Syndrome of kidney yin asthenia refers to the symptoms of endogenous asthenic heat due to consumption of kidney yin and insufficiency of nourishment. This syndrome is usually caused by consumption of kidney yin due to asthenic overstrain and chronic disease; or by consumption of kidney yin at the advanced stage of seasonal febrile disease; or by intemperance of sexual life and hypersexuality which exhausts yin.
 
Clinical manifestations:
Aching and weakness of the loins and knees, dizziness and tinnitus, insomnia and amnesia, seminal emission, scanty menstruation or amenorrhea, or metrorrhagia and metrostaxis, flushed cheeks in the afternoon, bone-steaming tidal fever, night sweating, dry mouth and throat, emaciation, yellowish and scanty urine, reddish tongue with scanty fur and thin and rapid pulse. Such symptoms are seen in some consumptive diseases (such as tuberculosis and tumor), sexual disorder and at the rehabilitative stage of some infectious diseases.
 
Analysis of the symptoms:
Aching and pain in the loins and knees, dizziness and tinnitus as well as amnesia are caused by consumption of kidney yin and malnutrition of cerebral marrow, orifices and bones; seminal emission is caused by yin asthenia .and fire exuberance, asthenic fire disturbing sperm house; scanty menstruation and amenorrhea are caused by consumption of blood and insufficiency of blood in the thoroughfare and conception vessels; metrorrhagia and metrostaxis are caused by extravasation of blood due to asthenic fire; restlessness, fever and insomnia are caused by asthenic fire disturbing mind; emaciation, bone-steaming tidal fever, flushed cheeks and night sweating, dry mouth and throat as well as yellow and scanty urine are caused by insufficiency of kidney yin, lack of moistening and nourishment as well as fumigation of asthenic fire; reddish tongue with scanty fur or without fur and thin and rapid pulse are the signs of yin asthenia and endogenous heat.

Key points for syndrome differentiation:
This syndrome is marked by aching and pain of the loins and knees, dizziness and tinnitus, seminal emission and irregular menstruation accompanied by yin asthenia and endogenous heat.