Myths & Facts: Can Covid-19 cause encephalitis? When to give prone ventilation?

— By KK Aggarwal

345: Can Covid cause encephalitis

Fact: Clinicians from Henry Ford Health System in Detroit, Michigan, have reported the first presumptive case of acute necrotizing hemorrhagic encephalopathy associated with COVID-19. [ published online March 31 in Radiology.]

Acute necrotizing encephalopathy (ANE) is a rare complication of viral infections, but until now, it has not been known to have occurred as a result of COVID-19 infection. ANE has been associated with intracranial “cytokine storms,” and a recent report in the Lancet suggested that a subgroup of patients with severe COVID-19 might develop a cytokine storm syndrome.

346: What is the latest in azithromycin and hydroxy chloroquine combination

A controversial study led by Didier Raoult, MD, PhD, on the combination of hydroxychloroquine and azithromycin in patients with COVID-19 was published on March 20. The latest results from the same Marseille team, which involve 80 patients, were reported on March 27.

The investigators report a significant reduction in the viral load (83% patients had negative results on quantitative polymerase chain reaction testing at day 7, and 93% had negative results on day 8). There was a “clinical improvement compared to the natural progression.” One death occurred, and three patients were transferred to intensive care units.

347: what about false negative in RT PCR

Fact: In many patients, it takes three to four swabs to get a positive RT-PCR. The Chinese ophthalmologist, Li Wenliang, who originally sounded the alarm about coronavirus, had several negative tests. He died from the infection.In one Chinese study, the sensitivity of RT-PCR — that’s the proportion of the infected who test positive — was around 70%.

348: When to give prone ventilation

Fact: to perform prone ventilation in patients who have refractory hypoxemia and COVID-19 pneumonia (i.e. acute respiratory distress syndrome [ARDS]),

349: When to use ECMO

Fact: Consider extracorporeal membrane oxygenation (ECMO) in patients who have refractory hypoxemia, COVID-19 pneumonia (i.e. ARDS), and have failed prone ventilation.

350: Is the lung involvement like high altitude sickness

Fact: In many patients they have low oxygen, but their lungs don’t look all that bad. In an editorial in the journal Intensive Care Medicine, Luciano Gattinoni, MD, a guest professor of anesthesia and intensive care at the University of Gottingen in Germany, and one of the world’s experts in mechanical ventilation, says more than half the patients he and his colleagues have treated in Northern Italy have had this unusual symptom. They seem to be able to breathe just fine, but their oxygen is very low.

According to Gattinoni, about 30% of COVID-19 patients who come to the hospital have more classic symptoms of ARDS. Their lungs are cloudy on imaging scans, and they’re stiff and inflamed, showing that they aren’t working well. The patients also have low levels of oxygen in their blood, and they are struggling to breathe. They look like patients with severe pneumonia caused by a virus. This is the type of lung trouble doctors are more used to seeing with respiratory diseases like influenza and SARS.

Patients with more classic ARDS-type COVID-19 often need mechanical ventilation right away, which forces air into the lungs to increase oxygen.

Patients with respiratory failure who can still breathe OK, but have still have very low oxygen, may improve on oxygen alone, or on oxygen delivered through a lower pressure setting on a ventilator.

Gattinoni thinks the trouble for these patients may not be swelling and stiffening of their lung tissue, which is what happens when an infection causes pneumonia. Instead, he thinks the problem may lie in the intricate web of blood vessels in the lungs.

Normally, when lungs become damaged, the vessels that carry blood through the lungs so it can be re-oxygenated constrict, or close down, so blood can be shunted away from the area that’s damaged to an area that’s still working properly. This protects the body from a drop in oxygen.

Some COVID-19 patients can’t do this anymore. So blood is still flowing to damaged parts of the lungs. People still feel like they’re taking good breaths, but their blood oxygen is dropping all the same.

This problem with the blood vessels is similar to what happens in a condition called high-altitude pulmonary edema, or HAPE.

He says these patients with more normal-looking lungs, but low blood oxygen, may also be especially vulnerable to ventilator-associated lung injury, where pressure from the air that’s being forced into the lungs damages the thin air sacs that exchange oxygen with the blood. [Medscape]

((The writer is President, CMAAO, HCFI and Past national President IMA))