| NARP | neuropathy-ataxia-retinitis pigmentosa [syndrome] |
|---|---|
| NTE | neuropathy target esterase; neurotoxic esterase; not to exceed |
| OPIDN | organophosphorus-induced delayed neuropathy |
| PION | posterior ischemic optic neuropathy |
| PN | papillary necrosis; parenteral nutrition; penicillin; perceived noise; percussion note; periarteriti... |