Bamboo Node

Abstract

Descriptions of vocal fold lesions related to autoimmune diseases are rare in the literature, and focus mainly on rheumatoid nodules. This is the first report in which autoimmune diseases were promptly suspected by the observation of a unique white transverse submucosal lesion in the vocal fold during clinical examination. This lesion, reported only in autoimmune disease, has been called the bamboo node and its features are different from those of rheumatoid nodules. We report here on two patients who did not have a diagnosis of systemic disease before investigation of their main complaint of hoarseness. At the patients' first visit, vocal fold bamboo nodes were seen in the vocal fold and the otolaryngologist suspected the presence of an autoimmune disease. We requested clinical investigation to clarify our suspicion that there was an underlying systemic disease. After the investigation, both patients were shown to have autoimmune disease, Sjögren's syndrome and systemic lupus erythematous, respectively. This paper emphasizes the important role of the otolaryngologist in the detection of these unique lesions in the vocal folds through the conventional laryngeal methods. These methods consisted of direct observation with a rigid laryngeal endoscope and investigation of the patient's distinctive vibratory pattern by means of laryngeal stroboscopy. The method of treatment we used to obtain the best outcome in terms of voice improvement is also discussed.

Introduction

Hoarseness, a change in the voice quality, has been described previously in the literature as the very first symptom in autoimmune disease.1, 2 Vocal fold lesions in autoimmune diseases are also described in the literature, although rarely. Mikkelsen³ described these lesions, which were mainly small submucosal vocal fold nodules, in a rheumatoid arthritis patient and they were hystopathologically similar to rheumatoid nodules found in other sites. Following this description, these sort of vocal fold nodules, which have been called rheumatoid nodules, were found in rheumatoid arthritis patients,4, 5, 6, 7 in systemic lupus erythematous (SLE),7, 8, 9 and in Sjögren's syndrome¹ patients.

In 1993, Hosako et al described a transversal cream-yellow band lesion at the midpoint of the upper surface of each vocal fold in a SLE patient. The vocal folds resembled the appearance of bamboo and its nodes.¹⁰ Following this case, this unique feature in the vocal folds was also seen in five other cases of autoimmune disease,2, 11, 12 which suggested that the lesions might be related to a disease of autoimmune activity.

We report here on two patients whose main complaint on visiting a doctor was hoarseness; the unique feature of bamboo nodules in the vocal folds led the otolaryngologist to suspect autoimmune disease in patients in whom systemic disease was not diagnosed. The lesions, which were promptly visualized using a rigid laryngeal endoscope at the first visit to our hospital, emphasize how important it is to suspect the presence of disease. The diagnosis of autoimmune disease in each case was confirmed after detailed clinical and serological investigation. Furthermore, evaluation of the main complaint of hoarseness and other clinical complaints, as well as serology and pathology, provided some evidence that there is a good correlation between the manifestations of these unique lesions in the vocal folds of patients with autoimmune disease activity. This paper emphasizes the important role of the otolaryngologist in recognizing these macroscopically visible lesions and discusses their treatment for the improvement of hoarseness.

On July 20, 1996, a 36-year-old female opera singer realized that she had difficulty maintaining high tones during a performance. Two months later she developed constant hoarseness and had to cancel all further performances. She visited an otolaryngologist who suspected a submucosal vocal fold cyst and referred her to our hospital for removal of the lesion under laryngomicrosurgery. She came to the Voice Clinic at the University of Tokyo Hospital in November 1996. The rigid laryngeal endoscopic examination showed a white transverse band lesion in the submucosal space at the junction of the anterior and middle thirds of her right vocal fold, which protruded slightly to the surface (Figure 1A) Stroboscopic visualization of the vibratory pattern revealed decreased right vocal fold mucosal wave and vibration amplitude, absence of mucosal wave at the site of the lesion, and a slit anterior to the lesion. The stroboscopic evaluation was frequently disrupted due to the onset of diplophonia, mainly at the end of the phonatory task. The macroscopic feature of the white submucosal lesion could not be classified as one of the lesions usually seen, but resembled the rare lesion previously described as a vocal fold bamboo node.¹⁰ Although at first the history seemed to indicate an usual case of nodules or other lesions in the vocal folds due to voice abuse, the unique appearance of the white transverse lesion, which had been previously reported only in autoimmune disease patients, led us to look for the presence of these systemic diseases. The patient was then referred to the internal medicine clinic.

The patient was free of any other clinical signs associated with autoimmune disease, although she mentioned that she had already experienced dryness of the mouth and decreased tear production for over 10 years, which was not bothersome to her. She had never sought treatment to solve the problem of mouth dryness. Blood examination in January 1997 showed that antinuclear antibodies (ANA) speckle was positive at a dilution of 1:320 and nucleo at 1:320, serum antibodies were positive for Sjögren's syndrome-A (SS-A) and Sjögren's syndrome-B (SS-B) (Table 1). Sjögren's syndrome was diagnosed as a result of the lip biopsy, which showed grade 4 chronic sialoadenitis with more than one focus showing infiltration of 50 or more histiocytes and lymphocytes per 4 mm² of salivary tissue (Figure 2). In addition, keratoconjunctivitis sicca was detected with rose bengal dye in the ophthalmology examination.

Since the patient did not have any clinical symptoms to contraindicate the surgery, even after the diagnosis of autoimmune disease, the lesion in the vocal fold (Figure 1A) (which was the cause of her main complaint of hoarseness) was excised on January 31, 1997 under microlaryngoscopy. Under microscopic view, a white submucosal transverse striped band at the junction of the anterior and middle thirds of her right vocal folds was observed. It was slightly prominent. The surgical technique consisted of a longitudinal incision lateral to the lesion on the superior surface of the vocal fold, followed by undermining the mucosal layer along the lesion. A whitish soft, crumbly substance without an encapsulating structure was found under the mucosal layer, which adjoined the vocal ligament transversally. Although this visible white substance was withdrawn, the absence of any distinct margin led to some doubts about whether the lesion had been completely removed during the surgery. Nevertheless, these doubts were discarded in the follow-up.

Specimens were stained with hematoxylin and eosin, and fibrosis around granulomatous lesions with central amorphous eosinophilic material was observed (Figure 3).

In March 1997, 2 months after the surgery, the patient was allowed to resume professional voice training. However, 1 month later she began to complain of fatigue and hoarseness. In May 1997 she complained of arthralgia, back pain, and a more evident hoarseness. Another transverse white lesion, or bamboo node, was detected in the vocal fold opposite the one from which the first lesion had been surgically excised (Figure 1B). Treatment with steroids (prednisolone 20 mg/day) was instituted to improve the clinical symptoms. In October 1997, the patient's disease was brought under control with a maintenance dose of 5 mg of prednisolone. In November 1997, a second microlaryngoscopic surgery was performed since her voice, although acceptable for normal conversation, was not suitable for professional use. The laryngeal and histological findings of the second microlaryngoscopy were very similar to those of the first procedure. In March 1998, the patient's voice was considered normal and the disease was under control, so she was allowed to go back to professional training (Figure 1C). Nevertheless, during 1998 she experienced frequent periods of hoarseness, which seemed to be highly related to fatigue and arthralgia. By July 1998, a tiny new lesion was observed in the left vocal fold (Figure 1D). Although her voice was almost normal for conversation, it was unacceptable for use in professional performances. Subsequently, she retired in 1999. Perceptual voice hoarseness examination according to the Japan Society of Logopedics and Phoniatrics GRBAS (Grade, Roughness, Breathiness, Asthenia, Strain) system,¹³ serum results, and clinical findings are summarized in Table 1.

In August 1994, a 28-year-old female primary school music teacher had a sudden onset of hoarseness. One month after the sudden hoarseness onset, she consulted an otolaryngologist and received some nonhormonal anti-inflammatory drugs, which did not change her voice quality. She came to the Voice Clinic at the University of Tokyo Hospital on July 6, 1995 complaining of hoarseness. During the first examination at the University of Tokyo hospital, her voice was diplophonic and hoarse. The rigid laryngeal endoscopic view showed bilateral whitish transverse band stripes in the submucosa, which lent a slightly protruded aspect to the vocal folds. One lesion was seen at the junction of the middle and posterior thirds of the right vocal fold and another was observed in the middle of the left vocal fold (Figure 4A). The site of the bilateral lesion within the vocal folds became more evident during the stroboscopic examination. Moreover, the stroboscopic view during chest voice phonation demonstrated a decreased amplitude vibration throughout the vocal folds, except in the lesion, where no vibration at all could be seen. Furthermore, phase shift in the vibratory pattern between the portions anterior and posterior to the transverse lesion in vocal fold was seen in the continuous image of the videostroboscopy (Figure 5). Glottal width measurement was used to make the distinctive vibratory pattern of the vocal folds clear for presentation purpose. The principle of this method is commonly used in the analysis of laryngeal images obtained in high-speed digital imaging system.¹⁴ A total of four points at the free edge were selected frame-by-frame and their displacements were tracked and plotted over time for the purpose of comparing the glottal width between the portions anterior and posterior to transversal lesions. To obtain these points, two scan lines, one in the anterior and another posterior to the transverse lesion, were set and the points where the free edges of the vocal folds cross these scan lines were selected for glottal width measurement (Figure 6). Although the vibratory pattern of the right and left anterior portions of the vocal folds could be considered almost normal due to complete closure and the absence of almost any phase shift, the reverse occurs in the right and left posterior portions. In these portions, both vocal folds dislocate to the same direction and no closure is seen. The left anterior and left posterior portions have almost a 180° shift.

As the macroscopically observed lesions were similar to what had been previously described as a vocal fold bamboo node, we suspected autoimmune disease and referred the patient to the internal medicine clinic for investigation.

Several examinations were performed and the patient was diagnosed with systemic lupus erythematosus (SLE) due to high titers of ANA. In addition, speckle was positive at a dilution of 1:2560, there was a low level of complement, and Raynaud's phenomenon was present, as well as arthritis (Table 3).

The patient received steroids (prednisolone at a dose of 30 mg/day) as an exclusive treatment and both the arthritis and hoarseness resolved.

On March 24, 1997, no lesions in the vocal folds could be seen (Figure 4B) and her voice was perceptually normal (Table 2). At that time she was receiving 7.5 mg prednisolone as a maintenance dose and there were no clinical symptoms or complaints. She returned to her teaching activities. Nevertheless, in May 1999, she noticed hoarseness during conversational speech which was not related to prior vocal abuse. There were no other clinical complaints simultaneously. To our surprise another bamboo node lesion in the right vocal fold was observed in the laryngological examination (Figure 4C) and SS-A and single-stranded DNA (SS-DNA), which were absent in the previously performed blood test, were detected (Table 2). As clinical complaints other than the hoarseness were absent, the prednisolone dosage was not increased and the patient was advised to undergo a period of strict vocal hygiene. Although the lesion is still present, the patient is working normally.