Sinusitis Case File

Sinusitis Case File

Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 48

A 10-year-old girl is brought to her pediatrician’s office complaining of headache for the past 2 weeks. Her mother had taken the girl to an optometrist, and her vision was normal. The patient states that she has been in good health and that she received a cat as a birthday present 1 month previously. On examination, she has a normal temperature, the tympanic membranes appear normal, and her throat is clear. There is some tenderness of the right cheek and over the right orbit.

⯈ What is the most likely diagnosis?

⯈ What is the anatomical explanation for this condition?

ANSWER TO CASE 48:

Sinusitis

Summary: A 10-year-old girl who had recently acquired a cat has had a headache for a 2-week duration. She is afebrile, with normal-appearing tympanic membranes and throat. She has right maxillary and frontal tenderness.

• Most likely diagnosis: Maxillary and frontal sinusitis

• Anatomical explanation for this condition: Blocked drainage of the sinuses secondary to an allergic reaction of the nasal mucosa

CLINICAL CORRELATION

Sinusitis, a condition common in Americans, is an inflammation of one or more of the six sets of paranasal sinuses, most of which are related to the orbits. Inflammation may be caused by viruses, allergies, and bacterial pathogens. The sinuses are usually sterile cavities that are lined by ciliated mucosa rich in mucous cells, and mucus drains directly into the nasal cavities through small openings, or ostia. Edema of the nasal mucosa can easily occlude these openings and lead to secondary infection. The maxillary sinus is most commonly involved, and sinus pain or pressure sensation is typical. Transillumination of the sinuses that demonstrates opacification may be helpful on physical examination. Radiographs may also be helpful; CT imaging is usually reserved for complicated cases. The recent acquisition of a cat by the patient suggests maxillary and frontal sinusitis caused by an allergy rather than an infectious agent. Oral or topical (spray) decongestants, antihistamines, and/or nasal steroids are often helpful. Antibiotics are not indicated at this time, but the patient should be instructed to watch for development of fever or an increase in tenderness. Complications include osteomyelitis, ocular cellulitis, and cavernous sinus thrombophlebitis.

APPROACH TO:

The Sinuses

OBJECTIVES

1. Be able to describe the location of the paranasal sinuses in the facial skeleton

2. Be able to list the openings in the nasal cavity through which the paranasal sinuses drain

DEFINITIONS

OSTEOMYELITIS: Condition in which the bone and bone marrow become infected

THROMBOPHLEBITIS: Condition in which a vein becomes inflamed in response to a blood clot

DISCUSSION

The paranasal sinuses are extensions of the nasal cavities into bones of the skull and are named for the bones in which they are located (Figure 48-1). These spaces are lined with respiratory mucosa, decrease the weight of the skull, and probably assist in humidifying inspired air. See Case 51 for the anatomy of the nasal cavity. The sphenoid sinuses are located within the sphenoid bone, are variable in size and number, and open into the sphenoethmoidal recess. The ethmoidal sinuses consist of a series of sinuses positioned between the medial wall of the orbit and the nasal cavity (at the level of the bridge of the nose). For descriptive purposes, they are divided into anterior, middle, and posterior ethmoidal cells, and each has a separate opening. The posterior ethmoidal cells open inside the superior nasal meatus. The middle ethmoidal cells elevate the ethmoid bone in the middle meatus, thus creating the ethmoid bulla on whose surface these cells open. Inferior to the ethmoid bulla is a groove, the semilunar hiatus. The anterior ethmoidal cells open into the anterior portion of the hiatus, called the infundibulum.

The largest sinuses are the maxillary and frontal sinuses, and their relatively large openings also drain into the middle meatus. The large maxillary sinus hollows the maxillary bone. The roof of the sinus, which also forms the floor of the orbit, is very thin and at risk in direct trauma to the orbit, which would cause sudden increases in pressure. Such trauma may cause “blowout” fractures of the orbital floor. The opening of the maxillary sinus is found in the semilunar hiatus. The frontal sinuses are found in the frontal bone between the inner and outer tables and in the portion that forms the roof of the orbit. It is drained by the frontonasal duct, which opens into the infundibulum, the anterior portion of the semilunar hiatus.

Figure 48-1. Sinuses in the coronal view. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:68.)

COMPREHENSION QUESTIONS

48.1 A 24-year-old medical student has been diagnosed with sinusitis and asks her physician why there is nasal drainage during the night but not during the day. Which of the following is the best explanation?

    A. Location of the ostia within the sinus

    B. Location of the ostia within the nasal passage

    C. Disruption of the drainage due to mastication

    D. Diurnal mucus production increases at night

48.2 A 22-year-old college student is being seen for possible sinusitis. The physician sees purulent drainage arising from the superior nasal meatus. Which of the following sinuses is likely to be infected?

    A. Frontal

    B. Maxillary

    C. Sphenoidal

    D. Ethmoidal

48.3 A 28-year-old neuroanatomy graduate student noted pain at the bridge of his nose and had been told that he had “sinus” infections. He was speculating about the afferent nerve supply from this area. Which of the following is the most accurate description of the sensory nerve innervation?

    A. Branches of CN III

    B. Branches of CN V

    C. Branches of CN VII

    D. Branches of CN IX

ANSWERS

48.1 A. The sinus most likely affected is the maxillary sinus. The ostia within the sinus are located superiorly in a location inefficient for gravity drainage. During sleep at night, the mucus flows out through the ostia.

48.2 D. The posterior ethmoidal sinus drains into the superior nasal meatus.

48.3 B. The paranasal sinuses are innervated by branches of CN V.

ANATOMY PEARL

⯈ The paranasal sinuses are named after the bones in which they are found (frontal, ethmoid, sphenoid, and maxilla).

⯈ The maxillary, frontal, anterior, and posterior ethmoidal sinuses open into the middle nasal meatus.

⯈ The maxillary sinus is the largest of the paranasal sinuses and is the most commonly infected sinus because its ostia are located superiorly.

⯈ Trauma to the orbit may result in a blowout fracture and, hence, orbital structures (such as extraocular muscles) may be pushed inferiorly into the maxillary sinus.

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:537, 552−553. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:960−964. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 42−45.

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