Cushing's disease is caused by a pituitary adenoma that secretes excess ACTH, resulting in too much cortisol production. It is the most common form of Cushing's syndrome. Signs include central obesity, fatigue, high blood pressure, and purple stretch marks. The document discusses evaluating the hypothalamic-pituitary axis and hormones, assessing anterior pituitary function with biochemical tests, and using MRI and visual field tests to diagnose patients with hypothalamic-pituitary abnormalities.

1. Cushing’s disease
Overview of hypothalamic-pituitary axis and
hormones.
Assessment of anterior pituitary function (basic
biochemical tests).
MRI and visual field assessment in patients with
HPA disease

2. Pituitary gland – Anatomy & Function
The pituitary gland is a pea-sized gland at the base of the brain,
divided into anterior/posterior lobes, and secretes various
hormones.
Hypothala
mic
Target Pituitary Feedback
Regulator
Gland Hormone Hormone
y
Hormone
Thyroid
TRH TSH T4 T3
gland
Gonad LHRH LH E2, T
Inhibin,
Gonad LHRH FSH
E2, T
Many GHRH,
GH IGF-1
organs SMS
Breast PIF Prolactin ?
CRH,
Adrenal ACTH Cortisol
ADH

3. Cushing’s disease - Introduction
Cushing’s disease vs. syndrome
Cushing’s syndrome = group of symptoms that
occur during ↑↑↑excess cortisol production
due to:
exogenous e.g. steroid medication
endogenous causes
pituitary gland adenoma – Cushing’s disease
Adrenal gland adenoma/carcinoma
ectopic ACTH tumours e.g. small cell lung cancer

4. Cushing’s disease = most
common form
of endogenous Cushing’s
syndrome.
It is caused by a pituitary
gland tumour that
secretes excessive
amounts of ACTH. This
type of tumor is

5. Pituitary Tumors:
hormone-secreting or non-secreting; most are benign;
may cause visual disturbances and headaches as they
grow and compress surrounding tissues; often results in
excessive amounts of one pituitary hormone and
decreases in others.
Signs and symptoms: Pituitary tumors may manifest
with signs and symptoms related to pituitary
hypofunction, specific hormone(s) hypersecretion,
and/or mass effect. Impingement on the chiasm or its
branches by a pituitary tumor may result in visual field
defects; the most common is bitemporalhemianopsia
Lateral extension of the pituitary mass to the cavernous
sinuses may result in diplopia, ptosis, or altered facial
sensation.Among the cranial nerves, the third nerve is
the most commonly affected.

6. Epidemiology
Incidence of endogenous Cushing syndrome is
about 13 cases per million individuals/yr. Of
these cases, approximately:
70% are due to Cushing disease, i.e. a pituitary ACTH-
producing tumor
15% to ectopic ACTH
15% to a primary adrenal tumor.

7. "normal" diurnal variation =
cortisol peaks 8 a.m. and
halves around 4 p.m. By
midnight cortisol should be
about zero or close to it with
blood and salivary levels.
Cushing's = circadian rhythm
is lost, "flat" diurnal levels of
cortisol, or even higher levels
at night instead of in the
morning.

8. Signs & Symptoms
depression and mood swings
moon face
weight gain around the trunk (central obesity)
proximal myopathy
Easy bruising, thin skin
Striae (purple)
Hypertension and mild diabetes
Oligo-/Amenorrhoea females
impotence - males
decrease in sex drive
Increased hair growth (hirsutism)

9. Cushing disease : headaches, polyuria, nocturia,
visual problems, or galactorrhea.
If sufficient mass effect from the tumor is
present on the anterior pituitary,
hyposomatotropism, hypothyroidism,
hyperprolactinemia or hypoprolactinemia, and
hypogonadism may develop.

10. 1) Diagnose Cushing’s syndrome
2) Investigate causes of Cushing’s Syndrome
3) Treatment

11. se without definitive lesions on MRI should undergo inferior petrosal sinus sampling (IPSS). IPSS is th