W2L3 Conn's syndrome & Pheochromocytoma

Question 1

Epi conn

Answer 1

• 1ry hyperaldosteronism 10% hypertensive pt

* Most com coz bilateral adrenal hyperplasia

Question 2

Pathophysiology conn

Answer 2

• Aldosterone coz renal Na retention & K+ loss = suppres renal renin synt
• Direct action aldosterone on distal nephron coz Na retention, loss H+, K+ ions= hypokalaemic alkalosis
• Aldosterone coz cardiac fibrosis, vascular endothelial dysfunction, nephroscleros

Question 3

Clinical features conn

Answer 3

• Moderate severe htn

* Hypokalemia(usually asymptomatic) pt w tetany, myopathy, polyuria, and nocturia (severe hypokalaemia)

Question 4

Screening conn

Answer 4

• Resistant to convent antihtn medic
• Htn asso w hypokalaemia (K+ <3.7mmol/L, irrespective of thiazide use)
• Htn before 40y
• Adrenal incidentaloma

Question 5

Investigations conn

Answer 5

• Measure aldosterone : renin ratio

* Electrolytes Na K ABG

Question 6

Confirmation of diagnosis conn

Answer 6

1. Test of choice(saline infuse test)
   - Admin 2L normal saline over 4h, measure plasma aldosterone at 0, 2, 3, 4h
2. Fail supp aldosterone in face of sodium/volume loading
3. Fludrocortisone supp test:
   - Give fludrocortisone 100 ug 6-hourly(4d)
   - measure plasma aldosterone basally & last day
   - Aldosterone fail supp in 1ry hyperaldosteronism
4. CT/MRI scan
   - CT & MRI scan=value identify adrenal nodules >5mm diameter.
   - Mass >4cm may carcinoma(xusual)
5. Adrenal vein sampling

Question 7

Ttt con

Answer 7

1. Surgery
   - Laparascopic adrenalectomy(choice)
   - Presurgical spironolactone ttt(50–400mg/d)
   - Htn cured 70%
2. Medical treatment
   - Option bilateral disease, solitary adrenal adenoma, unfit surgery
   - Mineralocorticoid receptor antagonist (spironolactone):
   - 50–400mg/day, once daily
   - Se=gynaecomastia & impotence(M), menstrual abn(F), GI eff

• Eplerenone(50–200mg/day, 2x daily)
  
  • less side effects than spironolactone.

Question 8

Phaeochromocytomas and paragangliomas def

Answer 8

• PCA= chromaffin tumor arise from adrenal medulla & secrete catecholamine
• Pagang=tumor arise from extra-adrenal sympa/para nervous tissue

Question 9

Who should be screened for the presence of a phaeochromocytoma?

Answer 9

• Fam his of MEN, neurofibromatosis,
• Paroxysmal sym
• Young w htn.
• Htn during general anes/surgery
• Unexplained HF
• Adrenal incidentaloma

Question 10

Clinical presentation pca

Answer 10

• Sustain/episodic htn
• Palpitation, headache, sweating w htn
• General: Sweating & heat intolerance >80%
• Neurological: headache(65%), seizures
• Cvs: palpitation(65%), chest pain, dyspnea
• GI: abd pain, constipation, nausea
• Skin: livedo reticularis

Question 11

Complications pca

Answer 11

• Cvs: lf ventricular failure, dilated cardiomyopathy (reversible)
• Respiratory: pulmonary edema.
• Metabolic: carbo intolerance, hypercalcemia
• Neurological: cerebrovascular, hts encephalopathy

Question 12

Factors precipitating a crisis pca

Answer 12

• Straining.
• Exercise.
• Pressure on abdomen-tumor palpation, bending over. 
• Surgery
• Drugs:
   -Anaesthetics 
   -Unopposed B-blockade
   -IV contrast agents
   -Opiates
   -Tricyclic antidepressants

Question 13

Investigations pca

Answer 13

• 24h urinary catecholamine & metabolite
• Raised plasma catecholamine
• Clonidine suppression
• imaging
• 123I-MIBG scan