Muscular dystrophy

Oculopharyngeal muscular dystrophy (OPMD) is an uncommon autosomal dominant disorder characterized by late onset and slow progression. Complications of OPMD include ptosis and progressive dysphagia leading to eventual malnutrition and aspiration. We report a rare case of OPMD complicating mechanical ventilator management following emergent surgery. OPMD and the resulting dysphagia contributed to multiple intubations, tracheostomy, aspiration pneumonia, and a prolonged hospital course. Awareness of the possibility of OPMD in intubated patients with a history of dysphagia is crucial for avoidance of complications.

Key words: dysphagia; mechanical ventilation; oculopharyngeal muscular dystrophy

Abbreviation: OPMD = oculopharyngeal muscular dystrophy

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Oculopharyngeal muscular dystrophy (OPMD) is an uncommon autosomal dominant disorder characterized by late onset and slow progression. Complications of OPMD include ptosis and progressive dysphagia leading to eventual malnutrition and aspiration. OPMD has not been reported in the critical care setting. We report an unusual case of OPMD complicating mechanical ventilation management following emergent vascular surgery.

CASE REPORT

An 83-year-old man of French-Canadian descent presented with an ischemic left foot. The patient had a medical history of a stable, 5-cm, infrarenal abdominal aortic aneurysm; hiatal hernia; mild-to-moderate obstructive lung disease; transient ischemic attack; right carotid stenosis; hypertension; hypercholesterolemia; and dysphagia. There was no documented history of reactive airway disease on pulmonary function testing. The patient was a circuitous historian and was unable to give details of his history. Surgical history was significant for an appendectomy in 1948, bilateral lower-extremity vein stripping in 1960, lumbar laminectomy in 1975, left total knee replacement in 1989 and 1993, right hip replacement in 1996, cervical disk surgery in 1997, and prostatectomy in 1997. Prior surgical procedures were without postoperative complications or weaning difficulties.

Physical examination findings were significant for bilateral ptosis, raised eyebrows, wrinkled forehead, extension of the neck, and atheroembolic appearing ischemia of the left toes. There was no weakness of the extremities. ECG findings were normal. Arteriography demonstrated multilevel occlusive disease with high-grade iliac stenosis, common femoral arterial disease, and an occluded left popliteal artery. The patient underwent an uncomplicated aortobifemoral bypass with Hemashield graft (Boston Scientific Corporation; Natick, MA) and left profundaplasty. Intraoperatively, he received a neuromuscular blocker. Postoperatively, he was managed in the ICU without propofol, glucocorticoids, or neuromuscular blockers. The patient was weaned off of mechanical ventilation and extubated on postoperative day 2. He had difficulty clearing his oral secretions and was shortly reintubated for airway protection, then was again extubated on postoperative day 5. The patient was then noted to have difficulty maintaining a clear airway and was reintubated on postoperative day 6. He subsequently developed purulent sputum and lower lobe infiltrates on chest radiography. Sputum culture findings were significant for Enterobacter aerogenes and Escherichia coli. Further medical history obtained from the family was suggestive of progressive dysphagia. Neurologic evaluation was then obtained. OPMD was diagnosed on the basis of the history of progressive dysphagia combined with the characteristic adaptive facial features, contraction of the frontalis muscle with extension of the neck. The facial adaptation is due to compensation for limitation of the visual field in bilateral ptosis. OPMD was restricted to the levator palpebrae and pharyngeal musculature. Once OPMD was diagnosed, the patient underwent a tracheostomy and percutaneous gastrostomy tube placement on postoperative day 10. Noninvasive ventilation was not employed because of airway protection issues due to the inability to clear oral secretions. The patient was treated for aspiration pneumonia and was successfully weaned from mechanical ventilation. On postoperative day 20, he was discharged to a rehabilitation facility.

The patient denied knowledge of persons in his family with dysphagia or ocular disorders. Further investigation of family history revealed dysphagia in the patient's mother and his two diseased brothers. There was no family history of surgical complications. Careful review of outside hospital records was significant for a hospitalization 15 months earlier for aspiration pneumonia. A swallow evaluation at that time was significant for aspiration, and an esophagogastroduodenoscopy demonstrated Barrett esophagus, a hiatal hernia, and a mild stricture at the cricopharyngeus muscle. The stricture at the cricopharyngeus was dilated, and a percutaneous endoscopic gastrostomy tube was placed. The tube was removed several months later at the request of the patient. He was then maintained on a mechanical soft diet and maintained a stable weight for the year prior to presentation.

DISCUSSION

OPMD presents in the fifth and sixth decade with the insidious onset of progressive ptosis followed by slowly progressive dysphagia. Early signs of OPMD are usually not recognized by the patient. OPMD is the only muscular dystrophy that presents more commonly in the elderly. (1) As the disease progresses, extraocular and other voluntary muscles may become involved. Proximal upper-extremity and lower-extremity weakness is a common late finding. (2) There is no cardiac involvement. The characteristic adaptive posture is termed vise-en-l'air: contraction of the frontalis muscles and extension of the neck. The dysphagia is a failure of the oropharyngeal phase of swallowing that progresses over many years. Complications resulting from dysphagia range from discomfort on swallowing in moderate cases to malnutrition, weight loss, and aspiration pneumonia in severe dysphagia. Treatment of OPMD with upper-esophageal myotomy results in success or partial improvement in 81% of patients. Recurrence of dysphagia and aspiration eventually occur in very long-term follow-up (> 8 years). (3) Factors associated with favorable outcome after cricopharyngeal myotomy include adequate residual pharyngeal propulsion and absence of weight loss. (4)

OPMD is most commonly reported in French and French-Canadian patients. Non-French cases have been reported in Japan, Germany, Australia, Uruguay, Italy, and the Jews of Uzbekistan. The prevalence of OPMD in France is estimated at 1 in 200,000. French-Canadian OPMD patients are likely descendants of a couple who immigrated to Quebec in 1634. (5) In the United States, OPMD is a condition seen in those of French-Canadian descent. The first French-Canadians were recruited from Quebec to work in the mills of Rhode Island in the 1840s. Eventually, one third of the population of Quebec immigrated to New England.

This case illustrates how slowly dysphagia progresses in OPMD. The mean age of presentation for dysphagia in OPMD is 68 years (range, 44 to 91 years). (4) Our patient had been intubated without complication at least six times for his various surgical procedures, the most recent being 3 years earlier. Clinically significant dysphagia and aspiration was present 15 months prior to presentation. The insidious nature of the progression of dysphagia allows the patient to compensate by chewing food for longer periods of time. Without notice to our patient, an adaptation to a soft mechanical diet likely occurred, leading to his late presentation.

The differential diagnosis of this case includes myasthenia gravis, myotonic dystrophy, amyloidosis, and critical illness polyneuropathy. In myasthenia gravis, waxing and waning striated muscle weakness and fatigability exists. Nearly all patients have ptosis with rapid fatigability on prolonged upgaze or eyelid twitches. Dysphagia occurs in combination with dysarthria due to bulbar muscle weakness and results from slow and weak tongue movements, fatigue of deglutation, and food retention in the oropharynx. (6) Surgery and neuromuscular blocking agents can worsen existing myasthenia, and curare can produce myasthenia-like clinical findings. Myotonic dystrophy is characterized by cardiac conduction abnormalities, variable cognitive impairment, mild extremity weakness, and weakness of the neck, jaw, and facial muscles. When the condition is advanced, the patient has wasting of the temporal, masseter, and sternocleidomastoid muscles and ptosis. Smooth-muscle abnormalities cause delayed relaxation of the pharynx and reduced esophageal motility leading to dysphagia. Amyloidosis can manifest with esophageal involvement presenting as dysphagia due to involvement of smooth and striated muscle. (7) Although amyloid deposition in muscle can produce a pseudomyopathy, ptosis is not present. When the nervous system is involved in amyloidosis the cranial nerves are usually spared. Critical illness polyneuropathy is an axonal polyneuropathy, with variable findings ranging from prominent distal-extremity weakness to quadriparesis. Additional clinical findings include decreased or absent deep tendon reflexes, and preserved cranial nerve function. (8) In our case of OPMD, contrary to the above disorders, weakness was constant, unrelated to fatigue and isolated to the levator palpebrae and pharyngeal musculature.

Drug usage in the ICU can cause impaired muscle function. Acute corticosteroid use is associated with steroid-induced myopathy. Experimental evidence suggests that steroids are associated with type-IIb muscle fiber atrophy. (9) This may manifest clinically in diaphragmatic weakness and impaired weaning. Neuromuscular blocking agents can cause muscle dysfunction by persistent blockade of the neuromuscular junction and by acute myopathy via augmented muscle catabolism during inactivity. (8) Long-term usage of neuromuscular blocking agents is associated with prolonged neuromuscular blockade by unknown mechanisms. Propofol alone does not appear to have effects that impair muscle function. Transient worsening of muscular dysfunction in patients with OPMD has not been reported with the use of steroids, neuromuscular blockers, or propofol.

This case illustrates how OPMD, an uncommon clinical entity, contributed to a common problem in the intensive care setting. The difficulty in clearance of pulmonary secretions is a widespread problem in recently extubated patients. Respiratory therapy, frequent suctioning, and conservative use of sedation are employed to decrease the incidence of aspiration pneumonia and avoid reintubation. In this case, despite aggressive respiratory care, OPMD contributed to multiple intubations, tracheostomy, aspiration pneumonia, and a prolonged hospital course.

Awareness of OPMD in patients receiving mechanical ventilation with a history of dysphagia is crucial for improving long-term outcome. An appreciation of the importance of early tracheostomy in patients with advanced OPMD is essential.

REFERENCES

(1) O'Rourke KS. Myopathies in the elderly. Rheum Dis Clin North Am 2000; 26:647-672

(2) Domenech E. Swallowing disorders. Med Clin North Am 1999; 83:97-113

(3) Fradet G, Pouliot D, Robichaud R, et al. Upper esophageal sphincter myotomy in oculopharyngeal muscular dystrophy: long-term clinical results. Neuromuscul Disord 1997; 7(Suppl 1):S90-S95

(4) Perie S, Eymard B, Laccourreye L, et al. Dysphagia in oculopharyngeal muscular dystrophy: a series of 22 French cases. Neuromuscul Disord 1997; 7(Suppl 1):S96-S99

(5) Brunet G, Tome FM, Samson F, et al. Oculopharyngeal muscular dystrophy: a census of French families and genealogic study. Revue Neurologique 1990; 146:425-429

(6) Dray TG, Hillel AD, Miller RM. Dysphagia caused by neurological deficits. Otolaryngol Clinic North Am 1998; 31:507-524

(7) Friedman S, Janowitz HD. Systemic amyloidosis and the gastrointestinal tract. Gastroenterol Clin North Am 1998; 27:595-614

(8) Anzueto A. Muscle dysfunction in the intensive care unit. Clin Chest Med 1999; 20:435-452

(9) Nava S, Gayan-Ramirez G, Rollier H, et al. Effects of acute steroid administration on ventilatory and peripheral muscles in rats. Am J Respir Crit Care Med 1996; 153:1888-1896

* From the Division of Critical Care Medicine (Drs. Christopher and Yodice) and Department of Vascular Surgery (Dr. Patterson), the Miriam Hospital, Brown University School of Medicine, Providence, RI; and Department of Neurology (Dr. Horkan), Beth Israel Deaconess Medical Center, Harvard-Medical School, Boston, MA.

This work was performed at the Division of Critical Care Medicine at the Miraim Hospital, Providence, RI.

Manuscript received February 22, 2001; revision accepted May 25, 2001.

Correspondence to: Kenneth Christopher, MD, Division of Critical Care Medicine, The Miriam Hospital Brown University, 164 Summit Ave, Providence, RI 02906; e-mail: Kenneth_Christopher_MD@Brown.edu

COPYRIGHT 2001 American College of Chest Physicians
COPYRIGHT 2002 Gale Group