Table 2.
Lists of the most common CNS-related symptoms of mild CO poisoning, hypobaric hypoxia (HH), and COVID-19/long COVID-19. The symptoms of mild CO poisoning were listed in their order of prevalence by Haldane (1895). Order of prevalence was also intended by the authors in HH and COVID-19. Symptoms suggest hypoxia, primarily affecting the brain. In mountain climbing, the first symptom of HH is headache; the next are fatigue and high-altitude pulmonary edema (HAPE). The next step is unconsciousness. HAPE is induced by a hypoxic environment and is characterized by interstitial edema, shown as “ground-glass opacity” in chest CT.
| Mild CO-Poisoning [112,113] | Aviation/Ballooning/Mountain Climbing | COVID-19/Long Covid |
|---|---|---|
| (in order of prevalence) | (Hypobaric hypoxia) [114,115,116,117] | [55,56,118,119,120,121,122,123] |
| Fatigue/lethargy | Visual disturbances | Anosmia |
| Headache | Headache | Fatigue |
| Numbness and tingling | Fatigue, lethargy | Headache |
| “Brain fog” | Dizziness, nausea | Dyspnea |
| Dizziness, nausea | Impaired fine touch & motor skills | “Brain fog” |
| Sleep disturbances | Personality & mood changes | Impaired consciousness |
| Palpitations | Sensory loss | Dizziness, nausea, tinnitus |
| Visual impairments | Confusion | Palpitations |
| Loss of consciousness | Loss of consciousness | Sleep disturbances |
| Neuropsychological symptoms |