acute kidney injury

Introduction:

The unprecedented coronavirus has caused huge health concerns to patients with morbidities. Individuals suffering from serious health issues like diabetes, obesity, kidney concerns are facing great health risks because of the Coronavirus. Also, the virus is causing damage to the vital organs like kidneys, liver, heart, and lungs in some cases thus causing a threat to life in them.

It has been seen that most patients who were suspected or confirmed Covid-19 patients may have issues of acute kidney injury after the Covid-19 effect. However, there is only a few data on the temporal trends in the relation of the Coronavirus with acute kidney injury. Early data have suggested that such cases have declined over the pandemic era, although the reason behind this decrease is still unknown.

Clinical characteristic and histopathology:

Kidney disease among Covid-19 patients can result in the acute injury of the organ, hematuria, or proteinuria results in high-risk mortality. It still remains unclear that the acute kidney injury (AKI) is caused mainly due to 

  1. Hemodynamic changes 
  2. Hypovolemia
  3. Hyperglycemia
  4. Drugs like remdesivir, NSAIDS
  5. Sepsis
  6. Cytokine discharge or 
  7. Covid -19 virus that leads to the direct cytotoxicity.

The reported incidents of the corona patients who are hospitalized vary depending on the severity of the disease in the patients who are under study. In the two observational studies of over 5000 patients who were hospitalized with Covid-19, AKI was noted among 32% to 37% of the patients. And, among these patients, one and a half percent of patients had mild disease, and the remaining had moderate to severe one.

AKI was linked with the need for mechanical ventilation and a longer duration of hospitalization. And it has been witnessed that about one-half of the AKI patients did not achieve complete recovery of their kidney function during their discharge from the hospital.

The cases that are susceptible to AKI are older people, black Americans, or male, having hypertension, diabetes, obesity, heart-related issues, low baseline estimated Glomerular filtration rate, or higher interleukin-6 level, or requiring mechanical ventilation or vasopressor medications.

In another study of 3000 serious Covid-19 patients, 21% developed serious AKI requiring Kidney replacement therapy – (KRT) within the 14 days of admission to the ICU unit. The 28-day mortality among such patients was approximately 50%. The main risk factors for the death included – old age, oliguria, and admission to hospitals that had limited or no proper ICU facilities.

Of all those patients who survived 34% were KRT dependent during discharge and more than half are still KRT dependent by two months. It is still not clear whether the KRT dependence is due to the severity of serious illness or it is due to the specific pathophysiology pertaining to the Coronavirus.

 Another study compared the incidence of AKI among the hospitalized patients with or without the coronavirus. This incidence was higher among the 2600 patients who have Coronavirus as against over 19,500 patients who were hospitalized for other reasons.

Covid-19 was continued and linked with the higher rate of AKI despite controlling for demographics variables, the prevalence of hypotension, comorbidities, selected lab results, and the use of nephrotoxic medications, vasopressors, or mechanical ventilation.

The indicators of inflammation like C-reactive protein and ferritin were found to be on the elevated scale among the patients who had coronavirus as against those who were not infected with the said virus.

However, comparisons of AKI between groups controlling these inflammatory indicators were not possible for only a few patients without covid-19 who had these checked during their stay in the hospital. The histopathology of the kidney was examined in the autopsy series of 42 patients who lost their lives with Corona. The mean age of these patients was 72 years and 88% were over 60 years of age.

Most patients had the common Comorbidities including diabetes, hypertension, acute kidney ailment, obesity, and coronary artery or cerebrovascular disease and only two of the patients had no underlying comorbidities. AKI mostly the third stage was eminent among 31 of the 33 patients. About 62% of patients exhibited varying degrees of acute tubular necrosis. One patient has a collapsed focal segmental glomerulosclerosis and many had sequelae of their medical comorbidities.

ATN was a major kidney finding and Glomerular lesions were reported in some Covid-19 patients. Whether the covid-19 virus causes the infection in the kidney is still unknown. However, the presence of the virus-like particles has been seen in the SARS- CoV-2 patients.

The Ultra-structural in-situ hybridization used in some studies has confirmed the presence of viral RNA or the viral proteins inside the tissue of the kidney. The other studies, however, have failed to indicate the presence of the virus in the kidney of the Covid-19 patients.

Evaluation of AKI in the patients who are hospitalized

 In dealing with the Covid-19 virus patients who develop AKI, emphasis should be placed on the optimization of volume status to exclude and treat functional AKI while avoiding hypervolemia that might worsen the respiratory status of the patient.

The diagnosis of other AKI factors should be taken into account in a manner similar to other seriously ill AKI patients. The manual urine sediment examination is to be done for all the Covid-19 patients as urine samples are not considered highly infectious. However, some typical testing like kidney and bladder ultrasound may not be performed on Coronavirus patients due to the concerns of infection exposure.

Management of AKI in hospitalized patients

Patients with dialysis and AKI – The indicators for KRT for the acute kidney injury remain the same irrespective of the Coronavirus status of the given patient. However, alterations in KRT management that can be undertaken during the Covid-19 outbreak include:

  1. Covid-19 patients with AKI who need KRT should be co-localized on a separate floor or ICU, when possible. Co-localization within the side-by-side rooms can enable one dialysis nurse to deliver dialysis to more than one patient at the same time. If the patient is negative in the pressure isolation room, then one hemodialysis nurse will be required to attend to the care of that patient in the 1:1, patient-nurse ratio.
  2. Patients suspected or confirmed Coronavirus patients who are not seriously ill but have AKI  and require KRT should be dialyzed in their room of isolation instead of being moved to the inpatient dialysis ward.
  3. Continuous kidney replacement therapy  (CKRT) is preferred among many seriously ill AKI patients. For Hemodynamically stable patients who could tolerate occasional hemodialysis, CKRT, or Prolonged intermittent kidney replacement therapy (PIKRT) should be performed based on the availability of the machine and the staff. CKRT and PIKRT can be managed without 1:1 hemodialysis nursing support. This will help minimum wastage of personal protective equipment PPE and also limit the exposure among hemodialysis nurses.
  4. CKRT machines can be either placed inside the isolation room or outside extending their tubing. Placing the machine outside reduces the need for repeated entry into the room to troubleshoot and manage the machine. This minimizes the wastage of PPE. But, using extended tubing requires extra tubing connections and increases the chances that the tubing will become disconnected from the venous line. This increases the risks of clotting because of the longer length of the tube.
  5. If CKRT capacity in the hospital is overloaded, then the machines can be used to deliver extended random treatment like 11 hours instead of continuing with a higher rate of flow. Also, the machine can be rotated between the patients every 24 hours.
  6.  Hospitals that are facing a shortage of replacement fluid for CKRT can lower the delivered dose to 15mL per kg for one hour from the usual 20 to 25mL per kg for one hour, especially among the patients who are not hypercatabolic.
  7. When supplies of commercially prepared replacement fluid are finished, hospitals and pharmacies may develop their own replacement fluid by combining all of the below:
  • 1L of  0.9% saline with potassium chloride as required
  • 1L of 5% dextrose water with 150mEq sodium bi-carbonate
  • 1L of 0.9% saline with 1g magnesium chloride
  • 1L of 0.9% saline with 1g calcium chloride

This will yield a 4L solution containing 153mEq/L sodium, 37.5mEq/L bicarbonate, 2.6L magnesium, 2.25mmol/L calcium, and an unsteady amount of potassium

8. Circuit thrombosis during KRT occurs regularly in patients with Coronavirus as against other patients. In absence of any challenges, corona virus patients should receive anticoagulation during KRT. This can be the form of regional anticoagulation using un-fractionated heparin or citrate or systemic anticoagulation with low molecular weight or un-fractioned heparin.

9. If possible, remote monitoring with video and audio units should be used to troubleshoot the alarms outside the rooms and to reduce the need for dialysis nurses or nephrologists to enter the isolation room of Covid-19 patients.

10. As the presence of the covid-19 virus or other similar viruses have been reported in the effluent no special provisions for disposal of CKRT effluent are required.

11. When the CKRT or hemodialysis machines are limited, doctors may need to consider AKI treatment with peritoneal dialysis PD, and the important considerations for the same include:AKI patients treated with PD have similar rates of all-cause mortality, recovery functions of the kidney, and infectious complications as against the patients treated with other complications.

A. PD requires comparatively less equipment, resources, and infrastructure as compared to other KRT forms. Clinical staff and nurses can be trained to provide PD.

B. Among mechanically ventilated patients, PD can enhance intra-abdominal pressure, obstruct the respiratory system, and may worsen respiratory failure. However, it can be used in these patients when CKRT and intermittent hemodialysis are not available. However, it can be a challenging affair, though one case study found it to be safe and feasible.

C. In order to reduce the contact between health care workers and AKI patients with coronavirus, an automated PD with a cycler should be used.

D. There are many options for the safe disposal of PD effluent for patients with end-stage kidney disease in an AKI setting. There is no data yet indicating that PD effluent is infectious.

E. There is no clear role management of the usage of Extra corporeal hemoperfusion devices for cytokine removal like Cytosorb during the pandemic and such they are not used among the seriously ill covid-19 patients with or without dialysis requiring AKI

Covid-19 Patients with AKI who do not require dialysis: Such patients should be managed with the limited contacts as possible. Ultrasound and the physical examination should be arranged with the consulting teams to minimize contacts.

Differences in the management of AKI among the patients with Covid-19 may include limited use of intravenous fluids. Most of the coronavirus patients with pneumonia have variable degrees of oxygen requirements. Fluid resuscitation should be individualized and should be on the basis of traceable objective measures like inferior vena cava collapse on ultrasound. Also can replace with plasma expanders like albumin infusions. Also avoiding nephrotoxic drugs, contrast studies etc.

Managing AKI in covid patients is challenging and there is limited data available.