[A 9-year-old boy with 'pinpoint pain' caused by pyomyositis]

BACKGROUND

Pyomyositis is a rare bacterial infection of striated muscle, usually caused by Staphylococcus aureus.

CASE DESCRIPTION

A healthy 9-year-old boy was referred to us because of pain in the hip and fever. We noticed he could point to the pain with one finger; this is referred to as 'pinpoint pain'. An MRI indicated a diagnosis of pyomyositis of the iliacus muscle and piriformis. The infection was caused by S. aureus. The boy recovered completely and swiftly with antibiotic therapy.

CONCLUSION

This specific type of pyomyositis in the hip is rare, especially in children. Being able to localise the pain with one finger is a typical characteristic of this condition. MRI is the investigation of first choice to confirm this diagnosis.

Myocardial infarction in a neonate with left-sided congenital diaphragmatic hernia

We present a case study of a newborn girl with a left-sided congenital diaphragmatic hernia and a myocardial infarction (MI). The occurrence of MI in newborns has been associated with cardiac malformations and abnormalities of the coronary arteries or thromboembolization. In our patient, echocardiography revealed left ventricular dysfunction, persistent pulmonary hypertension and an inferolateral MI. Within 24 hours cardiac function and oxygenation did not improve and the baby died. Autopsy showed massive MI, a small aortic valve and ascending aorta, and hypoplasia of the distal aortic arch and isthmus. An accessory spleen was also present. The present report underlines the importance of cardiac evaluation in patients with congenital diaphragmatic hernia.

Complement factor H-associated atypical hemolytic uremic syndrome in monozygotic twins: concordant presentation, discordant response to treatment

Hemolytic uremic syndrome not associated with diarrhea (diarrhea negative, atypical) is less common than the diarrhea-positive typical form, but frequently results in end-stage renal failure. Although there are anecdotal cases of successful treatment with fresh frozen plasma alone, the value of this treatment compared with plasma exchange (PE) is difficult to assess. We describe monozygotic female twins who presented at 5 years of age with factor H-related (c.3572 > T; Ser1191Leu) atypical hemolytic uremic syndrome within months of each other. In the first twin to present, 10 sessions of PE with fresh frozen plasma replacement (40 mL/kg) resulted in resolution of hemolysis and improvement in plasma creatinine level (1.9 to 1.5 mg/dL [166 to 137 micromol/L]). Subsequently, 17 infusions of fresh frozen plasma were administered during a 4-month period for recurrent thrombocytopenia. However, within 4 months, plasma creatinine level increased to 5.1 mg/dL (450 micromol/L), necessitating peritoneal dialysis. When the second twin presented with the same disease, an extended PE regimen was instituted. After 10 daily sessions, PE was continued once every 2 weeks. Two recurrences were treated successfully with daily PE for 7 days. After 44 months of follow-up, kidney function is normal (plasma creatinine, 0.6 mg/dL [53 micromol/L]; creatinine clearance, 119 mL/min/1.73 m2 [1.98 mL/s/1.73 m2]) on maintenance PE therapy. In conclusion, the response to treatment of these monozygotic twins suggests that long-term PE may have benefits over plasma infusion alone.

Posttransplantation cytomegalovirus-induced recurrence of atypical hemolytic uremic syndrome associated with a factor H mutation: successful treatment with intensive plasma exchanges and ganciclovir

Atypical hemolytic uremic syndrome (HUS) can recur after renal transplantation and often leads to graft loss. In some series of familial HUS, the risk of early graft loss due to recurrence of HUS approaches 100% despite any therapy. This led some authors to claim that kidney transplantation is contraindicated in those patients. The authors describe an 8-year-old girl with end-stage renal failure owing to familial atypical HUS with a factor H mutation who underwent successful transplantation using continuous prophylactic plasma exchange (PE). Twenty-four months after transplantation, plasma creatinine level is 1.2 mg/dL (106 micromol/L) despite 2 recurrences of HUS contemporaneous to 2 cytomegalovirus infections, which resolved with PE intensification and ganciclovir. This strongly suggests that cytomegalovirus infection may trigger posttransplant recurrent HUS. The feasibility of kidney transplantation in case of atypical HUS related to factor H mutation using continuous prophylactic PE intensified during relapses should be confirmed in prospective studies.

Atypical relapse of hemolytic uremic syndrome after transplantation

Atypical hemolytic uremic syndrome (HUS) frequently leads to end-stage renal failure and can relapse after transplantation. A 12-year-old girl presenting with familial atypical HUS with a factor H mutation was successfully transplanted 6 years after a first transplant that had failed because of immediate recurrent HUS. Prophylactic plasma exchange before and after transplantation was used. Two months after transplantation, concomitant with a reduction in plasma exchange frequency, the plasma creatinine increased from 70 micro mol/l to 194 micro mol/l in 2 weeks without thrombocytopenia or signs of hemolytic anemia. The patient had minimal clinical symptoms and a presumptive diagnosis of graft rejection was made. Despite treatment with six daily pulses of methylprednisolone, plasma creatinine continued to increase and a graft biopsy was therefore undertaken. This showed the typical appearance of a thrombotic microangiopathy without any evidence of rejection. Despite daily plasmapheresis and replacement of cyclosporine with tacrolimus, there was no improvement and transplant nephrectomy was undertaken. This patient demonstrates that HUS can recur in a kidney transplant without the diagnostic hematological features and emphasizes the need for early transplant biopsy in such patients showing a decline in transplant function.

Inherited multicentric osteolysis with carpal-tarsal localisation mimicking juvenile idiopathic arthritis

Five patients with multicentric carpal-tarsal osteolysis are presented: a mother and her three children with an autosomal dominant mode of inheritance and one of the children with nephropathy, the fifth a sporadic case also with renal involvement. The main findings common to these five patients are symptoms and signs simulating arthritis of the wrists and/or ankles starting at a young age and mimicking juvenile idiopathic arthritis. Early signs of osteolysis and shortening of the carpus or tarsus are radiological characteristic. The disease may be associated with a peculiar face, but most importantly with nephropathy. The pathogenesis is still unknown.

CONCLUSION

Recognition of this disease and differentiation from juvenile idiopathic arthritis is important to avoid unnecessary investigations and treatment. Follow-up of renal function is indicated.