For the purposes of this mind map, amenorrhea refers to not having any menstrual bleeding for six months or longer in a female of reproductive age. This clinical mind map is based upon the pathophysiologic category of diseases and whether the amenorrhea is primary (never had menstrual cycles) or secondary (had menstrual cycles in the past but not currently). Primary causes include 1) constitutional delay 2) certain chronic conditions if started earlier than menarche 3) congenital abnormalities such as outflow tract obstruction, and 4) genetic disorders such as Kallman’s syndrome. The remaining causes on this clinical mind map typically result in secondary amenorrhea.
A further breakdown is based upon whether a structural, congenital, endocrine or other cause is present. Almost no urgent/emergent situations exist for this patient presentation. Most causes of amenorrhea are either physiologic or due to constitutional delay and can readily be identified. However, if the clinical picture presents differently, a clinician can do a further work up. A clinician can identify an outflow tract obstruction based upon a physical exam. Most remaining causes involve disruption at any level in the Hypothalamo-Pituitary-Ovarian-Adrenal axis. History and physical exam related questions can help a clinician narrow the differentials. Most often patients with endocrine abnormalities have additional features of the relevant endocrine disorders which a clinician must keep in mind. Probable diagnoses in the table below are listed in the order of Physiologic, Outflow tract obstruction, Hypothalamo-Pituitary-Ovarian-Adrenal axis and others. This order is not consistent with epidemiology and prevalence of these diagnoses, but is one useful way to memorize these differentials.