A girl of three years and ten months of age was assessed in consultation due to recurrent episodes of muscle weakness in the lower limbs, with spontaneous recovery in minutes.
Personal history without interest.
Controlled pregnancy without incidents; birth by vaginal delivery.
Artificial breastfeeding.
Perinatal and psychomotor development was normal.
No muscle weakness or cramps reported up to six months before.
In the family history highlights familial hyperkalemic paralysis in several family members of the paternal branch (father, uncle and paternal aunt, paternal grandmother) without providing further data and without knowing to need genetic study.
The symptoms began about six months before visiting the clinic, being previously asymptomatic; referred 3-4 intermittent episodes, on separate days, of muscle cramps and feeling of numbness of the lower limbs while spontaneous pain was noticed.
No other symptoms or involvement of other limbs were observed.
From these episodes the patient asymptomatic.
Clinical and neurological findings were normal at the time of consultation, with normal strength, sensitivity and osteotendinous reflexes.
The suspicion of familial hyperkalemic paralysis, blood count and biochemical tests were requested, and the results were normal.
Normal blood count, normal blood and urine electrolytes, K 4.5 mEq/l with potassium excretion (KEF) 13%.
It was not possible to perform sputum analysis with the clinic.
Electromyography (EMG), creatine phosphokinase (CPK) and electrocardiogram (ECG) were not performed due to new symptoms.
Electromyography (EMG) was normal.
Clinical suspicion, given the family history, although the symptoms were not very evident, a genetic study of the SCN4A gene (OMIM +603967) was requested, detecting a mutation in heterohr70get.
At the time of diagnosis, treatment with oral acetazolamide was not initiated, since episodes of muscle weakness were not repeated and serum potassium values were normal in the controls.
Periodic clinical and laboratory follow-up will be performed to assess whether, at any time, medical treatment needs to be initiated.
A non-potassium-rich diet was prescribed.
