Adrenal Lab Questions

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? or 2)Low?

Answer 1

If the Renin Concentration is High - Possible Causes:

• Renin Secreting Tumor (Likely)- Further Imagimg
• RBF↓ - caused by external vessel compression or Internal occlusion by Embolism/Thrombus

​If the Renin Concentration is Low - caused by 2 variations of Primary Hyperaldosteromism - Con’s Syndrome:

• Bilateral Adrenal Hyperplasia 66%-Enzyme Defects
• Adrenal Adenoma 33%

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

Cortisol↓+Aldosterone↓= Primary Adrenal Inssuficiency - 3 Major possible causes:

• If the onset was Slow: Autoimmune - Addison’s Disease (Anti-21-OHases) - ACTH Stimulation test to Confirm
• If the onset was Fast: Infectious - Waterhouse Fridrichsen syndrome (or TB) - Presence of Petechial Rash and CSF microscopy reveals Gram negative Diplococci.
• Congenintal Adrenal Hyperplasia - 21-OHase Def.​​

Question 3

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+ 6.2 mmol/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. Diagnosis?

Answer 3

• Hyponatremia and Hypokalemia = Aldosterone↓
• All other symptomes including bronze skin from POMC↑+MSH↑ point to Adrenal Insufficiency
• Cortisol↓ and Aldosterone↓= 1º Adrenal Insuffic.
• ACTH↑ with ACTH stimulation test failed means that this is Addison’s Disease (usually Anti-21-OHases)
• Treatment: Cortisol and Aldosterone Suplements

Question 4

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?

• Cushing’s syndrome - Exogenous / ACTH Tumor
• Cushing’s Disease - Pituitary Ademoma / CRH↑
• Dexamethasone = Synthetic negative feedback to ACTH

Answer 4

No response to small dose of Dexamethasone means that this is not an exogenous rooted problem. High Dose stimulation possible results:

1. If ACTH↓ with Cortisol↑ = “Adrenal (Autonomous) Cushing’s” from Hyperplasia/Neoplasm
2. If ACTH↑ with no supression = Small cell lung carcinoma secreting ACTH (“ectopic source”)
3. If ACTH↑ but with supression = PItuitary Adenoma secreting ACTH (90% of cases) - Cushing’s Disease!

​CRH Stimulation test is also possible if unclear results.

Question 5

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 5

ACTH↑ with no response to Low and High dose ACTH stimulation = Ectopic ACTH Secretion Syndrome - Most likely a Small cell Lung Carcinoma.

• All symptomes are caused by high level of Cortisol in the blood! (Mineralocorticoid and Gluconeogenic activity)
• Chest/Abdomen CT to find the ectopic source.

Question 6

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 6

Dexamethasone High Dose stimulation possible results:

• ACTH↓ with Cortisol↑ = “Adrenal (Autonoumos) Cushing’s” from Hyperplasia/Neoplasm:
• Adrenal Carcinoma - Multiple Steroid hormone secretion!
• Adrenal Adenoma - Cortisol/Aldosterone/Other.
• Here the symptomes fit the Cortisol↑!

Abdominal CT and possible Adrenalectomy should be preformed.

Question 7

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 7

Cortisol↓ with Virilization=Androgenital syndrome - Caused by Congenital Adrenal Hyperplasia.

• Most commonly due to 21-OHase Def. that reroutes the steroid synthesis to androgen path with low Aldosterone and Cortisol.
• In this case since Hypertension is a symptom - 11β-Hydroxylase deficiency is the rare cause (5%)!
• It results in 11-DOC↑ - Less potent but an Aldosterone Precursor = Hypertension and Hypokalemia.

Question 8

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 8

Congenital Adrenal Hyperplasia caused by 21-Hydroxylase deficiency (Most common one):

• Aka “Salt Losing” / Classical Form
• Hypotension and Low Na = Aldosterone↓
• Precocious puberty = Androgens↑
• DHEA and 17-Ketosteroids level should be High in urinary secretion
• Cortisol level should be low - syntheis aberration!

Question 9

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 9

Pheochromocytoma:NE secreting tumor of the adrenal medulla aka”10%Tumor= Bilateral+Extraadrenal+Familial+Malignant!”

• Symptoms from: Adrenergic Stimulation↑
• Vanillylmandelic Acid = Catecholamine Degredation product.
• Serum Chromogranin is a PCC marker

Tests: HMA↑ in urine = Dopamine↑, Clonidine suppression test - a catecholamine that wont supress in PCC, 131I-MIBG = Adrenal Specific Scintography.