Dose
A normal result is a decrease in cortisol levels upon administration of low-dose dexamethasone. Results indicative of Cushings disease involve no change in cortisol on low-dose dexamethasone, but inhibition of cortisol on high-dose dexamethasone. If the cortisol levels are unchanged by low- and high-dose dexamethasone, then other causes of Cushings syndrome must be considered with further work-up necessary. After the high-dose dexamethasone, it may be possible to make further interpretations. †ACTH as measured prior to dosing of dexamethasoneEquivocal results should be followed by a corticotropin-releasing hormone stimulation test, with inferior petrosal sinus sampling. References

Theodore C. Friedman, M.D., Ph.D. Professor of Medicine-UCLA Chairman, Department of Internal Medicine Charles R. Drew University (2013). [1]
Cyclic neutropenia (CyN) is a rare hematologic disorder and form of congenital neutropenia that tends to occur approximately every three weeks and lasting for few days at a time due to changing rates of neutrophil production by the bone marrow. It causes a temporary condition with a low absolute neutrophil count and because the neutrophils make up the majority of circulating white blood cells it places the body at severe risk of inflammation and infection. In comparison to severe congenital neutropenia, it responds well to treatment with granulocyte colony-stimulating factor (filgrastim), which increases the neutrophil count, shortens the cycle length, as well decreases the severity and frequency of infections. Signs and symptoms
The common symptoms of neutropenia are recurrent fever, malaise, inflammation of the tissues surrounding the teeth, mouth ulcers, inflammation and bacterial infection of the respiratory tract, digestive tract, skin, and abdominal pain. It is considered that the greatest risk for death is from developing necrotizing enterocolitis (NEC), peritonitis, bacteremia or Clostridium and Escherichia coli sepsis and septic shock, and pneumonia. Causes
Cyclic neutropenia (CyN), like severe congenital neutropenia (SCN), is a rare disorder. It is considered that in the general population, CyN has a frequency of one in one million. It is the result of autosomal dominant mutation in ELANE gene located on the short arm (p) of chromosome 19 (19p13.3), the gene encoding neutrophil elastase, which is also the most common cause of the SCN. It sporadically occurs as a de novo mutation variant or can be present among members of the same family.