Annals of African Medicine

CASE REPORT
Year
: 2020  |  Volume : 19  |  Issue : 2  |  Page : 147--149

Hypokalemic paralysis as an initial presentation of Sjogren syndrome


Durga Shankar Meena, Deepak Kumar, Gopal Krishana Bohra, Sunil Kumar Bhambu 
 Department of Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India

Correspondence Address:
Dr. Durga Shankar Meena
Department of Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan
India

Abstract

Sjogren syndrome (SS) is a systemic autoimmune disorder with predominant exocrine gland involvement leading to sicca symptoms. Among extraglandular manifestations, renal disease is the most common. Tubular interstitial nephritis and renal tubular acidosis (RTA) are the common presentations. Mild hypokalemia associated with distal RTA is common in SS, however, severe hypokalemia causing paralysis is unusual. We report the case of a 26-year-old female who presented with hypokalemic paralysis. On evaluation, distal RTA was diagnosed. Further evaluation showed positive SS-a/SS-b antibodies in high titer, which confirms the diagnosis of primary SS. Our report illustrates that SS is a rare but important cause of hypokalemic paralysis.



How to cite this article:
Meena DS, Kumar D, Bohra GK, Bhambu SK. Hypokalemic paralysis as an initial presentation of Sjogren syndrome.Ann Afr Med 2020;19:147-149


How to cite this URL:
Meena DS, Kumar D, Bohra GK, Bhambu SK. Hypokalemic paralysis as an initial presentation of Sjogren syndrome. Ann Afr Med [serial online] 2020 [cited 2020 Aug 4 ];19:147-149
Available from: http://www.annalsafrmed.org/text.asp?2020/19/2/147/285737


Full Text



 Introduction



Chronic interstitial nephritis is the most common renal presentation in Sjogren syndrome (SS). The clinical manifestations of interstitial nephritis are variable, which include Fanconi syndrome, distal renal tubular acidosis (RTA), nephrogenic diabetes insipidus, or mild asymptomatic hypokalemia. RTA in SS is usually mildly symptomatic, observed in up to 25% of patients.[1] Our patient had one episode of similar weakness with mild hypokalemia which recovered with potassium supplementation, and the patient was diagnosed as hypokalemic periodic paralysis. Renal involvement can occur in SS even before sicca symptoms. Although hypokalemic paralysis as a complication of RTA is rare, we highlight hypokalemic paralysis as an initial presenting symptom in a patient with SS.

 Case Report



A 26-year-old female presented to the emergency department with chief complaints of acute-onset weakness of all the four limbs for the last 3 days. The weakness was progressive, and she was not able to walk at the time of hospitalization. There was one episode of similar weakness 15 days back, for which she was admitted and treated with potassium supplementation. There was no other significant illness in the past. There was no history of vomiting, diarrhea, fever, or altered behavior. Drug history was not significant. General physical examination revealed mild pallor. Neurological examination revealed motor weakness (power 2/5 in the lower limbs and 3/5 in the upper limbs). Deep tendon reflexes were diminished in all the four limbs. There was no sensory deficit. Rest of the systemic examination was unremarkable. Her laboratory analysis revealed normal anion gap hyperchloremic metabolic acidosis [Table 1]. In the absence of gastrointestinal loss or diuretic use, we suspect RTA as a probable cause of metabolic acidosis. Urinalysis revealed pH 7.45, which was failed to lower with ammonium chloride test (0.1 g/kg), which further consolidate our diagnosis of distal RTA. Ultrasonography abdomen was unremarkable, and there was no evidence of obstructive uropathy. On further evaluation of distal RTA, her autoimmune profile showed positive antinuclear antibody and anti SS-a/SS-b antibodies in high titer. Thyroid functions were normal, and viral markers were also negative (hepatitis B, C, and HIV). After ruling out the other causes, the possibility of SS was considered. Our patient was admitted to have dry eyes and dry mouth for the last 6 months. Schirmer test was also positive (4 mm in the right eye/5 mm in the left eye). A final diagnosis of hypokalemic paralysis with distal RTA associated with SS was made. She was started on potassium chloride (intravenous) and sodium bicarbonate. After 1 week, her muscle power recovered completely with normalization of all laboratory parameters. At discharge, the patient was put on oral potassium citrate. At 3 months of follow-up, she has been symptom free with no further episode of hypokalemia.{Table 1}

 Discussion



SS is characterized by chronic lymphocytic infiltration of salivary, lacrimal, and parotid glands, leading to sicca symptoms (xerophthalmia and xerostomia). The extraglandular disease spectrum is variable with features suggestive of arthralgia, arthritis, pulmonary disease, Raynaud phenomenon, RTA, cytopenias, vasculitis, and lymphoma. Renal involvement is common in SS, with tubulointerstitial inflammation being the usual presentation. Glomerulopathy is rare in SS but associated with a poor prognosis. The prevalence of distal RTA is reported from 5% to 70% in different studies.[2],[3]

The exact mechanism by which SS causes distal RTA is incompletely understood. The complete absence of H-ATPase pump in cortical collecting duct is one of the proposed theories described in some studies.[4],[5] Another possible mechanism is carbonic anhydrase 2 inhibition caused by the high titer of autoantibodies, which leads to defective H+ secretion.[6] Hypokalemia is common in RTA, but severe hypokalemia mimicking periodic paralysis is rare. There are case reports describing hypokalemic paralysis as a first presentation in SS.[7],[8],[9],[10],[11] Our patient had previously one episode of mild weakness of all the four limbs with hypokalemia and diagnosed as hypokalemic periodic paralysis and now presented with severe hypokalemic paralysis with RTA.

There is a reduction in proximal sodium reabsorption secondary to metabolic acidosis, which causes severe hypokalemia in distal RTA. Moreover, the increased distal sodium delivery and aldosterone activity secondary to volume contraction results in increased renal potassium excretion.

In the cases of life-threatening hypokalemic paralysis, treatment should be focused on potassium correction, rather than metabolic acidosis. In addition, alkali therapy might aggravate the hypokalemia by shifting potassium into the cells and bicarbonaturia. Corticosteroids and other immunosuppressants are reserved for rapidly declining renal function.[3] One previous report had described the recurrence of RTA within 6 months of steroids,[11] however, successful treatment was reported in other case reports.[7],[8]

 Conclusion



Mild asymptomatic renal disease is common in SS, although hypokalemic paralysis and at times respiratory failure can be an initial presentation. It is imperative to keep the possibility of SS as a differential while evaluating a patient with hypokalemic paralysis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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