Cushing's Syndrome Flashcards
Cushing’s syndrome screening tests
- LDDST
- UFC
- LNSC
Symptoms/signs suggestive of CS
Easy bruising, facial plethora, proximal myopathy, abdominal striae
Which abdominal striae are suggestive of CS?
> 1cm wide and reddish purple in colour
Cut-off for LDDST
Cortisol >50 nmol/L
LNSC cut off
> 0.1 mcg/dl or 5.24 ng/ml
24H UFC cut off
170mmol/24 H or 45mcg/24H
If 2-3 screening tests positive, what to do next?
ACTH level - late afternoon
ACTH cut offs
Low <10
High >20
Indeterminate 10-20
Low ACTH
ACTH-independent Cushing’s syndrome
Image adrenals
High ACTH
Confirmed ACTH dependent Cushing
Intermediate ACTH - what to do next?
CRH stimulation
If ACTH >20 - ACTH dependent
If <20 - independent
Next investigation for ACTH dependent Cushing
Pituitary MRI
Pituitary MRI for Cushing - macroadenoma
Cushing’s disease confirmed
Pituitary MRI adenoma 6-9mm - what to do next?
Either
A. IPSS or
B. CRH/DDAVP stimulation test PLUS Whole Body CT
Pituitary MRI adenoma <6mm - what to do next?
IPSS definitely required
Positive CRH/DDAVP test
ACTH up by >35%
Cortisol up by 15-20%
Positive IPSS
Central:Peripheral > 3:1
IPSS lateralisation
Ratio > 4:1
HDDST positive
Cortisol suppressed by >50% in CD; not in ectopic CS
Treatment of CD
A. Surgical Resection
B. Medications
C. Radiotherapy
D. B/L adrenalectomy
Post-op cortisol levels
<2 ug/dL - best response, but up to 5 ug/dL predicts good prognosis
>10 ug/dL - failed surgery
Other indicators of remission post OP in the first week
ACTH < 5 pg/mL
24-H UFC < 20mg/day
Clinical: Decrease in weight, hyperpigmentation, BP and glucose
Tests to be done 6 weeks after surgery for CD
LNSC
Midnight plasma cortisol
These are also the earliest tests to become abnormal in case of recurrence
Test to predict the risk of recurrence post-surgery
DDAVP stimulation test
