A 65-year-old woman with a history of chronic obstructive pulmonary disease is brought to the intensive care unit after being intubated in the emergency department for severe respiratory distress. Intubation was difficult to perform and required 2 attempts. She has had 3 exacerbations in the past 2 years that required hospitalizations, but has never been intubated before. Her other medical problems include rheumatoid arthritis, hypertension, moderate obesity, and a transient ischemic episode 3 years ago. She has smoked 1 pack of cigarettes per day for the past 40 years.
Examination reveals diffuse, scattered wheezes and decreased aeration throughout the lungs. She is started on high-dose methylprednisolone, bronchodilator inhalers, and antibiotics. She received neuromuscular blockade with pancuronium for one day due to severe agitation and patient-ventilator dyssynchrony. Subsequently, she was continued on a lorazepam drip for sedation for 3 days.
On the fifth day of hospitalization, she has markedly improved breath sounds with occasional wheezes. Weaning attempts with pressure support ventilation on the fifth and sixth days of hospitalization were unsuccessful due to low tidal volumes and tachypnea. She has marked muscle weakness in all her extremities and examination shows decreased muscle tone and absent deep tendon reflexes. Sensory examination is indeterminate. Lab studies show a serum creatine kinase of 980 IU/L and normal hepatic and renal function.
Which of the following is the most likely cause for the failed ventilator weaning in this patient?

Question

A 65-year-old woman with a history of chronic obstructive pulmonary disease is brought to the intensive care unit after being intubated in the emergency department for severe respiratory distress.  Intubation was difficult to perform and required 2 attempts.  She has had 3 exacerbations in the past 2 years that required hospitalizations, but has never been intubated before.  Her other medical problems include rheumatoid arthritis, hypertension, moderate obesity, and a transient ischemic episode 3 years ago.  She has smoked 1 pack of cigarettes per day for the past 40 years.
Examination reveals diffuse, scattered wheezes and decreased aeration throughout the lungs.  She is started on high-dose methylprednisolone, bronchodilator inhalers, and antibiotics.  She received neuromuscular blockade with pancuronium for one day due to severe agitation and patient-ventilator dyssynchrony.  Subsequently, she was continued on a lorazepam drip for sedation for 3 days.
On the fifth day of hospitalization, she has markedly improved breath sounds with occasional wheezes.  Weaning attempts with pressure support ventilation on the fifth and sixth days of hospitalization were unsuccessful due to low tidal volumes and tachypnea.  She has marked muscle weakness in all her extremities and examination shows decreased muscle tone and absent deep tendon reflexes.  Sensory examination is indeterminate.  Lab studies show a serum creatine kinase of 980 IU/L and normal hepatic and renal function.
Which of the following is the most likely cause for the failed ventilator weaning in this patient?

Quizplus · Accepted Answer

11ec193a_9710_f072_853d_dbceaeac726b_MD0002_00 This patient's presentation is consistent with critical illness myopathy (CIM), which is commonly seen in ICU patients with asthma or COPD treated with steroids. Risk factors for CIM include systemic corticosteroids (strongest risk factor), neuromuscular blocking agents, and sepsis. Patients usually present several days after IV steroid or paralytic agent administration with flaccid quadriparesis (proximal > distal muscles) and/or difficulty weaning from mechanical ventilation. Facial muscle weakness may also occur. Sensation is usually normal, but reflexes may be decreased. Critical illness myopathy is more common than critical illness polyneuropathy (CIP), but patients sometimes have a combination of the two. Diagnosis is suspected clinically and can be confirmed by EMG/NCS. Serum creatine kinase levels can be normal or mildly elevated. Muscle biopsy can also show myopathy with loss of myosin. Treatment of CIM involves stopping or reducing steroids as soon as possible, aggressive management of underlying medical conditions, and occupational and physical rehabilitation. Prognosis is generally good with reversal of symptoms over weeks to months, but recovery may require prolonged hospitalization. (Choice A) Atlantoaxial disease in patients with rheumatoid arthritis may lead to cervical subluxation, which can cause myelopathy. However, there would be signs of long tract involvement (eg, spasticity and hyperreflexia) on physical examination. (Choice C) Guillain-Barré syndrome (acute inflammatory demyelinating polyneuropathy) is a rare disorder that can cause diffuse weakness, but usually develops gradually over a longer time course (1 to 2 weeks). (Choice D) Prolonged neuromuscular blockade is a rare disorder due to prolonged use of paralytic agents (days) in the setting of hepatic or renal insufficiency. This leads to prolonged circulation of drug metabolites. This patient has had one day of pancuronium use and has normal hepatic and renal function, making this condition unlikely. (Choice E) Rhabdomyolysis usually presents with markedly elevated serum creatine kinase levels (typically > 5000 IU/L). In addition, the muscle weakness is not as marked and deep tendon reflexes are intact. Educational objective: Critical illness myopathy (CIM) should be considered in any critically ill patient who develops generalized weakness or difficulty weaning from the ventilator. The strongest risk factor for CIM is the use of intravenous glucocorticoids. Therapy involves avoidance of glucocorticoids and rehabilitation, and prognosis is generally favorable. __________ References: Critical illness polyneuropathy and myopathy: a major cause of muscle weakness and paralysis. (http://www.ncbi.nlm.nih.gov/pubmed/21939902) Neuromuscular manifestations of critical illness. (http://www.ncbi.nlm.nih.gov/pubmed/15825186) ICU-acquired weakness. (http://www.ncbi.nlm.nih.gov/pubmed/17494803)

A 65-Year-Old Woman with a History of Chronic Obstructive Pulmonary