Kidney and urinary tract disorders - UTI Flashcards
Kidney and urinary tract disorders
UTI
Presentation of UTI in infants and children:
Infants:
Fever
Vomiting
Lethargy or irritability
Poor feeding/failure to thrive
Jaundice
Septicaemia
Offensive urine
Febrile convulsion (>6 months).
Children
Dysuria and frequency
Abdominal pain or loin tenderness
Fever with or without rigors (exaggerated shivering)
Lethargy and anorexia
Vomiting, diarrhoea
Haematuria
Offensive/cloudy urine
Febrile convulsion
Recurrence of enuresis.
Kidney and urinary tract disorders
Bacterial and host factors that predispose to infection
- UTI is usually the result of bowel flora entering the urinary tract via the urethra, except in the newborn when it is more likely to be haematogenous
- The commonest organism is E. coli, followed by Klebsiella, Proteus and Pseudomonas and Strep. faecalis. Proteus infection is more commonly diagnosed in boys than in girls, possibly because of its presence under the prepuce
- Proteus infection predisposes to the formation of phosphate stones by splitting urea to ammonia and thus alkalinising the urine.
- Pseudomonas infection may indicate the presence of some structural abnormality in the urinary tract affecting drainage
Kidney and urinary tract disorders
Incomplete bladder emptying
Contributing factors in some children are:
- infrequent voiding, resulting in bladder enlargement
- Vulvitis
- Incomplete micturition with residual post-micturition bladder volumes
- Obstruction by a loaded rectum from constipation
- Neuropathic bladder
- Vesicoureteric reflux.
Kidney and urinary tract disorders
Vesicoureteric reflux
Reflux with associated ureteric dilatation is important, as:
- urine returning to the bladder from the ureters after voiding results in incomplete bladder emptying, which encourages infection
- the kidneys may become infected (pyelonephritis), particularly if there is intrarenal reflux
- bladder voiding pressure is transmitted to the renal papillae; this may contribute to renal damage if voiding pressures are high.
Kidney and urinary tract disorders
Investigation
Atypical UTI includes:
- Seriously ill or septicaemia
- Poor urine flow
- Abdominal or bladder mass
- Raised creatinine
- Failure to respond to suitable antibiotics within 48 h
- infection with non-E. coli organism.
An initial ultrasound will identify:
- Serious structural abnormalities and urinary obstruction
- Renal defects (but poor at identifying renal scars
Kidney and urinary tract disorders
Enuresis
Daytime enuresis:
Consider causes – developmental or psychogenic, bladder instability or neuropathy, urinary tract infection, constipation, ectopic ureter.
Secondary (onset) enuresis:
Consider – emotional upset, UTI, polyuria from an osmotic diuresis in diabetes mellitus or a renal concentrating disorder.
Kidney and urinary tract disorders
Proteinuria
Causes of proteinuria:
Orthostatic proteinuria
Glomerular abnormalities
Minimal change disease
Glomerulonephritis
Abnormal glomerular basement membrane (familial nephritides)
Increased glomerular filtration pressure
Reduced renal mass
Hypertension
Tubular proteinuria
- Persistent proteinuria is significant and should be quantified by measuring the urine protein/creatinine ratio in an early morning sample (protein should not exceed 20 mg/mmol of creatinine)
- A common cause is orthostatic (postural) proteinuria, where proteinuria is only found when the child is upright, i.e. during the day.
- It can be diagnosed by measuring the urine protein/creatinine ratio in a series of early morning urine specimens.
- The prognosis is excellent and further investigations are not necessary
Kidney and urinary tract disorders
Nephrotic syndrome
heavy proteinuria results in a low plasma albumin and oedema. The cause of the condition is unknown, but a few cases are secondary to systemic diseases such as Henoch–Schönlein purpura (HSP) and other vasculitides, e.g. systemic lupus erythematosus (SLE), infections (e.g. malaria) or allergens (e.g. bee sting).
Clinical signs of the nephrotic syndrome are:
Periorbital oedema (particularly on waking), the earliest sign
Scrotal or vulval, leg and ankle oedema
Ascites
Breathlessness due to pleural effusions and abdominal distension.
Kidney and urinary tract disorders
Nephrotic syndrome
Investigations
Urine protein – on test strips (‘dipstick’)
Full blood count and ESR
Urea, electrolytes, creatinine, albumin
Complement levels – C3, C4
Antistreptolysin O or anti-DNAse B titres and throat swab
Urine microscopy and culture
Urinary sodium concentration
Hepatitis B and C screen
Malaria screen if travel abroad.
Kidney and urinary tract disorders
Nephrotic syndrome
Management
Nephrotic syndrome:
- Clinical signs – oedema (periorbital, scrotal or vulval, leg and ankle oedema, ascites, pleural effusions)
- Diagnosis– heavy proteinuria and low plasma albumin.
Steroid-sensitive nephrotic syndrome:
- Characteristic features – 1 to 10 years old, no macroscopic haematuria, and blood pressure, complement levels and renal function are normal
- Management – oral corticosteroids, renal biopsy if unresponsive or atypical features
- Complications – hypovolaemia, thrombosis, infection (pneumococcal), hypercholesterolaemia
- Prognosis – may resolve or else there may be infrequent or frequent relapse.
Kidney and urinary tract disorders
Haematuria - Causes
Non-glomerular:
Infection (bacterial, viral, TB, schistosomiasis)
Trauma to genitalia, urinary tract or kidneys
Stones
Tumours
Sickle cell disease
Bleeding disorders
Renal vein thrombosis
Hypercalciuria.
Glomerular:
Acute glomerulonephritis (usually with proteinuria)
Chronic glomerulonephritis (usually with proteinuria)
IgA nephropathy
Familial nephritis, e.g. Alport syndrome
Thin basement membrane disease.
Kidney and urinary tract disorders
Haematuria - Ivestigations
All patients:
Urine microscopy (with phase contrast) and culture
Protein and calcium excretion
Kidney and urinary tract ultrasound
Plasma urea, electrolytes, creatinine, calcium, phosphate, albumin
Full blood count, platelets, clotting screen, sickle cell screen.
If suggestive of glomerular haematuria
ESR, complement levels and anti-DNA antibodies
Throat swab and antistreptolysin O/anti-DNAse B titres
Hepatitis B and C screen
Renal biopsy if indicated
Test mother’s urine for blood (if Alport syndrome suspected)
Hearing test (if Alport syndrome suspected).
Kidney and urinary tract disorders
Acute nephritis
- Post-infectious (including streptococcus)
- Vasculitis (Henoch–Schönlein purpura or, rarely, SLE, Wegener granulomatosis, microscopic polyarteritis, polyarteritis nodosa)
- IgA nephropathy and mesangiocapillary glomerulonephritis
- Anti-glomerular basement membrane disease (Goodpasture syndrome) – very rare.
Kidney and urinary tract disorders
Post-streptococcal and post-infectious nephritis
- Usually follows a streptococcal sore throat or skin infection and is diagnosed by evidence of a recent streptococcal infection (culture of the organism, raised ASO/anti-DNAse B titres) and low complement C3 levels that return to normal after 3–4 weeks.
- Streptococcal nephritis is a common condition in developing countries, but has become uncommon in developed countries.
- Long-term prognosis is good.
Kidney and urinary tract disorders
Henoch–Schönlein purpura
Henoch–Schönlein purpura is the combination of some of the following features:
Characteristic skin rash
Arthralgia
Periarticular oedema
Abdominal pain
Glomerulonephritis.
It usually occurs between the ages of 3 and 10 years, is twice as common in boys, peaks during the winter months and is often preceded by an upper respiratory infection. Despite much research, the cause is unknown. It is postulated that genetic predisposition and antigen exposure increase circulating IgA levels and disrupt IgG synthesis. The IgA and IgG interact to produce complexes that activate complement and are deposited in affected organs, precipitating an inflammatory response with vasculitis.
Kidney and urinary tract disorders
IgA nephropathy
Familial nephritis
Vasculitis
Systemic lupus erythematosus (SLE)
Acute nephritis:
- Cause: usually post-infectious or follows a streptococcal infection, but also vasculitis (including Henoch–Schönlein purpura), IgA nephropathy and familial nephritis
- Clinical features: oedema (around the eyes), hypertension, decreased urine output, haematuria and proteinuria
- Management: fluid and electrolyte balance, diuretics, monitor for rapid deterioration in renal function.
