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Abstract(s)
As plaquetas são responsáveis pela hemóstase primária através de processos de adesão
e agregação plaquetária. Estas células provêm dos megacariócitos e têm um tempo de
vida entre 7 a 14 dias, acabando por ser destruídas no baço.
(1)
A Trombocitopenia Imune (PTI), anteriormente designada por Púrpura
Trombocitopénica Idiopática ou Imune, é uma doença autoimune que afeta tanto
crianças como adultos. Esta fisiopatologia é caracterizada pela diminuição do valor das
plaquetas inferior a 100 x 109/L e, pelo risco aumentado de discrasia hemorrágica.(2)
Verifica-se uma produção abundante de autoanticorpos com alvo na membrana das
plaquetas.(1) Epidemiologicamente afeta 2 a 5 crianças em 100 000, sendo a principal
causa de trombocitopenia sintomática em idade pediátrica.(1,7)
A PTI subdivide-se em Primária, caracterizada por trombocitopenia isolada, ou em
Secundária, todas as outras causas imunomediadas de trombocitopenia, com exceção
da forma primária. A PTI primária pode ser classificada em recém diagnosticada (< 3
meses), persistente (3 – 12 meses) ou crónica (= 12 meses).(2)
Na maioria dos casos, aparecem subitamente hemorragias mucocutâneas, com
confirmação laboratorial de trombocitopenia isolada (plaquetas < 100 x 109/L) e um
esfregaço de sangue periférico normal. O diagnóstico é feito por exclusão de PTI
secundária e de outras causas de trombocitopenia.(5)
O tratamento é feito consoante as manifestações clínicas, com recurso a fármacos de
primeira linha (corticoides, imunoglobulina intravenosa e anti-D). Caso não se
verifique resposta a estes fármacos, pondera-se a utilização de intervenções de segunda
linha (esplenectomia) ou fármacos de segunda linha (agonistas do recetor da
trombopoeitina, rituximab e micofenolado de mofetil).
(5)
Nas crianças o prognóstico é geralmente muito bom, com uma percentagem alta de
remissão da doença, sendo a mortalidade muito rara.
(17,35) Aproximadamente 20 a 30%
dos casos evoluem para PTI crónica.(10)
No presente trabalho procede-se à descrição de um caso clínico de uma criança do sexo
masculino com 4 anos, diagnosticado no segundo ano de vida com PTI Persistente,
tendo evoluído para uma forma Crónica. Neste momento a criança referida encontra-se sob terapêutica com fármaco de segunda linha, apresenta uma boa resposta e ausência
de recidivas.
Com base neste caso clínico, realizou-se uma revisão da literatura sobre
Trombocitopenia Imune Crónica, procurando identificar e demonstrar a complexidade
da sua abordagem e tratamento.
Platelets play a main role in primary hemostasis through platelet adhesion and aggregation. These cells are formed by precursor cells called Megakaryocytes and are destroyed in the spleen within 7 to 14 days.(1) Immune thrombocytopenia (ITP), previously known as Idiopathic/ immune thrombocytopenia purpura, is an autoimmune disease that affects both children and adults. It is characterized by low platelet counts (less than 100x109/L) and increased risk of bleeding. (2) In this disorder autoantibodies target the platelets’ membrane antigens. (1) It affects 2 to 5 children in 100 000, being the main cause of symptomatic thrombocytopenia in the Paediatric population.(1,7) ITP can be divided into primary, characterized by isolated thrombocytopenia, and secondary. The latest includes all other immune-mediated thrombocytopenia with an underlying cause. Primary ITP can be categorized into Newly Diagnosed (<3 months), Persistent (3-12 months) and Chronic (= 12 months).(2) Typically presents with sudden onset of mucocutaneous hemorrhages, confirmed by full blood count with isolated thrombocytopenia (platelet count <100 x 109/L) and normal blood film. Primary Immune thrombocytopenia is diagnosed by exclusion of secondary ITP and elimination of all other possible causes of thrombocytopenia.(5) Treatment is based on the clinical manifestations. First line medications include corticosteroids, intravenous immunoglobulins, and anti-D. If patients do not respond to standard treatment, then second line interventions (splenectomy) or agents (thrombopoietin receptor agonist, rituximab, mycophenolate mofetil) are considered.(5) Children tend to have a good prognosis with high chances of remission and low mortality rates.(17,35) Approximately 20 to 30% of the cases develop chronic ITP.(10) During this paper I aim to discuss/ explore the case study of a 4-year-old male initially diagnosed with Persistent ITP in his second year of life, which is now chronic. At present, this patient is receiving a second line agent with good clinical response and no relapses. Based on this clinical case, I have done a literature review on Chronic Immune thrombocytopenia, aiming to identify and understand the complexity of its clinical approach and treatment.
Platelets play a main role in primary hemostasis through platelet adhesion and aggregation. These cells are formed by precursor cells called Megakaryocytes and are destroyed in the spleen within 7 to 14 days.(1) Immune thrombocytopenia (ITP), previously known as Idiopathic/ immune thrombocytopenia purpura, is an autoimmune disease that affects both children and adults. It is characterized by low platelet counts (less than 100x109/L) and increased risk of bleeding. (2) In this disorder autoantibodies target the platelets’ membrane antigens. (1) It affects 2 to 5 children in 100 000, being the main cause of symptomatic thrombocytopenia in the Paediatric population.(1,7) ITP can be divided into primary, characterized by isolated thrombocytopenia, and secondary. The latest includes all other immune-mediated thrombocytopenia with an underlying cause. Primary ITP can be categorized into Newly Diagnosed (<3 months), Persistent (3-12 months) and Chronic (= 12 months).(2) Typically presents with sudden onset of mucocutaneous hemorrhages, confirmed by full blood count with isolated thrombocytopenia (platelet count <100 x 109/L) and normal blood film. Primary Immune thrombocytopenia is diagnosed by exclusion of secondary ITP and elimination of all other possible causes of thrombocytopenia.(5) Treatment is based on the clinical manifestations. First line medications include corticosteroids, intravenous immunoglobulins, and anti-D. If patients do not respond to standard treatment, then second line interventions (splenectomy) or agents (thrombopoietin receptor agonist, rituximab, mycophenolate mofetil) are considered.(5) Children tend to have a good prognosis with high chances of remission and low mortality rates.(17,35) Approximately 20 to 30% of the cases develop chronic ITP.(10) During this paper I aim to discuss/ explore the case study of a 4-year-old male initially diagnosed with Persistent ITP in his second year of life, which is now chronic. At present, this patient is receiving a second line agent with good clinical response and no relapses. Based on this clinical case, I have done a literature review on Chronic Immune thrombocytopenia, aiming to identify and understand the complexity of its clinical approach and treatment.
Description
Keywords
Crianças Crónica Hemorragia Plaquetas Primária Pti Trombocitopenia Imune