The Final FRCR: Complete Revision Notes by Vincent Helyar

Author:Vincent Helyar
Language: eng
Format: epub
ISBN: 978-1482259728
Publisher: CRC Press
Published: 2017-10-25T04:00:00+00:00

Figure 4.6 (a) Plain abdominal x-ray shows prominent, bilateral medullary nephrocalcinosis (white arrow). (b) Ultrasound of the thyroid gland (longitudinal view) shows a well-defined lesion at the base of the gland in keeping with a parathyroid adenoma (white arrow).

CT

●The pattern of calcification points to the underlying pathology—confluent calcification in renal tubular acidosis and punctate calcification in medullary sponge kidney.

Cortical

Most are due to cortical necrosis (e.g. from complicated pregnancy/shock or renal vein thrombosis), glomerulonephritis or hyperoxaluria.

US

●Echogenic (calcified) cortex

CT

●Characteristic tramline calcification suggests cortical necrosis.

Oncocytoma

Benign tumour derived from epithelial cells—it is rare. Mostly asymptomatic. Difficult to differentiate from RCC based on imaging alone, so it is often excised.

US

●Mass with or without echogenic central scar.

●Vascularity tends to radiate out from the centre like spokes on a wheel.

●Usually >5 cm.

CT

●Poorly enhancing compared to adjacent renal parenchyma.

●Central, lower-density scar seen in up to a third of cases (could also be necrosis in a RCC).

Papillary necrosis

Inflammation or ischaemic necrosis at the tip of the papilla that may then slough off and obstruct the collecting system. Causes include pyelonephritis, obstruction, sickle-cell, TB, cirrhosis, analgesic, renal vein thrombosis, diabetes.

CT

●Sloughed papilla appears as a filling defect in the collecting system

●The calyx appears clubbed due to loss of the papilla

Pelvi-ureteric junction obstruction

Mostly congenital, often diagnosed in adulthood. Most unilateral. Varying aetiologies, including crossing vessels, abnormal collagen infiltration at the PUJ, kinks, etc.

US

●Hydronephrosis on prenatal/postnatal scan

●Marked ballooning of the renal pelvis with normal-calibre ureter

Nuclear medicine

●MAG3 study used to assess renal function pre-operatively/to distinguish non-obstructive dilatation

Posterior urethral valves

Only occurs in males. It is due to a membrane in the posterior urethra causing near-complete obstruction to the flow of urine. Age of presentation depends on degree of obstruction. Mostly diagnosed after birth.

US

●Hydronephrosis

●Renal dysplasia

●Urinoma or urinary ascites

Nuclear medicine

●Micturating cystourethrogram is the gold standard—calibre change in the posterior urethra.

●Reflux is also common.

Prune belly (Eagle–Barrett) syndrome

Congenital deficiency of abdominal musculature, urinary tract anomalies and cryptorchidism. Mostly affects males. Associated with cardiac anomalies in 10%.

US

●Grossly dilated collecting system, ureters, bladder (Note: Thin-walled) and urethra

●Check for cryptorchidism

Pyonephrosis

Infected urine in the context of an obstructed kidney. Needs urgent drainage (i.e. nephrostomy/ureteric stent) to preserve the kidney.

US

●Hydronephrosis, collecting system filled with echogenic debris (i.e. pus)

●Thickened urothelium may be seen

CT

●Useful to find cause of obstruction.

●Look for presence of gas in the pelvis (emphysematous pyelitis).

●Hyperdense ‘urine’ (i.e. pus).

Reflux

Box 4.3 Grading reflux

I.Ureters only

II.Reaches pelvis, no dilatation

III.Mild dilatation but no calcyeal clubbing

IV.Moderate dilatation with calcyeal clubbing

V.Severe dilatation with tortuous ureter

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