Is It a Cardio Issue or Pulmonary? How to Differentiate

A major challenge facing primary care physicians arises when patients present with symptoms such as shortness of breath, fatigue, or difficulty breathing that can be respiratory or cardiovascular in nature, or in rare cases, both. Medscape Medical News asked four leading primary care experts which considerations should go into a differential diagnosis, which conditions are most concerning, and which factors indicate that it may be time to refer to specialty care. 

Interstitial lung diseases (ILDs), for example, affect approximately 400,000 individuals in the United States. Their relative rarity means ILDs are frequently underrecognized. In addition, diagnosis can be challenging, because their symptoms — such as shortness of breath and coughing — are shared with more common conditions like asthma, chronic obstructive pulmonary disease (COPD), and various heart disorders. This symptom overlap often results in misdiagnosis or delays in identifying the true cause, which in turn postpones appropriate treatment and diminishes patients’ quality of life.

To address these challenges, the American College of Chest Physicians worked with primary care physicians to create a toolkit specifically for the primary care setting. This resource is intended to improve early recognition of ILD signs and symptoms, ultimately supporting more accurate and timely diagnoses. 

COPD and heart failure, in contrast, are two very common presentations with overlapping symptoms. But there are ways to tell them apart. There also are many less common respiratory conditions that can masquerade as cardiovascular, so it takes some clinical acumen and experience to make the diagnosis. 

A classic sign of heart failure is orthopnea, or shortness of breath when a patient lies down because the blood or the fluid redistributes. Sometimes shortness of breath means COPD or asthma, or COPD in conjunction with asthma. 

“With classic heart failure you gain fluid, so you have weight gain. With pure respiratory issues, that isn’t something you typically see, so there are differentiators between the two,” said Wilson Pace, MD, professor emeritus of family medicine at the University of Colorado in Denver, Anschutz Medical Campus, who currently works as chief medical and technology officer at the DARTNet Institute.

“My first message is just try to make the right diagnosis,” said Alan Kaplan, MD, chair of the Family Physician Airways Group of Canada. An incorrect diagnosis can lead to inappropriate therapy, which can cause side effects and other issues to come up, he added. 

It’s primary care 101, but getting a comprehensive patient history and performing a physical examination are great places to start. An objective measurement of lung function such as spirometry or peak flow should also be performed. 

Learning From History

Without a prior diagnosis of a chronic lung disease, “clearly you have to think more of an acute process — like an acute pneumonia or a severe bronchitis — as opposed to a chronic disease like COPD or asthma,” Pace said. 

There are other common conditions that cause shortness of breath and cough, Pace added, such as a pulmonary embolus. “So really, in the primary care sphere, it would be pulmonary embolus, pneumonia, acute bronchitis, COPD, and heart failure,” he added. 

“You obviously have to get a good patient history. The physical diagnosis is very helpful, but many people with cardiac disease — unless they have heart failure, for example — may really not have any physical findings,” said Barbara Yawn, MD, a researcher and adjunct professor of family and community health at University of Minnesota at Minneapolis.

With heart failure, a patient may have jugular venous distension or edema, especially pedal edema in their ankles and feet. In contrast, with pulmonary disease, on the physical exam you may hear wheezing, diminished breath sounds, or nothing abnormal, she said, “so it can be tricky.”

To make things even more complicated, sometimes complex respiratory issues cause heart problems over time. One of the most common secondary diagnoses in long-standing COPD is heart failure, and in that case, it’s typically right-sided heart failure from the lungs themselves. In this case, “as you treat the lung disease, the heart starts feeling better, or you treat the heart and the lung disease gets better,” Pace said.

Rule Out the Most Common Conditions

Yawn recommends ruling out heart failure and other cardiovascular diseases first. Ask about angina. Keep in mind that women often have different presentations of angina compared with men, she added. 

With COPD, emphysema, and other chronic lung diseases, patients will report that some days are better than others — but there are no days when they feel perfectly fine. This can help distinguish more complex respiratory conditions from others with episodic symptoms, such as asthma or allergies. 

Questions to ask during patient history-taking include:

• Did they smoke? When did they stop? How much did they smoke? Were they exposed to smoke from others?
• Were they born prematurely?
• Did they experience a lot of infections when they were young children?
• What is or was their occupation? Did they work in an industry with a lot of fumes, particularly 15 or 20 years ago when workplace protections were fewer?
• Were they bakers? “People are always surprised about bakers, but flour is really everywhere in the air in a bakery, and the lungs don’t like inhaling flour,” Yawn said.

Patient age can also guide a differential diagnosis. Asthma is far more common in younger adults than it is in older adults, whereas both chronic respiratory disease and cardiovascular disease increase in likelihood with age, said Neil Skolnik, MD, professor of family and community medicine at the Sidney Kimmel Medical College, Thomas Jefferson University, in Philadelphia. A different scenario is someone in their fifties, sixties, or seventies who might have hypertension, high cholesterol, or a history of diabetes. “All of those things make cardiovascular disease more likely, like coronary artery disease or congestive heart failure.”

To Refer or Not to Refer

“It’s science, it’s art, but it’s also the experience,” Yawn said when asked what factors lead to a specialist referral. If someone comes in acutely short of breath with chest discomfort, she sends them to the emergency room. “That one is reasonably straightforward.”

“It’s really important that if you’re feeling unsure or uncomfortable, it’s time to refer or at least consult with a specialist,” Yawn added. Sometimes the decision is made for primary care doctors, who are required to refer for pulmonary function testing or stress testing, for example.

In other instances, a patient may not respond adequately in a primary care setting, especially with more complex respiratory or cardiovascular conditions. 

“Those are situations where you get to the end of your rope and you say, ‘I don’t know what’s going on here,’ and you send them off to the pulmonologist for biopsies and further workup,” Pace said.

There is a long list of rarer conditions, such as allergic pneumonitis, eosinophilic pneumonitis, and pulmonary fibrosis, but those are not primary care diagnoses, he added. 

In the end it comes back to basics, Pace said. “I still believe, despite all of the fancy things we can do in medicine these days, that for the first-contact person for many, the primary care provider, it’s the listening, getting a careful history, and thinking through the questions that make a difference.”