10.1 Congenital and Inheritable Urinary System Conditions Flashcards
How does low birth weight affect the development of the kidneys, and why? What are the downstream effects of this?
- Most organs complete cell replication before the third trimester. On the other hand, the kidneys develop 60% of their glomeruli in the final trimester
- Infants born with lower birth weight are at greater risk of decreased number of glomeruli and hypertension, increasing risk of renal disease such as CKD
Interesting: why doesn’t urine reflux through the ureteric opening during detrusor contraction?
- When the detrusor contracts, so too does the distal ureter
- This rigs the pressure gradient such that the easiest place for the urine to flow is out the urethra, and not back through the ureters
Describe the two main types of vesiculoureteric reflux disease, and the causes that fall under these categories
Primary (inherited from birth):
- Short ureter (less than 5:1 length to diameter ratio)
- Ectopic ureteric opening
Secondary:
- Neuromuscular defects (spina bifida, cerebral palsy, immature bladder causing weaker than normal control etc.)
What is the typical vesiculoureteric reflux (VUR) disease presentation? In what patients might we suspect it?
- Commonly no symptoms (remember Andrew in the corner of the wet lab…)
- Suspected in recurrent UTIs, incidental hydronephrosis findings
What is the gold standard investigative diagnosis of VUR and PUV?
- Voiding cystourethrogram
- Contrast inserted into bladder, image taken as patient voids
What is a frequent complication of VUR? Why?
- Renal damage (scarring, renal HTN and CKD), w/ elevated creatinine
- This is because urine can reach back to the kidneys, causing hydronephrosis and infection. Leading to inflammation, scarring and dysfunction.
What are the 5 grades of VUR?
- Nondilated ureter
- Into pelvis + calyces without dilation
- Mild/moderate dilation of ureter, pelvis, calyces
- As above + tortuosity of ureters
- Gross dilatation of all streuctures. Loss of papillary impressions, ureteral tortuosity
How is VUR treated? Does this have a good or bad success rate? Does this treatment always occur?
- Managed through urethral reimplantation
- Has very high success rate
NO. Doesn’t always occur. If child is under 5, grades 1-3 may self-resolve.
Which is the only demographic affected by posterior urethral valves? Explain the abnormality that exists in this condition
- Only infant males are affected
- Occurs when thin membrane forms in the urethra, obstructing urien flow and causing bladder enlargement
Derive some complications of posterior urethral valves
- Acute urinary retention
- Lung hypoplasia
- CKD
How can PUV cause lung hypoplasia and CKD?
Lung hypoplasia: lung development depends on amniotic fluid, which is comprised in large part by urine. With less urine being released, less amniotic fluid interrupts lung development.
CKD: antenatal hydronephrosis can predispose to CKD, or can cause lasting damage that develops in to CKD.
How often is prenatal PUV surgery performed? What is the postnatal alternative?
- Performed rarely, very risk (for instance, high resp risk)
- Postnatal treatment is transurethral catheter ablation
What is the more common inheritance pattern of polycystic kidney disease
- It is autosomal dominant
- This “dominance” lets the cysts spread to other organs such as the liver, pancreas and spleen
What are the symptoms of ADPKD? Between what ages do they typically manifest?
- Symptoms include flank pain, haematuria, hypertension (RAAS activation), and renal impairment
- Typically appear between ages 30 and 40
Why does PKD predispose to brain aneurysms?
- Genes involved in PKD are known to play a role in blood vessel structure
- Therefore, affected vascular structure (+ HTN from RAAS overactivation) can predispose to aneurysms
