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Flashcards in Renal ID Deck (41)
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What is a renal abscess?

abscess that is confined to the kidney, and is caused either by bacteria from an infection traveling to the kidneys through the bloodstream or by a UTI traveling to the kidney and then spreading to the kidney tissue


usual causes of renal abscess?

- kidney inflammation
- multiple skin abscesses
- DM
- nephrolithiasis
- pregnancy
- neurogenic bladder (autonomic nephropathies - DM, MS)


What are sxs of renal abscess?

- fever
- chills
- abdominal pain
- wt loss
- dysuria
- hematuria
- malaise

- usually figure out that it is an abscess after sxs persist after t of abx
- abscess needs an IND


Dx renal abscess?

- UA: WBCs, bacteria, hematuria, proteinuria?
- CBC: leukocytosis
- KUB: small abscesses may be difficult to recognize - enlarged kidney, non-distinct outlines
- CXR: pleural effusion
- US: more helpful than XR
- CT: dx procedure of choice - 96% accurate in dx renal abscess, don't use dye at first (worried about kidney function)

imaging: start off with U/S


Tx of renal abscess?

- IV abx covering causative organism (ampicillin + amino glycoside) - use urine cultures
- open drainage - old school
- now: percutaneous drainage more common, abscesses greater than 5 cm need to be IND
- end stage: nothing else works, nephrectomy


What is acute pyelonephritis?

- affects the cortex with sparing of glomeruli and vessels. WHITE CELL CASTS in urine are pathognomic.
- bacteria infection can result from hematogenous spread or from ascending infection (usually due to predisposing condition) - usually E.coli, also proteus, klebsiella, and enterobacter


Prognosis of acute pyelonephritis?

- healthy adults usually recover complete renal fxn
- if coexistent renal disease is present, scarring or chronic pyelonephritis may result
- inadequate therapy could result in abscess formation


What is emphysematous pyelo?

- life threatening necrotizing infection of the kidneys characterized by gas formation within or surrounding kidneys
- the majority of pts have poorly controlled DM
- non DM pts are usually immunocompromised or have asscd urinary tract obstruction due to lithiasis
- pts with VUR, indwelling cath, stones, neurogenic bladder at risk
- w/o early therapeutic intervention this condition becomes rapidly progressive, generalized to fulminant sepsis and carries a high mortality rate


Sxs of acute pyelonephritis?

- shaking chills
- high fever
- arthralgias
- myalgias
- flank pain with CVA tenderness: colicky pain, urgency, frequency, N/V/D in peds


Dx of acute pyelonephritis?

- UA: WBC, bacteria, hematuria, WHITE CELL CASTS
- CBC: leukocytosis with left shift
- blood culture may also be positive
- U/S: may show hydronephrosis from a stone or other source of obstruction
- CT scan: dx procedure of choice - may show hydronephrosis and attentuation caused by inflammation/infection
(DON'T use dye)


Tx of acute pyelo? What other tests are needed?

- severe or complicating factors may require hospital admission
- blood and or urine cultures reqd to determine antimicrobial sensitivity
- cath may be neccssary in the case of urinary retention
- nephrostomy drainage may be reqd if there is ureteral obstruction
- common abx: IV: ampicillin(24 hrs after fever subsides), and then put on PO: cipro, ofloxacin, bactrim DS (weak) (abx are given for 21 days, f/u tx includes re-culturing urine several weeks after drug therapy is finished to rule out re-infection)
- pts that are at high risk for recurring infections (caths) require long term f/u
- fevers can persist up to 72 hrs (if its lasts longer - dx or tx isn't right)


Cause of chronic pyelonephritis?

- caused by renal injury by recurrent or persistent renal infection
- occurs almost exclusively in pts with major anatomical anomalies:
urinary tract obstruction
struvite calculi
renal dysplasia
VUR: most common (30-40% of young children with UTIs have VUR)
- assoc with progressive renal scarring which can lead to ESRD
- may occur in utero with renal dysplasia, although dysplasia may also be caused by obstruction
- UTIs also induce renal injury, which heals with scar formation, infection w/o reflux is less likely to produce injury


What is VUR?

- retrograde flow of urine from bladder to upper urinary tract
- normally ureter has antireflux action by: 1 - actively by trigonal muscle contraction and 2 - passively by flap valve mechanism
- One of the most common problems encountered by pediatric urologist


Incidence of VUR?

- overall: 10%
- 70% of infants presenting with a UTI has VUR
- female more like than males
- usually male has higher grade VUR than females
- genetic predisposition is positive in up to 40%


Etiology of primary VUR?

- congenital deficiency in the longitudinal muscle fibers in ureterovesical junction
- altering the normal ratio of length: width from 5:1 down to 1.4:1


Etiology of secondary VUR?

- bladder outlet obstruction at the posterior urethral valve or stenosis
- fxnl obstruction: neurogenic and non neurogenic bladder dysfxn (cerebral palsy)
- raised pressure due to obstruction (anatomical stricture, too tight)


How does a VUR UTI present in a newborn? older children? prenatally?

- newborn: usually nonspecific manifestation such as failure to thrive, difficult feeding, or lethargy
- older children: flank pain or abdominal pain, fever
- prenatally: dx by US with abdominal sweeling (late finding) - see hydronephrosis


Work up for VUR?

- UA: (for sig colony count)
greater than 100,000 count in mid-stream sample, or gerater than 10,000 in cathed or aspirated urine sample
- std VCUG (used for grading VUR 1-V) and US reqd in:
1 - child younger than 5 with UTI
2 - any male child with UTI
3 - febrile UTI


Prognosis of VUR?

- resolves spontaneously before adolescence in:
90% of Gr 1 reflux
80% of Gr 2
50% of Gr 3
10% of Gr 4
0% in Gr 5
- kidney most suscpetible to scarring in first year of life and at time of first upper tract infection
- scars develop less frequently after the age of 5
- VUR and scarring lead to HTN, progressive renal insufficiency and failure


Characteristics of chronic pyelonephritis?

- coarse, asymmetric, corticomedulalry scarring
- thyroidization of kidney
- eosinophilic casts seen in tubules:
chronic pye and
T - thyroidization (ext inflamm.)
E - eosinophilic casts
A - assymetric scarring


Sxs of chronic pyelonephritis?

- fever
- lethargy
- N/V
- flank pain or dysuria: some children present with failure to thrive


Dx of chronic pyelonephritis?

- UA: WBCs, bacteria, hematuria. Urine culture will usually isolate bacteria, although a neg culture doesn't exclude diagnosis as pt has most likely been on abx
- imaging: IVP helps est dx b/c they reveal caliceal dilation and blunting with cortical scars. Ureteral dilation and reduced renal size may be evident
CT also used
VCUG: may document reflux of urine to the renal pelvis and ureteral dilation
- cystoscopy images show evidence of reflux at the ureteral orifices
- renal sonogram may show calculi


Tx of stages 1 and 2 VUR for chronic pyelonephritis?

- this is reflux of urine to the ureter or renal pelvis without ureteral dilatation
- medical therapy with ABOs (amoxicllan, bactrim, septa, and nitrofurantoin)
- continue ABOs until puberty (most children will outgrow reflux by puberty) or until reflux resolves

- stage 1 and 2: get better on their own


Tx for stage 3 and 4 VUR (severe reflux)?

- surgery and medical therapies are equally effective

indications for surgery include:
- medical noncompliance with formation of new scars
- persistent reflux after puberty in women
- breakthrough infections in pts who are compliant

- surgery involves the reimplantation of the ureters


Other tx for chronic pyelonephritis?

- eliminate recurrent UTIs and ID and correct any underlying anatomic or functional urinary problems (ex: obstruction, urolithiasis)
- dietary protein restriction should be advised to prevent progressive renal injury
- aggressive BP control is beneficial to slow the progression of renal failure. ACEIs/ARBs are particularly beneficial
- careful f/u and monitoring for pregnant women with prompt tx for UTIs to prevent renal failure, preeclampsia, miscarriages
- routine screening is recommended for siblings of pts with VUR


What is XPN? (xanthogranulomatous pyenonephritis)

- unusual variant of chronic pyelonephritis that in 2/3 of cases is a complication of obstruction induced by infected renal stones.
- affected pts usually have massive destruction of kidney requiring nephrectomy
- shares many characteristics with a true neoplasm, in terms of radiographic appearance and ability to involve adjacent structures or organs
- pts are often immunocompromised in some manner
- although most cases of XPN are unilateral, bilateral disease has been reported


How common is XPN?

- occurs in approx 1% fo all renal infections, frequency of XPN appears to be increasing (increased risk in diabetics)
- XPN is 4x more common in women than men, and is usually noted in 50s, and 60s
- usually a hx of recurrent UTIs


Characteristics of XPN?

- displays neoplasm like properties capable of local tissue invasion and destruction, and has been referred to as a pseudotumor


Presentation of XPN in adults?

- most often occurs in middle aged women, with male to female ratio - 1:3 -4
- typical presenting features:
flank pain, fever, malaise, anorexia, wt loss, a palpable flank mass may be present, which may be tender or demonstrate CVA tenderness
(presents like pyelo)


Presentation of XPN in children?

- 2 different presentations
- most common form affects boys and girls equally and involves the entire kidney
- the other form which is more frequent in girls, is localized and may mimic a tumor (be thinking Wilm's tumor)
- presenting features:
flank and abdominal pain
growth and wt retardation
growth and wt retardation
- approx 1/2 of children have a palpable abdominal mass