Risperidone-Induced Acute Respiratory Distress in an Adolescent with Autism

To the Editor:

Risperidone is a Food and Drug Administration-approved atypical antipsychotic indicated for treatment of schizophrenia, bipolar disorder as well as irritability associated with autistic disorder. Commonly observed side effects in pediatric and adolescent patients include somnolence, extrapyramidal symptoms, prolactin elevation, and weight gain (Bishop and Pavuluri 2008). We describe here an acute respiratory distress after use of small dose of risperidone in an adolescent boy with autism.

Case Report

Lucas, ¹ a 17-year-old adolescent with autism presenting important social anxiety and persecutory thinking, started a treatment with risperidone oral solution (Risperdal^®) at 0.25 mg/night. He had a history of asthma during early childhood. Routine laboratory tests and electrocardiography check before the onset of treatment yielded normal results.

Twenty-four hours after the onset of the treatment (soon after the second dose), he presented an acute respiratory distress with stridor described by the family as “asthmatic crisis.” Salbutamol aerosol (Ventolin^®) was administered to him by his grandmother who was also asthmatic. His respiratory distress resolved rapidly. We were informed the next day and met him in our outpatient consultation. The general clinical status revealed no particularity compared with his baseline status. He had normal respiration. He had no eruption or other cutaneous reactions. The patient and his family did not want to make a rechallenge. Risperidone was then discontinued.

Discussion

The exact nature of this acute respiratory distress after use of risperidone is not clear.

Neuroleptic-induced laryngeal dystonia can result in “dysphonia, dysphagia, and a sense of tightness in the throat,” mimicking acute anaphylaxis (Ilchef 1997). The rapid evolution in our patient with single-dose administration of Salbutamol aerosol does not support this hypothesis.

What happened to Lucas could be a “general” asthmatic attack . Although Lucas has not been asthmatic for many years, it is well known that psychological dysfunction like anxiety is associated with poor evolution of asthma (Thomas et al. 2011). Before starting this treatment, Lucas was very anxious and worried about a “drug addiction.” It could be that this respiratory distress was not a direct side effect of risperidone but an asthmatic attack triggered by an allergen (not necessarily risperidone) and worsened by Lucas' anxiety about taking the drug. Allergic-like reactions specifically to risperidone have previously been reported (Terao et al. 1998; Reeves and Mack 2005) and respiratory symptoms like stridor could be part of an allergic reaction. Lucas' acute respiratory distress appeared after the second exposure of risperidone, which was in favor of a type-I hypersensitivity hypothesis. Laboratory testing such as total IgE testing, complete blood count, and white blood cell differential, if available, could have been helpful to confirm an ongoing allergic process in our patient. Breathing difficulty could occur in more severe allergic reactions—anaphylactic reactions (anaphylaxis)—that are sudden and widespread reactions involving more than one organ system. Typical symptoms include itchy rash, throat or tongue swelling, shortness of breath, vomiting, angiodema, low blood pressure, and so on. It is a life-threatening condition and needs emergency treatment. In the case of Lucas, a diagnosis of anaphylaxis is difficult to be retained since only an isolated respiratory symptom has been reported.

In the present situation, it would be interesting to apply a skin test (patch) with the possible causative agent (risperidone) and make a rechallenge of risperidone (e.g., with a different drug formulation). However, Lucas and his family refused this proposal.

In conclusion, we reported an acute respiratory distress after use of small dose of risperidone in an adolescent boy with autism. This reaction could be a drug-associated asthmatic attack or a type-I hypersensitivity to risperidone. When the exact mechanism is not clear, we have to, unfortunately, weigh the risks and benefits and make the drug rechallenge if we do not have an alternative treatment option.