19 June 2009
Understanding sinuses, sinusitis, rhinitis and the various problems that can afflict our sinuses.
During my consultation with patients, they often say to me, “Doctor, I have si-nus”. My usual reply will be “You mean to say that you have problems with your sinuses”.
We all have sinuses, four pairs to be exact. They are the frontal sinuses, located next to the midline of our foreheads above the eyebrows on both sides, the maxillary sinuses located in our cheek bones on both sides, the ethmoid sinuses, located on both sides between our eyes, and the sphenoid sinuses, which are located at the back of our noses at the middle of an imaginary line joining our ears.
Sinuses are normally air-filled spaces connected to the nose and lined by a thin lining called mucosa that is continuous with the lining of the nose. The openings of the sinuses into the nose are tiny holes called ostia (ostium=singu-lar) and the diameter of each ostium is usually only a few millimetres wide.
The mucosa of the sinuses and nose contains mucous glands and numerous microscopic finger-like or hair-like projections called cilia. These cilia beat in a specific direction and transport the mucous produced from the mucosa of the sinuses into the nose through their respective ostia.
Everyday, the mucosa of our nose and sinuses produce approximately one litre of mucous which is moved to the back of the nose by these beating cilia and then swallowed subconsciously. Any condition that adversely affects the mucosa, cilia or ostia will cause problems for the sinuses.
Being closely connected to each other, conditions affecting the nose can easily affect the sinuses.
When inflammation occurs in the nose and sinuses, the cilia stop beating and fail to transport the mucous, which then builds up in the sinuses. At the same time, the mucosa lining swells up and blocks up the ostia of the sinuses. The infection then changes the mucous from a colourless fluid to greenish pus in the affected sinuses.
Sinusitis refers to this condition when the mucosa of the sinuses is inflamed. Sinusitis and inflammation of the nose, known as rhinitis, occurs as a result of allergy, infection, irritation from chemicals and dust, or a combination of any of these. In some cases, the swelling of the mucosa becomes severe and bulges outwards to form polyps, which are like balloons filled with fluid. Such polyps can “grow” up to sizes of several inches and obstruct the sinuses and nose.
The presence of polyps usually implies severe inflammation and allergy. Individuals who suffer from asthma and allergic rhinitis are at higher risk of developing polyps in their noses.
Sinusitis is typified by symptoms of blockage or stuffiness of the nose, discharge from the nose, phlegm in the throat, loss of sense of smell, headaches or/and pain of the affected sinuses. Infection of the sinuses could be due to viruses, bacteria and fungus. “Colds” and flu are due to virus infection of the upper airways.
Once infected, the mucosa of the nose and sinuses rapidly succumb to secondary infection by bacteria. This is the reason for the change in colour of the discharge of the nose and sinuses from the initial clear colour to green when bacteria infection sets in. Most of the time, the immune system fights off the infection and we recover after several days when the cold or flu symptoms recede. Our noses clears up and the discharge becomes increasingly less and clearer.
Sometimes the symptoms persist and we require a course of antibiotic treatment to recover. When the duration of sinusitis lasts for days or up to a couple of weeks, it is called acute sinusitis. When the duration of an infection persists longer than a couple of weeks, it is called chronic sinusitis.
Sinusitis is very common and statistics from the US show that sinusitis affects 31 million Americans per year and 30% of the population of the US have sinusitis at some point in their lives
The diagnosis of sinusitis can be made by simple clinical examination, endoscopy of the nose, X-rays, computerised tomographic (CT) scans and magnetic resonance imaging (MRI). Simple clinical examination involves looking into the nose and if pus can be seen from the ostia of the sinuses, then the diagnosis of sinusitis can be made. The method, however is not very sensitive and sinus infections, polyps and tumours can be missed.
Endoscopy of the nose requires the use of a fibreoptic endoscope. This endoscope is placed in the nose of the patient to inspect the interior of the nose in detail. This is much more accurate and reliable than clinical examination. It is easily performed on patients in the clinic. Sinusitis is diagnosed if pus is seen emerging from the ostia of the respective sinuses or if the ostia is blocked by the presence of inflammatory tissues or polyps.
This method of examining the nose is relatively easy, quick and without any side-effects. Most specialists use camera systems attached to the endoscopes to display the images on monitors to enable patients to view the interior of their noses themselves and photographs may be taken for reference.
CT scans of the sinuses give clear images of the sinuses and also show the anatomy of the nose and sinuses in great detail. CT scans will pick up minute changes in the sinuses and therefore its interpretation is important with regard to the management of the patient.
The images consist of series of slices of the nose and sinuses from the front to the back, like slicing a loaf of bread. Specialists rely on CT scans as their maps of the nose and sinuses during surgery.
The limitation of CT scan is that the images captures are snap shots of the state of health of the nose and sinuses at that point in time. Therefore if a CT scan is done during or just after a cold, it will show swelling and abnormalities in the nose and sinuses, even though the nose and sinuses are normally healthy.
MRI is the newest imaging technology available. MRI is highly accurate and reliable for information on the soft tissues of the nose and sinuses. However, it is less favoured by specialists treating the sinuses as MRI does not show the fine bone details and landmarks of the sinuses. These bone details and landmarks are crucial during surgery to guide the surgeon through the complex anatomy of the sinuses and skull base, which has a high degree of variation from one patient to another.
Infection and allergy are the main causes of sinusitis. Once sinusitis is diagnosed, the treatment usually involves antibiotics to clear the bacterial infection and topical decongestants to reduce the inflammation and swelling. Where allergy is suspected to co-exist, steroids and anti-histamines are used to further reduce swelling due to the allergic reaction.
In the vast majority of cases of acute sinusitis, this treatment will resolve the sinusitis. It must be stressed at this point that all prescribed courses of antibiotics should be completed, with the exception of allergic reactions to the antibiotic or when serious side-effect occurs.
In cases where the sinusitis persists after a course of antibiotic treatment, the choice of antibiotic used needs to be reviewed and a different antibiotic should be prescribed. This is due to the ability of bacteria to develop resistance to a particular antibiotic if the antibiotic had been used frequently or injudiciously in the past.
For cases of chronic sinusitis or where medication and antibiotics have failed to treat the sinusitis, surgery or sinus washouts will be employed. A sinus washout can only be used for maxillary sinusitis and involves a large needle being pushed from inside the nose and through the thin bone of the sides of the nose into the maxillary sinus. Once inside the maxillary sinus, any pus or mucous is sucked out and saline is flushed through the needle into the maxillary sinus to wash mucous, pus or debris out through the ostium of the sinus. This is therefore only possible if the ostium of the sinus is patent and not obstructed by polyps or soft tissue swellings.
This procedure can be done under local anaesthesia in the clinic or under general anaesthesia in the operating theatre. Sinus washout is a simple procedure but it does not correct any underlying abnormality of the sinus as it serves only to flush out the infected sinus. For this reason, sinusitis may relapse after sinus washouts.
Surgery of the sinuses for sinusitis basically involves re-establishing drainage and aeration of the sinuses. It involves widening of the ostia of the sinuses, removing solidified debris, pus or fungal material from the sinuses, and removal of polyps or tissues obstructing the drainage routes of the sinuses.
Surgery of the sinuses can be broadly divided into two types, the “external” or “internal” approach through the nose. The “external” approach invariably requires an external incision on the face or in the mouth, thereby creating a scar while the “internal” approach avoids an external scar by approaching the sinuses from the interior of the nose.
Surgery to drain the maxillary sinus “externally” through the mouth was first described in 1743 in France by Lamorier and since then, various external approaches to the sinuses had been described and widely practised.
In the 1950s, Prof Walter Messerklinger, from Graz, Austria, first started using the fibreoptic endoscope to view and operate on the sinuses through the “internal” approach via the nose. This technique became popular after it was introduced in the US in 1984 and is now accepted and widely practised throughout the world. It is now the established surgical procedure for treatment of sinusitis and is called Functional Endoscopic Sinus Surgery (FESS).
FESS is not one particular operation but a range of surgical procedures carried out with a rigid nasal fibreoptic endoscope. Some call this “key-hole” surgery.
FESS currently accounts for the majority of operations done for the treatment of chronic sinusitis. This is because chronic sinusitis is primarily due to disturbance of the muco-ciliary transport system of the sinuses, causing blockage with infection by bacteria. Therefore, treatment with antibiotics alone is not sufficient as surgery is needed to re-establish the drainage and aeration of the affected sinuses.
Nevertheless, severe and extensive sinusitis should be adequately treated with antibiotics, decongestants and steroids to reduce the inflammation before surgery. Such untreated cases can be associated with excessive bleeding during surgery and this may make the surgery especially difficult and challenging, with higher risk of complications and recurrence of sinusitis.
FESS is usually carried out under general anaesthesia and may take several minutes to a couple of hours depending on the complexity and severity of the sinusitis. Following FESS, the patient may have some form of dressing applied inside the noses to soak up the blood or stop the bleeding for several hours up till a couple of days.
Patients are discharged from the hospital after removal of these dressings. They are usually prescribed medications such as antibiotics, decongestants, anti-histamines and nasal douches to “rinse” the interior of their noses and sinuses of blood clots, discharge and debris that will usually accumulate after surgery. They are then closely followed up by their specialists over the next two to three weeks after surgery for “nasal toilet”, which is cleaning out the blood clots and debris from the nose and operated sinuses.
Following surgery, care of the wound in the nose and sinuses is important. If wound care is less than optimal, the healing can be complicated by excessive scar tissue formation that can obstruct the sinuses again.
Likewise, infections can occur after surgery and this will need adequate treatment with the appropriate antibiotics to prevent re-infection of the sinuses and excessive scarring.
FESS has a relatively pain-free post-operative period. It is not unusual for the nose to feel blocked up, like in a bad cold, and to experience some bleeding for the first one to two weeks.
Nasal polyps removed during FESS may recur in up to 50% of patients years after the surgery. Such patients are usually advised by their specialist to use steroid sprays on their nose long term to prevent these polyps from recurring.
The “open” approaches had been reduced dramatically but not totally abandoned. They are still employed in difficult and recurrent cases of sinusitis or where surgery involves the removal of large tumours of the sinuses.
Sinus surgery and FESS are very safe operations, but like any other forms of surgery, they are not without risk of complications. Excessive bleeding after surgery may occur and in 2% of cases where a second operation, readmission to hospital or blood transfusion may be required. Bleeding is usually not a difficult problem to deal with after the bleeding point or blood vessel had been identified, cauterised or the nose packed with dressing.
Re-obstruction of the drainage routes of the sinuses may also occur and these can be difficult problems to rectify. The risk of re-obstruction is highly variable and it is determined by many factors, ranging from the presence of allergy problems and polyps, patient’s compliance of medications prescribed, surgical techniques employed during surgery, adequacy of post-operative care, development of post-operative scarring, post-operative infection, plus the extent and severity of sinus disease before surgery.
Located in close proximity to the sinuses are the eyes, optic nerve and brain. It has been re-ported, although rarely, of injury to the eye causing vision disturbances or even blindness in a few extreme cases following FESS. Likewise, injury to the brain and its lining has also been reported, leading to leakage of brain fluid, cerebrospinal fluid, from the compartment housing the brain and risking infection such as meningitis.
These complications are avoidable by the surgeon having the necessary expertise and training to be familiar with the complex anatomy of the sinuses before attempting to perform sinus surgery, attending courses for sinus surgery to keep abreast with new developments in the field of sinus surgery and using the CT scan images of patients’ sinuses for quidance during surgery.
In the last couple of years, innovative techniques have been introduced to improve the success rate and safety of sinus surgery. One of such new techniques available is balloon sinuplasty. This technique of FESS uitilises the balloon technology of coronary angioplasty. In essence, it involves threading a balloon over a flexible guide wire into the narrowed or obstructed sinus drainage route under X-ray guidance. The balloon is then inflated to a pressure of between twelve to sixteen atmospheres (the pressures of passengers car tyres is about two atmospheres) to widen the narrowed or blocked passage permanently without the need for any incision or tissue removal. This greatly reduces the recovery time, bleeding and the risk of scarring that may block up the passage again later.
In the last two to three years, this technique has been increasingly employed around the world and the reported success rates are over 90%.
This procedure however is only applicable to the frontal, maxillary and sphenoid sinuses and not the ethmoid sinuses. The latter still requires surgical removal of tissues during FESS.
Slow-release antibiotic capsules to be placed in the ethmoid sinuses is being developed and evaluated for clinical use. This may become available for use in the near future for the treatment of chronic ethmoid sinusitis.
Not infrequently, my patients have asked, “Can’t I just ignore my chronic sinusitis and leave it untreated?”
The potential complications of untreated sinusitis can be serious and hazardous. Complications include permanent loss of smell, polyps formation, chronic cough, pneumonia from pus dripping down the back of the nose and into the lungs, blindness due to the infection spreading from the sinuses through the thin bones that separate the eyes from the ethmoid sinuses, and even meningitis and/or infection of the brain due to the bacteria spreading to the brain from the sinuses.
These are not uncommon complications and I still see and treat several numbers of such cases each year due to late presentation of sinusitis for treatment.
This article was first published in www.thestar.com.my on 7 June 2009.