Euthyroid sick syndrome (also known as nonthyroidal illness syndrome) can be described as abnormal findings on thyroid function tests that occurs in the setting of a nonthyroidal illness (NTI), without pre-existing hypothalamic-pituitary and thyroid gland dysfunction. After recovery from an NTI, these thyroid function test result abnormalities should be completely reversible.
Multiple alterations in serum thyroid function test findings have been recognized in patients with a wide variety of NTIs without evidence of pre-existing thyroid or hypothalamic-pituitary disease. The most prominent alterations are low serum triiodothyronine (T3) and elevated reverse T3 (rT3), leading to the general term low T3 syndrome. Thyroid-stimulating hormone (TSH), thyroxine (T4), free T4 (FT4), and free T4 index (FTI) also are affected in variable degrees based on the severity and duration of the NTI. As the severity of the NTI increases, both serum T3 and T4 levels drop, but they gradually normalize as the patient recovers.
Reverse T3 is used to differentiate between this condition and secondary thyroid failure.

The patient has a non-functioning pituitary tumour as her hormone profile is normal.
Non-functioning pituitary tumours are relatively common. A large number of these tumours are incidentally found pituitary microadenomas (<1 cm) and are usually of no clinical importance.

Hyperthyroid patients show significantly lower resting arterial CO2 tension, tidal volume and significantly higher mean inspiratory flow and pa(O2) than healthy patients. This may of course lead to misdiagnosis of patients with hyperthyroidism as having hyperventilation syndrome.

Exposure to excessive androgens is usually accompanied by premature epiphyseal maturation and closure, resulting in a final adult height that is typically significantly below that expected from parental heights.

congenital adrenal hyperplasia (CAH) is associated with precocious puberty caused by long term exposure to androgens, which activate the hypothalamic-pituitary-gonadal axis. Similarly, CAH is associated with hyperpigmentation and hyperreninemia due to sodium loss and hypovolaemia.

Criteria for the diagnosis of diabetes

1. A1C ≥6.5%. The test should be performed in a laboratory using a method that is certified and standardized.*
OR
2. Fasting glucose ≥126 mg/dl (7.0 mmol/l). Fasting is defined as no caloric intake for at least 8 h.*
OR
3. 2-h plasma glucose ≥200 mg/dl (11.1 mmol/l) during an OGTT. The test should be performed as described by the World Health Organization, using a glucose load containing the equivalent of 75 g anhydrous glucose dissolved in water.*
OR
4. In a patient with classic symptoms of hyperglycaemia or hyperglycaemic crisis, a random plasma glucose ≥200 mg/dl (11.1 mmol/l).
*In the absence of unequivocal hyperglycaemia, criteria 1–3 should be confirmed by repeat testing.

Oestrogen therapy reduces plasma levels of LDL cholesterol and increases levels of HDL cholesterol. It can improve endothelial vascular function, however, it also has adverse physiological effects, including increasing the plasma levels of triglycerides (small dense LDL particles). Therefore, although HRT may have direct beneficial effects on cardiovascular outcomes, these effects may be reduced or balanced by the adverse physiological effects.

RET (rearranged during transfection) is a receptor tyrosine kinase involved in the development of neural crest derived cell lineages, kidney, and male germ cells. Different human cancers, including papillary and medullary thyroid carcinomas, lung adenocarcinomas, and myeloproliferative disorders display gain-of-function mutations in RET.
In over 90% of cases, MEN2 syndromes are due to germline missense mutations of the RET gene.
Multiple endocrine neoplasias type 2 (MEN2) is an inherited disorder characterized by the development of medullary thyroid cancer (MTC), parathyroid tumours, and pheochromocytoma.

Free T4 levels or the free T4 index is usually elevated, as is the free T3 level or free T3 index
– Assays for thyrotropin-receptor antibodies (particularly TSIs) almost always are positive.
– Detection of TSIs is diagnostic for Graves disease.
– Other markers of thyroid autoimmunity, such as antithyroglobulin antibodies or antithyroid peroxidase antibodies, are usually present.
– Other autoantibodies that may be present include thyrotropin receptor-blocking antibodies and anti–sodium-iodide symporter antibody.
The presence of these antibodies supports the diagnosis of autoimmune thyroid disease.
– The radioactive iodine uptake is increased and the uptake is diffusely distributed over the entire gland.

The patient has Cushing syndrome suggested by the elevated 24hr urine free cortisol. Hence, the mass is most probably a cortisol secreting adenoma.

The frequency of type-1 diabetes is higher in siblings of diabetic parents (e.g., in the UK 6% by age 30) than in the general population (in the U.K. 0.4% by age 30), while disease concordance in monozygotic (identical) twins is about 40% i.e. the risk that the unaffected twin will develop diabetes.