Infections of kidneys and Fluid collections

Most infections occur in the ___________ ascend into the kidneys

Bladder

Kidney infections are most commonly caused by …

Bacteria from the intestinal tract

Acute glomerulonephritis

Bilateral inflammation of glomeruli

Occurs as late complication of pharyngitis

Acute or chronic

Sudden onset of hematuria, azotemia, proteinuria

Acute glomerulonephritis is also caused by …

Other types of infection, autoimmune response, medications, toxins

Acute glomerulonephritis Labs

Increased serum BUN, and creatinine

Hematuria, proteinuria

Decreased GFR

Acute glomerulonephritis USA

Bilateral renal enlargement

May see increased cortical echogenicity with prominent pyramids

Increased RI

Ischemia or infarction causes hypoechoic foci in cortex

Acute glomerulonephritis

Chronic glomerulonephritis

Irreversible and progressive fibrosis

Usually progresses to end stage renal failure

Can lead to significant proteinuria, if chronic

Chronic glomerulonephritis USA

Atrophic, smooth kidneys with increase echogenicity

Chronic glomerulonephritis

Acute Pyelonephritis

Inflammation of renal collecting system

Caused by bacteria from ascending UTI

Females 15-35yrs

Unilateral

Antibiotic treatment and imaging studies not necessary

Acute Pyelonephritis is most commonly caused by:

E. Coli

Acute Pyelonephritis labs

Diagnosis made with increased WBC, bacteria and pus in urine

Acute Pyelonephritis USA

Varied appearance, mostly normal kidneys

Loss of distinction between renal cortex and medulla

Diminished sinus echoes in affected kidney

Diffuse:

• Unilateral or bilateral renal enlargement with diffuse swelling, loss of corticomedullary definition, calyceal clubbing

Focal:

• Normal renal size with focal, indistinct hypoechoic wedge-shaped segment parenchyma, similar to renal infarct

Chronic pyelonephritis

Nephritis associated with urinary bladder reflux and stasis

Chronic untreated bacterial infection

Begins in childhood

Uni or bilateral

Chronic pyelonephritis is more common in…

Women

Chronic pyelonephritis causes:

Scarring of cortex if untreated renal failure will occur

Chronic pyelonephritis Labs

Diagnosis usually made clinically with increased WBC and pus in urine

Chronic pyelonephritis Symptoms

High fever, malaise, lethargy, anemia, N/V

Chronic pyelonephritis USA

Small, shrunken, misshapen kidney with clubbing of calyces

Small kidney with clubbing of the calyces

Overlying cortical atrophy/scarring causes irregular kidney contour and cortical thinning

Increased corticomedullary echogenicity

Compensatory hypertrophy of contralateral kidney

Pyelonephritis

Emphysematous pyelonephritis

Bacterial infection associated with renal ischemia

Infection of parenchyma with gas formation

Commonly caused by E. Coli

Abscess formation with intrarenal air

Extend into perirenal space

LIFE THREATENING

Emphysematous pyelonephritis is most commonly seen in

Women, diabetics and IMMUNOSUPPRESSED pts

Emphysematous pyelonephritis Symptoms

Fever, leukocytosis, flank pain, dehydration, electrolyte imbalance

Emphysematous pyelonephritis Labs

Elevated WBC and glucose level, positive serum and urine bacterial cultures

Emphysematous pyelonephritis USA

UNILATERAL, enlarged, hypoechoic kidney

Multiple echogenic foci with reverberation/ring down artifact in the sinus or parenchyma

May demonstrate areas of echogenicity with dirty posterior shadowing

Emphysematous pyelonephritis

Malakoplakia

Chronic E. Coli infection

Unilateral enlarged kidney with multiple poorly defined cortical masses

Xanthogranulomatous pyelonephritis

Chronic bacterial infections cause chronic obstruction which leads to destruction of parenchyma and replacement with lipid laden macrophages

Unilateral and diffuse

70% with stones

More common in women and diabetics

Requires nephrectomy

Xanthogranulomatous pyelonephritis is assocaited with

Phlegmon formation

Xanthogranulomatous pyelonephritis Labs

Bacteria in urine, anemia, leukocytosis

Xanthogranulomatous pyelonephritis symptoms

Dull persistent pain, weight loss, UTI

Xanthogranulomatous pyelonephritis USA

Unilateral renal enlargement

Loss of corticomedullary definition

Sinus very echogenic

Debris filled calyces

Multiple echogenic foci with shadowing

Staghorn calculus and hydronephrosis are common

Xanthogranulomatous pyelonephritis

Mycetoma is also known as

Fungal ball

Mycetoma is associated with

Candidiasis infection that is caused by candida albicans

Most common fungal infection in the kidneys

Candidiasis

Mycetoma

Commonly seen in diabetics and immunosuppressed patients

Seen in pts that require long term use of indwelling urinary catheters, those with Hx of IV drug use, or long term steroid or antibiotic therapy

Treated with antifungal medication

Mycetoma Labs

Hematuria, bacteriuria, pyuria

Mycetoma Symptoms

Flank pain, chills and fever

Mycetoma USA

Hyperechoic

Non-shadowing mass within collecting system

Can be mobile, eval with different pt positions

Mycetoma

HIV nephropathy

Immunocompromised pts are at risk of numerous infections that damage the kidneys

INCREASED ECHOGENICITY OF KIDNEYS

Globular-shaped kidneys, decreased corticomedullary definition, decreased renal sinus fat

HIV Nephropathy

Corticomedullary renal abscess

Caused by ascending spread of bacteria in the urinary tract

End result of acute bacterial nephritis

Fever, chills, N/V, leukocytosis

Associated with diabetes, urinary tract obstruction, infected renal calculi, IV drug use

Renal carbuncle (abscess)

Refers to a renal abscess that forms in the parenchyma

Caused by hematogenous spread of staphylococcus aureus

Fever, chills, N/V, increased WBC

Renal abscess USA

Hypoechoic, complex mass with irregular borders

Fluid/debris levels

Thick walls

Shadowing from gas; may see ring down

Renal abscess

Hematoma

Collection of blood outside the kidney

Trauma or surgery

Vary in size and shape with location

Blood usually fills space available, causing shape irregularity

• Subcapsular/Intracapsular: Between the renal cortex and capsule

• Extracapsular/Perirenal: Outside the capsule, between the capsule and the liver (Morison pouch) or spleen

Hematoma symptoms

Pain and hematuria

USA Hematoma

Varied appearance with age

Complex mass

Debris

Septations

Intracapsular will usually indent or deform renal parenchyma

Extracapsular does NOT indent parenchyma

Extracapsular hematoma

Subcapsular hematoma

Urinoma

Leakage of urine from UPJ or UVJ

Post-op complication

Usually presents 1-2 weeks post transplant

May cause hydronephrosis due to ureter compression

USA Urinoma

Cystic collection adjacent to kidney, may see debris

Subcapsular fluid collections usually distort of indent renal parenchyma

Urinoma

Lymphocele

Encapsulated collection of lymph

Associated with trauma or surgery

Can have delayed presentation of up to 2-6 months after surgery

USA lymphocele

Cystic structure between kidney and bladder

The fluid commonly contains debris and septations

Hydronephrosis

Obstruction of urine outflow with dilated collecting system

Unilateral - UPJ stone, extrinsic compression from mass, malformed UVJ

Bilateral - Prostate enlargement, bladder mass, urethral obstruction, pregnancy (R>L)

Can lead to obstructive nephropathy

RI > 0.7 in arcuate arteries = associated nephropathy

Chronic hydronephrosis can cause

HTN, renal failure and sepsis

Most common site of obstruction by renal calculi

UVJ

USA hydronephrosis

Dilation of normal collecting system

Minimal - Prominent pelvis, small amount of fluid

Mild - Dilated pelvis and calyces, sinus echoes visible

Moderate - Dilated renal pelvis and calyces, no sinus echoes visible “bear claw”

Severe - Extremely dilated collecting system, compression of cortical tissue, formation of parapelvic cysts

Follow ureter to junction with bladder to determine level of dilation

Ask pt to void bladder and see if hydronephrosis persists

• = prox to urethra indicating possible urethrocele, UPJ obstruction or ureteral obstruction

Hydronephrosis

Pyonephrosis

Pus in collecting system

Infection in an obstructed system, usually UPJ obstruction

Fever, flank pain, leukocytosis and other symptoms

Dysuria, pyuria, hematuria

Associated with perinephric abscess, bacteriemia and septic shock

USA Pyonephrosis

Enlarged echogenic kidney with significant dilation of the calyces

Mobile echogenic debris and pt position dependent debris levels

Stones possible

May also see dirty shadowing or ring down from gas produced by bacteria

Pyonephrosis

Acute tubular necrosis (ATN)

Caused by prolonged ischemia or drug toxicity that damages renal parenchymal cells

Can be reversed if treated early enough

Most common cause of intrinsic acute renal failure

Acute tubular necrosis

USA ATN

Enlarged echogenic kidneys

Increased resistive index in parenchymal vessels

Pyramids appear more prominent

Acute renal failure

Acute renal failure

Acute inability to remove metabolites from the blood

CRITICAL but REVERSIBLE if caught early

Leads to abrupt decrease in renal function and acute reduction in urine output (oligouria)

Prerenal failure - Hypotension, volume depletion, heart failure, acute occlusion of the renal artery

Intrinsic failure - acute tubular necrosis, nephritic syndrome, interstitial nephritis, autoimmune diseases

Postrenal failure - Bilateral renal obstruction, oliguria, and empty bladder

Most common cause of acute renal failure

Tubular necrosis

Acute renal failure is caused by

Obstruction of urine flow, reduced renal perfusion or renal parenchymal disease

Acute renal failure labs

Increased potassium, BUN and creatinine

Acute renal failure symptoms

Hypovolemia, HTN, peripheral edema, hematuria, oliguria

Acute renal failure USA

Normal or increased echogenicity compared to liver/spleen

Kidneys are normal in size or slightly enlarged

Bilateral hydronephrosis indicates postrenal failure

Doppler evaluation should be performed on parenchymal arteries to measure the RI (>0.7 = intrinsic failure)

Chronic renal failure is also known as

Medical renal disease

Most common cause of Chronic renal failure

Diabetes mellitus

Other causes of Chronic renal failure are…

Renal vascular disease, chronic pyelonephritis, tuberculosis, lupus

Chronic renal failure Labs

Increased BUN and creatinine, hyperkalemia (elevated potassium)

Chronic renal failure

Considered end stage renal failure when kidney function is 10% or less

May require dialysis until transplant can be done

USA Chronic renal failure

Kidneys are small in size and very echogenic due to atrophy

Cortex is thinned (<10mm) with loss of corticomedullary border

Dialysis

Used to remove excess waste products and water from body when kidneys can no longer do it

Helps body control blood pressure and sodium potassium levels

Pts may experience HTN and uremia; N/V, swelling and fatigue

Hemodialysis

AVF created by connecting an artery and a vein, usually in the arm

Dialysis machine connected to the pt using two separate needles

Blood is removed from the body, sent through the machine and returned to body through AVF

Requires regular visits

Peritoneal dialysis

Used for pts with some residual kidney function

Eventually function will decline to a point that hemodialysis will be needed instead

Cleansing fluid is injected through an intraperitoneal catheter

Fluid filters waste products from the blood for a specified amount of time then drains out of abdomen

Can be done at home

These pts commonly demonstrate ascites

Chronic renal failure

What renal infection frequently occurs as a late complication of pharyngitis?

Acute glomerulonephritis

Which of the following is a symptom of acute glomerulonephritis?

Foggy urine

Hematuria

Proteinuria

All of the above

All of the above

Acute glomerulonephritis presents as ___________, while chronic glomerulonephritis presents as ___________

Bilateral renal enlargement; bilateral renal atrophy

What causes acute pyelonephritis

Ascending bacterial infection

Which of the following is a sign of acute pyelonephritis?

Loss of corticomedullary definition

Diminished sinus echoes in affected kidney

Calyceal clubbing

All of the above

All of the above

All the following are characteristics of Emphysematous pyelonephritis, except?

Commonly caused by E. Coli

Abscess formation with intrarenal air

Areas or ring down/dirty shadowing

Multiple renal calculi within parenchyma

Multiple renal calculi within parenchyma

What is a critical renal infection that requires an emergency nephrectomy

Emphysematous pyelonephritis

_____________________________ are more common in women and diabetics

Xanthogranulomatous pyelonephritis and emphysematous pyelonephritis

Mycetoma formation is associated with:

Candidiasis infection

Mycetoma formation is associated with which of the following?

Long term use of indwelling urinary catheters

Those with history of IV drug use

Long term steroid or antibiotic therapy

All of the above

All of the above

______________ refers to a renal abscess that forms in the parenchyma caused by hematogenous spread of staphylococcus aureus

Carbuncle

When evaluating a suspected renal hematoma, it is most important to document the location of the hematoma relative to:

Renal capsule

How is an intracapsular fluid collection differentiated from an extracapsular fluid collection of the kidney?

Presence or absence of parenchymal distortion

What sonographic characteristic indicates a lymphocele is present and not a urinoma

Lymphocele has septations in fluid