Renal/Urinary System Flashcards
Which organism causes 85-90% of paediatric UTIs?
E.coli
Which organism causes uncomplicated cystitis in boys in 30% of those with a UTI?
Proteus mirabilis
Which bacteria causes acute UTI is adolescents in both sexes?
Staphylococcus saprophyticus
Which viral infection is a rare cause of UTI in paediatrics?
Adenovirus
What % of boys and girls respectively will have had a UTI by the age of 7?
Girls 8%
Boys 2%
What are the risk factors for young people developing UTIs? (7)
- Age below one year
- Female sex (however in the first three months of life, UTI is more common in boys)
- Caucasian race
- Previous UTI
- Voiding dysfunction
- Vesicoureteral reflux (VUR)
- Immunosuppression
Why do UTIs need to be taken seriously in children?
There is an associated with urinary tract abnormalities
Which conditions can lead to urinary stasis?
- Renal calculi
2. Vesico-ureteric reflux
In infants less than 3 years of age, what are the symptoms/signs of a UTI?
- Fever
- Vomiting
- Lethargy
- Irritability
- Poor feeding
- Jaundice
- Haematuria
- Offensive urine
What are the imaging techniques used to investigate recurrent UTIs?
- USS
- DMSA - a radionuclide scan that uses dimercaptosuccinic acid
- MCUG - micturating cystourethrogram (can result in re-implantation of ureters in the bladder)
What is involved in DMSA testing?
Injection of radionuclide and then X-ray which will show areas of kidney that may be scarred that haven’t taken up the nuclide, and the computer can also tell you how much of each kidney has taken up the radionuclide - obviously you would hope it is 50/50.
What is haemolytic uraemic syndrome (HUS)?
It is a triad of:
- Microangiopathic haemolytic anaemia (Coombs’ test negative)
- Thrombocytopenia
- Acute kidney injury
What is the most common cause of HUS?
E.coli with somatic antigen 157 and flagella antigen 7 (O157:H7) also known as Shiga toxin-producing E.coli (STEC) as it produces a toxin called Shiga
Why is HUS a systemic disease?
Because the damaged arises from the circulating toxin which binds to endothelial receptors, particularly in the renal, GI and CN systems. Thrombin and fibrin are deposited in the microvasculature.
How does haemolysis occur in HUS?
The thrombin and fibrin which are deposited in small vessels leads partial occlusion of the vessels and subsequently haemolysis occurs
In addition to E.coli, which other pathogens can cause HUS? (3)
- Streptococcus pneumoniae and Shigella
- HIV and coxsackie virus
- Ciclosporin, tacrolimus
Which age range is most affected by HUS?
Children under 5
Where was the largest outbreak of HUS in the UK and how many people did it affect?
In Cumbria in 1999, affected 114 people
What are the risk factors for developing HUS? (5)
- Rural populations more affected than urban populations
- Warmer summer months (June-September)
- Young age (6 months to 5 years)
- Older people or those who are immunocompromised
- Contact with farm animals
When is HUS at its most transmissible?
During the diarrhoea phase
How does HUS tend to present? (4)
- Profuse diarrhoea that turns bloody 1 to 3 days later
- Fever
- Abdominal pain
- Vomiting
(most adults infected with E.coli 0157 remain asymptomatic)
What investigations are carried out in suspected HUS? - and when is clinical suspicion of HUS greatest? (7)
When they present with bloody diarrhoea
- FBC and film - evidence of haemolysis, anaemia and thrombocytopenia. A raised WCC and low platelet count are early indicators of development of HUS.
- LFTs
- Lactate dehydrogenase (high levels - HUS)
- CRP
- Clotting screen
- Stool culture
- Urine analysis (haematuria and proteinuria appear early in HUS)
What are the features of microangiopathic haemolysis? (3)
- Falling haemoglobin
- Fragmented red cells
- Falling platelet count
What are the differential diagnoses for HUS? (4)
- GI upset = acute gastroenteritis, appendicitis, IBD, intussusception
- DIC + sepsis
- HELLP syndrome (haemolysis, elevated liver enzymes, low platelet count)
- Thrombotic thrombocytopenic purpura
What is the management for HUS? (5)
- Fluid management
- Electrolyte management
- Antihypertensive treatment (nifedipine)
- Dialysis
- Monoclonal antibodies