Rooting through the more recent clinical literature on carbon monoxide poisoning from overseas unearths a few case studies that illuminate some of the difficulties surrounding this condition. In a report from 1993, doctors in Italy described the cases of a husband and wife who had been suffering from headaches, nausea, and neurobehavioral disturbances (which can be involve emotion, learning, or behavior) intermittently for over a year before their diagnosis. It took a careful review of the patient history to determine the source was a mis-functioning heating system. Low level exposure to carbon monoxide can cause symptoms that are overlooked or misdiagnosed.
In another case, a 41-year old woman with no prior history of cognitive or emotional problems developed severe psychiatric problems from carbon monoxide poisoning. Although the patient appeared to make a complete recovery after treatment (hyperbaric oxygen therapy or another therapy), delayed encephalopathy ensued and produced obsessive-compulsive disorder, depression, kelptomania, and psychotic behavior. Brain scans revealed damage in a number of areas. This pattern of symptom, recovery, and re-occurrence is thought to happen in as many as 12 percent of cases.
Together, these examples underscore the need for careful investigation when carbon monoxide poisoning might be suspect, and careful follow-up after an initial series of hyperbaric treatments. Valuable knowledge may be gained if the hyperbaric physician coordinates treatments with assessments by a neurologist.