Reflections on an elderly man with breathlessness

When a 68 year old man, a smoker, presents with breathlessness and rhonchi in the lungs, with an x-ray chest showing emphysema (increased air trapping), the most obvious clinical diagnosis is COPD. 

Since bronchial asthma is also a disease with rhonchi in the lungs, one may be asked whether this patient has bronchial asthma. As a rule of thumb, one can say that COPD is more likely in older individuals with wheezing while bronchial asthma is more likely in younger people. Having said this, we must not forget that late onset bronchial asthma is possible and COPD can occur in younger individuals with, say, alpha one antitrypsin deficiency. So age is not an absolute differentiating criteria. 

What are the more reliable differentiating points between COPD and bronchial asthma? In the history, an episodic nature of breathlessness or a diurnal variation in breathlessness, with completely asymptomatic periods in between, are strong points in favour of bronchial asthma. Based on spirometry, one can say that if the FEV1: FVC ratio remains below 0.7 after adequate bronchodilator therapy, the diagnosis is COPD. It is important to know that the reversibility of the bronchial tree should be used diagnostically only in the stable phase, not during a time when the patient is having an acute exacerbation.

Rhonchi in the lungs indicate bronchial narrowing. The typical physical sign of obstructive lung disease is rhonchi on auscultation but the absence of rhonchi does not rule out an obstructive lung disease. 

The clinical context in which one detects rhonchi is very important. In elderly people and in those with cardiovascular risk factors, the possibility of heart failure must always be considered as a differential diagnosis when they have rhonchi and crepitations in the lungs. When in doubt, treat with diuretics and bronchodilators until the diagnosis is clear. Based on the proverb "All that glitters is not gold" we have the clinical saying: All that wheezes is not asthma. This implies that wheezing need not always be due to bronchospasm but can also be due to extrinsic compression by edema or a mass.

The PEFR is a useful tool for managing patients with obstructive lung diseases because it gives us an objective parameter to measure the degree of bronchospasm. In this context, I wish to emphasise that even in COPD there is always an element of bronchospasm. The PEFR has both diagnostic and therapeutic implications. With the PEFR we can diagnose asthma and differentiate between asthma and COPD based on the degree of reversibility in readings. With the PEFR, we can also titrate medication in bronchial asthma. We know, for example, that we must prescribe oral steroids to a patient with bronchial asthma whose PEFR remains persistently below 50 percent of expected.

Crepitations in the lungs can indicate a number of possibilities according to the clinical situation. Consolidation of the lung, bronchiectasis, interstitial lung disease and left heart failure are some of the conditions that must come to mind when crepitations are detected in the lungs.

A low PaO2 alone or in combination with a high PaCO2 signify respiratory failure in a patient with COPD. What does a normal PaCO2 in a patient with acute exacerbation of asthma or COPD indicate? It indicates that there is insufficient alveolar ventilation and is a red flag. This is the rule of thumb: In all people who are hyperventilating, the PaCO2 must be low. If it is not low, it means there is insufficient alveolar ventilation. A danger sign.

Hyperinflation of the lungs is generally said to be present when we see that the domes of the diaphragm are flat and the right dome of the diagphram is below the anterior end of the 6th rib. In lungs with hyperinflation, the cardiac show will appear smaller than usual. If it appears normal or enlarged, cor pulmonale or some other form of heart disease must be suspected. 

In patients with COPD, pay particular attention to the pulmonary arteries. The main pulmonary artery is the convexity below the aortic knuckle on the left heart border. It is normally smaller than the aortic knuckle. When the main pulmonary artery is as big as or bigger than the aortic knuckle, one can suspect that it is enlarged because of pulmonary hypertension. Remember: Perihilar shadows in COPD can be due to enlarged pulmonary vessels.

An opacity in the lungs on chest x-ray only means that the air in the alveoli has been replaced by something else. Opacities in the lungs occur in consolidation (inflammatory fluid), pulmonary edema (non-inflammatory fluid), fibrosis and collapse as well as mass lesions. You will need to evaluate the nature of an opacity by looking for associated signs in the x-ray and by knowing the clinical features of the patient. Some opacities have characteristic associations - like consolidation in the upper lobes of the lungs strongly suggest tuberculosis infection. But these are not absolute and therefore not diagnostic. Upper lobe opacities for example can be due to silicosis, malignancies, granulomatous diseases, and Klebsiella pneumonia.

The perspective gap

In the book 'Give and Take' by Adam Grant, psychologist and professor at Wharton Business School, there is a term called the perspective gap. This refers to our inability to fully appreciate another person's distress when we ourselves are not experiencing a similar kind of distress. The perspective gap explains why physicians often underestimate the severity of the pain that their patients report. In this context, the author of the book gives an account of an incident that occurred in a San Francisco hospital where a respected oncologist wanted a spinal tap done for a patient with advanced metastatic cancer because he wanted to determine if the reason for that patient's deteriorating level of consciousness was meningitis.

The neurologist, who was requested to do the spinal tap, however had his doubts about the need for such a procedure because, not only would the procedure be painful for the patient, he believed it would not result in any significant clinical improvement. The patient and his relatives too did not want the procedure. However, after repeated explanations and much persuasion by the oncologist, the patient and family members agreed to the procedure believing that the oncologist could not be wrong. The neurologist finally did the spinal tap. Soon after that, the patient developed a pounding headache, slipped into a coma and died three days later from the cancer.

The neurologist goes on to say that this incident showed him how the oncologist uncritically accepted the notion that he was doing good. This is the perspective gap that we, as doctors, must always be aware of. The only way to avoid it is to always look at the advice we give to our patients from the point of view of the patients themselves. We should remember the perspective gap when we advice our patients about diabetic diets and also when our prescriptions contain too many medications.