“Acute Cough” means one going on 2-3 weeks. This arbitrary definition is because the vast majority of cases are due to simple viral infections, which get better on their own in that time frame. Therefore, we don’t order lots of tests, until viruses are no longer a consideration.
So we won’t consider a lot of diseases, like Lung Cancer. Sure, that causes a cough, which has to begin sometime, on its Day #1. But there’s not a specialist nor clinician in the world who’d find it then. To do so would mean getting CT scans on everyone with cough — the radiation would cause some cancers!
Diagnostic Step #1 for Acute Cough is to determine whether it’s due to a disease of the Upper or Lower Respiratory Tract (click the links for diagrams & anatomy). This is especially important, because Upper Respiratory Conditions don’t tend to kill, like lower ones might. Our limited list of possible causes is as follows.
|zzzUpper Respiratory Tract Conditions||zzzLower Respiratory Tract Conditions|
|** Common Cold|
** Allergic Rhinitis (“Allergies”; Hay Fever)
** Tracheitis (“Croup” in children under 3)
** Hypertension medication (“ACE-Inhibitors”)
** (if sudden onset while eating: Aspiration)
** Influenza (& other viruses)
** COPD (acute exacerbation)
** Acute Bronchitis
** Heart Failure
** Pertussis (“whooping cough”)
Ever since early 2020, whenever a patient has a recent cough, the first thing we think about is Covid-19. We don’t even let them in the building, and arrange for them to get a Covid test. But some patients with cough need to be seen right away, even it’s just briefly. Every office and clinic has its own mechanism, maybe whisking them to a designated exam room, maybe sending them to an ER. These are patients who, in addition to a cough, also have:
- “True” Shortness Of Breath [also defined below].
- Fever (>100.6⁰ F; 38⁰ C) [especially if >60 years-old]
If the Covid test is positive, we know what they have. If it’s negative, since 15% to 20% of tests can be false-negative, we likely act as if they really have Covid, tell them to isolate (google: “CDC Covid Isolation”), and test them again in 1-2 days. If a repeat test is still negative, they most likely do not have Covid, & we continue our diagnostic thinking as described below.
While we’re waiting for the results of Covid testing, we still try to figure out what else they may have. If they have a fever for less than 4 days and it’s Influenza season (“the flu,” Dec. to April), and we may just treat them for it. If they have true shortness of breath, we’d want to somehow have them examined in person, maybe in an ER.
Going on from Covid, to diagnose “Acute Cough,” we want to know if there’s also
- Upper Respiratory Symptoms, and NO Shortness of Breath;
- Some Shortness of Breath, but NO Fever; OR
- NO Upper Respiratory Symptoms, NO Shortness of Breath, NO Fever
- Can also click link for blurb on Sudden Onset of Coughing While Eating
You can click those links now, or read on a little more when they’ll appear again.
Basic Concepts for Diagnosis
Interestingly, it’s impossible for anyone to feel where a cough “is coming from,” because all cough is due to irritation of cough receptors (nerves), which are only present at the bottom of the throat & down into the trachea. Upper respiratory conditions cause a cough because mucus from the nose drips down the back of the throat into the trachea. Asthma & pneumonia cause cough because the bronchi have microscopic hairs called cilia which sweep mucus up to the trachea.
I’ve had patients slap their chest and insist, “I feel the cough is here!” That’s because enough post-nasal drip triggered the cough reflex, which made the chest muscles contract vigorously. But the origin was from the nose. Indeed, debilitated and bedridden persons may suffocate from pneumonia without any cough, because their immune system is so weak that the lungs’ defenses can’t clear the pus upward.
We distinguish upper respiratory tract disorders from lower ones by:
** Upper Respiratory Symptoms:
- Nasal Discharge (“runny nose”) [we say “my nose is running,” but not a “running nose”]
- Nasal Congestion (Stuffed Nose — air doesn’t seem to want to get in)
** Shortness of Breath (SOB), if truly present, means lung involvement [we unapologetically use the very common medical abbreviation]
- “True” SOB does NOT mean feeling weary and fatigued, or a sense of suffocating during a coughing spell, or feeling unable to breathe through a clogged-up nose. It does not only occur while thinking deeply.
- “True” SOB always worsens with exertion.
- A person who feels they have to huff-and-puff while climbing a hill or stairs, which they easily could have whisked up a few weeks earlier, definitely has something wrong with their lungs or heart (or a major obstruction in the trachea, very rare).
** Listening to the Lungs by stethoscope (& maybe the heart too)
** Fever, i.e. temperature over 100.6° F. (38.0° C.)
1. If Upper Respiratory Symptoms are prominent, we know the nose is involved. But the lung might be too.
2. If there’s cough plus true SOB, we’re dealing with the lung (or, rarely, the heart).
3. If we hear abnormal sounds in the lung, well, something’s happening there.
NOTE that here we’re discussing a patient who’s mainly concerned about a Cough, but might also have some SOB. We discuss diagnosis of Shortness of Breath more under its own topic.
So now let’s put our key information together. Pick from the links below to understand how we clinicians think, as we attempt to diagnose — Acute Cough PLUS:
- Upper Respiratory Symptoms, and NO Shortness of Breath
- Some “True” Shortness of Breath, but NO Fever
- NO Upper Respiratory Symptoms, NO Shortness of Breath, NO Fever
- Sudden Onset Coughing While Eating
Advice to Patients who Phone In
When my patients wonder if they need to see me for an acute cough, I give the following advice:
First, get a Covid test, and isolate. If the test is negative and you’re still sick, get another test in 2 days. If you’re short of breath, especially when you walk or exert, go to an ER.
Most coughs are due to harmless viruses that get better on their own. But do request a visit if 2 weeks have gone by and the cough hasn’t started to get even the least bit better:
- This is especially recommended if there are no upper respiratory symptoms
- If there’s true SOB → get seen much sooner (the more the SOB, the sooner)
- Cough + Fever + true SOB → get seen right away (maybe in ER)
- Cough + Fever + Pain with Breathing → get seen right away (maybe in ER)
- Cough + Fever + Elderly → go to ER
- Cough + true SOB + Elderly → go to ER
See also Acute Cough for the clinician’s condensed thought-process when face-to-face with a patient.