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* From the Department of Respiratory Medicine, T.N. Medical College, BYL Nair Hospital, Mumbai, India.
Correspondence to: Jyotsna M. Joshi, MD, Professor and Head, Department of Respiratory Medicine, BYL Nair Hospital, Mumbai 400 008, India; e-mail drjoshijm{at}email.com
A 52-year-old, nonsmoking man was referred for evaluation of excessive daytime sleepiness, snoring, nonrefreshing sleep, and abnormal limb movements during sleep over the past 6 months. He also complained of dysphagia, dysarthria, and sialorrhea for the last 8 months. He had no other systemic complaints.
Physical Examination
General examination was unremarkable except for a body mass index of 28 kg/m2 and presence of fasciculations of the right facial muscles. His neck circumference was 15 inches, and there was no evidence of any craniofacial abnormality, macroglossia, enlarged tonsils, or adenoids. There was no motor weakness, and all the deep tendon reflexes were normal. Respiratory system examination showed no abnormality.
Laboratory Investigations
Hematologic and serum biochemistry findings were normal. Awake-state arterial blood gas analysis showed pH 7.363; PO2, 77.2 mm Hg; PCO2, 47.4 mm Hg; and HCO3, 26.3 mEq/L. Spirometry findings were within normal limits, with FVC of 2.99 L (81% of predicted), FEV1 of 2.54 L (84% of predicted), and FEV1/FVC ratio of 85%. Multiparameter respiratory monitoring during sleep using a portable polysomnography that records airflow with oronasal flow sensors, snoring by microphone, oxygen saturation by pulse oximetry, thoracoabdominal movements, and body position by sensors revealed 10.3 hypopneas per hour associated with oxygen desaturation throughout the night and minimum saturation of 63% (Fig 1 ). CT of the brain and MRI of the spine were unremarkable. Anti-acetylcholineesterase antibodies were negative. Barium swallow showed stasis in the pyriform fossa, and esophageal manometry revealed upper-esophageal sphincter dysmotility and spasm.
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Answer: Electromyography (EMG) to confirm amyotrophic lateral sclerosis (ALS). This patient’s EMG studies revealed motor axonal degeneration of C8/T1 innervating muscles of upper limb and distal muscles of the feet.
Discussion
ALS, also called Lou Gehrig disease, is a rapidly progressive neurodegenerative disorder belonging to group of motor neuron diseases in which symptoms may develop with limb onset, bulbar onset, or both. With limb onset, the extremities and torso are affected initially. Fifteen to 20% of patients with ALS may present with bulbar onset, as observed in our case. Subsequently, limb weakness also develops in these patients.
Respiratory complications (Table 1 ) represent the more frequent cause of death in ALS patients. Excessive daytime somnolescence and sleep-disordered breathing are rare initial symptoms of ALS. The prevalence of sleep-disordered breathing in ALS varies from 16.7 to 76.5%. The principal cause of sleep-disordered breathing and nocturnal desaturation is diaphragmatic weakness in cases of limb-onset ALS. Arnulf et al reported a significant reduction of rapid eye movement (REM) sleep duration in ALS patients with diaphragmatic dysfunction, and hypothesized that REM sleep reduction could be a possible protective mechanism against hypoventilation. Ferguson et al showed that the pattern of sleep-disordered breathing in patients with ALS was similar to patients without ALS with respiratory muscle weakness, and consisted of REM-related nonobstructive hypopneas and central apneas. However, Kimura et al studied 18 patients with ALS (11 with a predominantly bulbar form, and 7 with a nonbulbar form) having neither respiratory complaints nor subjective symptoms of sleep disturbance by using an ambulatory multiparameter monitoring system during sleep. Three patients of the bulbar group showed significant sleep-disordered breathing, and the patterns of apnea/hypopnea suggested that both bulbar weakness and minimal diaphragmatic weakness might have caused sleep-disordered breathing in these patients at an early clinical stage. Other sleep disturbances in patients of ALS include insomnia, hypersomnia, circadian rhythm disturbances, and parasomnias. Sleep disruption in patients of ALS may also be due to anxiety, depression, pain, choking, excessive secretions, fasciculations and cramps, and the inability to turn freely in bed.
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Bulbar involvement in ALS causes dysphagia, dysarthria, and sialorrhea. Severe dysphagia, although common in the latter stages of ALS, can represent the first symptom in the bulbar form of the disease. Patients with ALS gradually face the danger of aspiration as oropharyngeal and hypopharyngeal swallowing pressure progressively worsens. Upper-esophageal sphincter spasm is an important cause of aspiration. Both videofluoroscopic and manometric evaluation are quite useful for follow-up of swallowing function in patients with ALS.
Management of patients with ALS is multifaceted. The pulmonologist can play an important role in improving their quality of life. Sialorrhea, a risk factor for pneumonia, is managed with anticholinergic agents such as atropine or amitriptyline taken orally, hyoscine transdermally, glycopyrronium bromide subcutaneously, or via gastrostomy. Speech, language therapy, and techniques to ease mastication are required to prevent aspiration. As these patients are likely to have aspiration related to pulmonary infections, antibiotics should be instituted promptly if there is clinical evidence of upper or lower respiratory tract infections. Annual influenza vaccination should also be administered.
Assisted ventilation provided in various ways is the treatment of choice in patients with ALS and sleep-disordered breathing and respiratory muscle weakness. Nocturnal noninvasive ventilation (NIV) in the form of bilevel positive airway pressure devices that deliver different levels of positive pressure in inspiration and expiration is the mainstay of treatment in ALS patients with sleep-disordered breathing. Continuous NIV should be initiated for the following reasons: (1) the presence of symptoms related to respiratory muscle weakness, ie, dyspnea, orthopnea, disturbed sleep, morning headache, poor concentration, excessive daytime sleepiness (Epworth sleepiness scale > 9); (2) evidence of respiratory muscle weakness (FVC < 80% or sniff nasal pressure < 40 cm H2O); and (3) evidence of significant nocturnal desaturation on overnight oximetry or morning ear lobe blood gas PCO2 
6.5 kPa. NIV support improves quality of life and survival in patients with ALS with respiratory muscle weakness. It reduces the work of breathing, promotes gas exchange, improves sleep-disordered breathing, sleep architecture, cognitive function, and daytime symptoms of breathlessness and excessive sleepiness. One factor that may limit the efficacy of NIV and make patient adaptation and tolerance difficult is bulbar involvement. Failure of NIV due to failure to stabilize gas exchange and inability to tolerate, need for ventilation for > 20 h/d, and need to protect the airway from excessive secretions and chronic aspiration are indications of invasive ventilation through tracheostomy. Families should be included in discussions about the patient’s options when evaluating for need for tracheostomy, because much of the burden of caring for a patient receiving tracheostomy ventilation falls on them.
In the present patient, diagnosis of bulbar form of ALS with sleep-disordered breathing was suspected due to symptoms of dysphagia, dysarthria, sialorrhea, and excessive daytime somnolence with a normal CT and MRI of the brain findings and normal anti-acetylcholineesterase antibodies. The diagnosis of ALS was confirmed by EMG. Esophageal manometry was done to assess the motor function of esophagus, as the patient had dysphagia and sialorrhea and normal barium swallow except stasis of barium. Upper-esophageal dysmotility and spasm on manometry and stasis of barium on barium swallow were due to bulbar weakness. Portable polysomnography showed the presence of sleep-disordered breathing, which was likely to be both due to bulbar and diaphragmatic weakness. Our patient was prescribed nocturnal bilevel positive pressure ventilation support, and he showed significant improvement in quality of life and cognitive function.
Clinical Pearls
1. Excessive daytime sleepiness and sleep-disordered breathing are rare initial symptoms of ALS; however, the frequency of sleep-disordered breathing in patients with ALS is very variable (16.7 to 76.5%).
2. Multiparameter respiratory monitoring during sleep should be included in the routine evaluation of ALS patients to predict respiratory failure even in absence of symptoms.
3. Sleep-disordered breathing in patients with ALS commonly consists of REM-related nonobstructive hypopneas and central apneas.
4. Sleep-disordered breathing in patients with predominant bulbar form of ALS may be due to both bulbar weakness-related obstructive apnea/hypopneas and nonobstructive hypopneas due to minimal diaphragmatic weakness.
5. The degree of nocturnal desaturations is related to severity of diaphragmatic weakness.
6. Noninvasive ventilatory support forms the mainstay in managing patients of ALS with respiratory muscle weakness, as it improves quality of life, cognitive functions, and even survival.
Footnotes
The authors have no conflicts of interest to declare.
Received for publication October 11, 2005. Accepted for publication November 12, 2005.
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