Kidney Infections (Lecture 17)

What is acute pyelonephritis (APN)? What are the routes of infection? What is pt population and CP? What tests are done? How is it treated?

- Acute bacterial inflammation of renal parenchyma and pelvis

Routes of infection:

- Ascending (E. coli)**

- Hematogenous seeding (staphylococcus aureus)

- Pt population: women aged 15-35

- CP: fever, chills, bladder symptoms (dysuria, frequency, urgency)

- Tests: bacteriuria, pyuria, leukocytosis

(usually diagnosed only w/ blood work, imaging is only done if there are complications)

- Tx: antibiotics

What are the SF for acute pyelonephritis?

- Normal (m/c)

- Inc renla size

- Compressed renal sinus

- Altered echotexture

- Parenchymal gas (only seen sometimes)

- Absence of flow

What complications are associated with acute pyelonephritis? (HINT: 2) Who is at risk for these complications (HINT: 3)

- Renal abscess (w/ parenchymal necrosis) and perinephric abscess

- Pt's at risk: diabetics, urinary tract obstruction, immunocompromised

What does an abscess look like sonographically?

- Solitary

- hypoechoic

- Post enhancement

- Gas w/ dirty shadow

What are the d/d for acute pyelonephritis? (HINT: 2)

- Complicated cysts

- RCC

What is pyonephrosis? What are its causes? (HINT: 2) What is the CP? What are the SF? What is the d/d (HINT: 1)? What is the treatment?

- Purulent debris in dilated, obstructed collecting system

Causes:

- young ppl = UPJ stone obstruction

- elderly = malignant ureteral obstruction

- CP: same as abscess (fever, chills pain)

- SF: hydronephrosis; possibly hydroureter; debris, gas, and stones in collecting system

- D/D: TCC

- Tx: IV antibiotics, nephrostomy tube for drainage, eliminate obstruction

What is emphysematous pyelonephritis? What is the pt population and CP? What are the SF? What are the d/d? What is the treatment?

- Severe necrotizing infection (E.coli) of renal parencyhma, characterized by gas formation within collecting system, renal parenchyma, or perirenal tissues

- Pt population: middle-aged diabetic women

- CP: fever, flank pain

- SF: parenchymal destruction, streaky gas (non-dependent), loculated gas

- d/d: stones, pseudokidney

- Tx: severe = nephrectomy, less severe = antibiotics, percutaneous drainage, control diabetes

What is emphysematous pyelitis?

Air within the collecting system only

What is chronic pyelonephritis? What is the pt population and CP? What are the SF? What are the treatment?

- Chronic progressive renal disorder caused by infection superimposed on congenital vesicoureteric reflux or intrarenal reflux (predisposes pt to infections = chronic pyelonephritis)

- Pt population: female children

- CP: asymptomatic, polyuria, nocturia, pain, fever, chills, mild proteinuria

- SF: irregular border (cortical thinning w/ echogenic poles), atrophy, loss of CMJ and normal architecture, dilation of collecting system

- Tx: antibiotics, restrict dietary protein intake, surgical reimplantation of ureters

TRUE or FALSE: Chronic pyelonephritis can appear normal or with atrophy and cortical thinning.

FALSE: Chronic pyelonephritis can NEVER appear normal

What is xanthogranulomatous pyelonephritis? What are the pt population and CP? What are the SF? What is the d/d?

- Rare chronic bacteria infection that causes lipid-laden macrophages to move in and take over (unilateral)

- Pt population: middle aged diabetic women

- CP: wt loss, pain, UTI

- Triad: obstructing staghorn calculi, inc renal size, lack of renal function

- SF: diffuse = inc renal size, staghorn calculi; focal = hypoechoic areas

- D/d: pyonephrosis