Final answer:
The young woman should be evaluated for polycystic ovary syndrome (PCOS) and thyroid dysfunction, which could explain her absent periods, erratic energy, and sleep pattern. Both conditions require a thorough medical evaluation, including hormone level testing and possibly an ultrasound.
Step-by-step explanation:
If a very thin, young woman reports not having had periods for 8 months with erratic energy levels and sleep, and if her last period was extremely painful, she may need to be tested for two conditions. Given the symptoms described, she could be evaluated for polycystic ovary syndrome (PCOS) and thyroid dysfunction.
PCOS is a hormonal disorder with symptoms that include irregular periods, excess facial hair, acne, and being overweight. Thyroid dysfunction, on the other hand, could manifest with symptoms such as weight fluctuations, irregular menstrual cycles, changes in energy and sleep patterns, and could impact menstrual regularity and fertility.
A careful medical history, physical examination, and laboratory testing would be necessary to confirm these diagnoses. Lab tests might include hormone levels, such as testosterone, thyroid hormone tests, and possibly an ultrasound to examine the ovaries. Being underweight and experiencing stress are also known contributors to irregular periods and should be considered.