AUTHOR AND EDITOR INFORMATION

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• Miscellaneous
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INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
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• Medication
• Follow-up
• Miscellaneous
• Multimedia
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Background

Siewert first described the combination of situs inversus, chronic sinusitis, and bronchiectasis in 1904. However, Manes Kartagener first recognized this clinical triad as a distinct congenital syndrome in 1933. Because Kartagener described this syndrome in detail, it bears his name. Kartagener syndrome (KS) is inherited via an autosomal recessive pattern. Symptoms result from defective cilia motility.

Pathophysiology

Camner and coworkers first suggested ciliary dyskinesia as the cause of KS in 1975. They described 2 patients with KS who had immotile cilia and immotile spermatozoa. These patients had poor mucociliary clearance because the cilia that lined their upper airways were not functioning.

Later, Afzelius discovered that bronchial mucosal biopsy specimens from patients with similar respiratory complaints showed cilia that appeared abnormal, were poorly mobile, and were missing dynein arms. In 1977, Eliasson and coworkers used the descriptive phrase immotile cilia syndrome to characterize male patients with sterility and chronic respiratory infections.

In 1981, Rossman and coworkers coined the term primary ciliary dyskinesia (PCD) because some patients with KS had cilia that were not immobile but exhibited an uncoordinated and inefficient movement pattern. Current nomenclature classifies all congenital ciliary disorders as PCDs in order to differentiate them from acquired types. KS is part of the larger group of disorders referred to as PCDs. Approximately one half of patients with PCD have situs inversus and, thus, are classified as having KS. Afzelius proposed that normal ciliary beating is necessary for visceral rotation during embryonic development. In patients with PCD, organ rotation occurs as a random event; therefore, half the patients have situs inversus and the other half have normal situs.

Ciliated epithelium covers most areas of the upper respiratory tract, including the nasal mucosa, paranasal sinuses, middle ear, eustachian tube, and pharynx. The lower respiratory tract contains ciliated epithelium from the trachea to the respiratory bronchioles. Each ciliated cell gives rise to approximately 200 cilia that vary in length from 5-6 microns and decrease in size as the airway becomes smaller.

The typical ciliary axoneme consists of 2 central microtubules surrounded by 9 microtubular doublets. Each doublet has an A subunit and a B subunit attached as a semicircle. A central sheath envelops the 2 central microtubules, which attach to the outer doublets by radial spokes.

The outer doublets are interconnected by nexin links, and each A subunit is attached to 2 dynein arms that contain adenosine triphosphatase; one inner arm and one outer arm. The primary function of the central sheath, radial spokes, and nexin links is to maintain the structural integrity of the cilium, whereas the dynein arms are responsible for ciliary motion.

The cilium is anchored at its base by cytoplasmic microtubules and a basal body comprised of a basal foot and rootlet. The orientation of the basal foot indicates the direction of the effective cilial stroke. Just above the base, the cilium is composed of microtubular triplets (previously doublets) without associated structures, but at the tip, only the B subunits remain.

Cilia propel overlying mucus via a 2-part ciliary beat cycle. First, the power stroke occurs when a fully extended cilium moves perpendicular to the cell surface in an arclike manner. Then, the recovery stroke follows, in which the entire cilium bends and returns to its starting point near the cell surface. Once a cilium starts to move, the complete beat cycle is obligatory.

The cycle is mediated by dynein arms from the A subunit that attach to the B subunit of the adjacent microtubule. Adenosine triphosphate is hydrolyzed by the dynein arms and the 9 microtubule doublets as they slide against each other.

Patients with PCD exhibit a wide range of defects in ciliary ultrastructure and motility, which ultimately impairs ciliary beating and mucociliary clearance. The most common defect, first described by Afzelius, is a reduction in the number of dynein arms, which decreases the ciliary beat frequency.

Sturgess described how the radial spoke, which serves to translate outer microtubular sliding into cilial bending, was absent in some patients with PCD. Cilia in other patients lacked central tubules; however, instead of the central tubules, an outer microtubular doublet transposed to the cell of the axoneme was present that displayed an abnormal 8+1 doublet-to-tubule pattern. Both the radial spoke and the transposed doublet defects impaired mucociliary clearance.

Other ciliary defects include an abnormal basal cell apparatus with giant roots and double feet, cilia lacking all internal microtubular structures, and even cilia twice the normal length that beat in an uncoordinated undulating fashion. Pedersen compared the type of ultrastructural defect to ciliary motility and found that dynein defects caused hypomotility and microtubular defects (ie, caused asynchrony). He also found that normal ciliary ultrastructure occasionally was associated with hypermotility or inefficient ciliary trembling.

Some patients with clinical features of PCD have a ciliary ultrastructure that appears normal, but their arrangement and beat direction is disoriented, which causes inefficient mucociliary transport. These findings illustrate the importance of analyzing ciliary motility and ultrastructure when considering a diagnosis of PCD.

Frequency

United States

The frequency of KS is 1 case per 32,000 live births. Situs inversus occurs randomly in half the patients with PCD; therefore, for every patient with KS, another patient has PCD but not situs inversus.

Mortality/Morbidity

Clinical manifestations include chronic upper and lower respiratory tract disease resulting from ineffective mucociliary clearance. Males demonstrate infertility secondary to immotile spermatozoa.

• Upper airway
  • Nose: Patients may exhibit chronic, thick, mucoid rhinorrhea from early in childhood. Examination usually reveals pale and swollen nasal mucosa, mucopurulent secretions, and an impaired sense of smell. Nasal polyps are recognized in 30% of affected individuals.
  • Sinuses: The recurrent chronic sinusitis typically produces sinus pressure headaches in the maxillary and periorbital regions. Sinus radiographs (which largely have been supplanted by CT scans) typically demonstrate mucosal thickening, opacified sinus cavities, and hypoplastic frontal sinuses. Symptoms usually improve with antibiotic therapy but have a propensity for rapid recurrence.
  • Ears: Recurrent otitis media is a common manifestation of PCD. Examination may reveal a retracted tympanic membrane with poor or absent mobility and a middle-ear effusion. Further testing usually demonstrates a flat tympanogram and bilateral conductive hearing loss secondary to thick middle-ear effusion. Many patients undergo repeated tympanostomy tube insertion, often complicated by chronic suppurative otitis media. Other associated otologic disorders may include tympanosclerosis, cholesteatoma, and keratosis obturans.
• Lower respiratory tract
  • Chronic bronchitis, recurrent pneumonia, and bronchiectasis are common conditions associated with PCD. Patients presenting with bronchiectasis should be evaluated for KS. Chest radiographs may illustrate bronchial wall thickening (earliest manifestation), hyperinflation, atelectasis, bronchiectasis, and situs inversus (in 50% of patients with PCD). Bronchiectasis usually occurs in the lower lobes in patients with KS, while patients with cystic fibrosis have bronchiectasis predominantly in the upper lobes.
  • Obstructive lung disease may be another component of KS symptomatology. It probably results from elevated levels of local inflammatory mediators in a chronically irritated airway.
• Other features include digital clubbing and diminished female fertility. Recently, PCD has been associated with esophageal problems and congenital cardiac abnormalities.

Sex

No sex predilection exists.

Age

Clinical manifestations of chronic sinusitis, bronchitis, and bronchiectasis are more severe during the first decade of life but remit somewhat by the end of adolescence.

CLINICAL

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History

Patients present with chronic upper and lower respiratory tract disease resulting from ineffective mucociliary clearance. Immotile spermatozoa result in male sterility.

Physical

KS is characterized by the clinical triad of chronic sinusitis, bronchiectasis, and situs inversus.

• Upper airway
• • Nose: Patients may exhibit chronic, thick, mucoid rhinorrhea from early in childhood. Examination usually reveals pale and swollen nasal mucosa, mucopurulent secretions, and an impaired sense of smell. Nasal polyps are recognized in 30% of affected individuals.
  • Sinuses: The recurrent chronic sinusitis typically produces sinus pressure headaches in the maxillary and periorbital region. Symptoms usually improve with antibiotic therapy but have a propensity for rapid recurrence.
  • Ears: Recurrent otitis media is a common manifestation of PCD. Examination may reveal a retracted tympanic membrane with poor or absent mobility and a middle-ear effusion. Other associated otologic disorders may include tympanosclerosis, cholesteatoma, and keratosis obturans.
• Lower respiratory tract
• • Chronic bronchitis and recurrent pneumonia are common conditions in patients with PCD. Thus, upon physical examination of the patient's chest, increased tactile fremitus, rhonchi, crackles, and, occasionally, wheezes may be present.
  • Obstructive lung disease may be another component of KS symptomatology. It probably results from elevated levels of local inflammatory mediators in a chronically irritated airway. Therefore, wheezing may occur. The lung examination may be normal during intercurrent periods when the airway is not actively inflamed.
• Other features
• • Cardiovascular examination of a patient with KS demonstrates a point of maximal impulse, and the heart sounds are heard best on the right side of the chest.
  • Extremities may exhibit digital clubbing.

Causes

The cause of PCD is genetic, with an autosomal recessive inheritance pattern.

DIFFERENTIALS

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Other Problems to be Considered

Adenoid hyperplasia
Allergic bronchopulmonary aspergillosis
Bronchial obstruction
Chronic aspiration
Congenital cartilage deficiency
Cystic fibrosis
Idiopathic nasal polyposis
Inhalation of toxic substances
Postinfectious bronchiectasis
Pulmonary sequestration
Samter triad
Severe atopy
Tracheobronchomegaly
Yellow nail syndrome

WORKUP

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Lab Studies

• Semen analysis in postpubescent males may reveal abnormal sperm motility and ultrastructure.

Imaging Studies

• Sinus radiographs (which largely have been supplanted by CT scans) typically demonstrate mucosal thickening, opacified sinus cavities, and hypoplastic frontal sinuses.
• Chest radiographs may illustrate bronchial wall thickening as an early manifestation of chronic infection, hyperinflation, atelectasis, bronchiectasis, and situs inversus (in 50% of patients with PCD). The presence of situs inversus strongly suggests KS.
• Bronchiectasis occurs in the lower lobes in patients with KS and immunoglobulin deficiency, while bronchiectasis predominantly occurs in the upper lobes of patients with cystic fibrosis.
• High-resolution CT scan of the chest is the most sensitive modality for documenting early and subtle abnormalities within airways and pulmonary parenchyma when compared to routine chest radiographs. Consideration should be given to this imaging technique early in the presentation of PCD syndromes, when a chest radiograph may not be sensitive enough to identify disease processes or when another differential is being considered.

Other Tests

• Saccharine test: Saccharin or another substance is placed in the nose, and the speed of transport into the nasopharynx is measured to calculate mucociliary clearance (used infrequently because of awkwardness and dubious reliability).
• Audiologic testing usually demonstrates a flat tympanogram and bilateral conductive hearing loss secondary to thick middle-ear effusion.
• Pulmonary function studies
• • Spirometry often reveals an obstructive ventilatory defect with decreases in the ratio of forced expired volume in 1 second to forced vital capacity, reduced forced expired volume in 1 second, and a reduced forced expiratory flow of 25-75%.
  • Static lung volumes also may demonstrate hyperinflation.
  • The response to bronchodilators is variable in patients with PCD.

Procedures

• Mucosal biopsy
• • The specimen should come from ciliated epithelium, preferably when the patient is not acutely ill. Infectious processes can alter cilia motility, even in a healthy host.
  • Tracheal biopsies require general anesthesia but provide excellent specimens. Nasal mucosa is more readily available. Nasal brushing is least invasive but frequently yields an inadequate specimen.
  • Children with suspected PCD often require an adenoidectomy. Because adenoid tissue has a ciliated surface, adequate material is available for histopathologic and electron microscope examination. Knowledge of this fact should eliminate the need for other invasive biopsies.
• Nasal endoscopy is a sensitive indicator for nasal polyposis.

Histologic Findings

The mucosal biopsy specimen should be examined for ciliary movement using light microscopy. Light microscopic quantitation of ciliary beat frequency, coordination, and amplitude, although available in very few medical centers, can identify ciliary dyskinesia in patients with normal ultrastructure. Light microscopy alone offers a reliable and simple method of excluding PCD, but light microscopy and electron microscopy in combination provide a higher degree of accuracy.

The specimen should be placed in glutaraldehyde and sent for electron microscopy, which is the criterion standard examination for the diagnosis of PCD. Quantitative diagnostic criteria do not exist; however, ciliary ultrastructure is examined qualitatively for abnormalities in dynein arms (inner and outer), radial spokes, central sheaths, nexin links, and ciliary transposition and orientation. The most common ultrastructural defect is an absence or decrease in the number of inner or outer dynein arms. A radial spoke deficiency commonly appears with a dynein arm deficiency. Other ultrastructural abnormalities with nexin links, central sheaths, and ciliary transposition and orientation are considered nonspecific for PCD because they can occur in healthy people and those with recurrent respiratory infections.

Electron microscopic diagnosis of ciliary ultrastructure is expensive, time consuming, and described by some experts as inadequate. Patients with KS also may have normal ultrastructure, which decreases the sensitivity of electron microscopy.

Efforts have been undertaken to standardize the clinical criteria for the diagnosis of KS. These criteria include dextrocardia, a ciliary beat frequency of less than 10 Hz/s, and a mean cross-section dynein arm count of less than 2. If the patient does not have dextrocardia, PCD presents a much greater diagnostic challenge. Genetic testing ultimately may become the principal means of establishing this diagnosis.

TREATMENT

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Medical Care

• Antibiotics, intravenous or oral and continuous or intermittent, are used to treat upper and lower airway infections. Although prophylactic antibiotics should be used with great caution in this era of emerging antibiotic resistance, children with PCD are especially good candidates for long-term low-dose preventative antibiotics.
• Obstructive lung disease, if present, should be treated with inhaled bronchodilators and aggressive pulmonary toilet. Mucolytics may be helpful. Anecdotal reports indicate that inhaled antibiotics, oral and inhaled corticosteroids, and recombinant human DNAase have been used, but no large studies support the use of these agents.

Surgical Care

• Tympanostomy tubes are required to reduce conductive hearing loss and recurrent infections.
• • Many patients undergo repeated tympanostomy tube insertions, often complicated by chronic suppurative otitis media.
  • Chronic otorrhea may require special measures for aural hygiene, such as regular otomicroscopy, acetic acid irrigations, or culture-guided topical or systemic antibiotic therapy.
  • Because of anticipated long-term middle-ear disease, inserting tympanostomy tubes is the most sensible method of maintaining the myringotomy because the tube can be expected to stay in the tympanic membrane longer than routine grommets.
• When sinus disease is refractory to medical management, functional endoscopic sinus surgery leads to transient improvement in upper and lower respiratory tract symptoms. The antiquated procedure of making a nasal antral window underneath the inferior turbinate may have a role in the management of PCD because this procedure relies on gravitational rather than ciliary clearance of mucus.

Consultations

Consultations from an otolaryngologist, geneticist, pulmonologist, social services agent, or obstetrician/gynecologist (infertility) may be indicated.

Activity

Activities can be performed as tolerated; however, patients usually experience mild limitations in physical tolerance.

MEDICATION

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Early intervention should be instituted with antibiotics directed at specific organisms identified by nasal secretions and/or expectorated sputum samples. Sensitivities of these samples should be obtained because resistant microorganisms can develop. Mucolytics may be helpful in specific individuals.

Drug Category: Antibiotics

Used to treat acute or chronic infection or for prophylaxis against infection. Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Drug Category: Mucolytics

Thin mucous secretions.

FOLLOW-UP

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• Follow-up
• Miscellaneous
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Prognosis

• Chronic childhood infections can be very debilitating, but the range and severity of clinical symptoms is wide. Fortunately, the disease usually becomes less problematic near the end of the patient's second decade, and many patients have near normal adult lives.

MISCELLANEOUS

Section 9 of 11  

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• While physicians may be accused of failing to diagnose PCD, currently, these disorders are not known for their medicolegal risks.

Special Concerns

• Future and controversies
• • In vitro fertilization holds promise for fertility problems.
  • The field of genetics holds the best hope for future advances in diagnosis and therapy.

MULTIMEDIA

Section 10 of 11  

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• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Photomicrograph of a ciliated border of respiratory epithelium.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
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Article Last Updated: Jan 3, 2007