Initially, COVID-19 was called the novel Coronavirus-infected pneumonia due the 2019 Coronavirus causing a pneumonia-type illness. The interim name was aptly chosen based on the fact that COVID-19 is a respiratory tract infection with primarily respiratory tract symptoms. For the most part, the 2019 Coronavirus respiratory symptoms are symptoms typical of a respiratory infection: sore throat, coughing, nasal congestion and phlegm that may be difficult to get rid of. However, there are also more unusual symptoms such as loss of smell and complications such as Coronavirus-related lung function impairment. Read on to learn what are the most common 9 respiratory effects of COVID-19.
(1) Loss of smell
Loss of smell is one of the earliest symptoms of Coronavirus infection. If it’s not caused by seasonal allergies, the common cold, the flu or some other condition. While it is a symptom of neurological origin, loss of smell can also be classified as a respiratory tract symptom because it affects the nose which is considered the first organ of the human respiratory system. It has been found to occur early on in the COVID-19 infection and even precede other more typical respiratory symptoms.
In a study of 214 hospitalized patients diagnosed with COVID-19, smell impairment was the second most common neurological symptom (of the peripheral nervous system), reported in 5.1% of cases. In a report based of data from South Korea, China, Germany and Italy, 2 out of 3 or 30% of confirmed Coronavirus cases experienced some degree of loss of smell. The exact number is theorized to be much higher since asymptomatic and sub-clinically symptomatic individuals are not taken into account as they either exhibit no symptoms whatsoever or have a mild form of the disease that causes them to be overlooked for testing, thus missing diagnosis.
But what exactly causes the loss of smell in Coronavirus infections? The lack of smell (and taste) in Coronavirus infections is due to the virus infecting nervous system cells from centers of the brain responsible for processing information from the senses (sight, smell, taste etc.). Another proposed explanation is direct infection of the nose by the SARS-CoV-2 virus and subsequent immune system involvement which result in inflammation and even cell death. See these 9 neurological symptoms of COVID-19.
(2) Sore throat
A sore throat is one of the most common symptoms of a respiratory infection, including COVID-19. But because it is so common, it is often overlooked as a symptom of COVID-19 in mild forms of the disease. Even so, data collected up to this point shows it is a common symptom of COVID-19 and occurs early in the onset of the disease (see study above). What causes the sore throat is direct infection with the SARS-CoV-2 virus via inhalation of droplets, contaminated food products, dirty hands etc., and subsequent immune system reaction causing an inflammatory response meant to stop the spread of the infection.
(3) Dry cough
Coughing is a symptom typical of respiratory tract infections, which COVID-19 is. COVID-19 causes a type of dry cough which means there is no production of sputum (that is, phlegm or mucus that is coughed up). However, the cough can become productive in which case it may indicate an infection secondary to COVID-19 which demands immediate medical attention. The type of cough specific to the novel Coronavirus infection is acute meaning it is of sudden onset and lasts less than 3 weeks. Also, coughing is the second most common COVID-19 symptom, estimated to occur in almost 2/3 of all symptomatic cases, hence the importance of not dismissing such a symptom these days.
- Is it a Coronavirus cough or allergies?
Since the pandemic overlaps the spring season, there is concern an infection with the novel Coronavirus may mimic seasonal allergy symptoms or seasonal allergies may mask the infection. So in order to tell whether it’s a Coronavirus cough or an allergy cough, make note of other symptoms. For example, allergies cause itchy eyes, nose, throat and ears and watery eyes and a runny nose, but no fever. Coughing with allergies is also limited to when there is exposure to allergens, but subsides soon after the allergen is inactivated (e.g. drinking water, washing face, showering) or removed (e.g. changing clothes). But sneezing is quite frequent, especially with pollen allergies. The novel Coronavirus does not cause itchiness, sneezing or a runny nose, but it does cause persistent coughing and a fever as well as other symptoms typical of a respiratory tract infection (chills, body aches, a sore throat) and digestive symptoms (diarrhea, nausea, vomiting).
The type of cough that typically occurs with COVID-19 is a dry cough, meaning phlegm or mucus is not usually produced, at least not in mild forms of the disease. Should the disease progress to more severe forms, there is usually lung involvement and significant strain on the immune system. These and other factors may increase the risks of a secondary infection, viral, bacterial or other (e.g. viral pneumonia – Note: COVID-19 was initially called the novel Coronavirus-infected pneumonia). A secondary infection such as a viral pneumonia can cause symptoms such as phlegm or mucus production which is a protective mechanism that is meant to help trap viruses, dead immune system cells that fought the infection and other cell debris so they can be removed from the lungs.
(5) Nasal congestion
Nasal congestion, or nose stuffiness in layman’s terms, is a symptom of low incidence in COVID-19 infections. This being said, it can occur and is believed to be a direct effect of the novel Coronavirus SARS-CoV-2 infecting the nasal passages and disrupting normal function and of subsequent immune system involvement causing inflammation as a response to the infection, leading to cell destruction.
However, seasonal allergies are notorious to cause nasal congestion, in addition to a runny nose and postnasal drip. To be able to tell the two apart, make note of other symptoms you may be experiencing. For example, itchiness of the eyes, ears, nose and throat, red and watery eyes, sneezing, excessive mucus production with clear or white mucus, sleepiness or insomnia and cessation of most, if not all symptoms soon after the allergen is inactivated or removed, as well as a history of pollen allergies likely indicate seasonal allergies. But a fever, chills and chills alternating with fever, a relentless cough, body aches, chest pain and shortness of breath indicate a respiratory infection. Also read about the common cold vs allergies: how to tell the difference.
(6) Dyspnea, or shortness of breath
Dyspnea is the medical term for breathing difficulties caused by shortness of breath. It is a symptom typical of lung disease, including respiratory infections of the lung, and heart disease. COVID-19 does cause both lung disease in the form of viral pneumonia, as well as cardiovascular complications such a viral myocarditis, or inflammation of the heart muscle (find out what are the cardiovascular side effects of COVID-19). Both lung and heart disease can present with symptoms such as shortness of breath.
Shortness of breath is a common symptom of COVID-19, although there are cases of shortness of breath with the novel Coronavirus infection, but no fever or other more common symptoms. Data collected up to this point suggest that shortness of breath occurs in roughly 30% of COVID-19 cases. It is estimated that it takes 5 days from the onset of the disease until shortness of breath presents as a symptom. Also, the symptom appears to be indicative of more severe disease and predict the need for intensive care in hospitalized patients (source).
(7) Chest pain, tightness, pressure
Can the novel Coronavirus cause chest pain? The answer is yes, it can. Whether it’s chest discomfort, a feeling of tightness or pressure in the chest or downright chest pain, it can be a sign the Coronavirus infection has advanced to the lungs. If you have a respiratory infection and it progresses to chest discomfort or pain, shortness of breath or a productive cough and a subsequent change in mucus color, it is imperative you seek medical help immediately. Whether it’s the novel Coronavirus or some other respiratory infectious agent, medical attention is needed. Because symptoms such as chest discomfort or pain, but also shortness of breath and other breathing difficulties, fever and a dry or productive cough, or both, are commonly signs of pneumonia which is also a side effect of severe forms of COVID-19.
(8) Lung damage
Another of the more severe respiratory effects of the novel Coronavirus infection is lung damage. SARS-CoV-2 is notorious for having the ability to attach itself to any and all cells containing certain receptors, such as the angiotensin-converting enzyme 2, or ACE2. Some lung cells have a high level of ACE2 expression which is what makes the lungs particularly susceptible to infection with the novel Coronavirus. As it infects the lungs, SARS-CoV-2 tips off the immune system which triggers an inflammatory response directly proportional with the severity of the infection. The chain of events that ensues ultimately causes cell death and results in lung damage that can impair lung function, hence symptoms such as shortness of breath, rapid breathing, difficulty breathing, blue lips and face and complications such as respiratory failure and acute respiratory distress.
- Does Coronavirus cause permanent lung damage?
Given the novelty of the pathogen, it remains to be seen whether or not it causes permanent damage to the lungs. What is known with certainty at this point is that there is Coronavirus-related lung function impairment. An estimated 20% to 30% loss of lung function has been observed to occur in severe forms of COVID-19, although current data is presumed to be too scarce still to report for the entire population.
Coronavirus-related lung function impairment has been hypothesized to be temporary. At the same time, it remains unknown how long it may take to fully recover one’s lung function (months, years). Find out more about what the novel Coronavirus does to the lungs and other body parts it affects in the article What does COVID-19 do to the body?
(9) Respiratory failure
One of the more serious respiratory effects of the novel Coronavirus infection is respiratory failure which is essentially failure to maintain normal gas exchanges between the air in the lungs and blood, resulting in oxygen deprivation. Oxygen deprivation is responsible for symptoms such as blueish skin, especially blueish lips and face, or confusion. Infectious agents causing infections of the respiratory tract are one of the main causes of respiratory failure. The novel Coronavirus SARS-CoV-2 is such as infectious agent. It is known to directly infect the lungs via the ACE2 receptors (angiotensin-converting enzyme 2) on the surface of lung cells and lead to lung tissue damage that can result in respiratory failure.
The effects of the novel Coronavirus infection on the lungs may culminate with Acute Respiratory Distress Syndrome (ARDS) which is essentially respiratory failure caused by infiltration of fluids in the lungs due to lung tissue damage. ARDS is a potentially fatal complication of COVID-19, a sign of organ dysfunction.
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