eMedicine Specialties > Pediatrics: Surgery > Otolaryngology

Sinusitis

Author: Girish D Sharma, MD, Associate Professor, Department of Pediatrics, Rush University Medical Center, Rush Children's Hospital; Director of Pediatric Pulmonary Section and Rush Cystic Fibrosis Center
Coauthor(s): Hinna Khan, MD, Staff Physician, Department of Pediatrics, Rush University Medical Center
Contributor Information and Disclosures

Updated: Oct 22, 2008

Introduction

Background

Sinusitis, the inflammation of one or more paranasal sinuses, is a common pediatric problem. Sinusitis can be acute (lasting <30 d), subacute (lasting >30 d to <90 d), recurrent (>3 episodes and lasting <30 d duration over 6 mo or >4 episodes/y), or chronic (lasting >90 d).¹  Upper respiratory tract infection (URTI) is a common pediatric problem; as many as 10% of URTIs can be complicated by acute sinusitis. Untreated chronic sinusitis can lead to life-threatening complications.

Chronic sinusitis may be noninfections and related to allergy, cystic fibrosis, gastroesophageal reflux, or exposure to environmental pollutants.^1,2 Some studies have suggested a higher incidence of complications associated with fungal sinusitis.^3,4 Untreated chronic sinusitis can lead to life-threatening complications as in patients with cystic fibrosis.⁵

Pathophysiology

A brief review of the anatomy, physiology, and development of the sinuses enhances the understanding of the pathophysiology of sinusitis.⁶

A normally sterile environment, paranasal sinuses are spaces in the facial bones. The sinuses open into the nose via small openings called ostia.⁷ The maxillary and ethmoid sinuses form at 3-4 months' gestation. Thus, an infant is born with 3-4 ethmoid cells and tiny teardrop-shaped maxillary sinuses. By the teenage years, each maxillary sinus progressively enlarges to an adult capacity of 15 mL. In healthy individuals, the ethmoid sinuses increase in number to 18-20, and each drains by an individual ostium that is 1-2 mm in diameter.

The frontal sinus develops from an anterior ethmoid cell and moves to its supraorbital position when the individual is aged 6-7 years. Frontal sinuses may begin to develop at this age but usually do not appear radiologically until the individual is aged approximately 12 years. The maxillary, anterior ethmoid, and frontal sinuses drain into the middle meatus; the posterior ethmoid and sphenoid sinuses drain into the superior meatus (see Media file 1).

Secretions produced in the sinuses flow by ciliary action through the ostia and drain into the nasal cavity. In the healthy individual, flow of sinus secretions is always unidirectional (ie, toward the ostia), which prevents back contamination of the sinuses. In most individuals, the maxillary sinus has a single ostium (2.5 mm in diameter, 5 mm² in cross-sectional area) serving as the only outflow tract for drainage. This slender conduit sits high on the medial wall of the sinus cavity in a nondependent position. Most likely, the edema of the mucosa at these 1-3 mm openings becomes congested by some means (eg, allergy, viruses, chemical irritation) that causes obstruction of the outflow tract stasis of secretions with negative pressure, leading to infection by bacteria.

Anterior and posterior ethmoid sinuses are composed of multiple air cells separated by thin bony partitions. Each cell is drained by an independent ostium that measures only 1-2 mm in diameter. These small openings are readily clogged by secretions or are occluded by swelling of the nasal mucosa. The sphenoid sinuses sit immediately anterior to the pituitary fossa and just behind the posterior ethmoid.

All sinus ostia drain into the nares at locations beneath the middle and superior turbinates (see Media file 1). The posterior ethmoid and sphenoid sinuses drain into the superior meatus below the superior turbinate. The ostia of the maxillary, anterior ethmoid, and frontal sinuses share a common site of drainage within the middle meatus. The common drainage pathway of the frontal, maxillary, and anterior ethmoid sinuses within the middle meatus allows relatively localized mucosal infection processes to promote infection in all these sinuses. This region is called the osteomeatal complex and can be visualized by coronal CT scan.

The sinus cavities are lined with pseudostratified, ciliated, columnar epithelium. Goblet cells in the epithelium and submucosal seromucous glands contribute to the airway surface liquid (ASL),⁸ which is 5-100 μm thick and covers the epithelium. Ciliary beat at the rate of 8-15 Hz is continuously moved by the cilia at a speed of 6 mm/min. The successful maintenance of sinus drainage represents a complicated interaction between ciliary action, mucus viscosity, size of sinus ostia, and orientation of body structures. The ciliary action can be affected due to local factors, such as infection and local hypoxia that is associated with complete occlusion of sinus ostia.

Ciliary action can also be affected by genetic factors (eg, dyskinetic cilia syndrome) or factors such as long-standing dehydration, anticholinergic medications and antihistamines, cigarette smoke, or chemical toxins. Additionally, ciliary action can be affected after certain viral infections.

The 2 layers of normal mucus produced in healthy states are an inner serous layer (ie, sol phase) in which cilia recover from their active beat and an outer, more viscous layer (ie, gel phase), which is transported by the ciliary beat. Proper balance between the inner sol phase and outer gel phase is of critical importance for normal mucociliary clearance. If the composition of mucus is changed, so that the mucus produced is more viscous (eg, as in cystic fibrosis), transport toward the ostia considerably slows, and the gel layer becomes demonstrably thicker. This results in a collection of thick mucus that is retained in the sinus for varying periods. In the presence of a lack of secretions or a loss of humidity at the surface that cannot be compensated for by mucous glands or goblet cells, the mucus becomes increasingly viscous, and the sol phase may become extremely thin, thus allowing the gel phase to have intense contact with the cilia and impede their action.

The ostia can be blocked by mucosal swelling, inflammation-associated systemic disorders (eg, cystic fibrosis, respiratory allergies, ciliary dyskinesia), immune disorders, or local causes (eg, trauma, rhinitis). Mechanical obstruction because of nasal polyps, foreign bodies, deviated septa, or tumors can also lead to ostial blockage.

Retained mucus, when infected, lead to sinusitis. Another mechanism hypothesizes that because the sinuses are continuous with nasal cavity, colonized bacteria in the nasopharynx may contaminate the otherwise sterile sinuses. These bacteria are usually removed by mucociliary clearance; thus, if mucociliary clearance is altered, bacteria may be inoculated and infection may occur leading to sinusitis.^1,7 One study suggested histopathological differences in children with chronic rhinosinusitis compared with adults.⁹ The sinus mucosa of young children with chronic sinusitis has less eosinophilic inflammation, basement membrane thickening, and mucus gland hyperplasia that is characteristic of adults with chronic rhinosinusitis.

Viral URTIs are the most important risk factor for the development of acute bacterial sinusitis;¹⁰ thus, daycare attendees are at a relatively higher risk.

Frequency

United States

Approximately 35 million people have acute, chronic, or recurrent sinusitis. Chronic sinusitis is estimated to affect 15% of the population. An average child is likely to have 6-8 colds (ie, URTIs) per year, and approximately 0.5-2% of URTIs in adults and 6-13% of viral URTIs in children are complicated by the development of acute bacterial sinusitis.^11,12

Race

No racial predilection is described.

Sex

No sex predilection is described.

Age

Prevalence of sinusitis is highest in adults aged 18-75 years, followed by people living in the Midwest and the South (associated with higher prevalence of allergies), and then children younger than 15 years. In children aged 5-10 years, URTI episodes can be associated with acute sinusitis.

Clinical

History

• Acute sinusitis symptoms
  • Suspect acute sinusitis in any patient with an upper respiratory tract infection (URTI) that persists beyond 7-10 days, particularly if the infection is severe and is accompanied by high fever, purulent nasal discharge, or periorbital edema (ethmoid sinusitis).
  • Coughing at night is the second most common symptom or sign of sinusitis following purulent rhinitis.
  • Headache, facial pain, tenderness, or edema is uncommon.
  • The condition may start as a URTI, and the patient may seem to be recovering; however, the condition becomes acutely worse around the seventh day of illness. This should be considered a red flag because most URTIs last 5-7 days.
• Chronic sinusitis symptoms
  • Symptoms of chronic sinusitis are more subtle and vary.
  • Fever, when present, may be low grade.
  • Malaise, easy fatigability, and anorexia may be present.
  • Nasal discharge may be of any character from thin to thick and from clear to purulent.
  • Halitosis is reported more commonly by parents of younger children.
  • Nasal obstruction with mouth breathing and associated sore throat may be present.
  • In some individuals with chronic sinusitis, parents may note occasional and painless morning eye swelling.
  • Older children may complain of loss of taste due to associated nasal obstruction and anosmia.
  • Nocturnal symptoms may include snoring and coughing due to associated postnasal drip.

Physical

Physical examination findings may not be helpful in making a diagnosis of acute bacterial sinusitis in a child because the findings are almost identical to those of a child with viral rhinosinusitis.^1,7 Presence of pus in the middle meatus suggests involvement of maxillary, frontal, or ethmoid sinuses; pus in the superior meatus suggests involvement of sphenoid or posterior ethmoid cells.

• In children younger than 6 years, the nasal examination usually consists of evaluating the anterior nasal cavity and middle meatus with anterior rhinoscopy using an otoscope and ear speculum.
  • The superior meatus can never be observed with this technique and is difficult to observe with nasal endoscopy, rigid rhinoscopy, or both.
  • Purulence running into the posterior nasal cavity and nasopharynx, observed only by rigid rhinoscopy, can indicate probable drainage from the sphenoethmoid recess, which drains the posterior ethmoids and sphenoid sinuses.
• In persons with acute ethmoiditis, especially in infants and younger children, periorbital cellulitis with edema of the soft tissues and erythema of the overlying skin is not uncommon.
• In individuals with chronic sinusitis, middle turbinates may be swollen and may cause substantial nasal obstruction.
• Hypertrophy and congestion of nasal mucosa may occur. Occasionally, nasal mucosa may be pale and boggy because of associated allergic rhinitis.
• Other signs of allergies, such as ocular shiners and a transverse crease on the nose due to constant rubbing, may manifest.
• Evidence of posterior nasal drip may be observed on the posterior oropharyngeal wall as it drips down from the nasal cavity.
• Local tenderness of sinuses on palpation or percussion may be elicited in some patients; however, this is a rare finding in children.

Causes

• Organisms usually recovered in children are Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Streptococcus species (groups A or B).
• Commonly recovered anaerobes are anaerobic gram-positive cocci (eg, Peptococcus species, Peptostreptococcus species) and Bacteroides species.
• Cultures obtained from patients with cystic fibrosis tend to reflect pulmonary flora (eg, Pseudomonas aeruginosa).
• Fungal sinusitis (eg, allergic fungal sinusitis) may appear similar to lower airway disorder and allergic bronchopulmonary aspergillosis.
  • Fungal agents associated with this condition include Aspergillus and Alternaria species.
  • Bipolaris and Curvularia species are the most common fungi recovered in allergic fungal sinusitis, accounting for 60% and 20%, respectively, in most studies.
  • Curvularia species is occasionally reported as the most common causative organism in the deep southern United States.

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