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Nephrology And Genito Urinary Notes

Medicine Notes > Paediatrics Notes

This is an extract of our Nephrology And Genito Urinary document, which we sell as part of our Paediatrics Notes collection written by the top tier of University Of Nottingham students.

The following is a more accessble plain text extract of the PDF sample above, taken from our Paediatrics Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Nephrology and GenitoUrinary

Assessment of Renal Function in Children

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Plasma Creatinine Concentration

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Rises progressively throughout childhood according to height and muscle bulk

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May not be outside normal until renal function has fallen by half

eGFR

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= k x height (cm) / creatinine (umol/L)

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Useful for monitoring renal function

Inulin or EDTA Glomerular Filtration Rate

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More accurate as clearance from the plasma of substances freely filtered at the glomerulus, and is not secreetd or reabsorbed by the tubules.

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Creatinine Clearance

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Requires timed urine collection and blood tests - rarely used

Plasma Urea Concentration

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Increased in renal failure often early indicator

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Urea increased by high protein diet and in a catabolic state

Radiological Investigation of the Kidneys and Urinary Tract

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Ultrasound

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Anatomy NOT function

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Visualise dilation, stones and nephrocalcinosis

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Non invasive and mobile

DMSA scan (99mTc dimercaptosuccinic acid)

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Static scan of renal cortex

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Detects functional defetcs such as scars

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V. sensitive wait at least 2 months post UTI to avoid diagnosing false scars

Micturating Cystourethrogram (MCUG)

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Anatomy and vesicoureteric reflux (VUR) and urtheral obstruction

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Invasive and unpleasant, high radiation

MAG3 Renogram (Mercaptoacetyltriglycine, labelled with 99mTc)

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Dynamic scan

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Label excreted from blood into urine

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Measures drinage

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Scan during micturition can identify VUR

Plain Abdominal XR

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Spinal abnormalities

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Renal stones may be identifiable

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Poor at showing nephrocalcinosis

Congenital Abnormalities Diagnosis on Antenatal USS

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Renal Agenesis

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Severe oligohydramnios (no urine production) resulting in Potter Syndrome fatality

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Potter Facies:Lowset earsBeaked noseProminent epicanthic foldsDownward slanting eyes

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Pulmonary hypoplasia respiratory failure

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Limb deformities talipes

Multicystic Dysplastic Kidney (MCDK)

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Failure of union of the ureteric bud with the nephrogenic mesenchyme

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Non functioning structure with large fluid filled cysts no renal tissue and no connection with the bladder

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Half involute by 2 years but nephrectomy may be indicated

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Potter syndrome if bilateral

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Other causes of cystic kidneysRecessive polycystic kidney disease (ARPKD)Autosomal dominant polycystic kidney disease (ADPKD)

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1 in 1000

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Hypertension and haematuria in childhood

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Usually manifests in adult life

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Multiorgan involvement:

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Intracranial aneurysm

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Liver and pancreatic cysts

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Mitral valve prolapse

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Tuberous sclerosis

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Autosomal dominant

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Hamartomas in the brain, skin and other organs

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Infantile spasm, seizure and metal retardation

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Hypomelanotic macules (ash leaf spots)

Postnatal Mangement of Anomalies Antenatal diagnosis of urinary tract anomaly Start prophylactic antibiotics

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Bilateral hydronephrosis and /or dilated urinary

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tract in a male

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Unilateral hydronephrosis in a male / Any anomaly in a female

USS within 48 hours (rule out posterior urerthal valves)

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Abnormal MCUG/ surgery

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Normal stop antibiotics and repeat USS at 3/12

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USS at 46 weeks*

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Normal stop antibiotics and repeat USS at 3/12

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Abnormal further investigation

*Newborn kidney has low GFR, urine flow and mild outflow obstruction - therefore delay USS EXCEPT in bilateral hydronephrosis rule out posterior urethral valves

Urinary Tract Infection

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Up to half of patients have a structural abnormality

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Pyelonephritis may damage the growing kidney by forming a scar, predisposing to hypertension and (if bilateral) chronic renal failure

Clinical Features

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Varies accoring to age

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Infants non specific

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Fever

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Vomiting

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Lethargy / irritability

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Poor feeding / FTT

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Jaundice

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Septicaemia

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Febrile convulsions

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Offensive urine

Children

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Dysuria and frequency

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Abdo pain or loin tenderness

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Fever with rigors

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Lethargy / anorexia

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Vomiting / diarrhoea

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Haematuria

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Febrile convulsion

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Offensive / cloudy urine

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Recurrence of enuresis

Collection of Samples and Investigation
**Urine sample should be tested in ALL children with unexplained fever >38oC**

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For a child still in nappies

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Cleancatch

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Adhesive plastic bag

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Urethral catheter

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Suprapubic aspiration (SPA)

Older children

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MSU*

Urine sample should be microscoped and cultured IMMEDIATELY

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Can be refrigerated to prevent overgrowth of contaminating organisms

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Culture of 105 per mm 90% chance of infectiono

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Contamination may occur with white cells and bacteria from the foreskin

Rises to 95% if two samples are +'ve

ANY growth in a catheter or SPA is considered +'ve

Dipstick testing

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Nitrite stick+'ve likely to inficate true UTI

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Leucocyte esterase stick test for WBCsNOT a reliable marker of UTIPresent in balanitis and vulvovaginitis

Interpretation of Results

Leucocyte esterase +'ve and

Regard as UTI

Nitrite +'ve Leucocyte esterase -'ve

Start antibiotics

Nitrite +'ve

Diagnosis depends on culture

Leucocyte esterase +'ve

Only start antibiotic treatment if clinical evidence of UTI

Nitrite -'ve

Diagnosis depends on culture

Leucocyte esterase -'ve

UTI unlikely

Nirtite -'ve

Repeat urine or send for culture if history suggests UTI

Blood, glucose and protein present

Useful to identify any other disease - nephritis, DM Will NOT discriminate between UTI or not

Further Investigation

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NICE guidance does NOT recommend USS for first UTI if there is a response to antibiotic treatment

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Unless <6 months OR atypical / recurrent UTI

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Atypical includes

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Seriously ill / septicaemia

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Poor urine flow

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Abdominal or bladder mass

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Raised creatinine

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Failure to respond to suitable antibiotics within 48 hours

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Non Ecoli organism

Imaging SEE case study pg333 of Illustrated for pics

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USS

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DSMA check for scarring 46 months later

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MCUG obstruction or reflux

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<6 monthsFirst time UTI that RESPONDS to treatment

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USS within 6 weeks of UTI

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Consider MCUG if abnormal

Atypical or recurrent

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USS during acute infection

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MCUG (give prophylactic antibiotics)

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DSMA 46 months post infection detects renal parenchymal defects

Aged 6 months and olderFirst time UTI which responds

*?USS is not recommended

If atypical

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USS during acute infection

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DSMA 46 months post infection

Recurrent UTIs

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USS within 6 weeks

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DSMA 46 months post infection

(Consider MCUG if:

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Dilation on USS

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Poor urine flow

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Family history of VUR*)

Over 3 years?

If atypical

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USS during acute infection

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NO further investigation

Recurrent UTI

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USS within 6 weeks

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DSMA 46 months post infection

Predisposing Factors Infecting Organism

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Result of bowel flora entering the urinary tract via the urethra

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In newborn likely to be haematogenous

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Commonest cause is E.Coli

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Others include

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Klebsiella

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Proteus (B>G, predisposes to the formation of phosphate stones by splitting urea into ammonia and therefore alkalising urine)

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Pseudomonas

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Strep. Faecalis

Incomplete Bladder Empyting

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Contributing factors

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Infrequent voiding

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Vulvitis

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Incomplete micturition with residual volumes

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Obstruction due to loaded rectum

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Neuropathic bladder

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Vesicoureteric reflux

Vesicoureteric Reflux

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1% of newborns

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3045% of those <5 years presenting with a UTI

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Ureters are displaced laterally and enter directly into the bladder, rather than at an angle

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Shortened or absent intramural course

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Strong family history

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Mild reflux into ureter only

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Severe reflux dilation of ureter, renal pelvis and calyceso

Associated with intrarenal reflux and renal scarring with UTI

Consequences of refluxUrine returning to the bladder after voiding incomplete bladder emptying encourages infectionPyelonephritisBladder voiding pressure is transmitted to the renal papillae; may result in damage if voiding pressures are high

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DiagnosisMCUG in infants <2 years oldIndirect cystogram

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Radionucleotide such a MAG3 scan

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First choice in chldren >2 years

TreatmentProphylactic antibiotics for 2 yearsMAG3 and DMSA are recommended for follow upRx - surgerySpontenrous regression in milder cases

Treatment

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<3 months old with suspicion of UTI / seriously ill

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IV antibiotics (cefotaxime)

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Substiture with oral when temperature subsides

Infants >3 months and children with acute pyelonephritis / upper urinary tract infection

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Bacteriuria and fever or bacteriuria and loin pain (even if not fever)

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Oral antibiotics with low resistance (co amoxiclav)

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OR IV cefotaxime followed by oral

Children with cystitis / lower urinary tract infection

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Oral antibiotics

Prevention

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High fluid intake / urine output

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Regular voiding

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