Recurrent Respiratory Papillomatosis

Recurrent respiratory papillomatosis is a rare respiratory disease characterized by the development of exophytic papillomas, affecting the mucosa of the upper aero-digestive tract (with a strong predilection for the larynx), caused by an infection with human papilloma virus. Symptoms at presentation may include hoarseness, chronic cough, dyspnea, recurrent upper respiratory tract infections, pneumonia, dysphagia, stridor, and/or failure to thrive.

Epidemiology

The prevalence of recurrent respiratory papillomatosis (RRP) is estimated at about 1/70,400 in the United Kingdom. Annual incidence of the disease is about 1/23,300 in children and 1/55,500 in adults in the United States. The adult form affects males more often than females.

Clinical description

A bimodal age distribution is characteristic, with the disease affecting either young children or young adults. Manifestations depend on the extent and progression of the lesions and include hoarseness, cough, wheezing, voice change, chronic dyspnea, choking and syncope. The symptoms tend to be more severe in children because of the rapid growth of the lesions and can lead to potentially life-threatening airway compromise. Coexisting laryngopharyngeal reflux disease worsens the clinical manifestations of RRP. The clinical course is variable ranging from mild disease with spontaneous remission to an aggressive disease or a chronic clinical course.

Etiology

RRP is caused by a human papillomavirus (HPV) infection. HPV-6 and HPV-11 account for most cases of RRP and within HPV subtypes are considered to be ''low-risk'', or generally not associated with malignancy. Nevertheless, HPV-11 infections most commonly present with an aggressive disease course. Rarely, RRP is caused by HPV types 16, 18, 31, and 33. In neonates, vertical transmission from an infected mother with noticeable genital warts at the time of delivery has been documented. Following infection in humans, HPV is able to promote a specific immune system dysfunction, hence favoring the development of papillomatosis. It is theorized that such behavior is related to specific virus capabilities and a possible genetic predisposition.

Diagnostic methods

Endoscopy is the reliable method used to reach a definite diagnosis. Multiple non-necrotic cauliflower-like smooth lesions can be observed on endoscopy. HPV genotyping can be performed by the detection of HPV DNA by polymerase chain reaction with consensus primers and subsequent restriction mapping or hybridization methods.

Differential diagnosis

The differential diagnosis includes acute laryngitis, upper respiratory tract infection, asthma, bronchitis, and other benign or malignant laryngeal tumors.

Management and treatment

The treatment goals when dealing with RRP are to secure airway patency, preserve the underlying laryngeal tissues, and maintain an acceptable quality of voice. Surgery is performed using either a microscope or an endoscope, adopting a variety of lasers or a microdebrider in order to debulk/remove the papilloma lesions. Complications that might follow surgical procedures include laryngeal stenosis and/or synechiae, which are usually less frequent when using a microdebrider. Adjuvant therapy, often offered to patients that require several surgical procedures, usually includes cidofovir and bevacizumab. Interferon, various virostatics (acyclovir, valacyclovir and cidofovir), indole-3-carbinol, office-based photoangiolytic laser surgery/photodynamic therapy, celecoxib, and the HPV vaccine have also been suggested or investigated (either in the past or are currently undergoing research) as possible treatment options.

Prognosis

The prognosis is often good and morbidity low in most cases. Younger children, especially those under the age of 3 years, and adults with HPV-11 infection generally experience a more severe disease course. Malignant degeneration can rarely occur. Resistance to therapy, frequent recurrences, and lower airway involvement are factors associated with a poorer prognosis.