Carbon monoxide poisoning

Additional clnical history: Patient sleeps in close proximity to an old furnace.


Findings

Focal bright T2 signal in the globus pallidus bilaterally.

Differential diagnosis: The focal bright T2 signal in the globus pallidus is somewhat specific for CO.

Other causes of bright T2 signal in basal ganglia/thalamus include:
- Wilson disease
- Small vessel ischemic disease (SVID)
- Creutzfeldt-Jacob disease
- Leigh disease
- Japanese encephalitis


Diagnosis: Carbon monoxide poisoning


Key points

Changes are typically seen in globus pallidus, but can occur in cerebral white matter (second most common), putamen, caudate, thalamus.

Radiology:
- Hypodense on CT
- T1W- can be normal, hypo- or hyperintense (edema or hemorrhage)
- T2W - hyperintense
- Diffusion WI - restricted diffusion

Pathologically one sees necrosis in globus pallidus with demyelination of periventricular white matter.
Presents with nonspecific symptoms of variable severity: Nausea / vomiting, headache, confusion, cognitive impairment, seizures, coma, death.
Clinically may have persistent sequelae or resolution of symptoms depending on severity and duration of exposure.
Most common cause of U.S. accidental poisoning.
Can confirm diagnosis with carboxyhemoglobin level.
Treatment: Hyperbaric O2 for acute cases.