Acute Respiratory Failure in Patients With Hyperprolactinemia, OSAS, and Unrecognized Myasthenia Gravis

Abstract

INTRODUCTION: Some reports showed an association between myasthenia gravis (MG) and raised level of prolactin (PRL) in women (1). We describe a case of a man who underwent surgery for a prolactinoma and suffered from severe respiratory failure in the 48 hours after surgery, being admitted to our Respiratory Intensive Care Unit (RICU); a diagnosis of MG with acute pump failure and OSA was done. CASE PRESENTATION: A 56 years old man was admitted on January 2013 to the Medical Unit of our Hospital in Perugia, Italy, due to a suspected prolactinoma. Patient complained asthenia, swallowing problem and mild fever. He was moderately obese and had an acromegalic appearance, moreover he reported a clinical hystory suggestive for obstructive sleep disorders (OSAS). A spirometry test showed a moderate restrictive defect with normal diffusion capacity. The prolactin levels were very high and a brain CT confirmed a pituitary adenoma. Patients had been transferred to neurosurgical departmentent where underwent surgery resection of adenoma. 48 hours later, acute respiratory failure developed and patient was admitted to our RICU; the subject appeared dyspnoic, tachipnoic, confused; ABG analysis demonstrated: pO2 11.8 Kpa (FiO2 35%), pCO2 13.06 Kpa, pH 7,18. Initially we performed noninvasive ventilation by mask but ABG analysis got worse and we decide to intubate and begin invasive ventilation. Medical treatment included antibiotics and cortisosteroids due to bronchospasm. Patient improved and was extubated two days later. A polisomnography registrated after extubation showed a mix pattern of central and obstructive apneas with hypoxemia. Patient underwent nasal CPAP treatment during the night. Due to persistence of swallowing defect and dysarthria, we carried out a sample for autoantibodies against the acetylcoline receptor that were extremely high: after neurological consultation diagnosis of myasthenia gravis was confirmed and we began treatment with piridostigmine bromide (60 mg TID). The symptoms of patients improved, ABG value are satisfactory during spontaneous breathing, spirometry improved and he was discharged from RICU to ward. Afterwards a chest CT showed a thimoma and a tymectomy has been programmed. Patient has been discharged to home and has been using nasal CPAP during the night. DISCUSSION: 20 percent of al patients with myasthenia gravis develop episodes of acute respiratory failure. Surgery is a well known precipitating factor especially if myasthenia is unsuspected. In this case the respiratory state of patients was also complicated from an undiagnosed OSA. The particularity of this case is the association among hyperprolactinemia, OSA and myasthenia. An association between prolactin level and myasthenia has been postulated in women and a link between myastenia gravis and autoimmune phenomena is hypothesized. In an other published case report (2) there was a favourable response of myasthenic symptoms after adenoma removal, but in our subject the removal of adenoma precipitated a severe respiratory failure requiring mechanical ventilation. Pharmacological treatment has improved CONCLUSIONS: Because the stimulating effects of prolactin on immune activation, in particular it has been shown to be expressed in T cells and conversely it also affects the function of T cells (3), hyperprolactinemia could be implied in the pathophysiology of MG but this very interesting point must be confirmed. Is extremely important to rule out a diagnosis of myasthenia before surgery when suggestive symtoms are present to avoid dangerous respiratory crisis, especially when other respiratory comorbility are present.