Paediatric Nephrology Flashcards
what physiological process causes nephrotic syndrome?
Nephrotic syndrome occurs when the basement membrane in the glomerulus becomes highly permeable to protein, allowing it to leak from the blood into the urine.
what is the most common age group affected by nephrotic syndrome?
2-5 years old
what is the clinical presentation of nephrotic syndrome?
signs, investigation results
signs:
- frothy urine
- generalised oedema
- pallor
Nephrotic syndrome features a classic triad of:
- low serum albumin
- high urine protein content (> 3+ protein on urine dipstick)
- oedema
Other features:
- deranged lipid profile, with high levels of cholesterol, triglycerides and LDL
- high blood pressure
- hyper-coagulability
Causes of nephrotic syndrome
- Minimal change disease most common in children
- can also be secondary to intrinsic kidney disease e.g. focal segmental glomerulosclerosis, membranoproliferative glomerulonephritis
- can also be secondary to underlying systemic illness e.g. Henoch scholein purpura (HSP), diabetes, infection, such as HIV, hepatitis and malaria
Describe minimal change disease.
Minimal change disease is the most common cause of nephrotic syndrome in children. It can occur in otherwise healthy children, without any clear risk factors or reason for developing the condition. It is not clear why it occurs in most cases.
A renal biopsy and standard microscopy in minimal change disease is usually not able to detect any abnormality. Urinalysis (analysis of the urine) will show small molecular weight proteins and hyaline casts.
minimal change disease management
- corticosteroids (i.e. prednisolone0
- most children make full recovery
Nephrotic syndrome management
- high dose steroids (i.e. prednisolone)
- low salt diet
- diuretics may be used to treat oedema
- albumin infusions in severe hypoalbuminaemia
- antibiotic prophylaxis in severe cases
- in steroid resistant children > ACEi’s, immunosuppresants such as cyclosporine, tacrolimus, or rituximab
what does nephritis refer to? what does it cause?
inflammation within the nephrons
It causes:
- reduction in kidney function
- haematuria
- proteinuria, although less than nephrotic syndrome
what are the two most common causes of nephritis in children?
- post-streptococcal glomerulonephritis
- IgA nephropathy (Berger’s disease)
what causes post-streptococcal glomerulonephritis?
- Post-streptococcal glomerulonephritis occurs 1 – 3 weeks after a β-haemolytic streptococcus infection, such as tonsillitis caused by Streptococcus pyogenes. - Immune complexes made up of streptococcal antigens, antibodies and complement proteins get stuck in the glomeruli of the kidney and cause inflammation.
- This inflammation leads to an acute deterioration in renal function, causing an acute kidney injury.
what causes IgA nephropathy (Berger’s disease)?
- This condition is related to Henoch-Schonlein Purpura, which is an IgA vasculitis.
- IgA deposits in the nephrons of the kidney causes inflammation (nephritis). When a renal biopsy is taken the histology will show “IgA deposits and glomerular mesangial proliferation”.
- It usually presents in teenagers or young adults.
- occurs 1-2 days after URTI
treatment for IgA nephropathy
- supportive treatment of the renal failure
- immunosuppressant medications such as steroid and cyclophosphamide to slow the progression of the disease.
signs and symptoms of babies with UTI
Babies will present with very non-specific symptoms:
- fever
- lethargy
- irritability
- vomiting
- poor feeding
- urinary frequency
Always consider (and exclude) a urinary tract infection in a child with a temperature, unless there is a clear alternative source of infection.
signs of symptoms of UTI in older infants and children (more specific)
- fever
- abdo pain, particularly suprapubic
- vomiting
- dysuria
- urinary frequency
- incontinence
Management of UTI in children < 3 months and > 3 months old.
- all children under 3 months with a fever should start immediate IV antibiotics (e.g. ceftriaxone) and have a full septic screen, including blood cultures, blood and lactate. Consider lumbar puncture.
- Oral antibiotics can be considered in children over 3 months if they are otherwise well.
- Children with features of sepsis or pyelonephritis will require inpatient treatment with IV antibiotics.
Typical Abx choices for UTI in children:
- trimethoprim
- nitrofurantoin
- cefalexin
- amoxicillin
when would you consdier a renal biopsy in a patient with nephrotic syndrome?
atypical features present:
- suggestions of autoimmune disease
- abnormal renal function
- steroid resistance
what cells are affected in minimal change disease?
podocytes (epithelial cells)
what are some acquired and congenital causes for steroid-resistant nephrotic syndrome?
Acquired:
- focal segmental glomerulosclerosis (FSGS): podocyte loss, progressive inflammation and slcerosis
Congenital:
- infant presentations
- NPHS1 - nephrin
- NPHS2 - podocin
- podocyte loss
what investigations can be used to diagnose acute post-infectious glomerulonephritis?
- bacterial culture
- positive antistreptolysin O titer (ASOT)
- low C3 normalises
Acute post-infectious glomerulonephritis treatment
- antibiotic
- support renal function: electrolyte/acid base
- overload/hypertension: diuretics
what cells of the glomerulus are affected in IgA nephropathy?
mesangial cells
what is the usual age of onset of Henoch Schonlein Purpura (HSP), an IgA related vasculitis?
5-15 years old
what criteria must be met for a diagnosis of Henoch Schonlein Purpura?
- mandatory palpable purpura
one of 4:
- abdominal pain
- renal involvement
- arthritis or arthralgia
- biopsy > IgA deposition
IgA vasculitis treatment
- symptomatic: gut, joints
- glucocorticoid therapy: may help with GI involvement
- immunosuppression: trial in moderate-severe renal disease
- long-term: hypertension and proteinuria screening
what criteria indicate acute kidney injury (AKI)?
- anuria/oliguria (< 0.5ml/kg/hr for > 8 hours)
- hypertension
- rapid rise in plasma creatinine: > 1.5x age specific reference creatinine (or previous baseline if known)
AKI management
- prevention
- 3 Ms:
Monitor: Paediatric early warning scores (BP), urine output, weight
Maintain: good hydration, electrolytes, acid-base
Minimise: Drugs - Identify underlying cause i.e. pre-renal, renal and post-renal
what are some renal causes of AKI?
- glomerular disease: haemolytic uraemic syndrome, glomerulonephritis
- tubular injury: acute tubular necrosis > consequence of hypoperfusion, drugs
- interstitial nephritis: NSAID, autoimmune
describe haemolytic uraemic syndrome, what causes it?
- Haemolytic uraemic syndrome (HUS) involves thrombosis in small blood vessels throughout the body, usually triggered by Shiga toxins from either E. coli O157 or Shigella.
- It most often affects children following an episode of gastroenteritis. Antibiotics and anti-motility medication (e.g., loperamide) used to treat gastroenteritis caused by E. coli O157 or Shigella increase the risk of HUS.
HUS leads to the classic triad of:
- microangiopathic haemolytic anaemia: Hb < 10g/dl and fragmented erythrocytes on blood film
- acute kidney injury
- thrombocytopenia (low platelets) < 150 x 10^9/l
HUS clinical presentation
E. coli O157 and Shigella cause gastroenteritis. Diarrhoea is the first symptom, which turns bloody within 3 days. Around a week after the onset of diarrhoea, the features of HUS develop:
- fever
- abdo pain
- lethargy
- pallor
- reduced urine output (oliguria)
- haematuria
- hypertension
- bruising
- jaundice (due to haemolysis)
- confusion
HUS management
- stool culture to establish causative organism
Hospital admission and supportive management with treatment of: - hypovolaemia (e.g. IV fluids)
- hypertension
- severe anaemia (e.g. blood transfusions)
- severe renal failure e.g. haemodialysis
what are some congenital anomalies of the kidney and urinary tract which cause 55% of paediatric CKD?
- reflux nephropathy
- dysplasia
- obstructive uropathy (e.g. posterior urethral valves)
what are some hereditary conditions which cause 17% of paediatric CKD?
- cystic kidney disease
- cystinosis
what are some syndromes that can cause congenital anomalies of the kidney and urinary tract (CAKUT)?
- Turner
- Trisomy 21
- Branchio-oto-renal
- Prune belly syndrome
How should recurrent UTIs be investigated for an underlying cause and renal damage?
- US scans
- DMSA scan, assesses scarring
- micturating cystourethrogram (MCUG), used to diagnose vesico-ureteric reflux
