How does coronavirus kill? Clinicians trace a ferocious rampage through the body, from brain to toes

Authors: By Meredith WadmanJennifer Couzin-FrankelJocelyn KaiserCatherine MatacicApr. 17, 2020 , 6:45 PM

On rounds in a 20-bed intensive care unit one recent day, physician Joshua Denson assessed two patients with seizures, many with respiratory failure and others whose kidneys were on a dangerous downhill slide. Days earlier, his rounds had been interrupted as his team tried, and failed, to resuscitate a young woman whose heart had stopped. All shared one thing, says Denson, a pulmonary and critical care physician at the Tulane University School of Medicine. “They are all COVID positive.”

As the number of confirmed cases of COVID-19 surges past 2.2 million globally and deaths surpass 150,000, clinicians and pathologists are struggling to understand the damage wrought by the coronavirus as it tears through the body. They are realizing that although the lungs are ground zero, its reach can extend to many organs including the heart and blood vessels, kidneys, gut, and brain.

“[The disease] can attack almost anything in the body with devastating consequences,” says cardiologist Harlan Krumholz of Yale University and Yale-New Haven Hospital, who is leading multiple efforts to gather clinical data on COVID-19. “Its ferocity is breathtaking and humbling.”

Understanding the rampage could help the doctors on the front lines treat the fraction of infected people who become desperately and sometimes mysteriously ill. Does a dangerous, newly observed tendency to blood clotting transform some mild cases into life-threatening emergencies? Is an overzealous immune response behind the worst cases, suggesting treatment with immune-suppressing drugs could help? What explains the startlingly low blood oxygen that some physicians are reporting in patients who nonetheless are not gasping for breath? “Taking a systems approach may be beneficial as we start thinking about therapies,” says Nilam Mangalmurti, a pulmonary intensivist at the Hospital of the University of Pennsylvania (HUP).

What follows is a snapshot of the fast-evolving understanding of how the virus attacks cells around the body, especially in the roughly 5% of patients who become critically ill. Despite the more than 1000 papers now spilling into journals and onto preprint servers every week, a clear picture is elusive, as the virus acts like no pathogen humanity has ever seen. Without larger, prospective controlled studies that are only now being launched, scientists must pull information from small studies and case reports, often published at warp speed and not yet peer reviewed. “We need to keep a very open mind as this phenomenon goes forward,” says Nancy Reau, a liver transplant physician who has been treating COVID-19 patients at Rush University Medical Center. “We are still learning.”

The infection begins

When an infected person expels virus-laden droplets and someone else inhales them, the novel coronavirus, called SARS-CoV-2, enters the nose and throat. It finds a welcome home in the lining of the nose, according to a preprint from scientists at the Wellcome Sanger Institute and elsewhere. They found that cells there are rich in a cell-surface receptor called angiotensin-converting enzyme 2 (ACE2). Throughout the body, the presence of ACE2, which normally helps regulate blood pressure, marks tissues vulnerable to infection, because the virus requires that receptor to enter a cell. Once inside, the virus hijacks the cell’s machinery, making myriad copies of itself and invading new cells.

As the virus multiplies, an infected person may shed copious amounts of it, especially during the first week or so. Symptoms may be absent at this point. Or the virus’ new victim may develop a fever, dry cough, sore throat, loss of smell and taste, or head and body aches.

If the immune system doesn’t beat back SARS-CoV-2 during this initial phase, the virus then marches down the windpipe to attack the lungs, where it can turn deadly. The thinner, distant branches of the lung’s respiratory tree end in tiny air sacs called alveoli, each lined by a single layer of cells that are also rich in ACE2 receptors.

Normally, oxygen crosses the alveoli into the capillaries, tiny blood vessels that lie beside the air sacs; the oxygen is then carried to the rest of the body. But as the immune system wars with the invader, the battle itself disrupts this healthy oxygen transfer. Front-line white blood cells release inflammatory molecules called chemokines, which in turn summon more immune cells that target and kill virus-infected cells, leaving a stew of fluid and dead cells—pus—behind. This is the underlying pathology of pneumonia, with its corresponding symptoms: coughing; fever; and rapid, shallow respiration (see graphic). Some COVID-19 patients recover, sometimes with no more support than oxygen breathed in through nasal prongs.

But others deteriorate, often quite suddenly, developing a condition called acute respiratory distress syndrome (ARDS). Oxygen levels in their blood plummet and they struggle ever harder to breathe. On x-rays and computed tomography scans, their lungs are riddled with white opacities where black space—air—should be. Commonly, these patients end up on ventilators. Many die. Autopsies show their alveoli became stuffed with fluid, white blood cells, mucus, and the detritus of destroyed lung cells.

For More Information: https://www.sciencemag.org/news/2020/04/how-does-coronavirus-kill-clinicians-trace-ferocious-rampage-through-body-brain-toes

Dysautonomia

Authors: Cleveland Clinic

What is dysautonomia?

Dysautonomia is a general term for a group of disorders that share a common problem – that is, an autonomic nervous system (ANS) that doesn’t function as it should. The ANS is the part of the nervous system that controls involuntary body functions (functions you don’t consciously control) like your heart rate, blood pressure, breathing, digestion, body and skin temperature, hormonal function, bladder function, sexual function and many other functions.

When the ANS doesn’t work the way it should, it can cause heart and blood pressure problems, breathing trouble, loss of bladder control and many other problems.

Who might get dysautonomia?

Dysautonomia, also called autonomic dysfunction or autonomic neuropathy, is relatively common. Worldwide, it affects more than 70 million people. It can be present at birth or appear gradually or suddenly at any age. Dysautonomia can be mild to serious in severity and even fatal (rarely). It affects women and men equally.

Dysautonomia can occur as its own disorder, without the presence of other diseases. This is called primary dysautonomia. It can also occur as a condition of another disease. This is called secondary dysautonomia.

Examples of diseases in which secondary dysautonomia can occur include:

For More Information: https://my.clevelandclinic.org/health/diseases/6004-dysautonomia

Covid-19 Story Tip: Brain Fog, Fatigue, Dizziness … Post-COVID POTS Is Real

Authors: Tae Chung, M.D., assistant professor of physical medicine and rehabilitation and neurology at the Johns Hopkins University School of Medicine and director of the Johns Hopkins POTS Program

For almost one year, COVID-19 has impacted the world and taken the lives of many people. While some survivors have fully recovered from this illness, others are still experiencing lingering effects, such as chronic fatigue, brain fog, dizziness and increased heart rate. These survivors have been called “long-haulers,” and experts say some of the symptoms they are experiencing are thought to be caused by postural orthostatic tachycardia syndrome (POTS), a blood circulation disorder.

Some patients may, at first, believe their symptoms are “all in their head,” but Tae Chung, M.D., assistant professor of physical medicine and rehabilitation and neurology at the Johns Hopkins University School of Medicine and director of the Johns Hopkins POTS Program, says “POTS is very real.”

While experts are still researching the long-term side effects of COVID-19, it is clear to experts that some survivors are experiencing the classic signs of POTS as a result of their COVID-19 diagnosis.

Chung says POTS is related to autonomic nerve dysfunction. He explains that the autonomic nervous system is responsible for involuntary control of many of our body functions, such as sweating, pupil movement, bowel movement and blood flow. Many POTS symptoms are thought to be related to inadequate control of blood flow, causing brain fog and dizziness. Chung suspects that COVID-19 may be associated with chronic inflammation in the autonomic nervous system, causing POTS.

For More Information: https://www.hopkinsmedicine.org/news/newsroom/news-releases/covid-19-story-tip-brain-fog-fatigue-dizziness–post-covid-pots-is-real

Extrapulmonary manifestations of COVID-19

Authors: Aakriti GuptaMahesh V. Madhavan[…]Donald W. Landry

Although COVID-19 is most well known for causing substantial respiratory pathology, it can also result in several extrapulmonary manifestations. These conditions include thrombotic complications, myocardial dysfunction and arrhythmia, acute coronary syndromes, acute kidney injury, gastrointestinal symptoms, hepatocellular injury, hyperglycemia and ketosis, neurologic illnesses, ocular symptoms, and dermatologic complications. Given that ACE2, the entry receptor for the causative coronavirus SARS-CoV-2, is expressed in multiple extrapulmonary tissues, direct viral tissue damage is a plausible mechanism of injury. In addition, endothelial damage and thromboinflammation, dysregulation of immune responses, and maladaptation of ACE2-related pathways might all contribute to these extrapulmonary manifestations of COVID-19. Here we review the extrapulmonary organ-specific pathophysiology, presentations and management considerations for patients with COVID-19 to aid clinicians and scientists in recognizing and monitoring the spectrum of manifestations, and in developing research priorities and therapeutic strategies for all organ systems involved.

For More Information: https://www.nature.com/articles/s41591-020-0968-3

Long covid: How to define it and how to manage it

Authors: Nikki Nabavi, editorial scholar

“Profound fatigue” was a common symptom in most people with long covid, she said, but added that a wide range of other symptoms included cough, breathlessness, muscle and body aches, and chest heaviness or pressure, but also skin rashes, palpitations, fever, headache, diarrhoea, and pins and needles. “A very common feature is the relapsing, remitting nature of the illness, where you feel as though you’ve recovered, then it hits you back,” she said.

Nick Peters added to this definition by highlighting a “distinction between very sick people who have recovered to an extent and [and have been] left with some impact of their severe sickness, versus those who had a relatively mild sickness from the start, in whom it is ongoing.”

Alwan described the fluctuations of her own illness: “It’s a constant cycle of disappointment, not just to you but people around you, who really want you to recover.”

Paul Garner, who also has long covid, described it as a “very bizarre disease” that had left him feeling “repeatedly battered the first two months” and then experiencing lesser episodes in the subsequent four months with continual fatigue. “Navigating help is really difficult,” he said.

Tim Spector said that his team at the Covid Symptom Study had identified six clusters of symptoms for covid-19,1 a couple of which were associated with longer term symptoms, indicating a possible way of predicting early on what might occur. “If you’ve got a persistent cough, hoarse voice, headache, diarrhoea, skipping meals, and shortness of breath in the first week, you are two to three times more likely to get longer term symptoms,” he said.

He said that patterns in the team’s data suggested that long covid was about twice as common in women as in men and that the average age of someone presenting with it was about four years older than people who had what might be termed as “short covid.”

But Spector added, “We do seem to be getting different symptom clusters in different ages, so it could be that there is a different type in younger people compared with the over 65s. As we get more data we should be able to break it into these groups and work out what is going on … which could be very interesting and help us to get early interventions for those at-risk groups.”

Peters said that the data showed fatigue was the most common trait in people who had symptoms beyond three weeks. He also said that around 80% of people who had symptoms lasting more than three weeks reported “having had clear good days and bad days.”

For More Information: https://www.bmj.com/content/370/bmj.m3489