3 Discussion
CADM typically presents with characteristic cutaneous manifestations of classic dermatomyositis without muscle involvement; almost all patients with CADM present at least one characteristic skin lesion[1]. In our present case, because of the absence of traditional muscle findings and atypical skin lesions after hospitalization, the diagnosis of CADM can be a challenge. In this case, facial erythema was noticed after induction of labor for a stillborn fetus, and the symptom vanished after oral prednisone administration. Meanwhile, the patient presented with no myalgia, and her creatine kinase level was normal during subsequent hospitalization.
Patients with CADM are often combined with ILD. It is known that RP-ILD is more common in the CADM subset. The patient initially presented with interstitial pneumonia and then developed refractory respiratory failure very quickly. Despite maximum respiratory support and the corresponding treatment, the patient’s status was aggravated continuously with a life-threatening hypoxemia. The mechanism of onset of RP-ILD is ill-informed; reports have suggested that the condition is highly correlated with CADM and MDA5 antibody positivity[10]. High SF has been shown to be another important indicator of poor prognosis of RP-ILD in CADM. The SF levels are reported to be higher with positive anti-MDA5 antibody than with negative anti-MDA5 antibody and higher in nonsurvivors than in survivors[11]. Furthermore, anti-Ro-52 is also a risk factor for ILD in CAMD[12]. The patient experienced pneumomediastinum and pneumothorax with the development of CADM and RP-ILD. Pneumomediastinum has also been reported to be more common in CAMD patients with positive anti-MDA5 antibody than in patients with negative anti-MDA5 antibody[13]. These reports indicate that our patient had a high anti-MDA5 antibody titer, a high anti-Ro-52 antibody titer, a high ferritin level, and the complications of pneumomediastinum and pneumothorax, all of which indicated the diagnosis of clinically amyopathic dermatomyositis and showed a poor prognosis.
ECMO provides temporary cardiopulmonary support in patients with severe but potentially reversible cardiac and/or respiratory failure unresponsive to maximal conventional management. While it does not reverse the underlying lung disease, it acts as a bridge to recovery by offering patients more time for treatment therapies to take effect. It can also reduce ventilator-induced lung injury and oxygen toxicity caused by mechanical ventilation, which can add further damage to already damaged lungs. Last, chronic systemic disease or refractory end-stage pulmonary disease, which was resistant to conventional therapy, was considered a contraindication to ECMO in the past. Pulmonary interstitial fibrosis associated with RP-ILD in CAMD is a rare indication for lung transplantation. However, ECMO can provide additional time for these patients who are being considered for lung transplant, and there are some reports of lung transplantation for RP-ILD[14]. In the course of this patient, lung protective ventilation strategy, lung recruitment maneuver and prone position were all performed to support ECMO, but pulmonary interstitial fibrosis gradually occurred, and the patient did not tolerate attempts to wean from ECMO. Our case indicated that ECMO has shown to be a valid rescue therapy in acute refractory respiratory failure secondary to RP-ILD and made further diagnosis and treatment possible. Although this patient did not completely recover her health at the end, ECMO added time to make an accurate diagnosis and offered the patient the opportunity for a lung transplantation.
Tacrolimus, a calcineurin inhibitor, is an effective immunosuppressive agent for the prevention of organ transplant rejection. However, PRES is a rare and serious neurologic complication of tacrolimus. Temporary cessation of tacrolimus and gradual reduction of the dosage may be effective strategies for managing PRES. However, these managements include risks of reducing immunosuppression, thereby leading to acute rejection. In our case, the strategy is to suspend tacrolimus for one day and gradually reduce the dosage to 0.5 mg/day. The patient’s neurological symptoms improved, and signs of acute rejection were absent.
In conclusion, when patients experience RP-ILD for no apparent reason, CADM should be considered, especially in patients who are positive for anti-MDA5 and anti-Ro-52 antibody and have a high ferritin level and complications of pneumomediastinum and pneumothorax. ECMO should be considered as a supportive therapy and initiated early in patients in acute respiratory failure secondary to RP-ILD since it could provide a true opportunity to improve survival for such a rare disease and its potentially deadly complications. In cases of refractory respiratory failure and pulmonary fibrosis, lung transplant may be an option. PRES is not very common, but more attention should be paid to the patients who are using immunosuppression drugs. Our findings suggest that temporary cessation of tacrolimus and dosage reduction may be effective management strategies for PRES. The results of our case are frustrating, but more experience and further studies are needed to evaluate the true value of this method.