Congenital/Hereditary Diseases

Congenital/Hereditary Diseases

Definition

- disorders at birth or caused by genetic mutations

-affects urinary system, may lead to infections, kidney damage, chronic kidney disease
Complications

-hydronephrosis, proteinuria, hematuria, UTIs, kidney stones,etc

-can live with one kidney, cannot live w/out both 

Diagnosis/Imaging

- diagnosed through imaging studies 

-Ultrasound (gold standard) - non invasive, non ionizing rad, safe

Unilateral Renal Agenesis (URA)

Definition

- congenital condition where one kidney and associated ureter fails to develop before birth 

- single functioning kidney - undergoes compensatory hypertrophy

- asymptomatic/discovered incidentally 

Associated Anomalies

- vesicoureteral reflux, hydronephrosis, reproductive tract abnormalities (females), hypospadias (males)

Supernumerary Kidney

Definition

- Rare congenital anomaly

- additional kidney beyond normal two that has its own blood  supply, collecting system, and capsule 

- forms due to abnormal division of kidney-forming tissues

Features

- small/rudimentary

- located below normal kidney on same side

- has own ureter or shares w/ another kidney

-separate blood supply from renal arteries

Hypoplastic Kidney (Renal Hypoplasia)

Definition

- congenital abnormality of reduction in size of kidney due to incomplete development of nephrons (fewer nephrons)

Types

- Unilateral Renal Hypoplasia

     -most common

     -one kidney smaller than normal, other kidney normal 

-Bilateral Renal Hypoplasia 

     -both kidneys underdeveloped 

     -serious - can lead to chronic kidney disease, or kidney failure

Kidney Malrotation 

Definition

- congenital anomaly - abnormal/ incomplete  orientation of kidney during fetal development 

- kidney may reach correct location but hilum does not face medially 

- Malrotation occurs when kidney: fails to rotate, rotates -  incompletely, excessively, and in wrong direction

Ectopic Kidney

Definition

- congenital anomaly - one or both kidneys located outside 

  normal fossa due to abnormal migration during fetal 

  development 

Types

1) Pelvic Kidney

     -most common, - kidney remains in pelvis near bladder 

2) Abdominal ectopic kidney

     - kidney ascends partially but does not reach renal fossa 

3) Thoracic (intrathoracic kidney) 

     - very rare 

     - kidney located in thoracic cavity from excessive ascent/ 

       diaphragmatic defects

4) Crossed renal ectopia

     - kidney crosses to opposite side and may fuse w/other kidney

Horseshoe Kidney

Definition

- most common renal fusion anomaly 

- kidneys fuse (more commonly at lower poles) during fetal development 

- forms U-shaped structure (horseshoe), lies typically lower in  abdomen than normal kidneys

-fusion occurs anterior to great vessels (aorta and IVC)

- has isthmus - connects the kidneys

Fused Kidney

Definition 

-AKA pancake kidney , fused kidney, complete renal fusion, disk lump, doughnut kidney 

- rare congenital renal anomaly 

- complete fusion of both kidneys w/out separating septum, forms single renal mass in the pelvis 

- more vulnerable to trauma/compression

Duplex Kidney (AKA duplicated collecting system)

Definition

- congenital anomaly - single kidney develops two ureters

- drains through single ureter (partial duplication) or two distinct ureters (complete duplication)
Types

- Partial Duplication (Bifid System) (Bifid Ureter) 

       - two renal pelves merge together into single ureter before entering the bladder

- Complete Duplication 

       - two separate ureters enter drain kidney 

       - e/ureter enters bladder on its own or one inserts ectopically

Ureterocele

Definition 

- Congenital cystic dilation (balloon-like) of distal ureter as it enters the bladder

- caused by stenosis of ureteral orifice 

- leads to obstruction of urine flow into the bladder 

Classifications

1) Intravesical Ureterocele - located in bladder, associated w/ single collecting duct, in adults 

2) Ectopic Ureterocele - extends beyond bladder neck, associated w/ double collecting system, in children 

Clinical Manifestations

- Infants and Children - UTIs, hydronephrosis, urinary obstruction, failure to thrive, abdominal/ flank mass

- Adults - recurrent UTIs, flank pain, kidney stones, hematuria 

Diagnosis/Treatment 

- Ultrasound (initial modality) - cystic structure within bladder 

- Voiding Cystourethrogram (VCUG)

-Treatment - endoscopic puncture/ incision of ureterocele

Posterior Urethral Valves

Definition

- congenital obstructing membranous folds located in posterior urethra

- causes bladder outlet obstruction 

- most common cause of lower urinary tract obstruction in male infants 

Complications 

- hydronephrosis, hydroureter, chronic kidney disease/ renal failure, bladder dysfunction, vesicoureteral reflux, pulmonary hypoplasia (from oligohydramnios)

Diagnosis/Imaging/Treatment 

- Ultrasound - initial eval 

     - prenatal findings: dilated posterior urethra (“keyhole sign”)

     - postnatal: urinary retention or dribbling 

-Voiding Cystourethrogram (VCUG) - gold standard 

-Treatment: definitive - endoscopic valve ablation

Glomerulonephritis

Definition

- Group of disorders - inflammation of glomeruli (filtering unit of kidneys)

- inflammation leads to impaired filtration - RBCs and protein leak into urine 

- associated w/ antigen/antibody reaction 

     - commonly caused by chronic autoimmune disorder

     - may occur weeks after acute respiratory/middle ear infection w/ strain of hemolytic streptococci

Clinical Manifestations 

- Nephritic: hematuria (“cola-colored” urine), hypertension, oliguria

- Nephrotic: hypoalbuminemia, hyperlipidemia 

- Complications: AKI, CKD, ESRD, hypertension 

Diagnosis/Imaging 

- Renal Biopsy (gold standard)

- Urinalysis - hematuria+proteinuria (hallmark finding) 

- Ultrasound (primary) - increased cortical echogenicity