Sinusitis

 

from Medscape General Medicine ^[TM]

Posted 11/01/1997

Alan H. Shikani MD, The Good Samaritan Hospital, Baltimore, Md.

 

Abstract and Introduction

 

Abstract

Inflammation of the mucosa in the area of the osteomeatal complex is a major factor in the pathogenesis of sinusitis, a common disease which afflicts 35 to 40 million Americans. Relatively minor swelling of the mucosa in the anterior ethmoid-middle meatal complex (osteomeatal complex) leads to frontal or maxillary sinus obstruction and secondary disease. The primary bacterial pathogens in acute sinusitis include Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis. Chronic sinusitis is associated with anaerobes, usually Bacteroides species, anaerobic gram-positive cocci, Fusobacterium species, Streptococcus, Veillonella, and Corynebacterium species. Radiologic studies complement the history and physical examination and include conventional sinus radiographs and computerized tomography (CT) scans. Magnetic resonance imaging is useful in the differentiation of soft tissue disease, but it is not the study of choice in the evaluation of sinus disease. Only CT provides excellent visualization of the fine bony anatomy and its important anatomic variants. Medical treatment of sinusitis consists of antibiotics and decongestants and the avoidance of any exacerbating environmental factors. Functional endoscopic surgery (FESS) is the surgical option of choice. This procedure removes the obstruction in the anterior ethmoids and permits spontaneous resolution of disease in the ethmoids, maxillary and frontal areas. Indications for FESS include chronic sinusitis that persists beyond 3 months of medical therapy, or documented recurrent acute sinusitis with related structural or inflammatory abnormalities in the osteomeatal unit. Indications for external sinus surgery include osteomyelitis, orbital complications, intracranial complications, and failure of the functional approach.

 

Introduction–Anatomy and Precipitating Factors

Anatomy and physiology of the sinuses and sinusitis. Sinusitis is defined as an inflammation of the lining of the membranes of any of the paranasal sinuses. The sinuses are lined with ciliated stratified columnar epithelium and are contiguous with the upper respiratory tract via the sinus ostia. Inflammation of the sinuses causes mucosal edema and increased sinonasal secretions. While the most common etiology is an upper respiratory tract infection, an acute exacerbation of allergic rhinitis, dental infection or manipulation, or trauma to the sinuses may also be causative. If sinus obstruction occurs, the retained secretions create a milieu that is ideal for bacterial growth resulting in bacterial sinusitis. 

 

The anterior ethmoid-middle meatal complex (osteomeatal complex) is a key area in the pathogenesis of sinusitis.^[1] The osteomeatal complex contains the narrow channels that provide for mucociliary clearance and ventilation of the anterior ethmoid, maxillary, and frontal sinuses. Relatively minor swelling of the mucosa in this area, such as those associated with viral upper respiratory tract infections or allergic rhinitis, may lead to frontal or maxillary sinus obstruction and secondary disease within these sinuses. Foreign bodies, including nasogastric tubes, nasotracheal tubes, and nasal packing risk blocking the osteomeatal complex and causing nosocomial sinusitis. When sinus drainage is obstructed, mucus, inflammatory cells and bacteria accumulate, oxygen tension in the sinuses is reduced, and opsonization/phagocytic, as well as immunoglobulin-dependent activities are impaired. Drainage and ventilation of the major paranasal sinuses are dependent on the patency of the osteomeatal complex.

Precipitating factors of sinusitis. A number of host factors predispose the patient to sinusitis.^[2] They include immunodeficiency, acetylsalicylic acid-asthma-polyposis triad, abnormal mucociliary clearance secondary to ciliary structural abnormalities, as in Kartagener’s syndrome, or secretory disturbances, such as those in cystic fibrosis. Local anatomic factors such as severe septal deviation also contribute to disease, but localized abnormalities in the area of the anterior ethmoid middle meatal area appear to be even more important.

Microbiology–Titer Differentiates Normal from Pathogenic

Multiple organisms have been isolated from infected sinuses. However, it is important to note that “normal flora” has been cultured from healthy uninfected sinuses. “Normal flora” include Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and anaerobes such as Bacteroides species, anaerobic gram-positive cocci, and Fusobacterium species. The presence of these bacteria is only “normal” if the titer of resident flora is low. When bacterial titers exceed 1000 colony forming units per milliliter of mucus (cfu/mL), they are considered pathogenic.

Sinusitis is classified as acute or chronic based on the duration of the infection. Acute sinusitis has been defined by the American Academy of Otolaryngology- Head and Neck Surgery as a sinus infection in which symptoms last less than 4 weeks. If the symptoms persist beyond 12 weeks of treatment, the sinusitis is labeled as chronic.

The primary bacterial pathogens in acute sinusitis are Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis. Bacteroides species and Staphylococcus aureus are found in 8% to 10% of patients with acute sinusitis.^[3] Chronic sinusitis is usually associated with anaerobes, most commonly Bacteroides species, anaerobic gram-positive cocci, Fusobacterium species, Streptococcus, Veillonella, and Corynebacterium species. Gram-negative bacteria predominate in nosocomial sinusitis, including Pseudomonasaeruginosa, Klebsiella pneumoniae and Enterobacter species.

Bacterial growth on cultures obtained from the nose or nasopharynx, and growth on those obtained with sinus aspiration or open antrostomy, frequently do not correlate, unless gross purulent discharge is visible through the sinus ostium and is available for culture.

 

Therefore, the initial approach to management is often clinical, based on history and physical examination.

Organisms that infect the sinuses only rarely, include Actinomyces species and Nocardia species. There should be a high index of suspicion for fungal sinusitis (eg, sinusitis induced by mycosis caused by fungi of the genera Aspergillus, Bipolaris, Candida, and Penicillium and of the order Mucorales) in immunocompromised patients and in those that do not respond to antibiotic therapy.

Diagnosis–symptoms of acute and chronic sinusitis. The symptoms of acute sinusitis are usually localized to the region of sinus involvement and may include discomfort, pain, headache, and tenderness. If the infection is in the posterior ethmoids and sphenoid, symptoms are described as deep in the head or referred to the occiput. Acute sinusitis is also typically accompanied by systemic signs such as fever, leukocytosis, and lassitude, along with purulent nasal discharge. The patient may report an olfactory disorder, pain with mastication, toothache and fever.

The symptoms of chronic sinusitis, tend to be more vague and poorly localized. In both types of sinusitis, one may have suppurative rhinorrhea, nasal obstruction, postnasal drainage, and pharyngitis. When a sinus is acutely infected, physical examination may reveal sinus tenderness, erythema and swelling of overlying skin, and a purulent nasal exudate. Transillumination sometimes provides information on the condition of the maxillary and frontal sinuses. Endoscopic examination of the nose and the sinuses with the telescope is the most reliable method to differentiate purulence, mucus, serous fluid, and thickened mucosa. Nasal endoscopy is utilized to evaluate the critical osteomeatal area and to identify and biopsy suspicious lesions.

Diagnosis–Radiologic Studies

Plain films. Radiologic studies complement physical examination and include conventional sinus radiographs and computerized tomography (CT) scans. The conventional (or plain film) examination usually consists of Water’s, Caldwell’s lateral, and basal views of the sinuses. These give excellent visualization of the frontal and maxillary sinuses and moderately good visualization of the sphenoid. However, plain film radiographs provide poor visualization of the ethmoid sinus due to density averaging. Plain films are therefore useful for diagnosing frontal and maxillary sinus disease but are of very limited use in the diagnosis of disease in the osteomeatal complex.

Strengths of CT and endoscopy. The best method to visualize the osteomeatal complex pathology and to diagnose local underlying causes of recurrent or chronic sinusitis is the CT scan.^[4] CT is usually best performed after acute sinusitis has been treated and has failed to clear with therapy. The scan is performed in the coronal plane without intravenous contrast and is viewed with magnification of the sinus area; window settings are similar to those used to visualize the lung. These parameters optimize the definition of fine anatomy, the visualization of gross disease, the identification of minor disease and any anatomic obstruction (Fig. 1). 

 

CT scan showing bilateral ethmoid and maxillary disease, with complete obliteration of both osteomeatal complexes.

 

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CT scan showing bilateral ethmoid and maxillary disease, with complete obliteration of both osteomeatal complexes.

Because the most frequent local cause of chronic sinusitis is osteomeatal disease and because the extent of the underlying osteomeatal pathology may be limited and easily treated, nasal endoscopy and CT are of particular value in patients with chronic sinusitis. Endoscopy provides the ability to visualize the middle meatus and adjacent ethmoid structure and to identify areas of persistent infection and edema. It allows the response to medical therapy to be accurately monitored and permits cultures to be performed with precision.^[5] The anatomy in this area varies widely among patients, and any abnormalities that narrow the osteomeatal channels and predispose the patient to infection can be identified. CT provides complementary information about the deeper sinuses and osteomeatal structures. However, when interpreting CT findings it must be remembered that a significant incidence of asymptomatic mucosal thickening may appear on CT scan.

Endoscopy provides a mechanism to accurately visualize disease within the maxillary or sphenoid sinus for definitive diagnosis of unusual radiographic findings. Maxillary sinuscopy is performed via a cannula inserted sublabially under local anesthesia. Biopsies can be performed and cysts removed during this procedure. Sphenoid sinuscopy may be performed via trocar introduced intranasally or after intranasal sphenoidotomy.

MRI versus CT. Magnetic resonance imaging (MRI) is useful in the differentiation of soft tissue disease, but it is not the study of choice for evaluating sinus disease. It does not outline the bone, whereas CT allows excellent visualization of the fine bony anatomy and its important anatomic variants. Bony changes may occur as a result of disease but, inflammatory disease typically expands bone and causes a reactive osteitis. Bone destruction is more suggestive of a malignant lesion, although such a lesion may also occur with severe infections and mucoceles. The use of intravenous contrast during sinus CT is indicated if an intracranial complication is suspected.

Nonsurgical Treatment

Sinusitis is medically managed with antibiotics and decongestants and by avoidance of any exacerbating environmental factors. Oral decongestants such as pseudoephedrine or phenylpropanolamine are helpful but should be used with care in hypertensive patients. In older male patients, these drugs may cause urinary retention. A nasal spray (eg, oxymetazoline) may be added to the therapeutic regimen, but should be used for no more than 3 to 5 days. Traditional approaches to treatment, such as steam or mist inhalation, are often not prescribed, but may relieve both the discomfort and drainage associated with sinusitis. Patients with signs and symptoms suggestive of allergic sinusitis, and patients with an exacerbation of chronic sinusitis, are also treated with anti-inflammatory corticosteroid nasal sprays such as fluticasone (Flonase), beclomethasone (Beconase, Vancenase), triamcinolone (Nasacort), budenoside (Rhinocort) or flunisolide (Nasarel). Prolonged use of topical steroids and short bursts of oral steroid therapy may also help to reduce swelling and relieve osteomeatal obstruction. Allergic patients also benefit from the use of antihistamines and desensitization. Smoke and other environmental pollutants that the symptoms should be avoided.

Antibiotics-drug choice and duration of therapy

A broad-spectrum antibiotic is typically chosen to cover the usual sinus pathogens (H influenzae, S pneumoniae, and B catarrhalis). Amoxicillin, 500 mg orally three times daily may be used as an initial treatment for management of sinusitis, but there is an increasing incidence of resistance to penicillins. Cephalosporins provide more powerful alternatives for nonresponders. The new cephalosporins include cefpodoxime (Vantin) 200 to 400 mg twice daily, ceftibuten (Cedax) 400 mg daily, cefuroxime (Ceftin) 250 to 500 mg twice daily, loracarbef (Lorabid)200 to 400 mg twice daily, or cefaclor (Ceclor PD) 500 mg twice daily. Another effective alternative is amoxicillin/clavulanate potassium (Augmentin) 500 to 875 mg twice daily. Augmentin is the only antibiotic that is approved for chronic sinusitis. Clarithromycin (BIAXIN) 250 mg to 500 mg twice daily or an azithromycin pack may be given to patients who are allergic to penicillins. Acute sinusitis frequently manifests with heavy bacterial growth of a predominant pathogen, but chronic sinusitis is typically a polymicrobial infection in which anaerobes are often present. Therefore, broad-spectrum coverage should be provided, and prolonged therapy (2 to 6 weeks or more) may be required.^[6]

If medical treatment fails to relieve the symptoms of maxillary sinusitis or pansinusitis, a repeat course, implementing a different, possibly broader-spectrum antibiotic is prescribed. The maxillary sinus is irrigated to remove inspissated material. This method is used to obtain an accurate culture in patients who are immunosuppressed or immunodeficient.

Special concerns in selecting therapy. Acute ethmoid sinusitis may lead to periorbital or infraorbital abscess, but this complication is rare outside the pediatric population. Acute frontal and spheroid sinusitis is a medical emergency because there is a potential for disease in these sinuses to spread intracranially. Patients with acute symptomatic frontal and sphenoid sinusitis are usually hospitalized and given intravenous rather than oral antibiotic therapy. Failure to improve with medical therapy requires surgical drainage. In the case of acute, poorly responding frontal sinusitis, frontal sinus trephine and irrigation are performed. The irrigation catheter may be left in place for several days. In persistent sphenoid sinusitis, sphenoidotomy 

 

Sinusitis: A Head and Neck Surgeon’s Perspective

from Medscape General Medicine ^[TM]

Surgical Treatment

The importance of managing the underlying problems, whether these are irritation, allergic factors, or structural nasal deformities, cannot be overemphasized. The goal of treatment is the restoration of normal ventilation and mucociliary clearance and ultimately the reversal of mucosal disease. Although the predominant symptoms and disease are often in the maxillary or frontal sinus, careful endoscopic evaluation and CT scan frequently reveals underlying disease in the osteomeatal area. This improved diagnostic accuracy has reduced the need for surgical procedures of the major sinuses.

 

Even when disease appears to be extensive, the initial approach is the intranasal removal of the underlying osteomeatal problem. This approach has been termed “functional endonasal surgery” or, when performed under endoscopic visualization, “functional endoscopic sinus surgery” or FESS.^[7-12]

The principle behind functional endoscopic surgery is that removing the obstruction in the anterior ethmoids will permit spontaneous resolution of disease in the ethmoids, maxillary and frontal areas. This technique, initially described in Austria and Germany, was imported to the US in 1984.

Surgical technique. Following the application of topical anesthesia and infiltration of the lateral nasal wall, an infundibulotomy is performed with a sickle knife (Fig. 2). Under direct vision through a Hopkinsreg. the uncinate process is removed (Fig. 3), followed by removal of the ethmoid cells, with a Blakesley forceps. Depending on the extent of disease, an anterior and/or posterior ethmoidectomy is performed, followed by a sphenoidotomy and/or exploration of the frontal sinus (Fig. 4). After completion of the ethmoidectomy, a middle meatal antrostomy is created with a backbiting forceps (Fig. 5). Depending on the amount of bleeding, a small Merocelreg. packing may be placed lateral to the middle turbinate.^[13-24] If a septoplasty is needed to either redress nasal airway obstruction or to gain access to the sinuses, it may be performed concurrently. Typically, the patient is prescribed antibiotics during the post-operative period. 

 

 

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Following the application of topical anesthesia and infiltration of the lateral nasal wall, an infundibulotomy is performed with a sickle knife. Reprinted with permission from the Archives of Otolaryngology-Head & Neck Surgery, 111: 643-649, 1985, © 1985, American Medical Association.

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Bony anatomy of the lateral nasal wall. The 4 bony laminae are numbered in the order they are encountered. Reprinted with permission from the Archives of Otolaryngology-Head & Neck Surgery, 111: 643-649, 1985, © 1985, American Medical Association.

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Anterior and/or posterior ethmoidectomy is performed, followed by a sphenoidotomy and exploration of the frontal sinus under direct vision. Reprinted with permission from the Archives of Otolaryngology-Head & Neck Surgery, 111: 643-649, 1985, © 1985, American Medical Association.

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Middle meatal antrostomy is created with a backbiting forceps. Reprinted with permission from the Archives of Otolaryngology-Head & Neck Surgery, 111: 643-649, 1985, © 1985, American Medical Association.

 

Indications for FESS. Indications for functional endoscopic surgery include chronic sinusitis that persists despite a minimum of 3 months of medical therapy, or documented recurrent acute sinusitis with related structural or inflammatory abnormalities in the osteomeatal unit. The functional approach can usually be performed under local anesthesia without external incision and dramatically reduces morbidity compared with standard open surgical techniques. Damage to normal anatomy is minimized, and packing is usually not required. This type of surgery, however, is complex and requires special skills if the risks to adjacent critical structures are to be minimized. After surgery, the secondarily involved mucosa recovers slowly. The extent of surgery performed with this approach varies from a very limited procedure to complete sphenoethmoidectomy (with opening of both maxillary and frontal sinuses).

The channels for sinus ventilation and mucociliary clearance within the osteomeatal complex are narrow and tortuous. Minor underlying disease in this area may therefore cause extensive secondary changes. Localized obstruction in the narrow opening of the frontal recess may therefore give rise to extensive frontal sinus disease. In identifying the role of osteomeatal disease in chronic or recurrent acute sinusitis, the site of disease is more important than the extent.

Indications for external sinus surgery. Indications for external sinus surgery include osteomyelitis, orbital complications, intracranial complications, and failure of the functional approach. A number of techniques have been described. The frontal sinus may be approached by an external frontoethmoidectomy by using a curvilinear incision in the area of the medial canthus (Lynch procedure). Another approach is via an incision across the eyebrows or behind the hair line. In the latter case, the anterior bony wall of the sinus is incised and moved anteriorly to provide access. The maxillary sinus is typically approached by a sublabial incision (Caldwell-Luc procedure), and the ethmoid by an incision on the side of the nose (external ethmoidectomy). Unfortunately, these procedures, particularly the frontal sinus osteoplasty, may create permanent changes in the sinuses that can be difficult to differentiate radiologically from disease recurrence. Since the introduction of functional endoscopic surgery, the frequency of open or external procedures has greatly diminished

Complications of Sinusitis

One of the more common complications of sinusitis, occurring primarily in children, is the spread of ethmoid infection into the orbit. The first indication of orbital involvement is inflammatory edema of the eyelids. Progression of the infection may be rapid with chemosis, ophthalmoplegia, and even visual loss. In the early cellulitic stage of the disease, intravenous antibiotic therapy is appropriate. However, careful evaluation and an orbital CT scan are required to rule out a subperiosteal abscess or intraorbital abscess, both of which require prompt surgical drainage.^[25]

Purulent frontal sinusitis may extend through the anterior wall and present as a Pott’s puffy tumor. Inflammatory sinus disease may also spread intracranially and result in meningitis or epidural, subdural, or brain abscess. The precise incidence of intracranial complications is not known. However, sinusitis is reported to be the source of 35% to 65% of subdural abscesses. It is important to note that such complications, although uncommon, are not rare. Intracranial complications most likely occur from acute frontal sinus disease, but may also arise from infections in the sphenoid, or less frequently, the ethmoid sinus. These complications are most common in adolescent patients, predominantly males. If there is a clinical suggestion of intracranial spread, lumbar puncture and intravenous contrast CT or magnetic resonance imaging should be performed. Magnetic resonance imaging is more sensitive for identifying early intracranial disease and epidural abscess. If intracranial infection occurs, early surgical drainage of the sinuses is usually performed and, when indicated, can be combined with surgical drainage of the intracranial collection.

Conclusion: Obstruction of the normal drainage patterns in the area of the osteomeatal complex is a major contributing factor in the pathogenesis of chronic sinusitis, a common disease which afflicts 35 to 40 million Americans. Medical treatment is successful in the majority of cases, but in those that do not respond, surgery is indicated. Evaluation by diagnostic endoscopy and computed tomography (CT) is performed to confirm the diagnosis before surgical intervention is considered. If the evaluation reveals an osteomeatal abnormality causative for chronic or recurrent disease, intranasal surgical removal of the inciting element can allow for the resolution of the secondary mucosal disease. Functional endoscopic surgery (FESS) is an approach for the treatment of chronic sinusitis used in the United States for the last 13 years. The restoration of mucociliary clearance by removal of ostial and adjacent ethmoid disease is the concept underlying this approach to management. The physician must understand the physiology of the paranasal sinuses and the pathophysiology of sinusitis to effectively manage this disease and to successfully perform functional endoscopic surgery.

Editorial Comment

Sinusitis–Often Underappreciated, Underdiagnosed, and Undertreated

Dr. Alan Shikani, in his article published in Medscape Pulmonary Medicine, calls attention to the important condition of sinusitis. Sinusitis accounts for 11.6 million physician office visits per year in this country and is the fifth leading cause for antibiotic usage. It is the most frequently reported chronic disease in the US, affecting 14.7% of the population.^[1] Sinusitis patients completing the Medical Outcome Study 36-Item Short Form Survey (SF36), a generic quality-of-life analysis tool, scored lower in bodily pain and social functioning than patients with COPD, congestive heart failure, angina, and back pain, indicating that the national health impact of chronic sinusitis is far greater than is currently appreciated.^[2] The clinician must maintain a high diagnostic index of suspicion, particularly for chronic sinusitis, because, as Dr. Shikani points out, the signs and symptoms of this disease are subtle. While clinical history and physical examination suffice to make the diagnosis of sinusitis in most cases, imaging modalities may sometimes be needed.

CT scan offers the distinct advantage over conventional radiographs in that it delineates the status of individual ethmoid air cells as well as the osteomeatal complex. A limited 4-slice coronal CT scan of the sinuses provides significantly more information than plain films, and at a much reduced radiation dose and cost.^[3] It should be emphasized that a positive CT of the sinuses is not specific for bacterial or fungal infections–patients with naturally-acquired common colds may also demonstrate sinus abnormalities.^[4]

Acute and chronic sinusitis generally respond to appropriate medical therapy. When the infection does not improve or recurs shortly after therapy is discontinued four possible explanations should be considered:

 

• underlying allergy
• immune deficiency
• fungal etiology
• mechanical or anatomic abnormality leading to obstruction

 

 

Structural or inflammatory abnormalities in the osteomeatal unit require surgical intervention, and functional endoscopic surgery (FESS) has clearly emerged as the procedure of choice.^[5] While Dr. Shikani discusses the advantages of FESS, he also emphasizes that the surgery is complex and requires special skills. FESS remains the number one cause for malpractice claims against otolaryngologists. Complications of FESS include hemorrhage, orbital hematoma, subcutaneous orbital emphysema, diplopia, CSF leak, meningitis, blindness, and death.^[6]

 

An appreciation of the incidence and quality of life changes associated with sinusitis, recognizing the often subtle clinical presentation, and institution of prompt medical and/or surgical therapy, will result in a satisfying clinical result in the vast majority of patients.

 

Raymond G. Slavin, MD, Director
Division of Allergy and Immunology
Department of Internal Medicine
St. Louis University Health Sciences Center
St. Louis, Mo

 

References

 

 

• Benson V, Marono MA: Current estimates from the National Health Interview Survey, 1993. National Center for Health Statistics. Vital Health Stat. 10(182), 1993.
• Gliklich RE, Metson R: The health impact of chronic sinusitis in patients seeking otolaryngologic care. Otolaryngol. Head Neck Surg113:104-9, 1995.
• Wippold FJ II, Levitt RG, Evens RG, et al: Limited coronal CT: An alternative screening examination for sinus inflammatory disease. Allergy Proc 16:165-169, 1995.
• Gwaltney JM Jr, Phillips CD, Miller RD, et al: Computed tomographic study of the common cold. N Eng J Med 330:25-30, 1994.
• Kennedy DW: Functional endoscopic sinus surgery technique. Arch. Otolaryngol 111:643-649, 1985.
• Stankiewicz JA: Complications of endoscopic sinus surgery. Otol. Clinics N Amer s2:749-758, 1989.