A 13-year-old boy presents for evaluation of a chronic productive cough and fever. Since birth, he has had persistent rhinitis, thick nasal drainage, and recurrent otitis media. He has been seen three times in the past year for pneumonia each time diagnosed and treated without a chest x-ray. On physical exam, heart sounds are greater on the right side and point of maximal impulse is felt in the right 5th intercostals space. A chest x-ray shows situs inversus totalis with dextrocardia (Figure 217-1). Computed tomography of the sinuses shows chronic sinusitis (Figure 217-2). The diagnosis of primary ciliary dyskinesia was considered and he underwent a biopsy of his nasal epithelium, which revealed abnormal ciliary structure and function. This confirmed the diagnosis and the physician explained the meaning of primary ciliary dyskinesia and the situs inversus to the patient and his parents. He was told that he will need aggressive treatments for all future infections.
Primary Ciliary Dyskinesia (PCD) is a rare genetic disease associated with abnormal cilia structure and function causing impaired clearance of bacteria from the lungs, paranasal sinuses, and middle ear, which leads to recurrent infections. It can be associated with other developmental abnormalities such as situs inversus totalis, nasal polyposis, and frontal sinus agenesis. Clinical manifestations include chronic cough and chronic rhinosinusitis and recurrent sinopulmonary and ear infections.
PCD is caused by genetic mutations on genes which code for proteins found in the ciliary outer dynein arm which controls the cilia beat force and frequency.
Motile cilia (Figure 217-3) contain a cylinder of 9 microtubule doublets, arranged around a central pair of microtubules in the characteristic “9 + 2” arrangement as viewed by cross-sectional views on electron microscopy.
Defective cilia (Figure 217-4) resemble sensory or primary cilia, which lack a central microtubule doublet and outer dynein arms, thus creating a “9 + 0” arrangement and leaving these structures immotile.
Defects in cilia during embryogenesis may result in left-right body orientation abnormalities, such as situs inversus or situs inversus totalis (Figures 217-1 and 217-5).
Any disturbance in the coordinated movement of cilia can contribute to poor mucous clearance resulting in more frequent and severe infections. It can inhibit sperm motility leading to infertility in men or cause fallopian tube dysfunction and infertility in women.4
FIGURE 217-3
Electron micrograph of motile cilia. Notice the long curving cilia demonstrating active movement. (Used with permission from Ian Myles MD, Steve Holland MD, and Harry Malech, MD. Scans were obtained for diagnostic and research purposes after informed consent under NIH IRB approved protocols.)