Dr K K Aggarwal: asymptomatic

Showing posts with label asymptomatic. Show all posts

Monday, March 16, 2020

We are learning every day and our knowledge about corona is changing every day COVID 19

We are learning every day and our knowledge about corona is changing every day

Infected people without symptoms might be driving the spread of coronavirus more than we realized?

Dr K K Aggarwal

President CMAAO, HCFI and Past national President IMA

New studies and a large coronavirus outbreak in Massachusetts bring into question reassuring assertions by US officials about the way the novel virus spreads.

So far, emphasis has been that the virus is spread mainly by people who are already showing symptoms, such as fever, cough or difficulty breathing. But it appears that a Massachusetts coronavirus cluster with at least 82 cases was started by people who were not yet showing symptoms, and more than half a dozen studies have shown that people without symptoms are causing substantial amounts of infection.

WHO has so far emphasized that asymptomatic transmission can happen, but have said that it's not a significant factor in the spread of the virus.

Let’s see opinions

1. CDC says "Some spread might be possible before people show symptoms; there have been reports of this occurring with this new coronavirus, but this is not thought to be the main way the virus spreads,"

2. Coronavirus response coordinator, Dr. Deborah Birx, seemed to strike a somewhat different note on asymptomatic transmission “ She said they're trying to understand people under the age of 20 who don't have "significant symptoms" -- "Are they a group that are potentially asymptomatic and spreading the virus?"

3. "We now know that asymptomatic transmission likely [plays] an important role in spreading this virus,": Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

4. In an article two weeks ago in the New England Journal of Medicine, Bill Gates, co-chair of the Bill and Melinda Gates Foundation, expressed concern about the spread of the disease by people who haven't yet developed symptoms, or who are only a bit sick.

"There is also strong evidence that it can be transmitted by people who are just mildly ill or even pre-symptomatic. That means COVID-19 will be much harder to contain than the Middle East respiratory syndrome or severe acute respiratory syndrome (SARS), which were spread much less efficiently and only by symptomatic people,"

5. "Asymptomatic and mildly symptomatic transmission are a major factor in transmission for Covid-19,": Dr. William Schaffner, a professor at Vanderbilt University School of Medicine and long-time adviser to the CDC.

Monday, August 1, 2011

Ask Dr KK: When should one decide for carotid endarterectomy or removal of blockages with catheter?

It is indicated for selected medically stable patients with asymptomatic carotid stenosis of 60 to 99 % who have a life expectancy of at least five years, provided the perioperative risk of stroke and death is less than 3 percent. However, long-term outcomes for patients with carotid blockages managed by intensive medical therapy may be similar to surgical management.

About the author: Dr K K Aggarwal is Padmashri and Dr B C Roy National Awardee, President Heart Care Foundation of India, Dean Board of Medical Education Moolchand Medcity, Sr. Physician & Cardiologist, Visiting professor Clinical Research DIPSAR, Past President Delhi Medical Association, Past Academic and Research Wing Head IMA, Chairman Ethics Committee Delhi Medical Council.

Ask Dr KK:What are the medical interventions for carotid blockages?

The interventions are management of hypertension, smoking cessation, use of statin drugs and low-dose aspirin.

Ask Dr KK: What is symptomatic carotid artery blockage?

Patients who have had a stroke or transient ischemic attack (mini paralysis) due to carotid stenosis are considered symptomatic and often benefit from carotid revascularization. Symptoms means transient or permanent focal neurologic symptoms related to the affected artery (same side loss of vision, opposite side weakness or numbness of an extremity or the face, difficulty in speech or loss of speech). Patients with nonspecific neurologic symptoms (dizziness or syncope/near syncope) are not considered in the definition of symptomatic carotid stenosis.

Ask Dr KK: When to screen for carotid blockages?

Carotid duplex ultrasonography is not recommended for routine screening of asymptomatic patients who have no clinical manifestations of or risk factors for atherosclerosis. However one should screen asymptomatic individuals who have:

Carotid bruit
Peripheral arterial disease
Coronary disease
Aortic aneurysm
Two or more risk factors for atherosclerotic disease.

Ask Dr KK: At what prevalence is screening beneficial?

Only at prevalence rates of over 20 % significant benefits are seen with at best about 100 strokes prevented for every 10,000 screened at 20 percent prevalence. Clinical features cannot identify asymptomatic individuals likely to have carotid stenosis. The annual risk of stroke in patients with asymptomatic carotid artery stenosis is relatively low.

Ask Dr KK: How common is carotid artery blockages in general population?

The prevalence of carotid stenosis in general population is less than 1 %. Screening with resultant surgical procedures causes more strokes than it can prevent. For severe (≥70 %) carotid stenosis, the prevalence increases with age from approximately 0 to 3 %.

Ask Dr KK: How risky is carotid stenting or surgery?

Both endarterectomy and carotid stenting are associated with an increased 30-day risk of stroke and death. These are in the range of 2.3 to 3.7 percent for endarterectomy.

About the author: Dr K K Aggarwal is Padmashri and Dr B C Roy National Awardee, President Heart Care Foundation of India, Dean Board of Medical Education Moolchand Medcity, Sr. Physician & Cardiologist, Visiting professor Clinical Research DIPSAR, Past President Delhi Medical Association, Past Academic and Research Wing Head IMA, Chairman Ethics Committee Delhi Medical Council.

Ask Dr KK: How reliable is Doppler Carotid study for detecting blockages?

The reliability is variable and operator-dependent.

Ask Dr KK: What are the screening methods available?

1. Carotid ultrasound followed by catheter angiography

2. Carotid ultrasound followed by MRA

3. Ultrasound alone

Ask Dr KK: Should I screen each patient for presence of carotid neck artery blockages?

The guideline says no. The potential harms include risks associated with the screening procedure itself like false positive findings leading to anxiety and the potential for unnecessary surgical procedures. Carotid angiography is associated with risk of neurological complications including stroke, with rates ranging from 0.1 to 1 %.