Sinus Infection (Sinusitis): Causes, Symptoms, Evaluation & Treatment

Sinusitis is an inflammation of the paranasal (ethmoid, frontal, maxillary, or sphenoid) sinuses. It is classified as acute or chronic, depending on how long the infection has been present.

ETIOLOGY AND PATHOGENESIS

Sinusitis occurs when pus is trapped in the sinus and is unable to drain completely through the Ostia into the nasal cavity.

a) Bacterial causes include H. influenzae, S. pneumoniae, streptococci, and M. catarrhalis.

b) Fungal causes are most common in patients with diabetes. Mucormycosis is particularly life-threatening.

PREDISPOSING FACTORS

— Chronic nasal edema

— Nasal polyps

— Nasal allergies

— Preceding upper respiratory tract infection

— Upper tooth abscess

CLINICAL FEATURES

1. Symptoms

a) Pain: Nasal congestion increases the pressure in the sinus, leading to pain that often worsens when the patient bends over. Patients may complain of a headache. Facial pain often corresponds to the affected sinus:

— Cheeks and upper teeth—maxillary sinus

— Eyebrow area—frontal sinus

— Eyes or behind the eyes—ethmoid sinus

b) Generalized malaise and periorbital edema are common complaints.

c) Nasal discharge is often blood-tinged and purulent. A postnasal drip may cause coughing and a sore throat.

2. Physical examination findings

a) Fever is often present in acute sinusitis but is rare in chronic sinusitis.

b) Tenderness to percussion may be present over the affected sinus.

c) The opacity of the affected sinus may be evident during transillumination. A negative transillumination does not rule out sinusitis because the test is only positive when the sinusitis is advanced.

DIFFERENTIAL DIAGNOSES

— Viral rhinitis

— Allergic rhinitis

— Vasomotor rhinitis

— Tumors

— Foreign bodies

— Wegener granulomatosis

EVALUATION

1. Laboratory studies: Typically not indicated. In acute sinusitis, a CBC may reveal an elevated white blood cell count.

2. Imaging studies

a) Radiographs: Plain sinus films may reveal air-fluid levels, cloudiness, or thickening of the sinus mucosa.

b) CT scans may identify an underlying predisposing anatomic condition (e.g., abnormally narrowed outlets, tumorous or cystic obstructions).

THERAPY

1. Supportive measures

a) An effort should be made to avoid air-borne irritants (e.g., smoke, pollen).

b) Although steam inhalation and environmental humidification are useful adjuncts, aggressive systemic rehydration is essential to mobilize and prevent reaccumulation of the thickened secretions.

c) Analgesics, decongestants, antihistamines, and steroids may also be helpful.

2. Antibiotic therapy: Not indicated in most cases. If determined necessary, acceptable regimens include:

a) Amoxicillin clavulanate (500 mg three times daily for 2 to 3 weeks)

b) Doxycycline (100 mg twice a day for 10 days)

3. Surgery: Surgical drainage of the sinus may be indicated if medical treatment fails. Surgery may also be indicated to correct underlying anatomic defects.

DISPOSITION

All patients diagnosed with sinusitis should be followed up until clinically cured.

1. Discharge: In the absence of complications (e.g., orbital cellulitis, osteomyelitis, septic cavernous thrombosis, contiguous spread to involve the nervous system), patients can be sent home with instructions to follow up in 1 to 2 days.

2. Admission is indicated for extremely ill patients, patients with orbital edema, and patients with nuchal rigidity or altered mental status.