Post Polio syndrome

(CHEST 2001; 120:659-661)

A 77-year-old man presented with slowly progressive fatigue, muscle weakness, daytime somnolence, hoarseness, and wheezing. He noted also a chronic cough especially with the ingestion of food and liquid. These symptoms had accelerated over the last several years. Poliomyelitis was diagnosed at 11 years of age, but he never had required ventilatory support. The patient maintained an active business career up until the time of his most recent hospital admission. He was a current one-half pack per day cigarette smoker with a total of 50 pack-years.

Physical Examination

The patient was slightly kyphotic and afebrile with a respiratory rate of 22 breaths/min, a pulse rate of 72 beats/min and regular, and a BP of 120/70 mm Hg. He was 5 feet, 10 inches in height and weighed 166 lb. Pulse oximetry measured while breathing room air revealed an oxygen saturation of 94%. There was no icterus, cyanosis, clubbing, or adenopathy detected. There was no obvious oropharyngeal crowding, and the gag reflex was intact. An examination of the chest revealed decreased breath sounds diffusely and prolonged expiration with no clear rhonchi or crackles. Heart sounds were normal, and no murmurs were discerned. There was no jugular venous distention, hepatojugular reflex, or dependent edema.

Laboratory Findings

Routine blood counts and measurements of blood chemistry were all within normal limits. A chest radiograph revealed changes that were consistent with bibasilar subsegmental atelectasis and an elevated left hemidiaphragm. Lung function testing revealed a decreased FVC of 2.27 L (56% of predieted), an [FEV.sub.1] of 1.61 (52% of predicted), a forced expiratory flow (midexpiratory phase) of 1.11 L/s (37% of predicted), an [FEV.sub.1]/FVC ratio of 71%, and a diffusion capacity of 14.2 mL/min/mm Hg (77% of predicted). Lung volumes revealed a total lung capacity of 4.62 L (65% predicted), a vital capacity of 2.27 L (58% of predicted), a residual volume of 2.35 L (88% of predicted), and a residual volume/total lung capacity ratio of 51%. This suggested a mixed obstructive/restrictive picture. Arterial blood gas measurements revealed the following: pH, 7.43; [PCO.sub.2], 38 mm Hg; [PO.sub.2], 72 mm Hg; and oxygen saturation, 92%.

Clinical Course

The patient had increasingly frequent admissions to the hospital for dyspnea and respiratory distress manifesting as lower respiratory tract infections. These conditions were diagnosed variously as purulent exacerbations of COPD or community-acquired pneumonia. They tended to improve with treatment with antibiotics, systemic corticosteroids, and bronchodilators. The daytime somnolence gradually worsened, interfering with the ability of the patient to work.

What is the cause of his weakness, daytime hypersomnolence, and recurrent lower respiratory tract infections?

What further investigations should be performed?

Diagnosis: Postpoliomyelitis syndrome with recurrent aspiration pneumonia secondary to dysphagia associated with bulbar neuropathy and obstructive sleep apnea

There are an estimated 1.63 million survivors of acute paralytic poliomyelitis (APP) in the United States; they most commonly present with dysphagia, with bulbar involvement evident in 10 to 15%. Up to 80% of survivors may develop the postpoliomyelitis syndrome (PPS) 30 to 40 years after the initial contraction of APP. In fact, PPS may represent the most prevalent motor neuron disease in the United States and is defined by a clinical syndrome consisting of fatigue, progressive muscular atrophy, cold intolerance, and joint pain. This syndrome must be distinguished from complaints related to musculoskeletal deformities, vertebral disk damage (scoliosis), degenerative arthritis, and nerve compression or entrapment syndromes that complicate paralytic illnesses such as poliomyelitis. The pathophysiology of PPS has not been established clearly and may involve chronic disintegration of the reinnervated motor unit. Lung function testing reveals an expected combination of restrictive and obstructive findings. Bulbar muscle involvement results in pharyngeal dysphagia with clear evidence of aspiration documented by videofluoroscopy and fiberoptic endoscopic evaluation of swallowing with sensory testing.

Videofluoroscopic studies have suggested that the majority of PPS patients with or without histories of bulbar involvement have swallowing difficulties, although about half are asymptomatic. The majority of patients have mild oropharyngeal dysfunction and more severe pharyngeal dysphagia with frequent laryngeal penetration that often is associated with an inadequate reflex cough, as demonstrated in our patient. This relatively common finding of silent laryngeal penetration may delay the appreciation of the role of dysphagia/aspiration in lower respiratory tract infections in this population. In patients with PPS, the mean interval between APP and the onset of dysphagia is about 27 years with the mean age of the patients about 45 years. Achalasia also rarely has been reported as a cause of postpolio dysphagia but was not apparent in this case.

Three patterns of sleep disturbances have been identified in patients with PPS: obstructive sleep apnea (OSA), hypoventilation, or a combination of conditions. Central apnea may occur secondary to a residual disturbance of the brainstem neurons, and OSA likely results from oropharyngeal weakness, or from pharyngeal laxity or deformity. This may be aggravated further by hypoventilation secondary to respiratory muscle/diaphragmatic weakness. OSA is well documented in poliomyelitis survivors and has been reported in 26% of patients with PPS. Furthermore, patients with OSA, in the absence of polio or other neurologic deficits, are at higher risk for aspiration.

Patients with PPS with or without bulbar involvement demonstrate a variety of overlapping pulmonary manifestations, including a high risk of swallowing disorders, aspiration, and sleep-disordered breathing. Unfortunately, these problems frequently are superimposed on chronic ventilatory insufficiency secondary to neuromuscular disease and to structural deformity of the thorax. Management strategies might include noninvasive positive-pressure ventilation and continuous positive airway pressure for ventilatory insufficiency and OSA. Dysphagia may be managed by education, a change in food consistency, and head and neck positioning, preferably under the guidance of a speech pathologist. In more severe cases, invasive strategies such as vocal cord medialization, tracheostomy, or cricopharyngeal myotomy may be entertained.

Our patient manifested significant pharyngeal dysphagia, and fiberoptic endoscopic evaluation of swallowing with sensory testing revealed a weakness of the soft palate, poor laryngeal elevation, and epiglottic tilt dysphagia and silent laryngeal penetration that were confirmed by videofluoroscopy. There was clear aspiration of pharyngeal secretions, food, and water, resulting in ineffective cough. We believe that this may have been the principal etiology of his recurrent respiratory tract infections. Prior to these investigations, the infections were all treated as infectious exacerbations of COPD or as simple community-acquired pneumonia. The patient also demonstrated a clear disproportionate left diaphragmatic paresis that was documented by a fluoroscopic evaluation of the diaphragm (sniff test). Polysomnography revealed OSA with a respiratory disturbance index of 8.2 disordered breathing events per hour of sleep. He initially was managed by education and evaluation by a speech pathologist and was started on a supraglottic diet. Unfortunately, this treatment proved to be insufficient, and he underwent percutaneous endoscopic gastroscopy largely for liquids and continues to follow a strict supraglottic diet. At that time, he was not thought to require nasal continuous positive airway pressure or nocturnal ventilation. He maintains an active lifestyle and full-time employment.

CLINICAL PEARLS

1. PPS may be complicated not only by ventilatory failure secondary to neuromuscular disease and thoracic deformity, but OSA and dysphagia.

2. Dysphagia in patients with PPS may occur with or without bulbar findings and increases the risk of aspiration pneumonia that can be aggravated further by the frequent inability to mount an effective cough.

3. The recognition of a lower respiratory tract infection in patients with PPS should prompt a dysphagia investigation with endoscopy and videofluoroscopy, as the aspiration is frequently silent.

4. Appropriate intervention would include speech pathology evaluation and specific feeding recommendations.

SUGGESTED READINGS

Agre JC, Rodrigues AA, Tafel JA. Late effects of polio: critical review of neuromuscular function. Arch Phys Med Rehabil 1991; 72:923-931

Aston JW Jr. Post-polio syndrome: an emerging threat to polio survivors. Postgrad Med 1992; 92:249-260

Culebras A. Sleep and neuromuscular disorders. Neurol Clin 1996; 14:791-805

Dowlaniuk M, Schentag C. Dysphagia in individuals with no history of bulbar polio. Ann NY Acad Sci 1995; 753:405-407

Hsu AA. Postpolio sequelae and sleep related disordered breathing. Mayo Clin Proc 1998; 73:216-224

Jones B, Buchlolz D, Ravich W, et al. Swallowing dysfunction in the postpolio syndrome: a cinefluorographic study. AJR Am J Roentgenol 1992; 158:283-286

Jubelt B, Drucker J. Postpolio syndrome: an update. Semin Neurol 1993; 13:283-290

Sonies BC, Dalakas MC. Dysphagia in patients with post-polio syndrome. N Engl J Med 1991; 324:1162-1167

Teramoto S, Sudo E, Masuse T, et al. Impaired swallowing reflex in patients with OSA syndrome. Chest 1999; 116:17-21

Trojan DA, Cashman NR, Shapiro S, et al. Predictive factors for post-polio syndrome. Arch Phys Med Rehabil 1994; 75:770-777

Trojan DA, Gendron D, Cashman NR. Electrophysiology and electrodiagnosis of postpolio motor unit. Orthopedics 1991; 14:1353-1361

(*) From the Long Island Jewish Medical Center, New Hyde Park, NY.

Received October 19, 2000; revision accepted December 15, 2000.

Correspondence to: Leonard J. Rossoff, MD, Division of Pulmonary and Critical Care Medicine, Long Island Jewish Medical Center, The Long Island Campus of the Albert Einstein College of Medicine, Room C-20, 270-05 76th Ave, New Hyde Park, NY 11042

COPYRIGHT 2001 American College of Chest Physicians
COPYRIGHT 2001 Gale Group