Respiratory Medicine

The questions below were raised by visitors to the STOMP (Straits Times Online Mobile Print) website in the AskST section of the website. eMenders doctors provided the answers to the questions raised as a public health education project. The information provided below is of a general nature and should not be treated as a replacement for medical advice. You should seek consultation from a medical or healthcare professional about your specific medical condition.


Breathing other people’s smoke is called passive or secondhand smoking. The non-smoker breathes “sidestream” smoke from the burning tip of the cigarette and “mainstream” smoke that has been inhaled and then exhaled by the smoker.

Sidestream smoke may be more harmful than mainstream smoke that has been filtered by the smoker’s lungs. Many potentially toxic gases are present in higher concentrations in sidestream smoke than in mainstream smoke. Secondhand smoke is a major source of indoor air pollution and nearly 85% of the smoke in a room results from sidestream smoke.

From either inhaling mainstream or sidestream smoke, or both, passive smokers suffer an increased risk of smoking-related diseases although the relative health risks from passive smoking are small in comparison with those from active smoking. Nonetheless, as smoking-related diseases such as ischemic heart disease and lung cancer are common, the overall public health impact is large. Hence we should all support the call for a complete ban on smoking in public places and workplaces.

In conventional medicine, doctors are trained to examine the tongue as part of the physical examination for patients. The doctor can detect certain abnormalities in the general functioning of the bodily systems from looking at the tongue. For example, cyanosis or a lack of oxygen in the blood can be detected by inspecting the colour of the tongue. In addition, looking at the coating on the surface of the tongue can also suggest the state of ones oral hygiene, nutrition, recent use of medications and general health status. Examining the tongue is also part of the examination of the mouth and oral cavity so that abnormalities such as tumours and infection can be detected.

The motion of sticking out ones tongue and saying ‘ah’ would allow the doctor to have a chance to inspect the condition of the throat and the tonsils. The presence of swelling, plaque, change of colour, or dehydration also indicates diseases of various types. A quick inspection of the oral cavity may also reveal any dental condition that may cause systemic symptoms (e.g. fever due to a dental infection).

In addition, inspection of the tongue can give a quick overview of a persons general health. Conditions such as diabetes may show up as dryness of the oral cavity and certain forms of bad breath (e.g. ketosis). Nasal sinus infections may also show up as bad breath. Deviation of the colour and contour of the tongue may also reveal certain dietary insufficiencies such as Vitamin B, iron, or folic acid.

Recently scientific evidence also showed that bacteria that stays in the oral cavity is related to other system conditions such as heart disease.

First, we need to make sure the diagnosis is correct. Bronchitis is caused by inflammation of the airways in the lower respiratory tract, i.e. the breathing tubes deep down inside our chest. This is different from pneumonia where the lung is not affected by the airways or breathing tubes. Hence, bronchitis needs to be differentiated from other lung conditions such as pneumonia and asthma.

Second, we need to determine the cause of the bronchitis. There are 2 main types of bronchitis: acute and chronic. The former is of recent onset and usually does not lead to long-term symptoms once it has been resolved. Acute bronchitis is usually caused by infection from bacteria or viruses. It can also arise from complications following the flu or common colds. Chronic bronchitis is a longer-lasting condition, usually as the result of long-term exposure to cigarette smoke or pollution. This form of bronchitis is quite different from the acute form of bronchitis, and is better referred to as a form of chronic obstructive pulmonary disease (COPD). You may be interested to to find out more about the cause and treatment of COPD.

As the lower airways are inflamed in bronchitis, the patient usually experiences persistent coughs, wheezing, and shortness of breath as a result of congested and narrowed breathing tubes in the chest. A feeling of chestiness may result.

Treatment of bronchitis should involve treating the infection that caused it, if possible with antibiotics, as well as medication to help reduce the airway inflammation and open up the airways. Medications that can reduce inflammation of the airways include inhaled steroids and bronchodilators (medicine that can help open up the airways). As bronchitis can make a person very sick, self-medication is definitely not advisable for this condition. It is recommended that you consult a doctor if you suffer symptoms of bronchitis.

Central hypoventilation syndrome (CHS) is very rare. It is due to a malfunction of the control centre for breathing (located in a part of the brain called the brainstem). CHS may be congenital (from birth) or acquired (as a result of disease to the respiratory centre of the brain). It is usually diagnosed on an overnight polysomnography or sleep study – this would show periods of cessation of breathing with no chest or abdominal effort and accompanying dip in oxygenation of the blood.

Essentially, breathing is under both voluntary (i.e. one can choose when to breathe) and automatic (do not have to keep thinking of breathing) control. When one sleeps, one loses voluntary control of breathing and the automatic control of breathing takes over – this is dysfunctional in patients with CHS. In cases of CHS, the breathing is insufficient to meet the demands of the body, thus the carbon dioxide and oxygen levels in the body are abnormally high and low respectively. The problem in such cases lies with the respiratory pump and not the lungs (For further description of the function of the normal respiratory system, please visit:

Brain imaging, blood and other relevant investigations may be performed to exclude secondary causes. Differential diagnoses to be considered would include conditions that could cause weakness of the muscles used for breathing. The following link helps to understand this condition better:

Specific causes of CHS are several but in children, the cause is probably idiopathic aka primary (CNS) hypoventilation. However, other causes e.g. previous infection or a tumour affecting the brainstem could also lead to CHS.

Spontaneous recovery of primary (CNS) hypoventilation is not really known. However, if brainstem tumour or abnormality is detected, this may be fixed with surgery and the person may breathe normally again. The syndrome usually gets worse with age as the abnormalities of carbon dioxide and oxygen usually worsen with time. Unless one can detect a cause (e.g. brainstem tumour and remove it), treatment is supportive i.e.. helps the person to ventilate or breathe normally. In milder cases, the respiratory support is required only during sleep (as the person is more likely to forget to breathe adequately during sleep). More severe cases will require ventilatory support around the clock to ensure normal well being.

Long-term ventilatory support for CHS will require long-term use of a ventilator (such as bipap as mentioned above). However, this often requires tracheostomy as well as being tied to a ventilator for long hours, if not the whole day. Obviously this adversely affects the persons quality of life. Another alternative is to implant diaphragmatic pacers to electrically stimulate the diaphragm (respiratory muscles) to breathe, so that the person is no longer dependent on a ventilator or tracheostomy and thus able to carry on with life as per normal. The first such procedure was performed on a 12 year old boy in Mount Elizabeth Hospital (Singapore) late last year.

From the description given in the question, the patient may require the following:

  1. confirmation that she is suffering from CHS, and not any other respiratory and/or neurological disorder;
  2. determination of whether the cause of CHS is primary, i.e. no other treatable causes can be found;
  3. optimal long-term ventilatory support if the condition is non-reversible.