Pathology of the Kidneys and UUT Part 4 Flashcards

Urolithiasis

• Definition: Commonly known as kidney stones.

• Mechanism: Concentrated urine leads to higher amounts of minerals and acid salts sticking together, forming calculi.

• Symptoms: Severe pain, potential obstruction distal to calculi.

• Treatment: Increased hydration; lithotripsy may be needed for larger or obstructed calculi.

• Sonographic Presentation:

  • Very echogenic with posterior shadowing.

  • Tiny renal and ureteric stones can utilize the twinkle artifact in sonography.

  • Variants observed: small calyceal stones, stones in the renal pelvis (both with and without renal dilation).

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Medullary Sponge Kidney

• Definition: A congenital, rare, benign condition.

• Characteristics: Involves dilatation of collecting tubules in renal papillae, leading to sponge-like cavitary regions in one or both kidneys; echogenic medullary pyramids.

• Associated Conditions: May contain nephrocalcinosis.

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Nephrocalcinosis

• Definition: Increased calcium levels in the kidney.

• Causes:

  • Hypercalcaemia due to hyperparathyroidism,

  • Certain medications,

  • Sarcoidosis,

  • Tuberculosis of the kidney,

  • AIDS-related infections,

  • Vitamin D toxicity.

• Sonographic Presentation: Calcifications primarily in the medullary pyramids with posterior shadowing dependent on the amount of calcification.

• Nephrocalcinosis vs staghorn renal stone - staghorn stll has medullae on top i.e. still visible whereas as the medullae are filled with nephrocalcinosis in medullary sponge kidney

  

Renal Artery Stenosis (RAS)

• Definition: Narrowing of the renal artery, leading to renovascular hypertension.

• Causes:

  • Atherosclerosis (at origin),

  • Fibromuscular dysplasia (distally).

• Clinical Presentation: Hypertension that cannot be controlled my medication

• Sonographic Indicators: Stenosis visible on colour Doppler; smaller kidney on affected side; smaller parenchyma

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Renal Infarction

• Definition: Area of the kidney with no blood flow due to thromboemboli or thrombus.

• Variability: Can affect the entire kidney or just a partial area (wedge defect).

• Differential Diagnosis: May mimic pyelonephritis or renal tumours.

• Symptoms: Pain accompanied by nausea, vomiting, fever, hypertension.

• How to differentiate between renal infarction and pyelonephritis - ask the patient if they have had a recent UTI

  

Obstructive Nephropathy

• Definition: Renal changes due to blockage of urinary flow leading to swelling (hydronephrosis).

• Causes:

  • Calculi (renal or bladder),

  • Benign prostatic hypertrophy,

  • Tumors (primary or secondary),

  • Scar tissue in ureters or urethra.

• Sonographic Signs: Hydronephrosis (uni- or bilateral), altered renal arterial hemodynamic, thinning of renal parenchyma over the long-term.

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Renal Transplantation

• Indication: Performed when a person’s own kidneys can no longer filter blood (end-stage kidney disease).

• Surgical Details: Usually utilizes the donor's left kidney; recipient's kidneys typically remain in position unless causing complications.

• Sonography Requests Include: Depend on the age of the transplant for evaluation; look for size, vascular issues, leaks, or hematomas.

• DON’T PUSH HARD - sitting in pelvus on patient so don’t have protection of ribs and abdominal muscles

Renal Trauma

• Complications: Can lead to laceration of the kidney, hematomas (perirenal or intra-kidney), and urinomas.

• Imaging Findings: Evidence of lacerations; increase in echogenicity around hematomas, lack of blood flow in hematomas.

• Lacerations will cause trauma so ask patient if they’ve have had recent trauma to differentiate from tumours

  

Review

• Understanding and describing renal pathologies using sonographic terminology is essential, including differential diagnoses.

• Key differentiation between nephrocalcinosis and staghorn calculus involves understanding their sonographic features.