|Year : 2016 | Volume
| Issue : 4 | Page : 252-254
Renal hypokalemic paralysis: A rare manifestation of Sjogren's syndrome
U Punitha Gnana Selvi, Kamatchi Diravidamani, S Priyanka Devi Sekar, Keerthana Sekar
Department of Dental Surgery, KAPV Government Medical College, Tiruchirappalli, Tamil Nadu, India
|Date of Web Publication||13-Dec-2016|
135c, Madurai Road, Manaparai - 621 306, Trichy District, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Sjögren's syndrome (SS) is typically associated with a lymphocytic, and plasmacytic infiltrate in the salivary, parotid, and lacrimal glands, leading to a sicca syndrome. This immune process can also affect nonexocrine organs, including the kidneys, producing an interstitial nephritis and defects in tubular function. Renal tubular acidosis develops in a large population of patients with SS, but most of the subjects are asymptomatic. In rare cases, hypokalemic paralysis becomes the primary presenting symptom. In this article, we report such a patient with acute paresis of skeletal muscles later diagnosed to be SS.
Keywords: Hypokalemia, muscle paralysis, renal tubular acidosis, Sjögren′s syndrome
|How to cite this article:|
Selvi U P, Diravidamani K, Sekar S P, Sekar K. Renal hypokalemic paralysis: A rare manifestation of Sjogren's syndrome. SRM J Res Dent Sci 2016;7:252-4
|How to cite this URL:|
Selvi U P, Diravidamani K, Sekar S P, Sekar K. Renal hypokalemic paralysis: A rare manifestation of Sjogren's syndrome. SRM J Res Dent Sci [serial online] 2016 [cited 2023 May 30];7:252-4. Available from: https://www.srmjrds.in/text.asp?2016/7/4/252/195667
| Introduction|| |
Sjögren's syndrome (SS) is an autoimmune disease evidenced by broad organ-specific and systemic manifestations. The most prevalent symptoms are diminished lacrimal and salivary gland function, xerostomia and keratoconjunctivitis sicca. Salivary and lacrimal glands are the most affected, thus leading to mouth and eye dryness.
SS has been associated with numerous extraglandular manifestations and could have varied presentations based on the sequence of occurrence of these symptoms. Clinically significant renal disease is observed in approximately 5% of patients with primary SS. Affected patients present with hyposthenuria and hypokalemic-hyperchloremic distal renal tubular acidosis (RTA). Distal RTA may be clinically silent, but untreated significant RTA may lead to renal stones, nephrocalcinosis, and compromised renal function. The purpose of this case is to highlight one of the under-reported presentations of SS that could easily be missed without the sicca symptoms. Distal RTA secondary to SS as a cause of hypokalemic paralysis has not been emphasized enough to be widely known in clinical practice. This article is a case report describing severe hypokalemic paralysis which was later confirmed as SS.
| Case Report|| |
A 37-year-old female presented to our hospital with an acute episode of breathlessness. The chief complaints of the patient were generalized weakness, paresis, and fatigue for 2 days. She had also developed polyuria, nocturia, burning micturition, nausea and vomiting for 2 weeks and fever for 7 days. She had no family history of similar symptoms.
On examination, muscle strength was 2/5 in the upper limbs and 4/5 in the lower limbs. Deep-tendon reflexes were positive in both upper and lower limbs; no sensory deficit was found, and the Babinski's test was negative. Xerosis of eyes and mouth and dental caries were noted. Schirmer test showed positive results (<10 mm of wetting in 5 min). The rest of the physical examination was unremarkable. The patient was intubated and placed on artificial ventilation for next 3 days.
Laboratory investigations at the time of presentation showed: Sodium 158.8 mEq/L (normal 135-145 mEq/L), potassium 2.1 mEq/L (normal 3.5-5.5 mEq/L), magnesium 1.4 mg/dl (normal 1.8-2.4 mg/dl), and normal calcium and chloride levels. Serum anion gap was calculated as 12.5 (normal 3-11). Blood gas investigations showed acidosis (pH = 7.40), pCO 2 of 16.7 mmHg (normal 35-45 mmHg), pO 2 of 75.3 mmHg, and bicarbonate of 16.4 mEq/L (normal 22-26 mEq/L). The picture was consistent with metabolic acidosis with respiratory compensation. Urine analysis showed urine pH of 6.8, potassium of >150 mEq/24 h (normal 25-100 mEq/24 h) and positive urine anion gap. The patient had elevated liver function test with serum glutamic oxaloacetic transaminase of 82 IU/L (normal 6-34 IU/L), serum glutamic pyruvic transaminase of 65 IU/L (normal 5-38 IU/L) and normal bilirubin levels. Renal function tests were normal. Ultrasonography abdomen revealed increased cortical echoes of both right and left kidneys along with an alteration in the comprehensive metabolic panel.
Her autoantibody screen was reported as follows: Serum SS-A (Ro) levels of 172.8 RU/ml (normal <20 RU/ml), SS-B (La) levels of >160 RU/ml (normal <20 RU/ml) and positive antinuclear antibody. The test report was strongly suggestive of SS. All other antibody tests were negative. Viral hepatitis titers were negative for hepatitis B and hepatitis C; thyroid function test was normal.
Electrocardiogram showing mild bradycardia [Figure 1]. Kidney biopsy was not performed in our case. Lip biopsy was taken from lower lip minor salivary glands and sent for histopathological examination (HPE) [Figure 2]. HPE confirms lymphocytic and plasmacytic infiltration of all the four minor salivary glands of forming small focal clusters [Figure 3]. A histological diagnosis of possible SS was concluded.
|Figure 3: Histopathology showing lymphocytic infiltration into the salivary gland acini|
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The patient was initially started on potassium chloride and magnesium sulfate intravenously along with antibiotics for urinary tract infection. Dental consultation was taken for dental caries. After discharge, she has been maintained on supportive treatment with oral potassium and bicarbonate supplements, artificial tear drops and lifestyle modifications like proper dental hygiene.
| Discussion|| |
SS is a systemic autoimmune disorder characterized by a unique set of signs and symptoms predominantly caused by a cell-mediated autoimmunity against exocrine glands. Extraglandular manifestations of the disease arise from a similar pathogenetic mechanism affecting the kidneys, liver, lungs, pancreas, and the nervous system. Renal involvement in SS has been known for a long time and has become one of the most commonly encountered extraglandular manifestation.  A study conducted by Ren et al. on 130 patients with primary SS concluded that distal RTA was present in as many as 70% of the patients studied.
Distal RTA is characterized by an inability of the kidneys to excrete hydrogen ions in the urine in a setting of metabolic acidosis resulting in inappropriately normal or alkaline urine. The condition can be diagnosed by normal anion-gap metabolic acidosis and positive urine anion gap. Renal potassium wasting leads to hypokalemia. Although distal RTA is very common in SS, it is usually asymptomatic and goes undetected in most cases. 
Hypokalemic paralysis in association with SS is rare and only occasionally is it the sole major manifestation that brings a patient to the doctor. Moreover, the cases reported in the literature recently, describe a single presentation of severe hypokalemic paralysis which was later confirmed as SS ,,, but a case presenting with repeated episodes of nonspecific weakness reminiscent of congenital hypokalemic periodic paralysis or a psychiatric disorder, is truly rare. Although distal RTA due to SS has not been included in the differential diagnosis of hypokalemic paralysis, it is necessary to be guarded of the possibility. Sudden hypokalemia is a very serious complication of distal RTA with severe, even fatal consequences. 
Elevated liver function test, as seen in our patient, is another common finding in primary SS with other extraglandular manifestations.  Although no other explanation may be found in most cases and the finding may have a benign course, the significance of this finding is to highlight the need to further investigate for any underlying cause of liver damage such as viral antibody titers and autoantibody screen.
The combination of corticosteroids and other immunosuppressants have been reported to slow progression of renal damage in SS , but the efficacy of the treatment has been largely demonstrated only in patients with rapidly progressing renal damage or insufficiency. ,, In fact, in a case reported by Reddy et al.,  hypokalemia and acidosis recurred after tapering the dose of prednisolone, having given it for 6 months. They concluded that a 6-month course of prednisolone may be ineffective in correcting the condition.
As curative therapy for such cases with SS continues to elude, symptomatic treatment remains the mainstay for these patients. Potassium replacement in our patient showed considerable improvement in the symptoms and she has now been maintained on oral potassium and bicarbonate supplements. The need for continued follow-up of renal function tests to look out for any deterioration could not be overemphasized.
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[Figure 1], [Figure 2], [Figure 3]