SINUSITIS

Sinusitis is inflammation of the paranasal sinuses, which may be due to infection, allergy or autoimmune issues. Most cases are due to a viral infection and resolve over the course of 10 days. It is a common condition with more than 24 million cases occurring annually.

Sinusitis can be acute (going on less than four weeks), subacute (4-8 weeks) orchronic (going on for 8 weeks or more). All three types of sinusitis have similarsymptoms, and are thus often difficult to distinguish. Acute sinusitis is very common. Roughly ninety percent of adults have had sinusitis at some point in their life.

Acute sinusitis

Acute sinusitis is usually precipitated by an earlier upper respiratory tract infection, generally of viral origin. If the infection is of bacterial origin, the most common three causative agents are Streptococcus pneumoniae, Haemophilus influenzae, andMoraxella catarrhalis[4]. Until recently, Haemophilus influenzae was the most common bacterial agent to cause sinus infections. However, introduction of the H. influenza type B (Hib) vaccine has dramatically decreased H. influenza type B infections and now non-typable H. influenza (NTHI) are predominantly seen in clinics. Other sinusitis causing bacterial pathogens include Staphylococcus aureusand other streptococci species, anaerobic bacteria and, less commonly, gram negative bacteria. Viral sinusitis typically lasts for 7 to 10 days,[4] whereas bacterial sinusitis is more persistent. Approximately 0.5% to 2% of viral sinusitis results in subsequent bacterial sinusitis. It is thought that nasal irritation from nose blowing leads to the secondary bacterial infection.

Acute episodes of sinusitis can also result from fungal invasion. These infections are typically seen in patients with diabetes or other immune deficiencies (such as AIDS or transplant patients on immunosuppressive anti-rejection medications) and can be life threatening.[In type I diabetes, ketoacidosis causes sinusitis by Mucormycosis.

Chemical irritation can also trigger sinusitis, commonly from cigarettes and chlorine fumes.[Rarely, it may be caused by a tooth infection.

Chronic sinusitis

Chronic sinusitis, by definition, lasts longer than three months and can be caused by many different diseases that share chronic inflammation of the sinuses as a common symptom. Symptoms of chronic sinusitis may include any combination of the following: nasal congestion, facial pain, headache, night-time coughing, an increase in previously minor or controlled asthma symptoms, general malaise, thick green or yellow discharge, feeling of facial ‘fullness’ or ‘tightness’ that may worsen when bending over, dizziness, aching teeth, and/or halitosis.[Each of these symptoms has multiple other causes. Unless complications occur, fever is not a feature of chronic sinusitis.[ Often chronic sinusitis can lead to anosmia, a reduced sense of smell.[In a small number of cases, acute or chronic maxillary sinusitis is associated with a dental infection. Vertigo, lightheadedness, and blurred vision are not typical in chronic sinusitis and other causes should be investigated.

Chronic sinusitis cases are subdivided into cases with polyps and cases without polyps. When polyps are present, the condition is called chronic hyperplastic sinusitis; however, the causes are poorly understood[4] and may include allergy, environmental factors such as dust or pollution, bacterial infection, or fungus (either allergic, infective, or reactive). Non-allergic factors, such as vasomotor rhinitis, can also cause chronic sinus problems.Abnormally narrow sinus passages, such as having a deviated septum, can impede drainage from the sinus cavities and be a contributing factorA combination of anaerobic and aerobic bacteria are detected in conjunction with chronic sinusitis, including Staphylococcus aureus and coagulase-negative Staphylococci. Typically antibiotic treatment provide only a temporary reduction in inflammation, although hyperresponsiveness of the immune system to bacteria has been proposed as a possible cause of sinusitis with polyps chronic hyperplastic sinusitis).

There are several paired paranasal sinuses, including the frontal, ethmoid, maxillary and sphenoid sinuses. The ethmoid sinuses is further subdivided into anterior and posterior ethmoid sinuses, the division of which is defined as the basallamella of the middle turbinate. In addition to the severity of disease, discussed below, sinusitis can be classified by the sinus cavity which it affects:

Maxillary sinusitis – can cause pain or pressure in the maxillary (cheek) area (e.g., toothache,headache)
Frontal sinusitis – can cause pain or pressure in the frontal sinus cavity (located behind/above eyes), headache
Ethmoid sinusitis – can cause pain or pressure pain between/behind the eyes and headachesSphenoid sinusitis – can cause pain or pressure behind the eyes, but often refers to the vertex, or top of the head.