Neonatal respiratory distress syndrome
A breathing disorder of premature babies caused by a lack of surfactant, which keeps the air sacs open. Antenatal corticosteroids and surfactant treatment have greatly improved the outlook.
Nightmare disorder
Frequent, very distressing nightmares from which people usually wake with clear recall and which lead to fear of falling asleep. Imagery rehearsal therapy, in which the dream is rewritten while awake, is effective.
Nipple correction
Surgical change in the size or shape of the nipple or areola, for example for inverted nipples. Risks include altered sensation, scars and possible impairment of breastfeeding.
See also: Breast reduction
Non-slip socks
Socks with rubberised soles intended to reduce slipping on smooth floors in hospitals or care homes. They are part of fall prevention but do not fully replace sturdy footwear.
Nephrogenic diabetes insipidus
Inability of the kidneys to respond to the hormone vasopressin, so that large amounts of dilute urine are excreted. Causes are inherited defects or medicines such as lithium; it is now also called AVP resistance.
See also: Diabetes insipidus
Neurogenic claudication
Exercise-related pain and weakness in the legs when walking due to narrowing of the spinal canal. Unlike circulatory problems, the symptoms improve mainly by bending forward or sitting.
See also: Intermittent claudication
Notochord
Rod-shaped structure in the early embryo that defines the longitudinal axis and stimulates formation of the nervous system. Remnants persist in the gel-like core of the intervertebral discs, and chordomas can arise from them.
See also: Chordoma, Intervertebral disc