Central Autonomic Dysfunction

Central autonomic dysfunction (CAD) is a clinical entity that is manifest by a myriad of symptoms, including hyperthermia, hypertension, diaphoresis, generalized rigidity, tachypnea, decerebrate postur­ing, tachycardia, and pupillary changes.

(185), hypothalamic midbrain disregulation syndrome

(186), central seizures, central storming, central fevers

(187), and posttraumatic hyperthermia (188). CAD is a result of an injury to the brain that interrupts the diencephalic-brainstem connection, leading to what is called “ brainstem release phenomenon (186).” Signs and symptoms will often disappear as neurologic improvement is noted, but medical management may be necessary for six months or more after injury in a select group of patients (189).

Management of CAD is usually initiated due to concern about an elevated body temperature. It is imperative the clinician rule out an infectious etiol­ogy, as central temperature elevation is a diagnosis of exclusion. CAD responds poorly to antipyretic med­ication (185), such as the nonsteroidal anti-inflam­matory drugs. This may be helpful when ruling out infection. Initial management at the bedside usually consists of attempting to lower the temperature by pro­viding cooling blankets and ice packs, turning down the temperature in the room, or providing a fan in the room to cool the patient. Often, the patient's hyper­tension is marked enough to warrant treatment with a beta blocker such as propranolol, which will also help reduce heart rate and can be used on an as-needed basis (187). Bromocriptine is used by some clinicians to reduce the symptoms of CAD and has ultimately resulted in a decreased need for antipyretics (189). Morphine in combination with bromocriptine has been useful in one study. ITB has also been reported to effectively treat CAD associated with TBI (100,190).

CAD is associated with a poor prognosis. In a ret­rospective review of a series of children with acquired brain injury, CAD correlated positively with more pro­tracted periods of unconsciousness and overall worse cognitive and motor outcomes one or more years post­injury. Follow-up computed axial tomography (CAT) scans in these children revealed ventricular enlarge­ment and marked brain atrophy (189).