Genito-Urinary System

Nephrocalcinosis

Mohamed Zaitoun

Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals

EgyptFINR (Fellowship of Interventional

Neuroradiology)-Switzerlandzaitoun82@gmail.com

Knowing as much as possible about your enemy precedes successful battle

and learning about the disease process precedes successful management

Nephrocalcinosisa) Calculib) Nephrocalcinosis

a) Calculi :1-Incidence2-Radographic Features

1-Incidence :-5% of population-If a stone passes into the ureter , there are

three areas of ureteric narrowing where the stone may lodge :

a) Just past the UPJb) Where the ureter crosses the iliac vesselsc) At the UVJ (most common)

2-Radographic Features :a) Plain Radiographyb) U/S c) IVPd) CT

a) Plain Radiography :-Radiopaque calculus , 90%-Radiolucent calculi are best detected by IVP

b) U/S :-Hyperechoic focus (calculus) , posterior

shadowing , calculi 3 mm or less may not be detected

c) IVP :-Delayed and persistent nephrogram due to

ureteral obstruction-Column of opacified urine extends in ureter

from renal pelvis to lodged calculus (diminished or absent peristalsis)

d) CT :-CT detects most calculi regardless of calcium

content

(a) IVP shows a normal flow from the kidneys, through the ureters, to the bladder (white arrows), (b) shows a kidney stone blocking the normal flow of urine in the ureter on the right

IVP (30-minute delay image) of the right kidney shows a moderately hydronephrotic collecting system to the level of a proximal ureteral stone (arrow)

On a scout image obtained before excretory urography, a calculus fills nearly the entirety of a bifid right renal collecting system, giving it a branched appearance that resembles the antlers of a stag

b) Nephrocalcinosis :-Refers to renal parenchymal calcification-The calcification may be dystrophic or metastatic

>>>1-Dystrophic calcification :-There is deposition of calcium in devitalized tissue

, usually resulting from ischemia or necrosis-This type occurs in infection, tumors , abscesses

and hematomas

T.B. autonephrectomy

T.B. autonephrectomy

2-Metastatic nephrocalcinosis :-Occurs most commonly with hypercalcemic

states caused by hyperparathyroidism , renal tubular acidosis and renal failure

-Classified according to calcium deposition into cortical or medullary nephrocalcinosis

a) Cortical Nephrocalcinosis :-Etiology :1-Acute cortical necrosis2-Chronic glomerulonephritis3-Chronic hypercalcemic states4-Ethylene glycol poisoning5-Sickle cell disease6-Rejected renal transplants-U/S :Cortical nephrocalcinosis is seen as increased cortical

echogenicity which may produce acoustic shadowing

b) Medullary Nephrocalcinosis :-Etiology :1-Hyperparathyroidism (40 %)2-Renal tubular acidosis (20 %)3-Medullary sponge kidney4-Bone metastases5-Chronic pyelonephritis , renal papillary necrosis6-Cushing’s syndrome7-Hyperthyroidism8-Malignancy , sarcoidosis , sickle cell disease , vitamin D

excess and Wilson’s disease

-U/S :Medullary nephrocalcinosis is apparent

when the medullary pyramids become more echogenic than the adjacent cortex , with time , further calcium deposition and stone formation occur with acoustic shadowing becoming apparent