Laboratory Diagnosis of Adrenal diseases

Question 1

Laboratory data of a patient with arterial hypertension include increased Na+
and decreased K+ concentrations. Urinary aldosterone excretion is twice normal. What is the most likely diagnosis if plasma renin activity is
1) high,
2) low?

Answer 1

Lab findings:
-2x urine aldosterone
-increase Na serum (due to increased Aldosterone)
-decrease K+ due to increase aldosterone
These are signs of Hyperaldosteronism

IF Renin High:
-Renal A Stenosis most common cause of Primary HT (narrows -> decrease GFR -> RAS ACTIVATION)

-could also be Renin Secreting Tumour

IF Renin Low:

• Primary Hyperaldostronism (overproduction of Aldosterone in Adrenal gland)
• may be Adrenal Adenoma (conn’s disease, bilateral idiopathic adrenal hyperplasia)

Question 2

Plasma cortisol level of a patient is lower than normal. Urinary aldosterone excretion is decreased and the patient is hypoglycemic.
What is the most likely diagnosis and what tests would you order?

Answer 2

Lab findings:

• decrease cortisol -> induces hypoglycemia
• decrease urine aldosterone

Conclusion:
-both aldost + cortisol decrease indicates Hypoaldostrenosim
>If secondary -> expect decreased ACTH
>if primary(addisons) -> expect normal ACTH and hyperpigmentation

Tests:
1)CHECK serum ACTH/Na+/K+

2) ACTH Stimulation Test:
adminster CRH -> see if cortisol rises (not in addisons)

*Waterson-Freidschon sy (menigococcal sy -> adrenal shock)

Question 3

Parameters:
serum Na
Serum K
plasma cortisol

Answer 3

serum Na+: 134-145
serum K+: 3.5 -5
Plasma cortisol: 5-25

Question 4

A 24-year-old man complains of gradually increasing weakness, weight loss
and loss of appetite. He was observed to have bronzed skin, however, he reported no
exposure to the sun. He was hypotensive and showed evidence of muscle wasting.
The results of the laboratory test included:
serum Na+ 125 mmol/l, serum K+ 6.2mmol/l,
plasma cortisol: 4 µg/dl (8:00 a.m.) (decreased), plasma ACTH: increased
above normal. An ACTH stimulation test failed to elicit response in plasma cortisol
level.
What is the most likely diagnosis?

Answer 4

Clinical Findings:

• weakness/Weight loss/ loss of apeptite -> Sign of Hypocortisolism
• Bronze skin -> sign of ACTH overproduction (as no cortisol inhibition)
• Low BP is sign of decrease cortisol

Lab Findings:

• Low Sodium: hypoaldostronism
• High K+ : hypoaldostronism
• cortisol below normal
• ACTH stimulation failed to increase plasma cortisol

Conclusion:
Addissons (decrease cortisol and aldost)

Test:
check for infection (w-f syndrome)

Question 5

A patient with Cushing’s syndrome entered the hospital for diagnostic studies.
Baseline plasma cortisol was elevated. A small dose of dexamethasone did not
suppress cortisol but 50% reduction occurred when large dose of
dexamethasone was given. Plasma ACTH was elevated. What is the most
likely diagnosis?

Answer 5

ptnt has cushing syndrome

Lab findings:
-elevated plasma cortisol

Conclusion:

• Dexamethosone Supression:
• > > Lose dose: did not supress cortisol (indicative of cushing syndrome)
• > > High dose: supressed cortisol by 50% with an ACTH increase (this indicates problem with pituitary gland)

Further Testing:
-imaging test to determine adenoma presence

Question 6

A hypertensive male patient enters the hospital for medical evaluation. His blood pressure is 180/95 mmHg; Serum Na+: 148 mmol/l, K+: 3.5 mmol/l,
fasting plasma glucose: 7.2 mmol/l. Baseline plasma cortisol was elevated.
A small dose of dexamethasone did not suppress cortisol.
A large dose of dexamethasone was given but there was little change in the blood cortisol from baseline values. Plasma ACTH was high. What is the most likely
diagnosis?

Answer 6

Clinical Findings:
-HT which is frequent patient with Hypercortisolism

Lab Findings:

• Serum Na+ increased
• Serum K+ is borderline
• Serum fasting glucose -> DM

Conclusion:
-Dexamethansone: neither high nor low dose supressed the blood cortisol (CUSHING SYNDROME indicated)
-Serum ACTH Is high -> ectopic ACTH production
TOGETHER cushing + ectopic (small cell lung cancer)

-BLOOD GLUCOSE -> ADRENAL DIABETES (cortisol stimulates gluconeogenesis and desensistizedhdhv insulin)

Question 7

A 40-year-old woman complains of amenorrhea and emotional disturbances, perhaps partially due to her increasing obesity which is concentrated around
the chest and the abdomen. Her X-ray studies show evidence of mineral bone loss (osteoporosis).
Laboratory results:
serum K+ 3.2 mmol/l,
fasting plasma glucose: 7.7 mmol/l,
plasma cortisol: 40 µg/dl (8:00 a.m.) (elevated),
plasma ACTH is lower than normal.
A large dose of dexamethasone did not suppress
the elevated cortisol level.
What is the most likely diagnosis?

Answer 7

Clinical Findings:
-Amenorrhea, Emotional stress (due to central obeisity and osteoporosis) => hypercortisolism

Lab Findings:

• serum K+ low ->it is normal in ectopic acth production so thats ruled out
• fasting glucose: adrenal diabetes
• Serum cortisol is very high -> cushing sy
• Serum ACTH is low

Conclusion:
Dexamethasone both high and low dose did not decrease cortisol.

-> ACTH independent Cushing Syndrome (adrenal Tumour - Conn’s disease)

Question 8

A young girl develops virilization and hypertension. Plasma cortisol is low,
ACTH is elevated.
What is the most likely cause of this condition? How are adrenal production of
glucocorticoids, mineralocorticoids and androgens affected?

Answer 8

Clinical findings:
-virilization and HT in young girl

Lab findings:

• plasma cortisol decreased
• plasma ACTH increased (as no negative feedback from cortisol)

Conclusion:

• Virilization: indicates overproduction of Androgens
• Together with HT: -> ANdrogenital Syndrome (lack of 11 B-hydroxylase)
• > lead to accumulation of minerocoritciof-11-dehdroxycorticosterone (causes Na and H2O retention which causes HT and pushes synthesis to Androgen production)

Question 9

A young boy develops precocious puberty and arterial hypotension. Plasma
ACTH is elevated, serum Na+ is low.
The deficiency of which enzyme is presumably responsible for the the above findings? Urinary excretion of 17-ketosteroids, DHEA and free cortisol are
probably normal, low or elevated?

Answer 9

Clinical Findings:
-hypotension and early puberty

Lab findings:
serum na is low
ACTH is high

Conclusion

• early puberty -> indicative sign of androgen synthesis
• together with hypotension -> androgenital
• deficient 21-Hydroxylase (pregnanolone ->11DOC)
• Accumulation of Pregnalone (no minerocorticoid effect) -> Na + and H2O depletion (hypotension)
• nudges to Androgen synthesis (accumulation of 17-ketosteroids and DHAP)

Question 10

A 40-year-old man complains of spells of headache, profuse perspiration
(diaphoresis), nausea and palpitations. Arterial blood pressure is markedly
elevated. Urinary VMA excretion is increased.
What is the most likely diagnosis? What test would you order to confirm your
diagnosis?

Answer 10

Clinical findings:

• headache
• sweating
• nausea
• palpitation

Lab findings:
urine VMA increased => end stage metabolite of E + NE
Increase levels indicate Increase release from Adrenal Medulla

Conclusion:

• increased sympathetic response (explained by incr. VMA)
• this is Phenochromocytoma (tumour of adrenal medulla)

Further Tests:

1) glucagon stimulation test
2) Clonidine supression test (a2-R/imiadizole receptor agonist)
3) CT Scan of adrenal medulla
4) MIBG scan (see if mass like structure in adrenal medulla)