Asthma commonly exists with other diseases. Treating them may also improve the chronic lung condition. However, it is also important to get asthma correctly diagnosed as some symptoms of these conditions may be misidentifed as asthma.
Asthma is a common chronic medical condition in Singapore, affecting 20% of children and 5% of adults. Although asthma is usually thought of as an isolated lung condition, many other diseases, termed comorbidities, often co-exist with asthma. It is important that patients and their doctors recognise them because untreated, they can worsen asthma, and may even be wrongly diagnosed as asthma in certain instances.
In this article, we shall discuss eight common comorbidities in asthma, and their treatments-.
Patients with allergic rhinitis (AR) often experience sneezing, itching of the nose and/or eyes, and runny nose after exposure to triggers such as house dust mite or animal fur. Up to 90% of patients with asthma have AR compared to about 9% in the general population. Patients with AR risk developing asthma, while patients with both asthma and AR report poorer control of asthma symptoms and quality of life.
Treatment: Intranasal corticosteroids (INCS) usually improve both AR and mild asthma symptoms. Immunotherapy (via injections or dissolved under the tongue) is sometimes required to control AR, But this mode of treatment should not be used by those with uncontrolled asthma.
Chronic rhinosinusitis (CRS) is inflammation of the nose and sinuses resulting in nasal congestion, nasal discharge, facial pain and/or a reduced sense of smell. The diagnosis can be confirmed through imaging (X-rays?) or nasoendoscopy by an Ear-Nose-Throat (ENT) specialist. Up to 40% of asthma patients have CRS. It is more prevalent in those with more severe asthma. Asthma patients with CRS have more asthma symptoms and more frequent asthma attacks.
Treatment: Treatment includes nasal rinses, INCS [explain what this is] and sometimes surgery. Some patients with poorly controlled asthma have reported improvement in asthma following intensive treatment of CRS.
Gastroesophageal reflux disease
Gastroesophageal reflux disease (GERD) typically presents itself as heartburn although some people with reflux may not experience any symptoms. GERD with symptoms occur in about 40-80% of patients with asthma, and is associated with more asthma symptoms.
Treatment: Includes lifestyle modifications like raising the head-of-bed during sleep, dietary changes, medications to reduce the amount of gastric acid production, but rarely surgery. Surgery is usually effective for treating symptoms of GERD, but has not been convincingly shown to improve asthma.
Obesity (BMI =30kg/m2) affects about 18% of patients with asthma but up to 39% of patients with severe asthma. Obesity affects asthma by impairing lung function, increasing airway inflammation and decreasing response to inhaled corticosteroids. These lead to poorer control of asthma symptoms and an increased frequency of asthma attacks. Patients with obesity may experience symptoms such as wheezing and breathlessness even if they do not have underlying asthma. They may be wrongly diagnosed and prescribed asthma medications that they do not require.
Treatment: Apart from improving other cardiovascular diseases [can cardiovascular diseases be imrpoved? Or should it be warding off?], weight loss of 5-10% has been shown to improve asthma control.
Obstructive sleep apnoea (OSA)
During sleep, muscles in the throat relax and cause the throat to narrow. In patients with obstructive sleep apnoea (OSA), the narrowing is severe enough to decrease or completely stop air from entering the airways. Patients with OSA may snore, experience poor sleep, awake at night choking, or feel unrefreshed after sleeping. Diagnosis is confirmed by a sleep medicine doctor using an overnight sleep study. Up to 40% of patients with asthma have OSA. Asthma patients with untreated OSA have more daytime and night time asthma symptoms, and may be at increased risk of asthma attacks.
Treatment: The most effective treatment for OSA is to use a continuous positive airway pressure (CPAP) device at night to splint open the airways. It has/its use has been shown to improve asthma symptoms.
Dysfunctional breathing (DB) is also known as breathing pattern disorder, in which the depth and rate of breathing exceeds what the body needs. The most commonly recognised pattern is hyperventilation, where a person breathes rapidly when faced with a stressful situation. It is estimated that 30% of asthma patients have DB. DB can be mistaken for asthma. Asthma patients with DB have more asthma symptoms and restrictions in their daily activities. DB is usually diagnosed only after other serious illnesses are excluded.
Treatment: Breathing exercises taught by physiotherapists usually improves asthma symptoms.
Vocal cord dysfunction
Our vocal cords usually open when we breathe in. In vocal cord dysfunction (VCD), the vocal cords close abnormally when the patient breathes in, resulting in shortness of breath, noisy breathing or tightness in the throat. VCD can be triggered by strong odours or other environmental irritants, exercise, and strong emotions. ENT specialists commonly use nasoendoscopy to diagnose VCD. About 20% of patients with asthma have VCD, and it is more common in those with more severe asthma. Patients with VCD may be misdiagnosed as having asthma, resulting in inappropriate use of asthma inhalers that can potentially worsen VCD.
Treatment: VCD is usually treated by speech retraining, although the effect on asthma is still uncertain.
Anxiety and depression
As with most chronic diseases, patients with asthma are at a higher risk of developing anxiety and depression. Anxiety and depression afflict 11-37% and 9-18% of patients with asthma, respectively. Patients with anxiety and depression may have more difficulty self-managing their asthma, resulting in poor asthma control.
Treatment: See a psychiatrist or psychologist sooner than later.
Among the common conditions encountered in patients with asthma, obesity, DB and VCD can result in symptoms mimicking asthma. Therefore early recognition of these conditions and a confirmed diagnosis of asthma are essential to avoid wrongly labelling patients as having asthma. At the same time, many of these conditions co-exist with asthma, and studies suggest that treating some of these conditions improves the control of asthma.
Be aware that other lung-related and medication-related comorbidities not covered here are also associated with asthma. Asthma should not be viewed as an isolated lung condition. Tackling these associated conditions is necessary to achieve the optimal health results for patients with asthma.
Attribute to Dr Tay Tunn Ren, Respiratory Physician, Changi General Hospital