Aldosteronism (Conn's
disease)
< Case presentation
>
The patient was a 61-year-old man who had hypertension under
anti-hypertensive treatment for 12 years. Recently, his blood
pressure fluctuated despite medication with good compliance. However, an
episode of hypertensive urgency with systolic blood pressure
up to 220mmHg and diastolic pressure exceeding 120 mmHg was
noted. He complained of excessive fatigability, both leg
weakness, and mild leg edema in the pretibial area in recent
two months. He visited a drugstore to buy some over- the-
contour medications, such as calcium channel antagonist,
angiotensin-receptor blocker and αblocker. However, his blood
pressure remained above 200/100 mmHg, which were equal in both
arms, after taking these medications. On physical examination,
no renal bruits were heard. Renal sonography revealed
bilateral renal parenchymal disease without renal atrophy.
Twenty-four-hour blood pressure monitoring not only confirmed
marked hypertension but also showed extreme dipping during
night-time.
< Course and Treatment
>
On admission, the serum potassium was 3.06 mmol/dL and the
blood gas analysis showed metabolic alkalosis. A chest
radiograph revealed cardiomegaly. The captopril test(Table
1)showed the supine plasma renin acitivity (PRA) and
plasma aldosterone were (ALD) were 37.2 (ng/ml/hr), and 0.03
(ng/dl), respectively after 25mg of captopril. The plasma
aldosterone/ plasma renin activity ratio was 1240 (ng/dl/ng
per ml/h), well above the cut-off level of 30 (ng/dl/ng per
ml/h). The results were consistent with a diagnosis of primary
aldosteronism. The postural test was performed and showed a
negative result without aldosterone elevation after
ambulation, which was compitable with aldosterone- producing
adenoma. A renal computer tomographic scan of the adrenal
gland was subsequently undertaken, which showed a small nodule
at the superior aspect of the left adrenal gland with a
diameter of 8mm. He received laparoscopic partial
adrenalectomy after the diagnosis of aldosterone –producing
adenoma. After discharge, he was followed-up in the
out-patient clinic and his blood pressure was 125/80 mmHg
without necessitating any antihypertensive drugs.
< Laboratory and Image Study
> Table
1.
1.
CBC/DC
Date |
WBC |
RBC |
Hb |
Hct |
MCV |
MCHC |
Plt |
|
/ul |
M/ul |
g/dl |
% |
fL |
% |
K/ul |
Dec 10 |
5980 |
4.4 |
12.6 |
36.9 |
83.9 |
34.1 |
272 |
2. Biochemistry
BUN |
Cre |
Na |
K |
Cl |
Ca |
T.protein |
AST |
albumin |
T-bil |
mg/dL |
mg/dL |
mmol/L |
mmol/L |
mmol/L |
mmol/L |
g/dL |
U/L |
g/dL |
mg/dL |
26.5 (<24) |
0.8 (<1.3) |
142 (135-145) |
3.06 (3.5-5.3) |
104 (98-108) |
2.2 (2.02-2.6) |
7.24(6.6-8.7) |
29 (<37) |
3.61 (3.5-5.0) |
0.3
(0.2-1.0) |
Arteril blood gas : |
PH 7.45, |
PCO2 41.3, |
PO2 92.5, |
HCO3 28.6, |
BE 4.7 |
|
(7.35-7.45) |
(35-45) |
(80-100) |
(22-26) |
(-3~+3) |
TSH |
0.9 |
(0.1-3.8 μIU/mL) |
Free T4 |
22.9 |
(9.8-23.8 ng/dl) |
Cortisol DL (8am) |
9.55 |
(am: 5 ~ 25 (μg/dL) ) |
Cortisol DL (4pm) |
8.42 |
(pm: 2.5 ~ 12.5 (μg/dL) ) |
ACTH (8am) |
12.7 |
( 10 ~ 65 (pg/mL) ) |
ACTH (4pm) |
10.4 |
( 10 ~ 65 (pg/mL) ) |
24 HR. URINE VMA |
6.743 |
( 1~7 (mg/24h)
) |
Urine ( 24 hrs 2300
ml)
Cre |
Na |
K |
Cl |
Ca |
mg/dL |
mmol/L |
mmol/L |
mmol/L |
mmol/L |
38.8 |
120 |
24.2 |
106 |
3.42 |
Daily K loss : 55.66mmol/d ;Daily Na loss
: 276 mmol/d
24 Hr Ccr : 77.45 ml/min (> 75)
Urinary potassium to creatinine ratio [UK /U cre
(nmol/nmol)]: 5.54 ( <2.5)
3. Diagnosis
test
【Captopril test】
Time |
PRA(ng/ml/hr) |
ALD(ng/dl) |
ALD / PRA ratio (ARR) |
0’ |
0.13 |
27.8 |
213.8 |
30’ |
0.03 |
37.2 |
1240
|
* (注
1 ) A positive
screening test was considered when the aldosterone-renin ratio
(ARR) was more than 30 (ng/dL per ng/mL/hr) and the plasma
aldosterone concentration (ALD) was more than 10 ng/dL (>
277 pmol/L).
【Posture Change test】
PRA |
(ng/ml/hr) |
ALD (ng/dl) |
ALD / PRA ratio (ARR) |
Before |
0.24 |
45.6 |
190 |
After |
0.42 |
17.3 |
41.2
|
** (注 2) A positive postural test was defined by an
ambulatory plasma aldosterone level that was either lower than
the supine baseline level or that was increased less than 30%
above that value (1, 2)
< Analysis
>
根據Conn的描敘,原發性皮質醛酮症起因於皮質醛酮素瘤,是一種可治癒的高血壓疾病。原發性皮質醛酮症患者的皮質醛酮分泌是部分自主的,其血清中腎素的濃度是低的,並且不會被體液擴張或是鈉鹽攝取過量所抑制。原發性皮質醛酮症的盛行率在沒有經過篩選的高血壓病人中顯然是不低,尤其是皮質醛酮和腎素(ARR)比例這個篩選方式被發現之後,認為是佔了高血壓病人中百分之十五。在一個沒有接受高血壓治療的病人測量血漿中皮質醛酮素濃度及血漿中腎素活性的比值(ARR)
(注
1),是一個比較可以接受用來分辨本質性高血壓和原發性皮質醛酮症的篩檢方法。皮質醛酮素瘤在女性較常發生,在兒童則很少發生。雙側腎上腺增生症在男生發生率較高,發生的年齡也高過皮質醛酮素瘤。原發性皮質醛酮症的臨床特徵並不具特異性。有些病人是完全沒有症狀或只有很輕的症狀,有些病人則有高血壓(例如:頭痛)、低血鉀(例如:多尿和夜尿、或是肌肉痙攣)或兩者都有的症狀。有時候,嚴重的肌肉無力、感覺異常、手腳痙攣或麻痺癱瘓可能會由於嚴重的低血鉀症而顯的明顯。而且這個現象又在亞洲、特別是在中國人顯的更為常見。除一些很小的腫瘤之外,CT
scan可以偵測到大部分的腎上腺腫瘤。雙側腎上腺增生(IHA)的病人,兩側腎上腺會增大或正常大小。但有一些雙側腎上腺增生的病人,一側的腎上腺可見到一結節;而皮質醛酮素瘤(APA)的病人,可能兩側都看到結節。
單側皮質醛酮素瘤,手術去除腫瘤為最佳選擇。大部分病人術後高血壓都能有明顯下降或恢復正常。術前可給予spironolactone治療血壓,其反應的好壞可作為手術結果的預測因子,雙側腎上腺增生(BAH)以藥物治療為最佳方式,單側或雙側腎上腺切除對血壓的控制效果都不佳。
【Reference】
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- 腎性高血壓及原發性皮質醛酮過高症,吳允升.吳寬墩;當代醫學、94年7月 第三十二卷第七期,528頁
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