Pathophysiology

Epidemiology

A large US epidemiological study of hospitalised children [2] reported:

• A Paediatric AKI incidence rate of 3.9 cases per 1000 admissions.
• Children with AKI had a significantly higher absolute mortality rate (15.9%) compared to children without AKI (0.6%).
• Mortality increased in children with AKI who were under 1 month of age (31.3% v 10.1%), required paediatric intensive care (32.8% v 9.4%), or required dialysis (27.1% v 14.2%)

The same study reported the following factors associated with Paediatric AKI:

• Shock
• Sepsis
• Intubation/Mechanical Ventilation
• Extracorporeal Support
• Circulatory Disease
• Cardiac congenital abnormalities

Aetiology

The aetiology of acute kidney injury in children has been traditionally divided into pre-renal, intrinstic/renal and post renal causes. The majority of these cases of AKI will be pre-renal due to hypovolaemia (e.g. gastroenteritis) that can be corrected with adequate fluid replacement. [6]

A Norwegian study of AKI in children managed at tertiary centres identified the most common aetiologies [7]:

Pre-renal (hypoperfusion)

• Dehydration/hypovolaemia (e.g. gastroenteritis)
• Sepsis
• cardiac disease

Renal causes

• Nephritic Syndrome
• Haemolytic Uraemic Syndrome
• Drugs related

Post renal causes

• Congenital anomalies of the kidney and urinary tract.