All trans retinoic acid syndrome

All trans retinoic acid (ATRA) syndrome is a condition that can occur with patients with acute promyelocytic leukemia who are on therapeutic all-trans-retinoic acid (ATRA).

It is characterized by fever, respiratory distress, pleural and pericardial effusion, weight gain, and pulmonary infiltrates noted on chest radiography.

All-trans-retinoic acid (ATRA) is a normal constituent of plasma. It is derived physiologically by intracellular oxidation of plasma retinol that has been absorbed from the intestines. ATRA is also used as an accepted therapy for acute promyelocytic leukemia. ATRA can differentiate acute promyelocytic leukemia blasts into mature granulocytes 

Radiographic features

Will depend on the system involved although many of the features are described in relation to the lungs.

Plain film

Although the imaging features are not specific, in the context of an appropriate clinical history, they may aid in early recognition of the ATRA syndrome. Recognised chest radiographic features that can be part of the ATRA syndrome include 

• increased cardiothoracic ratio
• increased vascular pedicle width
• ground-glass opacities
• peribronchial cuffing
• septal lines and 
• pleural effusion(s) 

In addition, chest radiography may show nodules and consolidation. 

CT chest

CT features may not be specific and the clinical context is extremely useful in image interpretation. According to one study, the most consistent CT findings were small, irregular peripheral nodules in the lungs along with pleural effusions ⁵.

Therapy and prognosis

Early intervention with high dose corticosteroids are thought to abort progression. While most patients do well the occurrence of ATRA syndrome was associated a lower event free survival.

Etymology

It was first described by Frankel et.al ^1-3