Acute kidney Injury uncovered

Kidneys are two bean-shaped organs, located just below the rib cage, on either side of your spine, and responsible for removing waste and extra water from the body. Urine, which is formed as a result, flows from the kidneys to the bladder via two muscular tubes called ureters and gets stored until the time and place are right to get eliminated from the body. The kidneys are made up of around a million filtering units called nephrons. Each nephron includes a filter, called glomerulous-which filters blood and tubule-which re-absorbs the needy substances back into blood while removing the waste.

So in simpler terms this is the system which maintains the normal regulation of fluid, electrolyte, and acid-base balance. And on today’s Health Capsule we are shedding light on one of the commonly come across disturbances affecting it; Acute Kidney Injury-AKI.

“Although people often perceive ‘kidney disease’ as an irreversible condition, it is usually the case with chronic kidney disease where acute kidney injury offers an opportunity for complete recovery, with prompt recognition and appropriate treatment” explains Dr Rajeewa Dassanayake, Consultant Nephrologist, Teaching Hospital, Kurunegala

Acute Kidney Injury (AKI) is the term used to describe a decline in kidney function occurring over days to weeks and the older term Acute Renal Failure has been replaced in order to describe the spectrum, from risk through to loss, better.

The incidence and prevalence of AKI vary widely by geographical location.

It is much commoner in hospitalised patients than in the community where the incidence increases in proportion to the severity of illness requiring hospitalization.

Decrease blood flow and direct damage to kidneys and obstructed drainage result in AKI
“The vast majority of Acute Kidney Injuries is due to a decrease in blood flow to the kidneys. 

This may occur with severe dehydration of any cause, notably with diarrhoeal illnesses, burns etc. Furthermore, blood loss, sepsis, heart failure and certain medications contribute. AKI can also occur due to the direct injury to kidneys, by abnormalities of the patient’s own immune system, external toxins and excess generation of toxins, inside kidneys (hemoglobin released by excess breakdown of red cells, or myoglobin released by excess muscle breakdown).

AKI can also occur as a result of urinary tract obstruction due to stones and abnormal narrowing of tubes causing a back pressure on kidneys. Additionally, snake bites and leptospirosis are not uncommon causes of AKI seen in Sri Lanka” describes Dr Dassanayake.

Poorly functional kidneys this way can lead to a build-up of waste products in blood, making it hard for the body to keep the right balance of fluid and other metabolic agents.

“However, as healthcare professionals we usually recognise AKI with a decreased urine output in spite of adequate hydration and worsening kidney functions identified through blood tests, (rising serum creatinine). More sensitive tests to recognize AKI are available, but not routinely used in clinical practice” said Dassanayake. 

Prompt treatment can save lives
Specific Treatment of AKI completely depends on the underlying cause and may vary from simple hydration of the patient, suppression of the immune system using medications or plasma exchange, to the surgically relieving of obstruction. 

“Interventions are also taken in order to prevent patients dying due to the accumulation of uraemic toxins, fluid overload due to decreased urine output, or due to rising potassium or acid levels in blood and include kidney support treatment- through dialysis to relieve the aforementioned problems, until the kidneys recover.

“Early and adequate fluid resuscitation when indicated, maintaining blood pressure and avoiding drugs toxic to the kidneys may prevent AKI in hospital. Early recognition of decreasing urine output and rising creatine will enable early therapeutic measures which will immensely contribute towards the reduction of complications and hospital stay, allowing a significant chance of full renal recovery” says Dr Dassanayake.

Take home message
“It is advisable for public to be aware of commonly come across risk factors for AKI including reckless usage of medications especially pain-killers and antibiotics without medical advice and getting exposed to extreme heat stress without adequate hydration, in order to stay away from unnecessary consequences ” Dr Dassanayake concludes.