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
What are some possible complications of PKD?
- End-stage renal disease
- HTN
- Polycystic LIVER disease
- Cerebral aneurysms (why?)
- Kidney stones
What are the ultrasound diagnostic criteria for PCKD that a sonographer might have to know?
age 15-39: three or more cysts in total
In forties and fifties: at least 2 in each kidney (4+)
Sixties and over: at least 4 in each kidney
What are our three main problems that need to be managed in polycystic kidney disease, and how do we do so?
- Flank pain: treat other causes (stones, infection, tumour), avoid aggravating activity, and possible referral to pain management
- Cyst haemorrhage: usually self-resolved with rest, analgesia, and fluids. If drop in Hb or haemo instability, then may require transfusion/embolisation
- Infected cyst/UTI: always antibiotics, may require nephrectomy
What are the three types of spina bifidia>?
- spina bifida occulta (incomplete spine formation, but spinal cord remains in the right place)
- Meningocele: meninges bulge out through opening
- Myelomeningocele: both spinal cord and meninges bulge outward
Maternal nutrition plays an important role in preventing spina bifida. What are some factors that come into play?
- Alcohol
- Caffeine
- Low folate/B12
- Hyperglycaemia (such as in diabetes)
- Low zinc, vitamin C, and choline
Non-nutritional factors that predispose to spina bifida
- Smoking
- Hyperthermia
- Low socio-economic infections
- Pregestational diabetes (link this to a nutritional cause…)
- Valproate (what kind of drug is this?)
Complications of spina bifida
- Neurogenic bladder (urosepsis, CKD)
- Non-urological (epilepsy, scoliosis)
Spina bifida urological treatment
Ensure adequate bladder drainage at all times
What is cerebral palsy
Umbrella term: permanent, non-progressive process that causes neurological impairment in the foetal brain
Causes of cerebral palsy (pre/peri/postnatal)
- Prenatal; congenital malformations, intrauterine infection/stroke
- Perinatal:: hypoxic brain injury, stroke, CNS infection
- Postnatal: periventrical infarct/intraventricular haemorrhage
What is the main urological complication that need to be managed in cerebral palsy?
Neurogenic bladder (incl. incontinence)
