A 60 years old woman with post anoxic motor infirmity, living in nursing home, was admitted for acute respiratory failure. Few days prior to admission, she presented abdominal pain and high-grade fever with cough. Her relatives reported an outbreak lower respiratory infection in her nursing home in the past weeks. She has no significant past history of respiratory illness. Physical examination showed superficial polypnea (respiratory rate >= 50/min), supraclavicular drawing, seesaw respiration and profound desaturation (SpO2 80% with high concentration oxygen mask). Chest radiograph showed bilateral extensive infiltrates (Fig. 1). She deteriorated rapidly and necessitated intubation and mechanical ventilation. The PaO2/FiO2 ratio was 65 at 11 cm H2O positive end-expiratory pressure. Diagnostic work up of this ARDS did not reveal any extra-pulmonary causal disorder. Intravenous broad-spectrum antibiotics (cefotaxime and spiramycin) were immediately started to cover both pneumococcus and atypical pathogens.
Blood investigations showed 4.83/muL white blood cell count, mainly formed of neutrophils (3.09/muL) elevated C-reactive protein (263 mg/L) and procalcitonin (2.7 mug/L), with normocytic anemia (hemoglobin 11.1  g/dL, MGV 92 fl); platelet 70 cells/mm3, BUN 13.9 mmol/L; serum creatinine 93 mumol/L; ASAT 121 IU/L; LDH 456 IU/L. Tracheo-bronchial aspirates obtained on admission, detected Mycoplasma pneumonia by universal polymerase chain reaction (PCR). Blood and urine cultures were negative. Legionella and pneumococcal urinary antigens were negative. According to international guidelines, sedation, prone position, inhaled NO and corticosteroids were administered. Outcome was favorable and the patient was weaned from the ventilator on day 9 and discharged from the ICU on day 13 without residual permanent damage. Serologic tests carried out on admission and 3 weeks after discharge showed 4-fold increase antibodies and the presence of anti M. pneumoniae IgM antibodies.