Adolescent-onset anti-MDA5 antibody-positive juvenile dermatomyositis with rapidly progressive interstitial lung disease and spontaneous pneumomediastinum: a case report and literature review.

BACKGROUND: Dermatomyositis with positive anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody has a distinct phenotype associated with small hand joint arthritis, mucocutaneous ulceration, palmar papules and less muscle involvement. It is also associated with increased risk of rapidly progressive interstitial lung disease (RP-ILD) and has a high mortality rate in adults. There is evidence that cases complicated with spontaneous pneumomediastinum (PNM) have an increase in mortality. While most of the evidence for this rare disease is derived from the adult literature, we report a case diagnosed in an adolescent complicated with both RP-ILD and PNM with a good outcome after aggressive immunosuppressive therapy. Our case also illustrates the potential challenges in diagnosis of this condition in the setting of non-specific clinical manifestations, the need for a high index of suspicion, and the importance of testing for myositis-specific antibodies (MSA) early to aid in diagnosis given the risk of rapid progression in these patients. CASE PRESENTATION: A 16-year-old Chinese female presented with fever and cough for 1 day, and finger swelling for 3 weeks. Physical examination revealed arthritis of fingers and wrists, ulcers and palmar papules over fingers, hyperpigmentation of interphalangeal joints, and rash over the neck. The diagnosis of dermatomyositis was made 1 month later with the onset of malar rash, Gottron's papules, calcinosis and myalgia. The diagnosis was supported by the presence of anti-MDA5 antibody and evidence of inflammatory myopathy on magnetic resonance imaging. In retrospect, she already had interstitial lung disease at first presentation manifested as cough and opacity on chest radiograph, which was later confirmed with chest computed tomography. She was treated according to adult guidelines with steroid and calcineurin inhibitor. Her disease was resistant to initial therapy and was complicated by RP-ILD and spontaneous PNM. Intensive immunosuppressive therapy including cyclophosphamide and rituximab were required to induce remission. CONCLUSIONS: Recognition of distinct clinical features of anti-MDA5 antibody-positive dermatomyositis and testing for MSA is crucial in patients with skin ulceration and abnormal pulmonary findings of unknown etiology, as prompt diagnosis with early aggressive treatment and anticipation of complications could make a difference in the outcome of this disease with high mortality.

Peritoneal Dialysis Access Revision in Children: Causes, Interventions, and Outcomes.

BACKGROUND AND OBJECTIVES: Little published information is available about access failure in children undergoing chronic peritoneal dialysis. Our objectives were to evaluate frequency, risk factors, interventions, and outcome of peritoneal dialysis access revision. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Data were derived from 824 incident and 1629 prevalent patients from 105 pediatric nephrology centers enrolled in the International Pediatric Peritoneal Dialysis Network Registry between 2007 and 2015. RESULTS: In total, 452 access revisions were recorded in 321 (13%) of 2453 patients over 3134 patient-years of follow-up, resulting in an overall access revision rate of 0.14 per treatment year. Among 824 incident patients, 186 (22.6%) underwent 188 access revisions over 1066 patient-years, yielding an access revision rate of 0.17 per treatment year; 83% of access revisions in incident patients were reported within the first year of peritoneal dialysis treatment. Catheter survival rates in incident patients were 84%, 80%, 77%, and 73% at 12, 24, 36, and 48 months, respectively. By multivariate logistic regression analysis, risk of access revision was associated with younger age (odds ratio, 0.93; 95% confidence interval, 0.92 to 0.95; P<0.001), diagnosis of congenital anomalies of the kidney and urinary tract (odds ratio, 1.28; 95% confidence interval, 1.03 to 1.59; P=0.02), coexisting ostomies (odds ratio, 1.42; 95% confidence interval, 1.07 to 1.87; P=0.01), presence of swan neck tunnel with curled intraperitoneal portion (odds ratio, 1.30; 95% confidence interval, 1.04 to 1.63; P=0.02), and high gross national income (odds ratio, 1.10; 95% confidence interval, 1.02 to 1.19; P=0.01). Main reasons for access revisions included mechanical malfunction (60%), peritonitis (16%), exit site infection (12%), and leakage (6%). Need for access revision increased the risk of peritoneal dialysis technique failure or death (hazard ratio, 1.35; 95% confidence interval, 1.10 to 1.65; P=0.003). Access dysfunction due to mechanical causes doubled the risk of technique failure compared with infectious causes (hazard ratio, 1.95; 95% confidence interval, 1.20 to 2.30; P=0.03). CONCLUSIONS: Peritoneal dialysis catheter revisions are common in pediatric patients on peritoneal dialysis and complicate provision of chronic peritoneal dialysis. Attention to potentially modifiable risk factors by pediatric nephrologists and pediatric surgeons should be encouraged.

Recurrent thrombotic thrombocytopenic purpura in a young boy with systemic lupus erythematosus.

Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal disease in childhood. The association of microangiopathic hemolytic anemia, schistocytes, and thrombocytopenia without fever, neurologic, and renal involvement is sufficient to suspect TTP at an early stage for prompt plasma infusion or exchange therapy. TTP has been increasingly described especially in association with systemic lupus erythematosus (SLE). We report the youngest Chinese boy who presented his SLE with TTP and subsequently experienced 9 relapses of TTP in a 2-year period. SLE disease activity index was low during his TTP relapses and therefore alertness of TTP relapse is required even in a relatively inactive period of SLE. TTP should be recognized even without renal or neurologic features and can respond to plasma therapy.

Lupus nephritis in Chinese children--a territory-wide cohort study in Hong Kong.

We report a multicenter study of Chinese children in Hong Kong with systemic lupus erythematosus (SLE) nephritis. Children were included if: they fulfilled the ACR criteria, had significant proteinuria or casturia, were Chinese and younger than 19 years and had been diagnosed with SLE between January 1990 and December 2003. Investigators in each center retrieved data on clinical features, biopsy reports, treatment and outcome of these patients. There were 128 patients (eight boys, 120 girls; mean age: 11.9+/-2.8 years). About 50% presented with multisystem illness and 40% with nephritic/nephrotic symptoms. Negative anti-dsDNA antibodies were found in 6% of the patients. Renal biopsy revealed WHO Class II, III, IV and V nephritis in 13 (10%), 22 (17%), 69 (54%) and 13 (10%) patients, respectively. The clinical severity of the nephritis did not accurately predict renal biopsy findings. The follow-up period ranged from 1 to 16.5 years (mean+/-SD: 5.76+/-3.61 years). During the study five patients died (two from lupus flare, one from cardiomyopathy, two from infections). Four patients had endstage renal failure (ESRF) (one died during a lupus flare). All deaths and end-stage renal failure occurred in the Class IV nephritis group. Chronic organ damage was infrequent in the survivors. The actuarial patient survival rates at 5, 10 and 15 years of age were 95.3, 91.8, and 91.8%, respectively. For Class IV nephritis patients, the survival rates without ESRF at 5, 10, and 15 years were 91.5, 82.3 and 76%, respectively. The survival and chronic morbidity rates of the Chinese SLE children in the present study are comparable to those of other published studies.