Syndrome of kidney yang asthenia refers to the asthenia cold symptoms due to failure of qi to transform resulting from decline of kidney yang and its failure in nourishing the body. This syndrome is usually caused by constitutional asthenia of yang, or decline of Mingmen fire in the aged, or impairment of kidney yang due to chronic disease, or involvement of the kidney in the disorders of the other visceral yang, or intemperance of sexual life and consumption of kidney yang.

Clinical manifestations:
Aching and cold sensation in the loins and knees, cold limbs and body, dispiritedness and lassitude, impotence, immature ejaculation, cold sperm, infertility due to cold in the uterus, sexual hypoesthesia, or loose stool, early morning diarrhea, or frequent micturition, clear and profuse urine, profuse noctural urine, bright whitish or blackish complexion and light colored tongue with white fur as well as sinking, deep and weak (especially over chi region) pulse. These symptoms are usually seen in hypothyroidism, hypoadrenocorticism, hypogonadism and chronic nephritis, etc.
 
Analysis of the symptoms:
Aching and cold sensation in the loins and knees, cold limbs and body, dispiritedness and lassitude are caused by asthenia of kidney yang and its failure in nourishing the body; bright whitish or blackish complexion is caused by asthenia and weakness of the kidney to warm and transport qi and blood, leading to internal exuberance of yin cold; impotence, immature ejaculation, cold sperm, infertility due to cold in the uterus, sexual hypoesthesia are caused by asthenia of kidney yang and Mingmen fire as well as decline in reproduction; frequent micturition, clear and profuse urine and profuse noctural urine are caused by insufficiency of kidney yang and its failure in warming and transporting qi; loose stool and early morning diarrhea are caused by decline of Mingmen fire and failure of fire to warm earth; light colored tongue with white fur as well as sinking, deep and weak pulse are the signs of insufficiency of kidney yang.

Key points for syndrome differentiation:
This syndrome is marked by decline in reproduction accompanied by cold limbs and body as well as aching and cold in the loins and knees.