| HUI | headache unit index |
|---|---|
| ICO | idiopathic cyclic oedema; impedance cardiac output |
| IHS | idiopathic hypereosinophilic syndrome; inactivated horse serum; Indian Health Service; integrated he... |
| MCH | Maternal and Child Health; mean corpuscular hemoglobin; muscle contraction headache |
| MIH | Master of Industrial Health; migraine with interval headache; minimal intermittent heparin [dose] |