NEPHRON
Nephron 1998;79:247-248
M.A. Muthusethupathi A. Vimala M. Jayakumar Suguna Rajendran
Department of Nephrology, Madras Medical College and Government General Hospital, Madras, India
Normotensive Primary Aldosteronism due to Adrenocortical Carcinoma
Dear Sir,
The major clinical and biochemical fea- tures of primary aldosteronism are hyperten- sion, hypokalemia, suppressed plasma renin activity and increased plasma aldosterone [1, 2]. Hypertension without hypokalemia is not uncommon but only 14 cases of primary aldosteronism without hypertension have been documented. We report a case of adre- nal cortical carcinoma presenting as normo- tensive primary aldosteronism.
A 40-year-old man was referred for eval- uation of episodic weakness of all four limbs associated with hypokalemia. His symptoms had begun 6 months previously when he had developed quadriparesis following oral fru- semide prescribed for pedal edema. Thereaf- ter, episodes of quadriparesis recurred spon- taneously 5 times during the 6-month peri- od. Blood pressure was normal. He had been a smoker for 10 years and was not a diabetic or hypertensive.
On examination, there were no features of Cushing’s syndrome or thyroid disease. His blood pressure varied between 90/70 and 120/80 mm Hg. Neurologic evaluation showed a flaccid quadriparesis.
Urinalysis was normal, PCV 33%, total leukocyte count 9.2 × 109/1, with a normal differential. Plasma urea was 4.5 mmol/l, creatinine 88 umol/1, sodium 134 mmol/l, potassium 2.3 mmol/1 (2-2.5), 24-hour uri- nary sodium 50 mmol and potassium 85 mmol. Arterial blood gas analysis re- vealed pH 7.44, Pco2 of 42.3 mm and bicar- bonate of 28.9 mmol/l. An electrocardio- gram showed features of hypokalemia.
An ultrasonogram showed an enlarged right adrenal gland with a hypoechoic mass (2.8 cm × 2.5 cm). The left adrenal gland
was normal. Kidneys and liver did not show any evidence of metastasis. An aortogram with a selective adrenal angiogram showed a dilated right inferior adrenal artery and a highly vascular adrenal mass (fig. 1).
He was started on spironolactone 100 mg 4 times daily and intravenous potassium chloride. He recovered his muscle power completely and was advised surgery. He was readmitted 6 months later with a recurrence of quadriparesis though he was on spirono- lactone. An ultrasonogram showed an in- crease in the size of the mass to 5.6 x 6 cm.
During surgery, the right adrenal gland was removed with the adjoining lymph nodes. Histopathology revealed adrenocorti- cal carcinoma with lymph node metastasis (fig. 2). From the 6th postoperative day, his serum potassium became normal without potassium supplements or spironolactone. He was discharged on the 15th postoperative day.
Blood for hormonal assays was collected: (1) preoperatively after 4 h of upright pos- ture, (2) after saline infusion, (3) intraopera- tively, (4) on the 6th postoperative day. Plas- ma renin activity was estimated by enzymat- ic RIA and aldosterone by RIA. As shown in table 1, his plasma aldosterone level was 7 times the normal. After volume expansion, his plasma renin activity and angiotensin II levels were still normal and plasma aldoste- rone remained high supporting a diagnosis of primary aldosteronism. The aldosterone level in the right adrenal vein of 81,600 pmol/l confirmed that the source of aldoste- rone was the right adrenal gland. The plasma aldosterone level became normal on the 6th postoperative day establishing that all or most of the abnormal aldosterone-producing tissue had been removed.
MRI of the abdomen 3 months after sur- gery showed no evidence of metastasis, and his blood pressure was 150/100 mm Hg.
| Plasma renin activity nmol/l/h | Angiotensin II pmol/l | Aldosterone pmol/l | Cortisol nmol/l | |
|---|---|---|---|---|
| Before surgery | 0.7 | 13 | 3,570 | 556 |
| (0.42-2.7) | (22-70) | (140-550) | (140-690) | |
| After volume expansion | 0.6 | 34 | 3,240 | 398 |
| (0.15-1.55) | (20-70) | (140-550) | ||
| Right adrenal vein | 3.8 | 50 | 81,600 | 4,490 |
| After surgery | 1.1 | 17 | 42 | 298 |
| (0.15-1.55) | (20-70) | (140-550) |
KARGER
Fax + 41 61 306 12 34
Dr. M.A. Muthusethupathi Professor and Head Department of Nephrology Madras Medical College and Government General Hospital Madras 600 003, Tamilnadu (India) Tel. +91 44 827 6464, Fax +91 44 828 3262
1
2
This patient had excessive secretion of aldosterone from a carcinoma of the right adrenal gland resulting in hypokalemia and periodic quadriparesis. There are two inter- esting features in our patient. Firstly, the adrenal cortical carcinoma was actually pro- ducing aldosterone. Aldosterone-producing adrenal carcinoma is a very rare cause of pri- mary aldosteronism, the frequency being 1- 1.2% [3].
Secondly, his blood pressure remained low to normal throughout the course of the illness. The fact that his blood pressure was 150/100 mm Hg 3 months after surgery sug- gests that he was indeed hypotensive as long as he had the tumor. Snow et al. [4] and Zip- ser and Speckart [5] first reported the asso- ciation of normal blood pressure in a case of adrenal adenoma and adrenal hyperplasia, respectively [4, 5]. Various explanations have been offered for the normal blood pres- sure with hyperaldosteronism seen in such
patients [6]: (1) the patient could have been hypotensive before the onset of the disease; (2) there is a blunted responsiveness to pres- sor agents; (3) associated hypopituitarism; (4) in some patients with primary aldoste- ronism, hypokalemia occurs early and hy- pertension much later; (5) enhanced activi- ties of vasodilatory kinins or prostaglandins could prevent hypertension. The exact cause for the interesting phenomenon of normal blood pressure in the presence of high aldo- sterone levels could not be established in this patient.
Acknowledgments
We wish to express our deep gratitude to Dr. Ross R. Bailey, Nephrologist, and to Dr. Tim Yandle, Department of Endocrinology, Christchurch Hospital, New Zealand, for the hormone estimations.
References
1 Conn JW, Rovner DR, Cohen EL, Bookstein II, Cerny JC, Lucas CP: Preoperative diagnosis of primary aldosteronism. Arch Intern Med 1969;123:113.
2 Conn JW, Cohen EL, Rovner DR: Normokal- emic primary aldosteronism. JAMA 1965;193: 200.
3 Young WF Jr, Klee GG: Primary aldosteron- ism: Diagnostic evaluation. Endocrinol Metab Clin North Am 1988;17:367-395.
4 Snow MH, Nichel P, Wilkinson R, et al: Nor- motensive primary aldosteronism. Br Med J 1976;i:1125.
5 Zipser RD, Speckart PF: Normotensive prima- ry aldosteronism. Ann Intern Med 1978;83: 655.
6 Kuruda T, Okamura K, Yoshinari M, Ikenoue H, Sato K, Yamashita Y, Takishita S, Fujishi- ma M: A case of normotensive primary aldoste- ronism with hypopituitarism, epilepsy and me- dullary sponge kidney. Acta Endocrinol 1989; 121:797-801.
Muthusethupathi/Vimala/Jayakumar/ Rajendran