫ Placental abruption, prolonged intrauterine fetal death, infected abortion, severe eclampsia, septic shock COMPLICATIONS ▪ Acute kidney failure SIGNS & SYMPTOMS ▪ Sudden decrease in urine output ▫ Oliguria/anuria ▪ Flank pain at costovertebral angle ▫ Renal edema stretching renal capsule Figure 122.3 The histological appearance of renal cortical necrosis. The cells which comprise the glomeruli and the renal tubules have a fuzzy outline and have lost their nuclei, indicative of necrosis. OSMOSIS.ORG 865
TREATMENT OTHER INTERVENTIONS ▪ Increase blood perfusion to renal cortex ▫ Intravenous (IV) ﬂuids ▪ If severe ▫ Hemodialysis Figure 122.4 An abdominal CT scan in the axial plane demonstrating bilateral renal cortical necrosis. The low-signal renal cortex surrounding the relatively high-signal renal medulla is known as cortical rim sign. 866 OSMOSIS.ORG