BACKGROUND

Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by a low circulating platelet count caused by destruction of antibody-sensitized platelets in the reticuloendothelial system. It’s the most common form of thrombocytopenia in childhood (Incidence, 4:100.000). Systemic lupus erythematosus (SLE) is an autoimmune disorder of unknown etiology which displays a broad spectrum of clinical and immunological manifestations, including thrombocytopenia. Mestanza-Peralta and colleagues have previously reported that thrombocytopenia is the initial manifestation of SLE in the 5% of the studied adult population.

AIM OF THE STUDY

To evaluate the prevalence of ITP as isolated first manifestation in a pediatric population with Lupus Nephritis and to characterize the nephropathy and the thrombocytopenia.

PATIENTS AND METHODS

50 patients with Lupus Nephritis

45 F/5 M (mean age12,2 yrs)

RESULTS (1)

11/50 patients (22%) with Lupus Nephritis presented ITP as isolated initial manifestation of SLE

10 F (F:M= 10:1)

Isthological Classification

§Class II: 2 pts (18.2%) §Class III: 3 pts (27.3%) §Class IV: 6 pts (54.5%)

RESULTS (2)

Age at presentation of ITP was 9.1 years (range, 6.3-12.7), while age at presentation of Lupus Nephritis was 13.3 years (range, 9.7-15.5), with a time interval of 4.2 years.

RESULTS (3)

Platelets values at the onset of “idiopathic” TP.

CONCLUSIONS

In contrast to Mestanza–Peralta and colleagues, who reported that thrombocytopenia was the initial manifestation of SLE in the 5% of an adult population, in our pediatric study ITP represents the isolated first manifestation of Lupus Nephritis in a statistically larger population (22%). This result leads to the hypothesis that in the pediatric population, ITP as isolated first manifestation of SLE may represent a predictive risk factor to the subsequent development of moderate-to-severe Lupus Nephritis. Risk factors in pediatric population with ITP are: chronic ITP, ANA positivity, female sex, and late presentation. These characteristics could determine a careful follow-up to promptly identify incipient signs of SLE.