Kidneys Flashcards
Bilateral renal agenesis assoc with
Oligohydramnios & pulmonary hypoplasia
Branches of renal artery
Main renal artery, 5 segmental arteries, interlobar arteries (between pyramids), arcuate arteries (parallel to pyramids), interlobullar arteries (perpendicular to pyramids).
The main renal artery comes off of aorta. At hilum divides into 5 segmental arteries. Those divide into interlobar arteries.
Interlobar arteries are between medullary pyramids. At the base of pyramid, arcuate arteries branch off interlobar. (Arcuate are parallel to renal capsule)
Arcuate arteries branch into interlobullar arteries. (perpendicular to renal capsule)
Unilateral renal agenesis is assoc with
Uterine duplication/bicornuate ut, and seminal vesicle agenesis in males.
Crossed renal ectopia
Kidney ascends to contralateral side
Crossed fused renal ectopia
Kidney goes to contralateral side and fuses with the other kidney
Horseshoe kidney
Lower poles fused. U shape. Lower poles at midline.
Ureter duplication
Partial or complete
Complete: 2 ureter, 1 is in ectopic location in the bladder. Frequent complication is ureterocele.
Ureterocele distal ureter into bladder with cystic dilatation. Causes obstruction. May cause upper pole to dilate.
MC male urinary obstruction
Posterior Ureteral Valve obstruction
Dilated bladder, hydroureter, hydronephrosis, urinoma
Most common cause of abd mass in newborns
MCDK
If see renal cell carcinoma, must evaluate ____
Renal vein and IVC for lymphadenopathy and liver mets.
Prune Belly Syndrome characteristics
Absent Abd wall musculature,
large distended urinary bladder, hydronephrosis/hydroureter,
bilateral cryptorchidism
Pyonephrosis
Pus in dilated pelvis secondary to infected hydronephrosis
Dependent echoes in the dilated pelvicaliceal system, debri, gas shadowing from infection.
Transitional cell carcinoma
MC cancer in renal pelvis
Squamous cell carcinoma and mucinous adenocarcinoma are also cancers in renal pelvis but not as common.
Bilateral renal masses
Malignant lymphoma/Hodgkin’s lymphoma
Mets
Tumors assoc with Von Hippel Lindau
RCC, hemangioma, phenochromocytoma, panc cystadenoma, cystadenocarcinoma, Adenoma, islet cell tumors, cyst in organs.
Wilms tumor/ nephroblastoma
MC malignant mass in the Abd of children under 8 yrs
Large renal tumor, sharply marginated, compressed renal tissue, focal hemorrhage & necrosis, calcifications, tumor invasion of IVC and RT atrium, tumor may cross midline, hypervascular
MCDK
Caused by atresia of uretopelvic junction during metanephric stage of intrauterine development. Week 8-10 GA. Collecting tubules enlarge and turn into cysts.
Assoc with contralateral UPJ obstruction, contralateral renal agenesis or hypoplasia
Cyst of varying shape/size, cyst don’t communicate, absence of sinus and parenchyma. Usually unilateral. Echogenic tissue interfaces between cysts
ARPKD/infantile polycystic kidney
Bilateral, infants, spongy large echogenic kidneys. Tiny cysts.
Obstruction from a stone
Uretovesical junction:
Ureteropelvic junction: MC
Ureteric obstruction of the level of pelvic inlet
Renal artery stenosis
Kidneys < 9cm L
Peak main renal artery vel > 100 cm/s
Renal artery / aorta ratio > 3.5
Pulsus tardus waveform of segmental renal artery
Peak systolic vel of Main renal artery compared to PSV of aorta. Renal artery to aortic ratio > or = 3.5 indicate a hemodynamically significant stenosis
Ureterocele
Round cystic structure that projects into the bladder lumen at the uretovesical junction
May obstruct & cause UTIs.
Structure that connects the apex of the bladder to the umbilicus
The median umbilical ligament (urachus)
Cystic dilatation of urachus = urachal cyst. Extends from umbilicus to bladder dome.
AIDs US findings
Hepatosplenomegaly, lymphadenopathy, hyper liver, hyper renal, liver abscess, Mets kaposi sarcoma, acute cholecystitis
3 parts of retroperitoneal
Perirenal, ant and post pararenal
Infantile polycystic kidney disease
Bilateral
Enlarged echogenic kidneys
Loss of cortical medullary distinction
Assoc with renal dysfunction, lung hypoplasia, periportal hepatic fibrosis, oligohydramnios in utero
Column of Bertin
Hypertrophied column of Bertin. Invagination between cortex. Should be < 3cm and continuous with no mass effect.
Dromedary Hump
Lateral bulge
Renal cell carcinoma
Solid hypo mass
Assoc with adult polycystic kidney disease, acquired cystic disease, Von Hippel Lindau, and Tuberous Sclerosis
Evaluate ipsilateral renal vein and IVC for mets, contralateral renal vein, Retroperitoneum for lymphadenopathy, and liver for mets.
Angiomyolipoma
Fat tumor, hyperechoic, propagation speed artifact
Renal vein thrombosis
Cause: IVC or renal vein extrinsic compression, nephrotic syndrome, renal tumors, renal allografts, trauma
Dilated clotted renal vein, absence venous flow in kidney, enlg hypo kidney, high resistive artery
Urachal Cyst
Cystic dilatation of urachus (median umbilical ligament)
Cystic structure superior or anterior to bladder
Lymphocele
Renal transplant complication or of pelvic surgery
Caused by leakage of lymph from a renal transplant or surgical disruption of lymph channels
Urinoma
Caused from renal trauma, surgery, or obstructing lesion
MC assoc with renal tx, PUV
3 muscles post to kidney from med to lat
Psoas muscle, quadratus lumborum, transverse abdominis
Solid renal mass evaluate
Ivc and renal veins for mets
Renal tx possible fluid collections
Urinoma
Lymphocele
Hematoma
Abscess
Kidneys
Begin form 3rd wk
Nephron function 8th wk
Pronephros
Mesonephros: Epi, vas deferans, ejact duct
Metanephros: kidney
Paramesonephric ducts/Mullerian duct: uterus, vag,
Kidneys migrate from pelvic to abdomen at
5-6yrs
Kidney size
9-12cm L
5cm W
2.5 cm AP
Concex laterally, concave medically
Cortex > 1cm
Sinus contains
Calyces, vessels, lymphatics, nerves, fat
Layers
- Inner fibrous capsule
- Middle adipose capsule
- Outer renal fascia/ Gerota’s Fascia/ Perinephric Fascia
Gerota’s fascia encloses
Kidney, adipose capsule, adrenal gland
Nephron
Functional unit of kidney. > 1,000,000
Filters blood, makes urine
Right kidney
2-8 cm lower than left
Function
Controls blood concentration and volume
Regulates blood ph
Removed wastes from blood
Renal agenesis
Bilateral is fatal
Unilateral absent kid and ureter. L>R
Assoc with contralateral Hypertrophy & genitial anomalies
Ureter duplication
Common
Complete duplication creates ureterocele that can’t enter bladder and backs up.
Partial starts as 2 ureters and merge
Extrarenal pelvis
Extra cystic area outside medial to kidney
Supernumery kidney
Rare
2 kidneys on one side and one on the other.
Ipsilateral kidney may be fused.
Ectopic kidney
Fail to migrate. In pelvis commonly. Rarely in thorax.
Crossed renal ectopia
Both kidneys on one side.
Crossed fused renal ectopia more common.
Horseshoe kidney
Fused at upper or lower poles. Lower pole more common. Connected by isthmus.
ADPKD
Autosomal Dominant Polycystic Kidney Disease
Adult
Multiple cysts varying sizes
75% with HTN
2 cyst < 30yrs
2 cyst/ kidney 30-59
4 cyst / kidney > 60
50% liver cyst assoc. also panc, spleen, and berry aneurysm
ARPKD / IPKD
Autosomal Recessive Polycystic Kidney Disease
Infantile Polycystic Kidney Disease
Infants, large echogenic spongy kidneys. Non functioning. Tiny cysts. Bilateral. Fatal.
MCDK
Multi Cystic Dysplastic Kidney
MC cause Abd mass in newborns. Neonates. Large cysts, loss of sinus, cyst don’t communicate.
Usually unilateral. Bilateral fatal.
Assoc with contralateral abnl UPJ
Potters syndrome assoc with bilateral MCDK
ACKD
Acquired Cystic Kidney Disease
90% of long term dialysis patients.
Various cysts. Hyperechoic. Norm to small kidney.
Medullary Cystic Disease
Rare
Dilated tubules with formation of Ca+ and stones in 10-15%
Echogenic pyramids, no posterior shadowing. Usually Bilateral.
Cyst with mural calcifications assoc with
Cancer
Milk of calcium cyst
Hyperechoic calcium moves within cyst with patient position
Para pelvic cyst
In hilum
Does not communicate with pelvis
May look like hydro
Von Hippel Lindau
Multiple organs and CNS tumors. Renal tumors and cysts.
Tuberous Sclerosis
Mental retard, seizures, cutaneous lesions, renal cysts, Angiomyolipomas
80% multiple bilateral angiomyolipomas
Uremic Medullary Cystic Disease / Nephronophthesis
Rare, progressive.
Uremic medullary cystic disease: adult
Nephronophthesis: child
Azotemia (inc nitrogen), anemia, salt wasting, polyuria
Sm cyst in medulla, echogenic pyramid, hyper cortex, normal to small kidneys
Angiomyolipomas / Renal Hamartoma
Blood vessel muscle fat
Echogenic well defined, solitary
Adenoma
MC benign tumor
Well defined iso hyper hypo, < 1 cm, in cortex
Oncocytoma / Oxyphilic Adenoma
Large vascular Adenoma
Males
Solitary, hypoechoic, stellate scar / spokes wheel
Hypernephroma / Renal Cell Carcinoma
MC renal cancer 85%
Males > females
Assoc with Tuberous Sclerosis, Von Hippel Lindau, dialysis, cystic diseases
Stage 1: kidney
2: Gerota’s fascia
3: renal vein, ivc, regional nodes
4: adj organs, distant mets, distant nodes
Pain, palp mass, hematuria, weight loss, fever, htn
Hypo usually, calcifications, complex with necrosis,
Color pseudocapsule / basket sign
Renal cancer mets to
Lungs MC, bone, contralateral kidney, nodes, liver, adrenal, brain
Transitional Cell Carcinoma
90% of primary pelvis tumors
Males > females
Carcinogen exposure
Near trigone usually
Hematuria, frequency, dysuria, suprapubic pain
Squamous Cell Carcinoma
10% of primary renal pelvis tumors
Hematuria, hydronephrosis, hypo-iso mass that splits central echo complex/sinus.
Renal Lymphoma
Usually NonHodgkins spread through blood
Hypo cortex, cystic/hypo mass with no enhancement, multiple, bilateral, enlargement.
Mets to kidneys
MC melanoma
Contralateral kidney, lymphoma, lung, breast, stomach, cervix, colon, pancreas
Multiple small bilateral hypo lesions
Wilms tumor / nephroblastoma
MC renal tumor in children
Usually before 3 yrs
Palp mass, pain, anorexia, n/v, fever, hematuria, malaise, htn
Large unilateral
Acute Renal Failure
Impaired kidney function over days-wks
Reversible with early tx
MC cause ATN Acute Tubular Necrosis
Other causes: cystic diseases, inflammations, toxin exposure, obstruction, diabetes, htn
Htn, weak muscles, GI bleed, infection
Enlg hypo kidneys
Chronic Renal Failure
Months-years
Irreversible
End stage renal disease
Small Echogenic kidneys
Need transplant or dialysis
Acute Tubular Necrosis
2nd to ischemia or toxic insult
Enlg hyperechoic kidneys
AIDs
Pneumocystis Carinii: diffuse Ca+
Sickle Cell Nephropathy
Glomerulonephritis, RV thrombus, papillary necrosis
Hematuria
Hypertensive Nephropathy
Uncontrolled htn leads to renal damage
Small kidneys Echogenic
Renal Atrophy
Thin cortex
Small
Acute Pyelonephritis
E. coli, infection
Enlg
Bld irritation fever chills headache back pain malaise
Normal kidney
Enlg, compressed renal sinus, hypo/hyper, loss of corticomedullary differentiation, poorly marginated mass, gas within parenchyma.
Chronic pyelonephritis
Small Echogenic thin parenchyma
Recurrent UTIs
Emphysematous Pyelonephritis
Gas forming bacterial Immunosuppressed, females with UTIs E. coli Life threatening Emergency nephrectomy Gas in sinus/cortex
Xanthogranulomatous Pyelonephritis
Rare. Chronic. Replacement of normal parenchyma Staghorn Calculi: big obstruction huge stone thing Hydro Diabetic females diffuse/segmental
Acute Glomerulonephritis
Inflammation necrosis of glomeruli
Echogenic cortex
Acute interstitial nephritis
Scarlet fever assoc, diphtheria, drug allergies
Enlg Echogenic mottled splotchy kidney
Renal/Perirenal Abscess/ renal carbuncle
Staph Aureus bacteria
Pain fever chills tender
Focal collection of inflammatory necrotic debri
Diabetics
Complex fluid collection. Gas. Shadow. Debri.
Pyonephrosis
Pus in dilated collecting system
Fever. Flank pain.
Dilated anechoic to hypo ureter. Fluid debri. Air.
Tuberculosis
From lungs to kidney via blood
Ca+
Candidiasis
MC cause of urinary tract fungal infection
Renal fungus balls Candida Immunosuppressed patients Fever chills flank pain Large kid. Echogenic fungus balls
Hydronephrosis
Dilation of renal collecting system
May lead to atrophy
Complete obstruction, serious damage after 3 wkd
Partial obstruction, serious damage after 3 months
False positive with overly distended bladder, large pelvis, prominent vessels, para pelvic cysts.
Nephrolithiasis
Kidney stones
Calcium, Uric acid, cysteine
Hot climates, fam hx,
Hematuria, oliguria, renal colic/cramp, n/v fever chills, pyuria, anuria
Echogenic foci, shadow, candle sign (little flow in jets), twinkle artifact.
Urolithiasis
Stone in urinary collecting system
Nephrocalcinosis
Ca+ in renal cortex. Variable etiology. Bilateral. Diffuse.
Cortical/medullary Echogenic
Highly Echogenic pyramids with or without shadowing
Assoc Hyperparathyroidism, vit D toxication, Hypercalcemia, medullary sponge kidney, Cushing’s syndrome, Alport syndrome, fanconi’s syndrome
Infiltrative disease/ renal medical disease
Renal cortical disease: Echogenic cortex. No differentiating sinus and cortex. Small.
Renal medullary disease: Echogenic pyramids.
Renal Papillary Necrosis: no differentiating cortex and sinus. Echogenic pyramids. Diabetes, obstruction, sickle cell, pyelonephritis, alcohol abuse. Multiple round/triangular cystic spaces in medulla. Echogenic pyramid with shadowing.
Renal Sinus Disease / renal sinus lipomatosis / fibrolipomatosis: fatty renal pelvis. Inc size sinus. Thin cortex. Fatty sinus.
Renal transplant.
Renal artery stenosis, MC correctable cause of hypertension.
1/3 due to atherosclerosis
2/3 due to fibromuscular dysplasia
Metanephros develops into
Ureteric bud & metanephric blastema
Lymphocele
Transplant complication
Fluid collection with septations & internal debri adj to kidney
Right renal artery courses
Post to ivc
Left renal vein courses
Ant to aorta. Post to SMA
