Renal Flashcards
What does a DMSA scan detect?
Static scan of the renal cortex
Detects functional defects e.g. scars
What do you need to remember when ordering a DMSA post UTI?
○ Very sensitive so need to wait at least 2 months after a UTI to avoid diagnosing false ‘scars’
What happens in an MCUG?
Contrast introduced into bladder through urethral catheter
What can an MCUG tell you?
Can visualise bladder and urethral anatomy
Detects vesicoureteric reflux and urethral obstruction
What’s the downside of an MCUG?
High radiation dose
What happens in a MAG3?
○ Dynamic scan
MAG3 (isotope labelled substance) is excreted from the blood into the urine
What can a MAG3 tell you?
Measures drainage, best performed with high urine flow
In children old enough to cooperate (>4 years), scan during micturition is used to identify VUR
What is a duplex kidney?
Two ureters drain from two separate pelvicalyceal systems
What are the common complications of a duplex kidney?
Obstructed hydronephrotic upper moiety and ureter, associated with bladder ureterocele
Ectopically inserted upper pole ureter entering urethra or vaginal, causing true continual incontinence
VUR into lower pole ureter, sometimes causing infection and scarring
What is a horseshoe kidney?
Two renal segments fused across midline, usually at lower poles
What is horseshoe kidney associated with?
Turner and Laurence-Moon-Biedl syndromes
What are the clinical features of horseshoe kidney?
Usually asymptomatic but increased incidence of PUJ obstruction and VUR so can develop UTI
What is the main defect in Potter syndrome?
Bilateral renal agenesis or bilateral multicystic dysplastic kidneys
Reduced fetal urine excretion leads to oligohydramnios, which causes fetal compression
What are the classical facies of Potter syndrome?
Low set ears
Beaked nose
Prominent epicanthic folds
Downward slant to eyes
What are the non-renal features of Potter syndrome?
○ Pulmonary hypoplasia causing respiratory failure
Limb deformities e.g. severe talipes
What’s the prognosis for Potter syndrome?
Fatal if not stillborn
What causes multi cystic dysplastic kidney disease?
failure of union of the ureteric bud with the nephrogenic mesenchyme
What is the resulting kidney like in multi cystic dysplastic kidney?
Non-functioning structure with large fluid-filled cysts with no renal tissue and no connection with the bladder
How is multi cystic dysplastic kidney managed?
Only needs nephrectomy if it remains very large or if hypertension develops
What are the features of AR polycystic kidney disease?
Diffuse bilateral enlargement of both kidneys
What are the features of AD polycystic kidney disease?
Separate cysts of varying size between normal renal parenchyma
Kidneys are enlarged
Causes hypertension and haematuria in childhood, and renal failure in late adulthood
Associated with cerebral aneurysms and subarachnoid haemorrhage
What are the cardinal features of Alport syndrome?
Hereditary nephritis with sensorineural deafness and anterior lenticonus (conical deformity of lens of eye seen with slit lamp)
What is the main defect in Alport syndrome?
Type IV collagen
How is Alport syndrome inherited?
X linked or AR
How does Alport syndrome present and progress?
Incidental microscopic haematuria or episode of macroscopic haematuria Deafness around 10 years Hypertension in mid teens Eye signs in mid-late teens Average age for ESRF is 21 years
What are the features of testicular torsion?
Acute abrupt onset of often severe pain Early puberty Swelling of testis and hemiscrotum often with erythema/discolouration Negative urinaylsis Needs urgent surgery
What are the features of torsion of the appendix of the epididymus?
More common than testicular tosion Subacute onset of pain over hours Pre pubertal Localised pain at upper pole of testis Can be managed conservatively but difficult to distinguish from torsion of testicle
