Why can’t I take an antibiotic for my cold: A primer on viruses.

This is another article I put up on my Medium.com account.

 

As I’ve mentioned in a prior post, and is likely noted in other posts on my blog (and numerous medicine related sites), a virus is genetic material — either DNA or RNA — encapsulated in a protein coat. In some cases there is also a lipid envelope around the protein coat.

This gets to the crux of why antibiotics don’t work on viruses. Viruses need a living cell to reproduce, and does so by co opting the metabolic pathways of the host cell it invades. Normal cells use DNA to pass genetic information from one (cell) generation to the next. The DNA gets transcribed into RNA which is then taken to the cytoplasm of the cell (in eukaryotic cells) or other parts of the cell (in bacteria/non eukarotic cells), where proteins and ribosomes/ribosomal RNA read the RNA and ‘transcribe’ it into a protein.

In some cases, viruses do code for novel (relative to cells) enzymes and/or proteins. EG, reverse transcriptase in HIV viruses (HIV is a RNA based virus, but it’s genetic code is converted to DNA for replication). Other viruses replicate the RNA directly for future virus particles. However, as I note above, the vast majority of the replication is done by the cell’s own proteins.

This is why antibiotics don’t work on viruses. Bacteria have have different types of cell walls than human cells. They require chemicals that our cells just don’t use. Penicillins and cephalosporins interfere with the cell wall construction as an example. Other antibiotics target pathways our cells don’t have (eg, trimethaprim-sulfamathoxazole targets folate production in bacteria. Our cells don’t produce folate so it doesn’t affect us). There are other examples that could be used as well that utilize a chemical’s affinity for a bacterial protein/enzyme more than for the equivalent in human cells.

Having said this, there are some antiviral drugs for some (not all) viruses. These target the proteins viruses code for that are novel to the specific virus/virus family.

Now at this point, you might be thinking “well, my great aunt _namehere_ was told she had a viral pneumonia, but when she got admitted to the hospital she was given antibiotics”. In some cases, a viral infection goes through its course and the person can develop a secondary infection that’s bacterial in nature. In that case, antibiotics might be warranted. Or she was given them to prevent the superinfection/secondary infection. This is true of any viral illness, even corona viruses, rhinoviruses and covid 19.

Coronavirus biology 101

This is a post I put up in my Medium.com account.

Initially I was going to write specifically about covid19 and how to prevent getting (perhaps — or at least decreasing the chances of getting) it. I realized there are more than enough articles already about that subject and can be found on the CDC website.

Instead I decided to write more generically about Coronaviruses and doing so, hopefully address questions some people might have, and that might not be answered by posts that deal with coronovid19. First of all a virus, unlike bacteria, algae, fungi and animal cells, is just a bunch of genetic material encapsulated by protien (and in some cases, a lipid coat). They don’t have any mechanism to move, metabolize, ingest nutrients, replicate genetic material etc. Viruses are entirely dependent on infecting cells, and co-opting their metabolic pathways to reproduce. With some, there are some genes that code for things that cells — be they bacteria or eukariots — don’t have. An example would be Reverse Transcriptase in HIV viruses (Reverse Transcriptase reads RNA from the HIV genome and encodes it into DNA for use in viral replication. The virus is still dependent on the cell for the actual copying and reproduction of said genetic material and of making new viruses).

In the case of Coronaviruses, the genetic material is single stranded RNA. There are other families of RNA based viruses, such as Rhabdoviruses (EG the virus that causes rabies), Orthomyxoviruses (one such causes Measles), and others. The virus that causes HIV also uses RNA as genetic material, but by some classifications isn’t considered an RNA virus because the RNA has to be coded back into DNA for replication.

Because viruses don’t have the proteins/cell parts/etc to replicate themselves, as I note above, they’re dependent on a host cell for replication. This is why antibiotics don’t work for the common cold (or other viral illnesses. Though in some cases, such as HIV and some viruses closely related to the chicken pox virus, there are antivirals that work). As they don’t have a cell wall that’s different from our on cells’ walls, antibiotics that affect the building of the bacterial cell walls won’t work. For example, penicillin and cephalosporins interfere with an enzyme and chemical specific to what bacteria use to make cell walls. Other antibiotics interefere with enzymes and other proteins that are different enough from human cell proteins that the antibiotics don’t affect us. Others (eg, bactrim, aka trimethaprim-sulfamethoxazole) interefere with bacteria specific metabolic pathways.

Having said that, some viruses do need a particular enzyme or protein to reproduce that human (and mammalian cells in general) don’t have and do provide a target for medications. These are different than antibiotics.

As for coronaviruses, many are respiratory pathogens. In humans some coronoviruses cause the common cold. As one might expect or know, transmission can be through inhaling droplets that have active virus in them (and is why sneezing and coughing can spread the common cold, COVID-19, and so forth — the virus particles can become aerosolized). They can remain infectious on surfaces. Though the amount of time they can remain viable and therefore infectious is different for each virus and varies as well due to environmental conditions.

Anyhow, I hope this helps people understand why for viral illnesses, doctors don’t just hand out antibiotics. For COVID 19 information, use the link I have at the start of this post (it will take you to the appropriate page at the CDC).

Sleep, Part 2

I realize it’s been a while since my last post. As promised, I’m putting up this addtional post on sleep.

Getting adequate sleep promotes good health, and is important in functioning well during the day.  This includes driving (if you’re sleep deprived, it’s as though you’re driving with a high blood alcohol level!). Rather than totally repeat what I posted last time, I’ll  talk mostly about how to maintain good sleep hygiene.

  1. Go to sleep and wake up at the same time every day, even on weekends.
  2. Avoid sedatives (even alcohol) to go to sleep. Granted there might be occasions where using something like Zolpidem for a night or two is apropriate, but all medications can effect the sleep cycle in untoward ways (some affect how deeply one sleeps, others can affect how much REM sleep one gets).
  3. If you snore (if you live alone you might not know), or are overweight there’s a high chance of you having OSA (obstructive sleep apnea). OSA can predispose one to arrythymias, diabetes, and daytime sleepiness for starters.
  4. Don’t eat within three hours of eating (this is more to prevent reflux than food’s effect on sleeping) and avoid caffeinated beverages too late in the day.
  5. Certain foods such as cherries can affect melatonin levels (whether it is because they contain melatonin or affect it’s degredation by the body is a different story), so having foods which can increase melatonin levels might help sleep. Though my preference would be to have whole, unrefined foods rather than taking suppliments.
  6. Regular exercise can help people sleep better.
  7. As mentioned in the previous post, if you can’t fall asleep in about 10-15 minutes, get out of bed and do something else for a while
  8. Use getting into bed for sleeping (and enjoying one’s spouse/significant other), not for reading, watching TV or other activities.

 

 

Facilitating Story-telling Leads to Patient Growth | Sarah Monahan, RN, QMHA | LinkedIn

Facilitating Story-telling Leads to Patient Growth | Sarah Monahan, RN, QMHA | LinkedIn.

I came across this article in linkedin.  It’s an interesting idea because when a physician uses the term “challenging patient” (s)he is likely referring to one of two kinds of patients. One kind is one with a lot of health problems, some of which interfere with the treatment of others (or perhaps just a couple complicated health issues).  However it is often used to refer to patients who are hard to reach/not very compliant/have poor insight to how their behavior affects their health.

Many times I ask myself how did the latter kind of patient get to where they are.  I haven’t yet used this with any of my patients, but it does seem like an interesting way to help patients.

Sugar: Madness Over a Macronutrient – MPR

Sugar: Madness Over a Macronutrient – MPR.

This article is interesting to me for a few reasons. One is that the current fad of calling refined sugar ‘evil’ (as well the fad of considering high fructose corn syrup as even worse than Satan) is something that has come and gone. This is something that the article does point out repeatedly.

The other is that, as with  many things dietary and lifestyle related, perhaps caution with somethings is warranted but that for many things (like sugar), a moderate approach is better.  It’s perhaps wiser to avoid refined sugar as much as possible (no two liter bottles of regular soda, have candy only occasionally, etc), but not get upset if one does have a can of soda or a piece of candy on occasion. If having something with a lot of refined sugar once in a while helps someone eat in a healthy manner, it’s better than going overboard with too much refined sugar. A can of soda or a piece of cake isn’t going to undo one month, or one week for that matter, of eating a healthy diet.

I would no more suggest that people don’t exercise because they might get injured than I’d say cut out sugar entirely. Better you do both (exercise and have sugar) moderately. That way if you do have something “bad” for you then won’t beat yourself over the head when you do so.

Talking with your doctor.

Since I’m coming up on my second anniversary here on wordpress (I joined in late December 2012 and first published this post in January of 2013), I thought I’d reblog it

doctorgladstone

As this is my first blog post I’d like to start of by saying a few of things. One is thank you for visiting my blog. The other is that I won’t be responding to specific questions on this blog, except perhaps in a relatively generic way. In other words, talk with your primary care physician before you act on anything you read in this blog. For that matter, it’s probably a good idea no matter where you get your medical information from. Lastly, I have yet to decide on a schedule for posting. I don’t know whether it will be once a week, once a month, something in between or even less frequently.

And now to the subject of today: suggestions for talking with your doctor and getting the most out of your visits.

As a practicing physician there are times when I think my patients and I speak…

View original post 1,061 more words

An aspirin a day….

For this post I thought I would write about staying healthy, but in a slightly different manner than I’ve done in previous blogs. In older blogs I’ve written about screening, vaccinations, etc.  In this one I thought I’d talk about using a medication to stay healthy, and in this case talk about aspirin.

Aspirin has been around for more than 100 years, and perhaps is a bit under appreciated since it is an over the counter medication (meaning one can buy it without a prescription). It is also something that is derived from a natural product. Willow bark had been used to treat fevers  and it was eventually found that salicylic acid was the active ingredient. Salicylic acid was then derived from this. I won’t go into the chemistry of this (I figure if you’re a bit of science nerd like I am you probably already know, and if not I don’t want to bore you).

Most people probably think of it as a pain killer or a headache medication.  It is much more than that. Aspirin plays an important role in treatment of patients who’ve had heart attacks – it helps treatment and also helps decrease the death rate from heart attacks. It is used in primary prevention heart disease as well. In the past high dose aspirin was used in the treatment of Rheumatoid Arthritis. It’s use in this latter population (at least for treatment of Rheumatoid Arthritis) has been eclipsed by other medications. However it still should be used to treat/prevent heart disease in this group of patients.

Use of aspirin in ischemic stroke patients is advised as well.

Though less studied at this point, aspirin use to prevent recurrent deep venous thrombosis, is a consideration (this is after someone has been treated with coumadin for an acceptable length of time).   A link to a review on this subject can be found here: http://www.ncbi.nlm.nih.gov/pubmed/24745726

There is some evidence linking aspirin intake to a decreased chance of developing colon cancer. At the moment there is not enough evidence to routinely suggest people take aspirin solely to prevent colon cancer. There is also some evidence that it only helps prevent colon cancer in certain groups of people – those that have a particular form of a particular gene. The only recommendation is for aspirin to help reduce the risk of heart disease.

Aspirin, like any other medication, has its downside as well. It can cause stomach ulcers. If the ulcers are large enough they can cause a lot of bleeding. It should not be used in children, except in rare circumstances and even then only then under the guidance of a pediatrician or other health care provider who provides a lot of treatment to children (EG pediatric rheumatologists, family practice physicians, etc).

Should doctors be environmentalists/advocates for the environment?

One thing that sometimes crosses my mind is whether physicians and other health care workers should also be environmentalists. After all the environment does play a role in people’s health. Contaminated water lead to outbreaks of water born diseases (John Snow, a London physician in the mid 1800’s is credited [at least in part] for ending a Cholera outbreak  by convince authorities to block use of a water pump at the center of the outbreak).  The cholera outbreak following the earthquake in Haiti several years ago is another example. Polluted air leads to increased respiratory disease.

Though in the U.S. and other developed nations with functioning governments, the chances of contaminating water with sewage is low. The one exception could be when severe weather overloads the septic systems in an area. However even in the Northeast U.S. where I live, beaches are monitored for coliform bacteria (this is a generic term for bacteria that live in our guts) and closed when the counts are too high.

Air quality effects health of populations – there were reduced hospitalizations in parts of Ireland after there were bans placed on burning coal.  When lead was taken out of gas (well, actually prevented from being put in gasoline…), blood levels of lead dropped. It’s a neurotoxin and high blood levels can affect brain development in children (hence the ban of lead in paint in the U.S.), and function in adults. For water, it’s not just bacterial contamination/pollution that is important. Chemical pollution can also affect health. Toxins can build up in the food chain – this is part of the reason why it’s suggested that pregnant women limit their intake of certain fish, for example. Mercury builds up in fish at the top of the food chain, such as in Tuna, and can adversely affect people neurologically and adversely affect developing brains. Studies continue to show an association between air pollution and respiratory  deaths.

Given the number of of medications that are derived in whole or part from the plant and animal world (aspirin, reserpine, taxol, digoxin, penicillin, streptomycin, are all plant and fungal products), an argument could be made that making sure plant and animal species don’t become extinct because it might affect future drug discovery. Before you say “but wait,….” think of this: heparin is derived from the linings of Pigs. ACE inhibitors were discovered through research on snake venom. There are some newer medications for Type 2 Diabetes which are derived/grew out of research on saliva from a lizard known as the Gila monster.

 

Men’s Health

My previous post was about women’s health. In this post I am going to review a couple of aspects of Men’s health. Most of the things men should be doing are things  people of both genders should be doing to stay healthy: stop smoking, exercising, eating a healthy diet, maintaining a healthy weight (or loosing weight if overweight).  Staying up to date with immunizations, such as yearly flu vaccination, is also important. Getting screened yearly for hypertension is important. Skin cancer screening is also important, though this might only need to be done every 2 years depending on whether you have any suspicious moles or lesions, prior history, you and your dermatologist’s comfort levels for yearly vs every other year screening. Cholesterol screening at appropriate intervals is important (a healthy male in his 20’s with no risk factors for heart disease only needs his cholesterol checked every 5 years or so. Older men and those with risk factors require monitoring more frequently and perhaps yearly if risk factors are present or if on treatment to lower cholesterol). I won’t get into more details about screening or other issues covered already in other posts.

Perhaps the biggest controversy in mens health is prostate cancer screening. The U.S. Preventive Services Task Force actually recommends against routine screening for prostate cancer in healthy men of all ages. Even the American Urological association recommends against screening for prostate under the age of 64 and in men with life expectancy of less than 10 years. For screening, a conversation with your primary care doctor is warranted before getting the test. The main reason it is controversial is that one runs the risk of finding a prostate cancer which is indolent (slow growing), non aggressive that one is likely to die with than of – meaning one is likely to die of some other disease before the prostate cancer becomes a problem. At this time we don’t have enough information to know what low grade/early prostate tumors are going to become aggressive and turn into problems. One therefor runs the risk of over treating something that would not be a problem.

Occasionally I’ve had patients ask for testosterone levels and had to talk to patients about testosterone replacement. Testosterone levels are not something  routinely checked unless there is a clinical reason (if there is loss of libido, erectile dysfunction, and so forth, then it’s worth getting). Testosterone replacement has been associated with an increased risk of heart disease so replacement benefits needs to be worth the increased risk.

Although I probably run the risk of repeating myself by saying this, but reducing the risk of heart disease, lung cancer, colorectal cancer by exercising, watching what one eats and getting appropriate screening applies to men’s health as well.