ICD-10-CM
- Naegleriasis (with meningoencephalitis)
- Naffziger's syndrome
- Nanophyetiasis
- Nanukayami
- Napkin rash
- Narcosis
- NARP (Neuropathy, Ataxia and Retinitis pigmentosa) syndrome
- Narrowness, abnormal, eyelid
- Natal tooth, teeth
- Near drowning
- Near-syncope
- Necator americanus infestation
- Necatoriasis
- Necrophilia
- Nelaton's syndrome
- Nelson's syndrome
- Nephralgia
- Nephroblastoma (epithelial) (mesenchymal)
- Nephronophthisis
- Nephropathia epidemica
- Nephroptosis
- Nephrorrhagia
- Nephrosonephritis, hemorrhagic (endemic)
- Nerves
- Nervousness
- Neumann's disease or syndrome
- Neurocirculatory asthenia
- Neurocysticercosis
- Neuroencephalomyelopathy, optic
- Neuroleprosy
- Neuromyasthenia (epidemic) (postinfectious)
- Neuromyotonia (Isaacs)
- Neuroretinopathy, hereditary optic
- Neurospongioblastosis diffusa
- Neutroclusion
- Neutrophilia, hereditary giant
- Newcastle conjunctivitis or disease
- Nezelof's syndrome (pure alymphocytosis)
- Niacin (amide) deficiency
- Nicolas (-Durand)-Favre disease
- Nicotinic acid deficiency
- Nightmares (REM sleep type)
- NIHSS (National Institutes of Health Stroke Scale) score
- Nisbet's chancre
- Nishimoto (-Takeuchi) disease
- Nitrosohemoglobinemia
- Njovera
- Nodal rhythm
- Nomad, nomadism
- NOMID (neonatal onset multisystemic inflammatory disorder)
- Nonexanthematous tick fever
- Nonexpansion, lung (newborn)
- Nonimplantation, ovum
- Noninsufflation, fallopian tube
- Non-ketotic hyperglycinemia
- Nonne-Milroy syndrome
- Nonovulation
- Nonpatent fallopian tube
- Nonpneumatization, lung NEC
- Nonvisualization, gallbladder
- Nonvital, nonvitalized tooth
- Non-working side interference
- Noonan's syndrome
- Norrie's disease (congenital)
- North American blastomycosis
- Norwegian itch
- Nosebleed
- Nose-picking
- Nosomania
- Nosophobia
- Nostalgia
- Notching nose, congenital (tip)
- Notch of iris
- Numbness
- Nursemaid's elbow
- Nutcracker esophagus
- Nutmeg liver
- Nutritional stunting
- Nymphomania