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| Year : 2009 | Volume
: 20
| Issue : 2 | Page : 285-287 |
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| Hypokalemic paralysis due to primary hyperaldosteronism simulating gitelman's syndrome |
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Timucin Kasifoglu1, Aysen Akalin2, Dondu Uskudar Cansu1, Cengiz Korkmaz1
1 Divisions of Rheumatology, Department of Internal Medicine, Eskisehir Osmangazi University Medical Faculty, Eskisehir, Turkey
2 Divisions of Endocrinology, Department of Internal Medicine, Eskisehir Osmangazi University Medical Faculty, Eskisehir, Turkey
Click here for correspondence address and email
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 Abstract | | |
Some diseases, such as Gitelman's syndrome, Bartter's syndrome, and primary hyperaldosteronism (Conn's syndrome), may bear some similar clinical and laboratory findings. Their treatment modalities being different from one another, the need for a scrupulous diagnostic evaluation arises as far as clinical practice is concerned. In this report, we present a patient with Conn's syndrome who was initially considered to have Gitelman's syndrome due to displaying a few overlapping features of both diseases. We also give an account of the hardships encountered during the diagnostic evaluation. Keywords: Hypokalemia, Myopathy, Gitelman′s syndrome
How to cite this article:
Kasifoglu T, Akalin A, Cansu DU, Korkmaz C. Hypokalemic paralysis due to primary hyperaldosteronism simulating gitelman's syndrome. Saudi J Kidney Dis Transpl 2009;20:285-7 |
How to cite this URL:
Kasifoglu T, Akalin A, Cansu DU, Korkmaz C. Hypokalemic paralysis due to primary hyperaldosteronism simulating gitelman's syndrome. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2013 May 24];20:285-7. Available from: http://www.sjkdt.org/text.asp?2009/20/2/285/45581 |
| Introduction | |  |
Acute muscular weakness is a common complaint in the emergency departments resulting from several causes. [1],[2] Paralysis is usually limited to skeletal muscles. Involvement of respiratory muscles or cardiac arrhythmia due to hypokalemia can result in life-threatening consequences. After improving hypokalemic paralysis by potassium replacement, all patients must be examined to detect the underlying aetiology. Although hypocalcemia, hypomagnesemia and metabolic alkalosis with hypokalemia can be seen in Gitelman's syndrome, vitamin D deficiency associated with a diseasecausing hypokalemia can manifest with similar laboratory findings. Therefore, a meticulous diagnostic approach to these patients is very important in clinical practice. In this case report, we present a patient who diagnosed as having hypokalemic paralysis attributable to Conn's syndrome associated with vitamin D deficiency. We also discuss some diagnostic hardships in evaluating her laboratory results.
| Case Report | | |
A 50-year-old woman was admitted to the emergency department with a sudden onset of progressive paralysis involving four extremities. She denied having nausea, vomiting, diarrhoea or the use of drugs, including diuretics and licorice. Her family history was unremarkable. One year ago she had preented to the hospital with muscle weakness and myalgias. Laboratory workup at that time revealed potassium level of 2.1 mEq/L (normal 3.5-5.5) but the cause of hypokalemia was not investigated in detail. During her current presentation blood pressure was 130/80 mmHg, she was afebrile with no respiratory distress. She had symmetric flaccid paralysis with areflexia in all extremities. Her muscle strength was 1/5 in the proximal muscle groups. Her laboratory tests revealed the following values: severe hypokalemia (1.51 mEq/L), metabolic alkalosis (pH 7.52), creatine kinase (CK) 6330 IU/L (16190), lactic dehydrogenase (LDH) 886 IU/L (240-480), aspartate aminotransferase (AST) 192 IU/L (7-39), alanine aminotransferase (ALT) 101 IU/L (2-40), calcium 7.3 mg/dL (8.510.5), phosphorus 2.1 mg/dL (2.7-4.5), magnesium 0.57 mmol/L (0.85-1.15). 25(OH) vitamin D level was 7 IU/L (> 25). Urinary potassium excretion was 70 mEq/day. Transtubular potassium gradient was 5.2. Parathormone (PTH) level was 178 ng/mL (15-65). Normal or negative tests included sodium chloride, blood urea nitrogen, creatinine, glucose, total protein, albumin, thyroid function studies, and liver. Intravenous administration of potassium chloride (KCL) at the rate of 10 mmol/h progressively improved her muscle strength with concomitant increase in her potassium levels. Muscle biopsy and electroneuromyography were performed one week after resolution of hypokalemia. Metabolic alkalosis, hypocalcemia and hypomagnesemia with hypokalemia prompted us to suspect of Gitelman's syndrome. However, because this syndrome mostly appears in younger ages, a few other possible factors, such as mineralocorticoid excess syndrome, were taken into consideration.
The aldosterone level was 395 pg/mL (20240), renin activity was 0.2 ng/mL per hour in supine position (0.2-3.4) and aldosterone/renin ratio was 197.5 (< 10). Abdominal ultrasound was unremarkable but dynamic suprarenal CT scan showed a 20 × 30 mm hypo dense mass in the left suprarenal area. After adrenalectomy, the pathology confirmed an aldosterone producing adenoma. The patient has been in a normokalemic state without KCL supplementation and her last muscle strength is 5/5 in all extremities. Serum calcium and magnesium levels remained in normal ranges with calcitriol and vitamin D supplementation.
| Discussion | | |
Acute hypokalemic paralysis, a clinical syndrome characterized by acute muscular weakness and low serum potassium levels, is a rare but treatable cause of acute myopathy. Among the reasons reported for development of hypokalemic myopathy are liquorice intake, [3] clay ingestion, [4] diuretic use, [5] Bartter's or Gitelman's syndrome. [6],[7]
Because concurrent presence of vitamin D deficiency and Conn's syndrome may simulate Gitelman's syndrome in consideration of hypokalemia, hypocalcemia, hypomagnesemia and metabolic alkalosis, we do not rule out the possibility that we could have diagnosed our patient as having Gitelman's syndrome if we had not conducted an intensive study into the aetiology of hypokalemia and other laboratory findings. In Gitelman's syndrome an autosomal recessive disorder, the diagnosis is usually made by late childhood or even adulthood cramps, severe fatigue, polyuria and nocturia symptoms. [8] In our patient, other electrolyte abnormalities with hypokalemia prompted us to suspect Gitelman's syndrome. However, a patient with Gitelman's syndrome is supposed to have high levels of plasma renin. [9] As to our patients, she had low levels of renin. Hypokalemia in a patient with myopathy should lead a physician to suspect Bartter's and Gitelman's syndromes, as well as primary hyperaldosteronism. Bartter's syndrome is a disorder characterized by hypokalemia, metabolic alkalosis, hyperreninemic hyperaldosteronism secondary to extra cellular fluid volume contraction and juxtaglomerular apparatus hyperplasia. Since Gitelman's syndrome has some common clinical and laboratory findings with those of Bartter's syndrome, Gitelman's syndrome is accepted as a variant of Bartter's syndrome. However, hypocalciuria, hypocalcemia, and hypomagnesemia are seen in Gitelman's syndrome but not in Bartter's syndrome. Our patient had hypocalcemia, hypomagnesemia and metabolic alkalosis. These laboratory findings complied with those of Gitelman's syndrome. However, hypocalcemia can also be seen in Conn's syndrome due to severe hypokalemia. In Conn's syndrome, hypomagnesemia may be suspected when hypokalemia is severe. [10] Chronic hypomagnesemia leads to intracellular magnesium deficiency and this, in turn, impairs secretion of PTH and also decreases response to PTH. Thus, in severe hypomagnesemia, PTH levels are undetectable or inappropriately low despite the stimulus of hypocalcemia. However, in our case, PTH levels were high despite low levels of magnesium. We, therefore, concluded that hypocalcemia could be due to factors other than hypomagnesemia. A low calcium and low phosphorus implied that our patient may have vitamin D deficiency. Because vitamin D deficiency leads to secondary hyperparathyroidism, which affects renal tubule phosphate transport, causes renal phosphate wasting and hypophosphatemia. [11] A very low level of 25(OH) vitamin D confirmed vitamin D deficiency in our case. However, we considered this could be a sheer coincidence and not necessarily related with Conn's syndrome.
Hypokalemic myopathy due to an adrenal adenoma producing mineralocorticoid is reported rarely. [12] The treatment of choice is surgical excision of aldosterone-producing tumour. Mineralocorticoid excess can be easily recognised by using ratio of plasma aldosterone level (ng/dL) to renin level (ng/mL/h), which is an indicator of increased aldosterone and suppressed renin levels. The ratio above 20 is usually suggestive of a functional adenoma causing mineralocorticoid exces. [13] Ultrasonography and CT scan sometimes fail to show the adrenal lesions smaller than 1 cm.
| Conclusion | | |
In conclusion, Conn's syndrome and Gitelman's syndrome should be considered in a differential diagnosis of patients with hypokalemic paralysis due to occasional overlapping laboratory findings. We also concluded that a correct interpretation of laboratory tests could be instrumental in excluding other reasons of hypokalemic myopathy.
| References | | |
| 1. | Ahlawat SK, Sachdev A. Hypokalaemic paralysis. Postgrad Med J 1999;75:193-7.  [PUBMED] [FULLTEXT] |
| 2. | Lin YF, Lin SH, Tsai WS, Davids MR, Halperin ML. Severe hypokalaemia in a Chinese male. Q J Med 2002;95:695-704. |
| 3. | van den Bosch AE, van der Klooster JM, Zuidgeest DM, Ouwendijk RJ, Dees A. Severe hypokalaemic paralysis and rhabdomyolysis due to ingestion of liquorice. Neth J Med 2005;63: 146-8. |
| 4. | Severance HW Jr, Holt T, Patrone NA, Chapman L. Profound muscle weakness and hypokalemia due to clay ingestion. South Med J 1988;81: 272-4. [PUBMED] [FULLTEXT] |
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| 8. | Stein JH. The pathogenetic spectrum of Bartter's syndrome. Kidney Int 1985;28:85. [PUBMED] |
| 9. | Bringhurst Fr, Demay MB, Kronenberg HM. Endocrine hypertension. In: Larsen R, Kronenberg HM, Melmed S, Polonsky KS, eds. Williams textbook of Endocrinology. Philadelphia: Saunders 2003;579-85. |
| 10. | Potts, JT. Diseases of the parathyroid gland and other hyper- and hypocalcemic disorders. In: Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, eds. Harrison's Principles of Internal medicine. Mc Grow Hill 1994;2151-83. |
| 11. | Bringhurst Fr, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Larsen R, Kronenberg HM, Melmed S, Polonsky KS, eds. Williams textbook of Endocrinology. Philadelphia,: Saunders 2003;1303-71. |
| 12. | Kasifoglu T, Korkmaz C, Pasaoglu O. Conn's syndrome (primary hyperaldosteronism) simulating polymyositis. Rheumatol Int 2005;25:133-4. |
| 13. | Kaplan NM. Clinical hypertension. 7th edn. Williams and Wilkins Baltimore: 1998;365-82. |
Correspondence Address:
Timucin Kasifoglu
Visnelik M. Oncag Sitesi E Blok Daire 13, Eskisehir
Turkey
PMID: 19237821
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