URINARY Section 5: CALCIFICATIONS Flashcards
Most common kidney stone
Calcium oxalate (75%)
Kidney stone
common in women + associated with UTI
Struvite stone
Kidney stone “unseen on x-ray”
Uric acid
Rare kidney stone + associated with congenital disorders of metabolism
Cystine Stone
the ONLY stones NOT seen on CT.
+ HIV
Indinavir
What stones form Stahorns?
Struvite Stones form Staghoms.
Kidney stone size = high likelihood of passing
< 5mm
Kidney stone size = high likelihood of NOT passing
> 1 cm
What kind of stone rarely require any invasive intervention?
Uric acid
What population is uric acid stone more common
Big fat people and/or diabetics - acidic urine - increased uric acid
Uric acid stone treatment
Uric acid stones very rarely will require any kind of invasive intervention (lithotripsy, etc…).
The reason is they are very pH dependent.
Potassium citrate or sodium bicarbonate = increases pH = melts stones
You can’t melt a calcium stone by messing with the pH.
Uric acid stone attenuation
< 500 HU
Non uric acid stone HU
higher HU at 80 kVp relative to 140 kVp.
What kidney stone shows the biggest HU change between high and low energies?
Calcium
a suspension of calcium crystals which frequently masquerades as renal calculi within a cyst or calyceal diverticulum
Milk of Calcium
Milk of Calcium
Ultrasound showing the layering “fluid - debris level” that changes with positioning of the patient.
Cortical Nephrocalcinosis
This is typically the sequela of cortical necrosis
Cortical Nephrocalcinosis
which can be seen after an acute drop in blood pressure (shock, postpartum, bum patients, etc…).
Cortical Nephrocalcinosis
a hypodense non-enhancing rim that later develops thin calcifications.
Mimic of Cortical Nephrocalcinosis
Mimic is disseminated PCP.
Medullary Nephrocalcinosis
Hyperechoic renal papilla / pyramids which may or may not shadow on ultrasound.
Medullary Nephrocalcinosis
Causes of Medullary Nephrocalcinosis
- Hyperparathyroidism - Most people say this is the most common.
- Medullary Sponge Kidney - Some people say this is the most common.
- Lasix - Common cause in children.
- Renal Tubular Acidosis (distal subtype - type 1)
A congenital cause of medullary nephrocalcinosis (usually asymmetric)
Medullary Sponge Kidney
The underlying mechanism in Medullary Sponge Kidney
a cystic dilation of the collecting tubules of the kidney
Medullary Sponge kidney is associated with
Ehlers-Danlos syndrome (a group of hereditary connective tissue disorders that manifests clinically with skin hyperelasticity, hypermobility of joints, atrophic scarring, and fragility of blood vessels)
and
Carili’s disease
