Sinus Infections

Sinus infections occur when fluid is trapped or blocked in the sinuses, allowing germs to grow.  A sinus infection, or acute rhinosinusitis (ARS) has two basic causes: viral or bacterial. Both viral and bacterial sinus infections share very similar symptoms and can be sometimes difficult to discern from each other clinically.  I would like to describe the clinical manifestations of sinus infections, how to try and differentiate bacterial from viral and treatment.

Sinus infections, whether bacterial or viral in nature have the following common clinical features:

• More than 4 weeks of purulent (yellow-green) nasal discharge
• Nasal obstruction
• Facial pain or pressure
• Ear fullness, cough, loss of smell, and/or headache

Not all of these symptoms need to be present. Other conditions that share these symptoms are the common cold and allergies.  Differentiating between viral and bacterial can often be challenging.  The clinical presentation alone cannot distinguish viral from bacterial sinus infections because the physical examination demonstrates no distinguishing features to separate the two. Guidelines published by The Infectious Diseases Society of America in 2021 suggest the following three criteria may be helpful in determining if a patient has a bacterial sinus infection:

• Persistent symptoms of a sinus infection lasting more than 10 days. In general, a viral form begins to show resolution by day 10.
• Severe symptoms or high fever greater than 102 F with a purulent nasal discharge or facial pain for three to four consecutive days at symptom onset.
• Worsening of symptoms of a sinus infection with high fever and purulent nasal discharge after five to six days of an illness that appeared to be improving.

Treatment for Viral
Because the overriding majority of cases of sinus infections are viral (0.5 to 2.0% bacterial), the initial treatment is aimed at symptomatic relief: antihistamines like Claritin, Allegra, Zyrtec with or without Sudafed, cough suppressant (dextromethorphan). Of course rest, fluids, and pain relief medications like acetaminophen and ibuprofen are helpful as well. It is important to realize that the treatment recommendations provided will not resolve or eliminate the symptoms of a viral sinus infection completely; only time (7-10 days) and your body’s immune system will accomplish that.

Treatment for Bacterial
If a patient does have clinical features of a bacterial sinus infection, then antibiotic therapy is warranted. There are treatment algorithms available for the management of bacterial sinus infections that take into consideration the recent antibiotic use, duration of symptoms, response to initial treatment and so on. For the sake of simplicity, the initial treatment of a bacterial sinus infection is the above mentioned OTC medications and a broad spectrum antibiotic. The drug of first choice is Augmentin, which is a combination of amoxicillin and clavulanic acid. In patients with a penicillin allergy, azithromycin (Z-pak) can be used, but in my experience is not as effective. In patients who fail the first round, drugs like cefdinir and Levofloxacin provide an even broader spectrum of coverage. In addition, these patients can sometimes improve with the use of either nasal steroids (Flonase) or oral steroids (prednisone). In the case of patients who remain symptomatic after multiple rounds of antibiotics and steroids, referral to an Ear-Nose-Throat (ENT) specialist and possible CT scan of the sinuses is the next appropriate step.

In sum, sinus infections are a very common form of infection in the urgent care setting. The vast majority of cases are due to viruses with a small percentage having secondary bacterial infection. The clinical features of the two causes are similar with some clinical criteria that can help the treating physician attempt to determine if bacterial infection is present. Treatment focuses on common sense with OTC medications, rest and fluids (the mainstay of therapy). If an antibiotic is deemed necessary, amoxicillin-clavulanic acid is the drug of first choice with azithromycin available for those allergic to penicillin-class antibiotics. In the case of treatment failure, broader spectrum antibiotics and steroids are often used. In those patients who fail to improve with these therapies or have recurrent episodes throughout the year, referral to an ENT specialist is often advised.