hypokalemic periodic paralysis is a rare disorder characterized by transient attacks of flaccid paralysis of varying intensity and frequency . reported incidence of hypokalemic paralysis in patients with type 1 renal tubular acidosis ( rta )
type 1 rta or distal rta ( drta ) is a disorder of renal tubular acidification characterized by hyperchloremic metabolic acidosis with a normal serum anion gap .
inherited forms include autosomal - dominant , autosomal - recessive , or x - linked recessive , of which autosomal - dominant form causing mutations in the basolateral chloride bicarbonate exchanger ( ae1 ) has been identified as the most common form of inheritance .
acquired causes include hypergammaglobulinemic states , such as hyperglobulinemic purpura , cryoglobulinemia , fibrosing alveolitis , sjogren syndrome , lupus , chronic active hepatitis , thyroiditis , graves disease , primary biliary cirrhosis ; disorders of calcium metabolism , e.g. primary hyperparathyroidism , vitamin d intoxication , idiopathic hypercalciuria , familial absorptive hypercalciuria , medullary sponge kidney .
renal involvement in systemic lupus erythematous is mainly glomerulonephritis and isolated tubular dysfunction is rare .
this unusual presentation of systemic lupus erythematosus ( sle ) was first presented by fortenberry and kenney in 1991 and infrequent cases have been reported in the literature ever since .
we present the case of a woman who was admitted with acute onset hypokalemic quadriparesis .
six months after the initial presentation , the patient fulfilled 5 out of 11 american college of rheumatology ( acr ) criteria for diagnosis of sle and patient was managed successfully with oral and intravenous potassium chloride , sodium bicarbonates and oral hydroxychloroquine and a short course of steroid .
a 30-year - old woman presented with gradually increasing weakness of both upper and lower limbs .
she reported having had a similar episode twice previously , most recently 2 months ago ; and at all of these occasions , she had documented hypokalemia and she was managed by a local physician with parenteral and oral administration of potassium chloride that improves her condition on these occasions . resting after exercise or eating
patient also had complaints of recurrent oral ulceration , photosensitivity , hair loss , loss of appetite , easy fatigability , pain in multiple joints and she experienced this pain almost throughout the day , but it was worse in the morning .
she had also off and on low grade fever over 3 months before admission but she had no burning in the urine , cough and abdominal pain or vomiting , pruritus , dryness of mouth , difficulty in swallowing , gritty or sandy sensation under eyelids and reynaud 's phenomenon . on the day of admission ,
the patient also complained of difficulty in swallowing solid food and inability to speak loudly but there was no history of visual blurring , diplopia , facial asymmetry , sensory , bladder , or bowel complaints .
she had a clear sensorium with no history of seizures , involuntary movements , root pains , or band - like sensation over the trunk .
she did not give a history of prior drug intake , colicky abdominal pain and recent vaccination .
six months before her current presentation , the patient had progressive weakness in all four limbs ; it started in one limb , but progressed to all four limbs within a few hours and her past medical record and history given by her husband revealed that she was conscious and oriented at the onset of weakness .
her eye movements were normal and there was no facial asymmetry and seizure at the onset of weakness . at current admission to our hospital in physical examination , blood pressure was 130/80 mm hg ; pallor was present .
musculoskeletal and neurological examination revealed muscle strength was poor ( flicker 1/5 ) in all the muscle groups .
laboratory investigations done revealed blood urea 28 mg / dl , serum creatinine 1.3 mg / dl , hypokalemia 2.2 mmol / l , hyperchloremic metabolic acidosis ( chloride 112 meq / l , arterial blood ph 7.279 ) and alkaline urine ( urinary ph 7.5 ) .
ultrasonography of the abdomen revealed right nephrolithiasis with bilateral normal size kidney and normal liver size and echotexture . in view of the normal anion gap acidosis ( 12.4 mmol / l ) , alkaline urine ( urinary ph 7.5 ) , low serum potassium ( 2.2 mmol / l ) , absence of fanconi 's syndrome ,
positive urinary anion gap ( 46 mmol / l ) , the diagnosis of drta was made .
type 2 rta was excluded , as her 24 h urinary excretion of phosphate and uric acid was normal with no glycosuria .
renal biopsy was deferred in view of normal renal function and no active sediment in urine routine microscopy .
her biochemical parameters corrected with treatment and she attained blood urea of 24 mg / dl , serum creatinine 1.0 mg / dl , potassium 3.9 meq / l , chloride 95 meq / l and arterial blood ph of 7.332 . she had continued on the oral supplements with sodium bicarbonate ( 500 mg twice daily ) and oral hydroxychloroquine 200 mg twice a day and had been asymptomatic on regular follow - up [ table 1 ] .
our patient initially presented with generalized weakness and was diagnosed drta due to sle on evaluation .
generalized weakness is a very subjective feeling and is an uncommon objective finding in outpatients and emergencies .
there is a large differential diagnosis for muscle weakness , but only a few medical conditions develop rapid onset generalized muscle weakness . on initial presentation , we kept the possibility of inflammatory myopathy , thyroid disorder , channelopathy and neuropathy and electrolyte disturbance as the cause of our patient symptoms .
investigations revealed that patient did not have inflammatory myopathy as she had normal creatine phosphokinase and serum lactate dehydrogenase .
she was diagnosed sle based on acr criteria for diagnosis of sle and drta on the basis of hyperchloremic metabolic acidosis , hypokalemia with a positive urinary anion gap and the absence of fanconi 's syndrome .
our case is considered to be an acquired form of drta with predominant tubular involvement in sle . in drta ,
the kidney is not able to adequately excrete an acid ( h+ ) load and loses its normal acid - base balance and characterized by hyperchloremic metabolic acidosis , a normal serum anion gap , a urinary ph 5.5 , hypokalemia , a positive urinary anion gap , nephrolithiasis and daily replacement of sodium bicarbonate 4 mmol / kg generally improve the conditions .
previous studies have also shown the association of sle with various tubular defects , drta being the most common type of tubular involvement in sle , although type 4 rta has also been recently reported .
tubular dysfunction is well - described in sle and coincides with active proliferative glomerulonephritis , although patients usually show manifestations of lupus rather than features of rta .
pasternack and linder found the deposition of immunoglobulin with complement as well as immunoglobulin - producing mononuclear cells around the tubuli , which was highly suggestive of an immunological process affecting the tubuli , eventually leading to the destruction of some of them . to conclude , tubular function should be assessed carefully in lupus patients and a work - up for the presence of sle should be done in all rta cases .
 we report recurrent hypokalemic periodic quadriparesis in a 30-year - old woman . 
 patient had also symptoms of multiple large and small joint pain , recurrent oral ulceration , photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus ( sle ) with distal tubular acidosis . 
 our patient was successfully treated with oral potassium chloride , sodium bicarbonate , hydroxychloroquine and a short course of steroids . 
 thus , tubular dysfunction should be carefully assessed in patients with sle . 
Introduction
Case Report
Discussion