Introduction: Primary Sjögren’s syndrome is a very rare disease during childhood. The affected children escape the correct diagnostic process due to atypical clinical presentation in children in comparison with classical sicca syndrome in adults. The submitted case report demonstrates a severe clinical course of primary Sjögren’s syndrome in a 14-year-old girl, who presented with first signs of the disease at the age of ten. Case report: The initial clinical problems of the patient were non-specific complaints of fatigue, loss of appetite, consequent weight reduction and low back pain. Within five months the clinical picture progressed until metabolic collapse, hypokalaemia, paralytic ileus and both central and peripheral nervous system involvement required intensive care of the patient. The diagnosis of primary Sjögren’s syndrome was in this stage of the disease based on laboratory investigation, with marked hyperimmunoglobulinaemia, positivity of antinuclear anti- bodies, positivity of anti SS-A and SS-B antibodies connected with positive anti SS-A in cerebrospinal fluid. Renal damage was represented by severe hypokalaemia, hypophosphataemia due to extreme high phosphate excretion, decreased renal concentration capacity, slightly decreased glomerular filtration rate and moderate tubular acidosis. Therapy was initiated with pulses of corticosteroids with subsequent combined immunosuppression with cyclosporin A. The recovery from quadrupa- resis and metabolic crisis was very slow despite the aggressive treatment. The long-time course was complicated by relapses of the disease. The most severe problem making the overall prognosis of the patient uncertain was represented by the subsequent attacks of retrobulbar neuritis with partial loss of vision. Conclusion: Primary Sjögren’s syndrome can occur during childhood. The children presented with a wide spectrum of clinical signs, different from typical sicca syndrome of adults. The demonstrated patient represents the extreme pole of severe systemic involvement in primary Sjögren’s syndrome.

        Key words: autoimunity, Sjögren’s syndrome, autoantibodies, children, SS-A, SS-B