COVID-19 and the human kidney: An overview

Chris Prashad

Article submitted as part of the Ministry of Health’s COVID-19 public information and education program. For questions, please email [email protected]
We can all appreciate that COVID-19 is a lethal condition that primarily affects the respiratory system. However, the effects of COVID-19 can directly or indirectly affect many other organs, with kidney injury becoming more widely recognized as data becomes available.
Humans usually have two kidneys that are best known for their role of filtering our blood and allowing us to get rid of toxic substances by excreting them in urine. Along with this vital function, the kidneys also have a role in regulating blood pressure and maintaining certain hormones in our body.
Without a properly functioning kidney, we would not be able to live – at least not without the help of an artificial means of removing toxins such as dialysis.

Effect on Kidney
There are many gaps in our understanding of COVID-19, but we have several scientific clues as to how this disease affects the kidneys.
1. COVID-19 can directly infect the kidneys: this virus is thought to use a substance called angiotensin that converts enzyme 2 (ACE2) to enter and infect body cells. ACE2 receptors can be abundantly found in the kidneys, making this organ the primary target for the new coronavirus, which in turn can directly cause kidney injury.
2. COVID-19 can cause a cytokine storm: when infected, the body reacts by producing an immune response that increases the production of certain inflammatory factors and other substances to combat the illness. In some people, the response to infection can be extreme, leading to overwhelming production of inflammatory substances, a situation referred to as a cytokine storm. The cytokine storm in an effort to kill the invasive virus can also destroy healthy tissue, including that of the kidneys.
3. Other underlying factors: people who become seriously ill with COVID-19 may have pneumonia, low blood pressure (sepsis) and clotting disorders, which affect the oxygen supply to the kidneys and inevitably lead to to injury. Those with underlying diseases such as diabetes, cardiovascular conditions, or cancer are also more susceptible to kidney injury from COVID-19.
Like the lungs and the respiratory system, COVID-19 can affect the kidneys along a spectrum, starting with mild to moderate damage that usually heals as the person heals, to more severe cases, which can impair kidney functions more permanently.
COVID-19 can injure and disrupt the kidneys to the extent that the individual may need life-saving dialysis – the majority of these patients are already seriously ill from the respiratory effects of coronavirus.
At present, there is evidence that leads us to believe that severe COVID-19 infection can lead to chronic kidney disease for those who were usually active kidneys, exacerbating the kidney condition for those already suffering from chronic kidney disease. Acute kidney injury in COVID-19 is also associated with an increased risk of death.

Kidney functions are usually assessed by simple and widely available blood tests (commonly referred to as BUN and Creatinine), or more complex measures when needed (glomerular filtration rate, renal biopsy).
The doctor will look for specific trends in your renal function blood tests, along with observing urine output to determine if a person has suffered a kidney injury. The management of patients with confirmed diagnosis of COVID-19 and acute kidney injury is individual, but will generally include:
1. Target the basic COVID-19 with the use of antibiotics, antivirals, immunomodulatory and anti-inflammatory drugs.
2. Maintain good blood pressure and fluid balance by using intravenous fluids and weight maintenance drugs as needed.
3. In cases of critically ill patients, about one-third may need some form of dialysis.

High risk
People who already live with primary kidney disease are at very high risk and in a very vulnerable group for becoming seriously ill with COVID-19. This is especially true if someone is on dialysis, has had a kidney transplant, has chronic stage kidney disease, or uses prednisolone daily (being treated for an autoimmune condition).
It is worth noting that people with chronic kidney disease are at three times higher risk of developing serious and life-threatening symptoms of COVID-19 compared with individuals without chronic kidney disease.
If you are someone who already has primary kidney disease, it is recommended that you adhere to protective guidelines. If you are on dialysis, you should not miss your treatments, but if you feel unwell, make sure you let a member of your healthcare team know.
COVID-19, as well as the circumstances surrounding it, have influenced all of our lives in Guyana, requiring us to adapt in so many different ways. This article allows us to understand a little more about the far-reaching consequences of this deadly disease.
Properly functioning kidneys are essential for life, so it is in everyone’s best interests to pay attention to the health of these organs. As COVID-19 continues to be at the forefront of our conversations, we should be aware that there are many more common conditions in Guyana that adversely affect and otherwise injure our kidneys.
Diseases such as diabetes, hypertension and renal stones continue to be responsible for acute and chronic kidney injury for many Guyanese and this should be no less of a priority.
If you are diagnosed and living with a chronic illness such as diabetes and high blood pressure, it is important that you have regular follow-up assessments with your medical practitioner, as the management of these conditions is often vital in protecting your kidney health.
Self-medicating is strongly encouraged! For those with no known illness, it is still important that you talk to your doctor about your kidney status and be guided accordingly.

Things to Remember
1. Kidney injury is common in severe cases of COVID-19 and is associated with poor outcome.
2. COVID-19 can damage the kidney through several different mechanisms.
3. Treatment options revolve around treating the basic COVID-19 as well as supporting the kidneys with medication, fluids and dialysis if needed.
4. Kidney injury from COVID-19 can be long term.
5. If you already have underlying kidney disease you are more likely to suffer from a serious illness of COVID-19 – you need to be proportionate more careful in your actions.
6. In Guyana, many other common conditions adversely affect our kidneys and deserve our attention.

Article submitted as part of the Ministry of Health’s COVID-19 public information and education program. For questions, please email [email protected]

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