Kidneys And Covid-19: Renal Manifestations Of Coronavirus

The United States reached the solemn milestone of surpassing 100,000 lives lost from Covid-19. Sadly, community spread of this novel coronavirus continues as cases and deaths in the U.S. relentlessly rise, now reaching 1.79 million and 104,000, respectively. Multiple clinical studies have also indicated that we’re dealing with more than just a “respiratory virus”: neurological, cardiac and clotting manifestations have been documented thus far. Here, I uncover the effects of COVID-19 on the renal system, gleaning insights from three of the nation’s kidney experts.
Outside the respiratory system, the kidneys are among the most common organs targeted by SARS-CoV-2. To illustrate the magnitude of the problem, among hospital ICUs in New York City – the epicenter of Covid-19 – approximately 20-40% of intubated patients had acute kidney injury (AKI) requiring dialysis (described later). Another study conducted by Northwell Health, New York state’s largest healthcare provider, found that among 5449 patients admitted with Covid-19, 36.6% developed AKI.
What Do the Kidneys Do?
We are born with two kidneys, each made up of a million nephrons which work together to perform multiple life-sustaining tasks. One major function is to act as the body’s filtration system: kidneys remove waste products and excess fluid through the urine. In addition, according to the National Kidney Foundation, kidneys play a critical role in regulating the body’s salt, potassium and acid content. Kidneys also produce hormones such as erythropoietin which promotes red blood cell production as well as other hormones that regulate blood pressure and calcium metabolism.

How Does Covid-19 Affect the Kidneys?
Covid-19 has been shown to impair renal function in several ways, ranging from poor blood flow to the formation of tiny blood clots which can clog the kidneys and prevent urine formation.

“By far the most common injury is Acute Tubular Necrosis or ATN, which happens when the kidneys do not get enough blood flow because a Covid-19-infected patient goes into shock and has very low blood pressure,” explained Herbert Lin, MD, PhD, FASN, associate professor of medicine, Massachusetts General Hospital and Harvard Medical School. Direct infection of the kidneys is also a possibility.
“There is likely a small subset of patients that have direct viral infections of the kidney but this is likely a rare event,” said Matthew Sparks, MD, Assistant Professor of Medicine, Division of Nephrology, Duke Medical Center, citing an NEJM study with “superb methodology.” In a recent paper, Dr. Sparks and colleagues emphasized that AKI can be a severe complication of Covid-19.

Unfortunately, many patients infected with Covid-19 sustained renal injuries so severe that their kidneys almost shut down completely. Dialysis, or kidney replacement therapy, is a procedure where blood is filtered by a machine to clean out the urine that builds up in the blood when the kidneys do not work well, described Dr. Lin.
At the height of the pandemic, New York City hospitals were seeing no shortage of patients requiring dialysis, according to David S. Goldfarb, MD, Clinical Director, Division of Nephrology at the NYU Grossman School of Medicine.
“A surprisingly high proportion of the people who needed ventilators to help them breath also had kidney failure that required dialysis,” recalled Dr. Goldfarb. “In fact, when everyone was talking about running out of ventilators, the medical centers in New York were worried about running out of dialysis machines for that many people.” The NYU nephrologist went on to point out that the combination of lung and kidney failure was associated with a very high mortality rate, though a few people did recover. The good news is that when most of these very sick COVID-19 patients recover, so will their kidneys.

What Should We All Know About Kidney Health?
The optimal way to care for our kidneys is by controlling our blood pressure (healthy diet, low salt, regular exercise, quitting smoking) and staying hydrated with water, not sugary beverages or alcohol. There are other methods, too.
“Avoid taking medications such as NSAIDs (e.g. ibuprofen) that can harm the kidneys if taken in excess,” reminded Dr. Lin. “And if you have diabetes mellitus, control your blood sugar as much as possible” as hyperglycemia can also cause long-term renal damage.
Dr. Sparks’ message to physicians: “Be cognizant of kidney function and other parameters such as proteinuria and hematuria in patients with COVID-19.” He also acknowledged confusion about management of common blood pressure medications such as ACE inhibitors and ARBs (angiotensin II receptor blockers): “Currently, there is no evidence that these medications alter the clinical course or lead to an increased risk of infection.”
The most sensible way to protect our kidneys, according to Dr. Goldfarb – don’t get the virus!
“Social distancing will prove effective, and wearing a mask cannot be underestimated.” Wise words rooted in long-standing public health from Dr. Goldfarb.

Other renal health considerations: patients with pre-existing chronic kidney disease will be at increased risk for AKI. In addition, depending on location and status of local hospital staffing, individuals receiving peritoneal dialysis at home may encounter disruption in delivery of PD supplies and nursing support. Kidney transplant programs will also likely be on hold given the multiple resources required including staffing.
What’s become obvious by now is that this coronavirus has triggered multiorgan damage and has catalyzed the global medical research community to examine its plethora of effects. I remain humbled by this pathogen and by sickness in general. To quote the great Canadian physician and father of modern medicine, Sir William Osler: “Medicine is a science of uncertainty and an art of probability.”
https://www.forbes.com/sites/lipiroy/2020/05/30/kidneys-and-covid-19-renal-manifestations-of-the-novel-coronavirus/#661ef0763851