|Year : 2014 | Volume
| Issue : 4 | Page : 494-496
Distal renal tubular acidosis and quadriparaesis in Sjögren's syndrome: A cunning congregate
Arundhati G Diwan1, Sachin A Adukia2, Shounak V Annachhatre2, Yuraj Singh Chowdhury3
1 Professor and Head, Department of Medicine, Bharati Vidyapeeth University Medical College and Bharati Hospital, Pune, Maharashtra, India
2 Postgraduate student, Department of Medicine, Bharati Vidyapeeth University Medical College and Bharati Hospital, Pune, Maharashtra, India
3 Intern, Bharati Vidyapeeth University Medical College and Bharati Hospital, Pune, Maharashtra, India
|Date of Web Publication||25-Jun-2014|
Arundhati G Diwan
Flat No. 16, Laxmi Abhishek, Laxmi Park Colony, Navi Peth, Pune - 411 030, Maharashtra
Source of Support: None, Conflict of Interest: None
Sjögren's syndrome (SS) is a chronic autoimmune disease, chiefly affecting the exocrine glandular function of salivary glands and lacrimal glands. Rarely, it involves the kidneys, central and peripheral nervous system, muscloskeletal apparatus and lungs. We report a rare constellation of SS with distal renal tubular acidosis and quadriparaesis in a young female. History of quadriparaesis was acute, with rapid progression. Supplementary treatment for severe hypokalemia was instituted at the earliest, lest the patient develop respiratory muscle weakness. Concomitantly, metabolic acidosis with alkaline urine was suspected and subsequently investigated. Eventually, this was attributed to impaired renal acidification of urine in the distal tubules. History of dryness of eyes and mouth since 6 months justified salivary gland biopsy. The results yielded a lymphocytic infiltrative pathology strongly favoring SS. The patient benefited from prompt potassium replacement therapy and had complete resolution over the next week. Supportive treatment for predictable manifestations was continued along with potassium supplements.
Keywords: Extraglandular Sjogren′s syndrome, hypokalemic paralysis, potassium chlorate
|How to cite this article:|
Diwan AG, Adukia SA, Annachhatre SV, Chowdhury YS. Distal renal tubular acidosis and quadriparaesis in Sjögren's syndrome: A cunning congregate. Med J DY Patil Univ 2014;7:494-6
|How to cite this URL:|
Diwan AG, Adukia SA, Annachhatre SV, Chowdhury YS. Distal renal tubular acidosis and quadriparaesis in Sjögren's syndrome: A cunning congregate. Med J DY Patil Univ [serial online] 2014 [cited 2019 Mar 25];7:494-6. Available from: http://www.mjdrdypu.org/text.asp?2014/7/4/494/135282
| Introduction|| |
Sjögren's syndrome (SS), also known as the sicca complex, is a chronic autoimmune disease frequently associated with xerostomia, keratoconjunctivitis sicca and connective tissue disorders such as systemic lupus erythematosus, rheumatoid arthritis or systemic sclerosis. Extraglandular pathology may involve the kidney (with resultant impaired urinary acidification, chronic kidney disease and tubulointestinal nephritis), brain, peripheral nerves, liver and lungs. ,, We describe a young female with acute onset quadriparaesis and hypokalemia who fully recovered with potassium supplementation.
| Case Report|| |
A 33-year-old female presented with acute onset weakness of all four limbs since 18 h, progressing over the past 4 h. Initially, she could walk with support, but was unable to do so at presentation. She gave no history of abdominal pain, joint pains, hair loss, photosensitivity, recent fever, urinary symptoms, convulsions or trauma. She gave a history of dryness of eyes and mouth since 6 months. There was no history suggestive of bulbar muscle weakness, hyperthyroidism or myasthenia gravis. She had a past history of persistent hypokalemia since 3 months, which was treated outside. However, she was not on any medication at present nor was she evaluated thus far.
General examination revealed mild pallor and normal vital parameters. Examination of the central nervous system revealed hypotonia with grade 3 power, proximally and distally, in all four limbs. No neck muscle weakness was present. All deep tendon reflexes were depressed with flexor plantars. Examination of the cranial nerves and sensory system was normal. The remainder of the systemic examination was normal. A diagnosis of hypokalemic periodic paralysis (HPP) was formulated and investigated. The patient had anemia (hemoglobin 9.6 gm/dL), hypokalemia (serum potassium 1.8 mEq/L), hypoalbuminemia (serum albumin 2.9 gm/dL) with hyperglobulinemia (serum globulin 4.0 gm/dL), raised ESR (54 mm at the end of 1 h), hyperphosphatemia (serum phosphorus 19.5 mg/dL) and hyperchloremia (serum chloride 110 mEq/L). Other tests for blood urea, serum creatinine, serum magnesium, corrected serum calcium and thyroid function tests were normal. Electrocardiogram showed U waves. Arterial blood gas analysis suggested metabolic acidosis (pH 7.29, pCO 2 29.4 mmHg, HCO 3 13 mmol/L). The urinary pH was 6.1 and the CT scan of kidney and urinary bladder (CT-KUB) was normal. The ammonium chloride loading test was deferred in view of highly alkaline urine despite metabolic acidosis. The anti nuclear antibody (ANA) blot test was positive for anti-Ro antibodies and anti-LA antibodies. Slit lamp examination showed keratoconjunctivitis sicca. This was supported by Schirmer's test [Figure 1], showing hypolacrimation with 7 mm wetting of the filter paper strip in both eyes. Biopsy of the submandibular salivary gland and lower lip [Figure 2] showed lymphocytic and macrophage infiltration, chiefly around the salivary ducts. Thus, a rare constellation of SS with distal renal tubular acidosis (dRTA) and hypokalemic quadriparaesis was diagnosed.
|Figure 1: Schirmer's test showing hypolacrimation with 7 mm wetting of the filter paper strip in both eyes (arrow)|
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|Figure 2: Biopsy of the submandibular salivary gland and lower lip, showing lymphocytic and macrophage infiltration, chiefl y around the salivary ducts (arrows)|
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Treatment with potassium chloride (diluted in intravenous fluids) and oral potassium citrate solution was instituted promptly since admission. Although hypokalemia and quadriparaesis persisted for the first 3 days, there was complete resolution of both these parameters thereafter. She remains symptom-free on regular follow-up, but continues to require potassium supplements.
| Discussion|| |
SS is a chronic autoimmune disease that may occur singularly or along with other autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis or systemic sclerosis. Exocrine failure may affect the eyes, oral cavity, skin or pancreas. The lungs, central and peripheral nervous system, musculoskeletal apparatus and kidneys are other organs to be affected. dRTA is a very rare feature of renal involvement in SS, manifesting as failure of acidification of urine with resultant alkaline urine and normal anion gap metabolic acidosis. ,, dRTA leads to sodium loss and volume contraction, with compensatory raised aldosterone. This causes increased resorption of sodium and increased urinary loss of potassium (via upregulation and activation of basolateral Na + /K + pumps) in the collecting duct of the kidney and, hence, hypokalemia.  Hypokalemia can be severe enough to cause myopathy of varying degrees, from minimal motor impairment to flaccid paralysis.
Hypokalemia can be associated with acid - base imbalance (metabolic acidosis due to dRTA or metabolic alkalosis in primary hyperaldosteronism) or can occur with normal acid-base parameters (thyrotoxic periodic paralysis due to increased intracellular movement of potassium, or familial and sporadic periodic paralysis). A very useful parameter for differentiation between renal and non-renal cause of HPP is the trans-tubular potassium gradient (TTKG). It is calculated as (urine potassium/plasma potassium) / (urine osmolality/plasma osmolality). TTKG < 2 supports a non-renal cause of hypokalemia while TTKG > 5 signifies increased renal losses of potassium as seen in dRTA. This differentiation has therapeutic implications as the potassium replacement required in the non-renal cause of HPP is greater than in renal HPP. 
The congregate of SS with renal involvement causing dRTA and hypokalemia paralysis is extremely rare. When investigating SS in HPP, it is imperative to look for historical, histopathological, serological and immunological evidence.  Also, the probable sequelae must be addressed while treating the patient. These include sicca symptoms (dryness and irritation of eyes, dysphagia, dental caries, hoarseness of voice), musculoskeletal symptoms (fatigue, arthralgia), nephrocalcinosis and chronic kidney disease and a greater propensity to develop lymphoid malignancies (non-Hodgkin's lymphoma). , Of special interest is SS in women who become pregnant, as there is increased incidence of neonatal lupus erythematosus with congenital heart block. 
Research in the treatment for SS has been unfruitful till now. Thus, a diagnosis of SS may help in better understanding the patient's condition, but, unfortunately, it has little bearing on treatment.
| References|| |
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[Figure 1], [Figure 2]