5TH NATIONAL CONFERENCE OF PEDIATRIC RHEUMATOLOGY, KOLKATA, 29TH & 30TH SEPTEMBER 2007
Amita Aggarwal
Additional Professor
Department of Immunology
SGPGI, Lucknow
Even though rheumatology is thought to be a laid back speciality, emergencies in pediatric rheumatology practice may arise due to
- Infections
- Vascular complications
- Multi-organ dysfunction
- Drug toxicity
Infection can occur denovo or as a result of imuno suppression. Infection of joints or muscles is to be treated as an emergency as it can lead to severe damage. Septic arthritis is usually seen in young children and involves hips, knees or ankles. The key to diagnosis is early joint aspiration and culture of synovial fluid. However in the meanwhile empirical antibiotic based on most prevalent organism in that age should be started. Tropical pyomyositis due to infection of muscles with Staph.aureus can have a very stormy course with pyopericardium, pyothorax, septic shock. Immuno-suppressed patients are at increased risk of tuberculosis, fungal infections and severe bacterial infection. A child with fever in this setting should be evaluated very carefully for a focus of infection and treated accordingly. Often it becomes difficult to differentiate disease flare from infection more so in SLE. If in doubt, treat for both.
Rheumatic disease itself can present as an emergency like massive GI bleed as a manifestation of GI vasculitis in HSP or polyarteritis nodosa, hypertensive encephalopathy in Takayasu's arteritis or SLE, acute renal failure with its associated complication in SLE and systemic vasculitis, pericardial tamponade in SLE, pulmonary hemorrhage in SLE and Wegeners granulomatosis, mononeuritis in vasculitis, stroke in SLE, vasculitis and anti-phospholipid syndrome.
Macrophage activation syndrome (MAS) is a life-threatening complication of childhood rheumatic diseases. Macrophage activation syndrome associated with JIA was first described by Hadchouel et al. in 1985. It is mainly seen with SOJIA and usually occurs around 4 years after onset of disease. Rarely it can be the presenting manifestation. It has rarely been described with other forms of JIA. MAS is characterized by fever, hepatosplenomegaly, lymphoadenopathy, profound depression of all three blood cell lines, deranged liver function, intravascular coagulation, and central nervous system dysfunction The diagnostic hallmark of the syndrome is the presence of numerous macrophages in the bone marrow phagocytosing blood cells (hemophagocytosis), with no evidence of malignancy. In a patient with SOJIA, fall in platelet count and total leukocyte count should make one suspicious about presence of MAS. MAS can be triggered by Infections especially viral infections, drugs like NSAIDs and DMARDs used in treating JIA like methrotrexate, sulfasalazine and penicillamine.
The clinical and pathologic manifestations of MAS are thought to result from the uncontrolled proliferation and activation of T-lymphocytes and well-differentiated macrophages, which leads to an unrestricted release of inflammatory cytokines, such as TNF-a, interleukin-1 and interleukin-6. Recently, natural killer cell function has been found to be deficient with less release of perforin. This may explain the distinctive susceptibility of these patients to the development of MAS.
MAS is a serious condition that is associated with considerable morbidity and high risk of fatal outcome. Early diagnosis and immediate therapeutic intervention are, therefore, critical. The treatment of MAS has traditionally been based on the administration of high-dose corticosteroids and, more recently, cyclosporine A. Anti-TNF therapy with Etanercept has been used with success. However, others have reported MAS being triggered by biological therapy.
