CASE REPORT

Recurrent Hypokalemic Periodic Paralysis Unmasks Sjogren Syndrome without Sicca Symptoms Yao-Min Hung1,3, Neng-Chyan Huang1,3,4, Shue-Ren Wann1,3, Yun-Te Chang1,3 and Jyh-Seng Wang2,3

ABSTRACT Hypokalemic Periodic Paralysis (HPP) may occur as a rare complication of Sjogren Syndrome (SS) and (RTA). A 64-year male patient came with HPP, and was later diagnosed with distal RTA. The patient, who had no xerostomia and xerophthalmia, was diagnosed with primary SS from serologic and histologic findings of minor salivary gland biopsy. The patient recovered after potassium replacement therapy. was also performed and revealed evidence of tubulointerstitial . Corticosteroids were administered and there was no recurrence of HPP during a 4-year follow-up period. The case highlights the significance of acute management in emergency department as it can unmask SS even if the SS is not associated with sicca symptoms. Hypokalemic paralysis associated with normal anion gap metabolic acidosis should prompt toward the diagnosis of SS.

Key Words: Hypokalemic paralysis. Renal tubular acidosis. Sjogren syndrome. Normal anion gap metabolic acidosis.

INTRODUCTION mouth or eyes. He stated that he suffered from acute Hypokalemia is a common disorder in Emergent Depart- onset of four limbs weakness 7 - 8 weeks ago and had ment (ED). Hypokalemic paralysis is an important been admitted to a local hospital, where the diagnosis of cause of acute flaccid paralysis that may even result in Hypokalemic Periodic Paralysis (HPP) was told. He did life-threatening cardiac arrhythmia and respiratory not seek medical help until 6 weeks ago when he was paralysis.1 Recognizing the underlying causes of brought to the ED due to similar episodes of muscle hypokalemic paralysis is essential for the appropriate weakness. management of affected patients and prevention of Initial physical examination and laboratory study recurrent paralysis attacks.2 Although Renal Tubular revealed normotension, severe hypokalaemia, and Acidosis (RTA) secondary to autoimmune interstitial metabolic acidosis. He was then admitted for work-up of nephritis develops in a large proportion of patients with HPP. During hospitalization, laboratory studies revealed Sjogren Syndrome (SS), most of the subjects are normal thyroid function, serum GPT of 26 U/L, GOT at asymptomatic.1 27 U/ L, ALP at 80U/L, sodium at 134 mEq/L, potassium Here, we present a case of primary SS without sicca at 1.4 mEq/L, chloride at 111 mEq/L, BUN at 11 mg/dL, symptoms but with recurrent episodes of hypokalemic creatinine at 1.0 mg/dL, and glucose at 118 mg/dL. The paralysis as the initial clinical presentation. initial arterial blood gas analysis in room air revealed pH of 7.23, PaO2 of 78 mmHg, PaCO2 of 28 mmHg, HCO3 CASE REPORT of 11.9 meq/dL, and blood anion gap 11.1 of mEq/L. A 64-year Chinese male was brought to the Emergency Urinalysis revealed pH of 7.0 and no pyuria or Department (ED) because of recurrent episodes of . The 24-hour urine chemistry study showed tetraparesis in the past several weeks. His past history proteinuria (480 mg/day), Ccr of 42 ml/minute, Ca of was negative for major systemic diseases or history of 129.6 mg/day and phosphate of 223.2 mg/day. Urine exposure to toxic chemicals, except for history of dental anion gap was 16 mEq/L. An intravenous bicarbonate caries for several years. The patient denied dryness of loading test with FEHCO3- of less than 3% confirmed the diagnosis of distal RTA. Oral 80 mg 1 Department of Emergency Medicine / Pathology2, Kaohsiung was given to define the defects in collecting tubule Veterans General Hospital, Kaohsiung, Taiwan. acidification. His urine potassium excretion increased 3 School of Medicine, National Yang-Ming University, Taipei, but urine pH decreased to 6.3 at 2 hours, indicating a Taiwan. defect in H-ATPase pump of cortical collecting tubules. 4 Department of Environmental and Occupational Health, The patient received potassium chloride and alkali National Cheng Kung University, Tainan, Taiwan. therapy and was discharged and followed-up at out- Correspondence: Dr. Jyh-Seng Wang, Department of Pathology, patient department. Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, However, second hospitalization happened to him Kaohsiung 813, Taiwan. because of recurrent episodes of foul limbs weakness. E-mail: [email protected] Further laboratory investigation revealed positive Received: April 17, 2014; Accepted: August 13, 2014. Antinuclear Antibody (ANA), 1:640 with speckled

S36 Journal of the College of Physicians and Surgeons Pakistan 2015, Vol. 25 (Special Supplement 1): S36-S38 Sjogren syndrome with recurrent hypokalemic paralysis

DISCUSSION Potassium disorders are the most common electrolyte abnormality identified in clinical practice. Presenting symptoms for hypokalemia primarily affect the cardiac, neuromuscular, and gastrointestinal systems.4 The approach for hypokalemia at ED usually include history taking, physical examination, evaluation of blood pressure, arterial blood gas and urine chemistry analysis. Generally, HPP can occur secondarily to excessive potassium loss.3 Thyrotoxicosis, ingestion, , barium poisoning, , and Bartter syndrome are among the disorders causing secondary HPP and enter the list of differential diagnoses.4 Thyrotoxic HPP has been reported in Asian population. The attack of paralysis is Figure 1: Labial gland biopsy showing diffuse lymphocyte infiltration with focal acinar destruction (H&E, x400). usually precipitated by exertion or heavy meal. Physical examination of patient with thyrotoxic HPP may show normal blood pressure, with thyroid enlargement, thrills, or/and hands tremor. However, arterial blood gas will not disclose acidosis or . On the contrary, diuretic ingestion will show with volume depletion, and sometimes hypomagnesemia. Clinical presentation of Gitelman syndrome and Bartter syndrome with HPP may include normal blood pressure, hypokalemic alkalosis, hypomagnesemia and secondary hyperaldosteronism.4 Primary hyperaldosteronism usually manifests in high blood pressure, hypokalemic alkalosis, hyporeninemia, and hyperaldosteronism. Urine analysis will show marked excessive potassium loss.4 Recurrent attacks of HPP as initial manifestation of

Figure 2: Renal biopsy showing features of tubulointerstitial nephritis primary SS is rare, but when it occurs it may precede composed of interstitial lymphocyte infiltrate and associated tubular atrophy. symptoms of dry eyes and dry mouth.1 HPP is a rare (H&E, x400). complication of distal RTA and occurrence of HPP during pattern, and positive anti-La SS(B) antibody. The results the course of SS has been reported in only a few of anti-dsDNA antibody, anti-RNP antibody, anti- patients. Soy et al. reviewed 18 cases of SS-associated centromere, Scl-70 antibody and anti-Lo SS(A) antibody HPP reported between 1966 - 2004 and found only 4 of were all negative. The result of serum complement them received both renal and lip/lacrimal gland biopsy.1 fractions assay was also normal. The Schirmer`s test for We continued a PubMed search about SS-associated dry eye was positive and sialoscintigraphy with HPP reported between 2005 - 2013 which revealed 7 radioisotope Tc-99m-pertechnetate showed class-II more cases.5-10 Including the present case, only 6 cases xerostomia. Labial gland biopsy showed diffuse have biopsy proved tubulointerstitial nephritis. Most of lymphocyte infiltration with focal acinar destruction the reported cases received corticosteroids treatment in (Figure 1). Renal biopsy confirmed the diagnosis of addition to large doses of potassium chloride tubulointerstitial nephritis showing focal interstitial supplementation to restore muscle strength. chronic inflammatory cells infiltration associated with Among these 26 reported cases of SS-associated HPP, tubular atrophy and interstitial fibrosis (Figure 2). The symptoms of HPP were all similar to that of our patient. glomerulus was unremarkable. However, some patients presented with severe The diagnosis of primary SS was established and pulse respiratory muscle weakness or even paralysis.7,14 methylprednisolone and cyclophosphamide treatment Interestingly, only 4 (15%) of them (including the present were prescribed while potassium and alkali supple- case) were male, with age of 64, 73, 74 and 78 years old mentation were also given for the distal RTA and respectively. The other 22 (85%) cases were females symptomatic relief of the hypokalemic paralysis. There with age ranging from 15 to 63 years old. Our patient is was no recurrence of HPP during a 4-year follow-up unique in initial presentation of recurrent HPP without period. sicca symptoms and finally found to have the diagnosis

Journal of the College of Physicians and Surgeons Pakistan 2015, Vol. 25 (Special Supplement 1): S36-S38 S37 Yao-Min Hung, Neng-Chyan Huang, Shue-Ren Wann, Yun-Te Chang and Jyh-Seng Wang of SS. The present case highlights the significance of 5. Morovic-Vergles J, Galesic K, Vergles D. Primary Sjogren's acute hypokalemia management in the ED as it can syndrome presenting as hypokalemic paralysis. Ann Saudi unmask SS even if it is not associated with sicca Med 2007; 27:125-7. symptoms. 6. Ramachandiran N. Apparently persistent weakness after recurrent hypokalemic paralysis: a tale of two disorders. South REFERENCES Med J 2008; 101:940-2. 1. Soy M, Pamuk ON, Gerenli M, Celik Y. A primary Sjogren's 7. Comer DM, Droogan AG, Young IS, Maxwell AP. Hypokalaemic syndrome patient with distal renal tubular acidosis, who paralysis precipitated by distal renal tubular acidosis presented with symptoms of hypokalemic periodic paralysis. secondary to Sjögren's syndrome. Ann Clin Biochem 2008; Report of a case study and review of the literature. Rheumatol 45:221-5. Int 2005; 26:86-90. 8. Agrawal S, Bharti V, Jain MN, Purkar PD, Verma A, Deshpande 2. Wi JK, Lee HJ, Kim EY, Cho JH, Chin SO, Rhee SY, et al. AK. Sjogren's syndrome presenting with hypokalemic periodic Etiology of hypokalemic paralysis in Korea: data from a single paralysis. J Assoc Physicians India 2012; 60:55-6. center. Electrolyte Blood Press 2012; 10:18-25. 9. Vaidya G, Ganeshpure S. Sjogren's syndrome with distal renal 3. Alfonzo AV, Isles C, Geddes C, Deighan C. Potassium tubular acidosis presenting as hypokalaemic paralysis. BMJ disorders--clinical spectrum and emergency management. Case Rep 2012; 2012. Resuscitation 2006; 70:10-25. 10. Yılmaz H, Kaya M, Özbek M, ÜUreten K, Safa Yıldırım I. 4. Duman O, Koyun M, Akman S, Guven AG, Haspolat S. Case Hypokalemic periodic paralysis in Sjogren's syndrome of Bartter syndrome presenting with hypokalemic periodic secondary to distal renal tubular acidosis. Rheumatol Int 2013; paralysis. J Child Neurol 2006; 21:255-6. 33:1879-82.

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