A quick reference for our Doctors
Antenatal Hydronephrosis
Hydronephrosis is one of the commonest abnormalities detected on antenatal ultrasound with a prevalence of 1-2 per 1000 live births
The diagnosis of antenatal hydronephrosis is based on the degree of dilatation of the AP diameter of the renal pelvis. The limits of normalcy vary with the gestational age.
Posterior urethral valves, pelviureteric obstruction and vesicoureteral reflux are the three important underlying causes. Rarer causes include Ureterovesical junction obstruction, megaureter, ureterocele, ectopic ureter and urethral atresia. The majority of cases are transient, non obstructing, non refluxing hydronephrosis that resolve spontaneously over the first year of life.
Poor kidney function may be reflected as oligohydramnios, hyperechoic kidneys and renal cysts
Postnatal USG should be done to confirm the diagnosis after day 3 of life.
If APD <10mm and the baby shows no ureteral or bladder abnormalities and is voiding well the USG may be repeated at periodic intervals. Child can be monitored by USG alone, for resolution or progression of findings. (3 months, 6 months, then 6-12 monthly until resolution)
Infants with AP diameter > 10mm need to be initiated on uroprophylaxis. They should undergo MCU .This can be done afte 6 weeks of age.
Infants with AP diameter > 10 mmm who have no VUR on MCU should undergo a DTPA or EC scan with diuretic renogram to look for PUJ obstruction
In male children with bilateral hydronephrosis it is imperative to rule out posterior urethral valves.
Clinical examination for a palpable firm bladder and the voiding pattern needs to be assessed. USG should be done early to confirm antenatal findings and an MCU should be done to look for posterior urethral valves
In a girl child, the USG may be done after 3 days and MCU can be deferred and done after one month of age
All infants with pelvis AP diameter > 10mm should be started on uroprophylaxis.
Antenatal diagnosis of Hydronephrosis based on AP diameter of Renal Pelvis
Second trimester | Third trimester | |
Mild | 4 mm | 7mm |
Moderate | 7 mm | 10mm |
Severe | 10 mm | 15 mm |
Postnatal investigations for unilateral hydronephrosis or bilateral hydronephrosis in girls:
- USG on D3 to 4 after birth
- If AP diameter > 10 mm start uroprophylaxis and do MCU after 6 weeks
- If MCU shows no VUR , DTPA or EC scan at 2 months
Postnatal investigations for bilateral hydronephrosis in a boy
- USG within 24 hours
- MCU to check for PUV after the USG
- If PUV , urine routine, RFT, catheterization and refer to pediatric surgeon
Indications for uroprophylaxis
- Post natal USG showing AP dimeter of renal pelvis > 10 mm
- Children with proved VUR
Drugs for uroprophylaxis in neonates
- Amoxycillin 10 mg /kg as a single dose at night OR
- Cephelexin 10 mg/kg as a single dose at night
When should you refer to a Pediatric Nephrologist?
1.All PUV who have abnormal RFT prior to valve fulguration
2 All PUV postoperatively
3.VUR s grade 3,4 and 5
Urinary Tract Infections (UTI)
UTI in children may be a red flag that indicates the presence of an underlying urological problem or functional bowel bladder dysfunction. Repeated attacks of UTI can cause renal damage with resultant scarring of the kidneys. Severe scarring could lead to the development of hypertension and sometimes to renal failure in later childhood or in early adult life.
The diagnosis of UTI requires three criteria to be fulfilled – Symptoms compatible with UTI, pyuria in routine urinalysis and a urine culture growing a single organism in significant numbers .Though a urine routine showing pyuria in a febrile child provides a provisional diagnosis , a urine culture prior to initiating antibiotics is necessary for confirming the diagnosis.
Moderate to high fever without a focus, f ever with vomiting, abdominal or back pain or frequency and burning micturition are some of the common symptoms of UTI
The presence of more than 5 leucocytes/hpf in a centrifuged sample of urine is indicative of significant pyuria. In severe cases urine maybe hazy and have WBC casts
The growth of a single species of bacteria in urine culture equal to or greater than 1,00,000 colony forming units /ml on a midstream sample of urine is considered as confirmatory evidence
The choice and route of administration of antibiotics depends on the age of the child and the presence of systemic symptoms. Children less than 3 months of age with UTI or those who are very sick need hospitalization and intravenous antibiotics. Children above 3 months of age who are not very sick can be treated with oral antibiotics on outpatient basis. The parenteral antibiotics used are either third generation cephalosporins or aminoglycosides. Monotherapy is recommended except in the new-born period. The oral antibiotics used are cefixime, co-amoxiclav, ciprofloxacin or cephalexin depending on the regional resistance patterns of bacteria.
Antibiotics are given for 7 to 10 days
USG should be done in all patients with UTI as soon as possible after the diagnosis of UTI.
MCU should be done after the completion of treatment of UTI in the following cases- in all children less than 1 year of age with UTI, in older children with recurrent UTI and in children who have abnormalities detected on USG.
DMSA is a radionuclide scan which can detect cortical scarring. It identifies those children who are at risk for future problems. It should be done 3 to 4 months after the treatment of the acute attack
Children less than 1 year who are awaiting further investigations, children with recurrent febrile UTI and those with diagnosed vesicoureteral reflux require urinary prophylaxis.
Cotrimoxazole or nitrofurantoin are the preferred drugs in children above 3 months of age. Cephalexin or amoxycillin can be used for prophylaxis in neonates and infants less than 3 months of age
Diagnosis of UTI
For a firm diagnosis of UTI, 3 criteria need to be met
1 Symptoms suggestive of UTI
2 Pyuria. Urine showing > 5 WBCs per hpf in a centrifuged sample of urine
3 Urine culture midstream sample showing 105 Colonies per ml of a single organism
Imaging in UTI
USG in all confirmed UTI
MCU in febrile UTI < 1 year of age, in recurrent UTI and in children with abnormal USG
DMSA
In all children with UTI four months after the attack to look for scarring
When should you refer to a Pediatric Nephrologist?
1.All PUV who have abnormal RFT prior to valve fulguration
2 All PUV postoperatively
3.VUR s grade 3,4 and 5
Nephrotic Syndrome
Nephrotic syndrome is one of the commonest kidney diseases that we see in children and is usually a spot diagnosis. It is characterized by generalized anasarca, massive proteinuria, hypoalbuminemia and hypercholesterolemia.
Most children with nephrotic syndrome present between two to seven years of age. They usually do not have hematuria or hypertension. Although biopsy is usually not needed, the histopathology on light microscopy is practically normal. Hence it is called a minimal change disease
Atypical features include age of onset below one year or above seven years , presence of hematuria, hypertension, raised serum creatinine, low serum C3 or extra renal involvement. When atypical features are present one may suspect a non-minimal change lesion or a secondary cause such as systemic lupus erythematosus or Henoch Schoenlein purpura.
1, Tests to establish the diagnosis include urine routine, serum albumin and serum cholesterol. 2 Tests for Renal function such as BUN and serum creatinine 3 Tests for infections include CBC, Mantoux test and X-ray chest. These should be done in all cases before starting steroid therapy.
The initial episode of nephrotic syndrome should be treated with steroids for 12 weeks. Prednisolone at a dose of 2 mg/kg per day in divided doses or as a single dose (maximum 60 mg daily) for 6 weeks, followed by 1.5 mg/kg (maximum 40 mg) as a single morning dose on alternate days for the next 6 weeks; therapy is then discontinued.
Diagnosis of Nephrotic Syndrome
Massive edema; Urine Albumin +++; Serum albumin < 2.5 g/dl; Serum cholesterol > 200 mg/dl
TREATMENT OF FIRST ATTACK
Prednisolone 2 mg/g/day daily as a single dose or in divided doses followed by 1.5 mg/kg on alternate days as a single morning dose
REMISSION
Urine albumin negative or trace in morning sample on 3 consecutive days with absence of edema
STEROID RESISTANT (SRNS)
Urine albumin positive despite 4 weeks of daily steroids at 2mg/kg/day
Which patients should be referred to a Pediatric Nephrologist?
- Age of onset < 1 year
- Hematuria, Hypertension, raised creatinine or extra renal involvement
- Refractory edema
- Positive family history
- Steroid resistant nephrotic syndrome
Relapsing Nephrotic Syndrome
Childhood nephrotic syndrome is a disease with relapses and remissions. Only a small number of children, not more than 20%, have a single attack and never relapse again. Most children will have relapses for several years following the diagnosis of nephrotic syndrome. Over half the children will have frequent relapses
Relapse is diagnosed when urine albumin is 3+ or 4+ for three consecutive early morning specimens, having been in remission previously.
The trigger for relapses is not known. Some relapses are triggered by infections, usually a viral upper respiratory tract infection (URTI). Infections should be treated before starting steroids. Resolution of infection might result in spontaneous remission in some cases, thereby avoiding the need for treatment with corticosteroids. Persistence of proteinuria after resolution of infections requires steroid therapy.
There is no rationale for the routine use of antibiotics in patients with nephrotic syndrome for prevention of relapse. Most URTIs are viral and do not need antibiotics. Antibiotics are only indicated for complications of URTI such as acute suppurative otitis media, streptococcal pharyngitis and sinusitis
A child who relapses not more than three times in a year is said to have an infrequent relapsing nephrotic syndrome. (IFRNS)
Prednisolone is administered at a dose of 2 mg/kg/day (single or divided doses) until urine protein is trace or nil for three consecutive days. Subsequently, prednisolone is given as a single morning dose of 1.5 mg/kg on alternate days for 4 weeks, and then discontinued
Children who have 4 or more relapses in a year are considered to have frequently relapsing nephrotic syndrome. (FRNS)
The initial treatment for a relapse would be to give oral prednisolone at 2mk/kg/day until remission is achieved followed by alternate day prednisolone at 1.5 mg/kg with gradual tapering of Prednisolone to maintain the patient in remission on alternate day dose of 0.5 mg/kg. This low dose can be given for for 9-18 months with close monitoring for steroid toxicity
Children with SDNS are those frequent relapsers who relapse while on tapering doses of steroids or within 2-weeks of steroid omission on two consecutive occasions
Second line treatment is started for 1. All SDNS. 2. For frequent relapsers who need prednisolone doses higher than 0.5 mg/kg on alternate days to maintain remission. 3. In those who have features of corticosteroid toxicity.
Levamisole is the most common second line drug used. It is administered at a dose of 2-2.5 mg/kg on alternate days for 12-24 months. Prednisolone is continued at a dose of 0.5 mg/kg/AD and then gradually tapered over a period of several months under cover of Levamisole.
The drugs available are Cyclophosphamide, Calcineurin inhibitors such as Cyclosporin or Tacrolimus; and Mycophenolate Mofetil. Rituximab is a third line drug used in severe cases who are steroid dependent despite the above therapies.
These drugs should be used only on the advice and close supervision of a pediatric nephrologist.
Children with frequently relapsing NS or SDNS do not routinely need a renal biopsy. Kidney biopsy is needed in these children prior to starting cyclosporine or tacrolimus.
Urine albumin 3+ or 4+ (or proteinuria >40 mg/m2/h) for 3 consecutive early morning specimens, having been in remission previously
Infrequent relapses
Three or less relapses a year
Frequent relapses
Two or more relapses in initial six months or four or more relapses in any twelve months
Steroid dependence
Two consecutive relapses when on alternate day steroids or within 14 days of its discontinuation.
Steroid resistance
Absence of remission despite therapy with daily prednisolone at a dose of 2 mg/kg per day for 4 weeks.
All children with SDNS
Children with steroid toxicity
Children who continue to relapse despite Levamisole for 6 months
All children who need additional immunosuppressive medication such as cyclophosphamide, mycophenolate, cyclosporine, tacrolimus or Rituximab
Chronic Kidney Disease
Any abnormality of kidney structure as detected by imaging studies or of kidney function as detected by blood or urine tests that persists for more than three months is called CKD. Not all children with CKD have elevated creatinine and not all will progress to renal failure. However, all of them have the potential for progression to renal failure.
Congenital Anomalies of the Kidney and Urinary Tract (CAKUT), account for more than half the cases of CKD.The three commonest anomalies are posterior urethral valves, vesico-ureteric reflux and hypodsyplastic kidneys. Glomerular disease, neurogenic bladder and hereditary renal diseases are some of the other important causes.
There are 5 stages of CKD. The classification is based on estimated GFR values. GFR is easily calculated at the bedside if we know the height in centimetres and the serum creatinine in mg /dl. The formula used is eGFR = K x Height/ serum creatinine. The value of the constant K is 0.413.
Stage I has GFR >90 ml/min, stage II has GFR 60-90 ml/min, stage III has GFR of 30-60 ml/min, stage IV has GFR of 15 to 30ml/min and stage 5 also known as end stage renal disease (ESRD) is when GFR is less than 15 ml/min
The following derangements can be present in a child with CKD especially when the child is in CKD 3 or more. Anemia, mineral and bone disease, cardiovascular disease, fluid, electrolyte, acid base disturbances, short stature or failure to thrive may be seen.
The main pillars of treatment are early and adequate treatment of the primary renal disease; evaluation and control of associated comorbidities, metabolic and hormonal derangements. Control of hypertension and proteinuria, dietary modification, complete immunization, avoidance of blood transfusions and monitoring eGFR and proteinuria for evidence of progression.
All children with CKD may not progress to ESRD. The progression to ESRD varies widely depending on the nature of the underlying disease, appropriateness of therapy received, control of comorbidities and the degree of proteinuria. Progression is faster in glomerular diseases compared to children with CAKUT and within any category it progresses faster with worsening proteinuria.
Once the child reaches ESRD with a GFR less than 15 ml/min renal replacement therapy should be started. Technical and psychosocial preparation should start much earlier.
The preferred option for treatment of ESRD is kidney transplantation either from a live or deceased donor. When transplantation is not immediately feasible maintenance dialysis should be instituted and continued until transplantation becomes feasible
Chronic Kidney Disease CKD
Persistent structural or functional renal abnormalities lasting for 3 months or more.
ESRD
Advanced CKD needing dialysis or transplantation with GFR < 15 ml/min
Calculation of eGFR
0.413 x height (cm) / creatinine (mg/dl)