In patients with Down syndrome (trisomy 21), which of the following is NOT increased in incidence?

In patients with Down syndrome (trisomy 21), which of the following is NOT increased in incidence?

• A. Malignant hyperthermia
• B. Hypothyroidism
• C. Smaller trachea
• D. Occipito-atlantoaxial instability

Answer: (A)

Down syndrome brings several anesthesia-related risks that are more common: thyroid dysfunction, airway anomalies with a relatively smaller trachea, and cervical spine instability from ligamentous laxity (occipito-atlantoaxial instability). Malignant hyperthermia, however, is not known to have an increased incidence in individuals with trisomy 21. MH is a rare pharmacogenetic crisis triggered by certain anesthetics and depolarizing muscle relaxants, and its risk isn’t tied to Down syndrome. So the option describing something not increased in this population is malignant hyperthermia. The other items reflect conditions that are indeed more common in Down syndrome and relevant to perioperative planning.

Down syndrome brings several anesthesia-related risks that are more common: thyroid dysfunction, airway anomalies with a relatively smaller trachea, and cervical spine instability from ligamentous laxity (occipito-atlantoaxial instability). Malignant hyperthermia, however, is not known to have an increased incidence in individuals with trisomy 21. MH is a rare pharmacogenetic crisis triggered by certain anesthetics and depolarizing muscle relaxants, and its risk isn’t tied to Down syndrome. So the option describing something not increased in this population is malignant hyperthermia. The other items reflect conditions that are indeed more common in Down syndrome and relevant to perioperative planning.