Year : 2003 | Volume
: 14 | Issue : 2 | Page : 190--193
Systemic Lupus Erythematosus with Distal Renal Tubular Acidosis Presenting as Hypokalemic Paralysis with Respiratory Failure
Parvaiz Ahmad Koul, Abdul Wahid, Bashir Ahmad Shah
Department of Internal Medicine, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir, India
Parvaiz Ahmad Koul
Department of Internal Medicine, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir
An eighteen-year-old woman presented with hypokalemic respiratory failure. She was found to have distal renal tubular acidosis (dRTA) as the underlying cause for hypokalemia. This was treated successfully, and no apparent etiology for the dRTA was discovered. Three years later she presented with full-blown picture of systemic lupus erythematosus (SLE) together with features of persistent dRTA complicated, this time, with bilateral renal calculi and nephrocalcinosis. It is very likely that the dRTA was an early feature that preceded the other markers of SLE. The moral of this case is that patients with dRTA should be followed-up carefully as a primary cause for the dRTA may show up in-due-course and to monitor the treatment so as to prevent long-term complications of the RTA.
|How to cite this article:|
Koul PA, Wahid A, Shah BA. Systemic Lupus Erythematosus with Distal Renal Tubular Acidosis Presenting as Hypokalemic Paralysis with Respiratory Failure.Saudi J Kidney Dis Transpl 2003;14:190-193
|How to cite this URL:|
Koul PA, Wahid A, Shah BA. Systemic Lupus Erythematosus with Distal Renal Tubular Acidosis Presenting as Hypokalemic Paralysis with Respiratory Failure. Saudi J Kidney Dis Transpl [serial online] 2003 [cited 2020 Sep 21 ];14:190-193
Available from: http://www.sjkdt.org/text.asp?2003/14/2/190/33028
Distal renal tubular acidosis (dRTA) is characterized by hyperchloremic metabolic acidosis and a defect in the acidification of urine. It may be associated with hypercalciuria, hypocitraturia, nephrolithiasis, nephrocalcinosis, hypokalemia, progressive renal failure and growth retardation. 
dRTA has been reported as an isolated familial disorder with variable modes of inheritance, a sporadic variety, an endemic form in south east Thailand or as an acquired abnormality in association with variety of disorders. ,, We have earlier reported the sporadic variety of dRTA presenting with hypokalemic paralysis of varying severity.  Systemic lupus erythematosus (SLE) is one disorder that has been associated with dRTA. ,
We herewith present a young woman who developed a hypokalemic respiratory failure as the initial manifestation of classical dRTA and went on to develop SLE over a period of three years.
An 18 year-old woman was admitted in July, 1994 with a one day history of progressive weakness of all the four limbs. Within few hours after admission, she developed difficulty in breathing. The patient had been prescribed some analgesics for a low backache and had developed two bouts of vomiting 6-8 hours before the onset of weakness. There was no history of diarrhea, loss of consciousness, convulsions, sphincteric involvement or ingestion of diuretics. The patient developed a similar episode of weakness one year earlier that involved her lower limbs and was managed at a general hospital as hypokalemic paralysis.
Clinical examination revealed well-nourished well-developed young woman with a grade 0 to 1 hypotonic areflexic motor quadriparesis with respiratory muscle weakness. The chest expansion was limited and accessory muscles of respiration were active. The rest of the general and systemic examination was normal.
The laboratory investigations revealed normal complete blood count, serum sodium 138 mmol/l, potassium 2 mmol/l, chloride 110 mmol/l, urea 13.5 mmol/l, the creatinine
100µ mol/l, glucose 6.3 mmol/l, calcium 8.9 mmol/l, phosphates 3.8 mmol/l, uric acid 210 µmol/l, bilirubin 11.9 µmol/l, alanine aminotransferase 132 U/l, the aspartate aminotransferase 89 U/l, creatinine kinase 1012 U/ml, and lactate dehydrogenase 644 U/l. Arterial blood gas analysis revealed pH 7.21, PC0 2 12.6 mm Hg, PO 2 55.5 mm Hg and HC03 10 mmol/l. The urine pH was 7.0 with urinary sodium 152 mmol/l, urinary potassium 21mmol/l.
A chest radiograph was normal and an electrocardiogram showed U waves compatible with severe hypokalemia. The patient required a ventilator support and intravenously administered sodium bicarbonate and potassium chloride. Her weakness improved and she was weaned off the ventilator over 36 hours.
Further investigations revealed normal 24hour urinary excretion of calcium, proteins, phosphates and uric acid, and negative for aminoacids, myoglobin and glucose. The serum levels of T 3 , T 4 and TSH were normal. The fractional excretion of bicarbonate after induced serum bicarbonate of 21 mmol/l was 3.5%. The radiographic and ultrasound examination of the abdomen were normal. Latex fixation test, antinuclear antibodies (ANA) and lupus (LE) cells were negative and serum immunoglobulin levels were normal. The nerve conduction studies were normal and electromyogram (EMG) showed a reduced interference pattern. All the family members of the patient had normal urinary acidification studies.
The patient was discharged on oral sodium bicarbonate therapy and continued to do well apart from a malar rash on exposure to sunlight. Three years later, she developed persistent malar rash, with bullous lesions over hands and feet. The malar rash would intensify upon exposure to sunlight. The patient also developed painless ulcers in the mouth.
The repeated investigations revealed a normal blood count with normal erythrocyte sedimentation rate (ESR). The dipstick test of the urine was positive for protein and negative for glucose. The urine microscopic examination revealed the presence of leukocyturia and hematuria. The urine culture was negative. The latex fixation test was positive. The serum ANA, Anti dsDNA and the Anti S m were positive and levels of C3 were reduced; LE cells were not detected and cryoglobulins were negative. The 24-hour excretion of proteins was 1.2 grams. The blood pH was 7.34 with bicarbonate of 19.6 mmol/l.
The light microscopic examination of the skin biopsy revealed thinned epidermis with hyperkeratosis and mononuclear lymphocyte infiltration around the dermal vessels, and the immunofluorescent microscopic examination revealed deposits of IgG, C 3 and C 4 at the dermoepidermal junction and around vessels.
The patient was started on 50 mg of prednisolone. Her skin lesions and oral ulcers improved and the steroids were tapered off over three months. Two months later, the patient developed a right ureteric colic, evaluation for which was inconclusive. The patient had stopped her sodium bicarbonate therapy for two years before she presented with gross hematuria. Ultrasonography revealed bilateral renal calculi which were confirmed, along with nephrocalcinosis, on intravenous pyelography. Arterial blood gas analysis revealed pH of 7.30 and bicarbonate 14.8 mmol/l. The urinary excretion of calcium, phosphate and uric acid was normal. The serum parameters were normal. The patient was resumed on sodium bicarbonate and is still followed up in our center.
Our patient had features of classical dRTA and subsequently developed SLE. Although dRTA has been previously reported with SLE, our report is, to our knowledge, the first patient who presented with hypokalemic respiratory failure as the initial manifestation of SLE.
Kozeny et al,  found evidence of dRTA due to proton secretory defect in 8 of 30 cases of SLE. Five of the patients with dRTA had the gradient type; two had unresponsive voltage dependent form, one had responsive voltage dependent form of dRTA, one had hyporeninemic hypoaldosteronism and one had a dRTA plus hypoaldosteronism.
Hypokalemic paralysis is one of the commonest presentations of dRTA seen in our part of the globe  and usually occurs as recurrent motor hyporeflexia. The episodes of paralysis and other complications of dRTA like nephrolithiasis, nephrocalcinosis, chronic renal failure and osteodystrophy are markedly decreased with the institution of alkali therapy.
No special pathological changes have been observed in the renal biopsies of patients with RTA when compared to the ones with out this syndrome.  Absence of the apical H+-ATPase was demonstrated in three cases of Sjogren's syndrome and classical dRTA upon immunofluorescent staining of renal biopsy specimens by monoclonocal antibodies to H+- ATPase.  This contrasts with the intense staining for H+-ATPase in a patient of lupus nephritis, hyperkalemia and a voltage defect (type 4) RTA.  These findings suggest that classical dRTA when associated with systemic disease, as an acquired abnormality, is the result of atypical function of H+-ATPase in the collecting tubule, presumably in the outer medullary and inner medullary segments. 
We conclude that patients with hypokalemic paralysis should be investigated for presence of dRTA and monitored for development of an immunological disorder such as SLE. Prolonged treatment is also necessary to prevent the complications of dRTA.
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