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Sarcoidosis is a multisystem disorder with protean manifestations in childhood.1 We report on a child with prominent muscular symptoms at presentation. Muscle involvement in childhood sarcoidosis has been described in only two previous reports to our knowledge.2,3 We believe that muscle biopsy has a valuable role in aiding the diagnosis of childhood sarcoidosis even in children with no clinical symptoms of muscle involvement.
A 10.5 year old girl presented with a nine weeks' history of fever, red eyes, loss of appetite, malaise, florid widespread rash, weakness, and lymphadenopathy. She attended a district general hospital and was diagnosed to have a mycoplasma chest infection and treated with antibiotics. She failed to respond despite three courses of erythromycin and had persistent conjunctivitis, florid rash over her trunk, erythema nodosum over her legs, and weight loss and was therefore referred to our tertiary rheumatology unit.
On review, she was pale, miserable, tired with muscle wasting, weakness, and lymphadenopathy. A complete investigation was carried out and haematological tests showed haemoglobin 102 g/l (normal 114–140 g/l) and white cell count 10.2 (normal 4–11). Her biochemical profile was normal and liver functions showed alanine aminotransferase 263 IU/l (normal 0–45 IU/l). Her autoantibody profile was negative, and inflammatory markers like C reactive protein 190 mg/l (normal <60 mg/l) and erythrocyte sedimentation rate 92 mm/1st h (normal <5 mm/1st h) were raised. Her lactate dehydrogenase 884 IU/l (normal ≤620 IU/l), serum angiotensin converting enzyme 133 IU/l (normal 15–55 IU/l), and antistreptolysin O titre >800 (normal <200) were all raised. Her creatine kinase was normal. Her chest x ray examination disclosed bilateral hilar lymphadenopathy with some pulmonary interstitial changes. An echocardiogram, cranial magnetic resonance imaging (MRI), magnetic resonance angiography, dimercaptosuccinic acid (DMSA) scan, and abdominal ultrasound were normal. Her muscle biopsy showed non-caseating, non-necrotising granulomas in fibrous septa and within muscle fascicles. In areas there were granulomas surrounding muscle fibres, the latter showing degenerative features (fig 1). The epitheloid granulomas had some admixed lymphocytes and giant cells. Skin biopsy showed granulomas in debris and subcutaneous tissues. A Mantoux test, gastric washings, and urine examination for acid fast bacilli were negative and bone marrow aspiration was normal. Ocular examination showed evidence of uveitis.
A diagnosis of sarcoidosis was made based on clinical and histological features and treatment was started with high dose methylprednisolone at 30 mg/kg/dose, followed by oral prednisolone. During the course of illness, she developed a tender liver and raised transaminases suggestive of hepatic disease.
Currently she is in remission with no symptoms and has been weaned off steroids completely. No symptoms have recurred during the past three years of follow up.
Childhood sarcoidosis is a chronic systemic disease of unknown cause, characterised by granuloma formation in affected organs. Childhood sarcoidosis is very rare, and the only incidence study done in children gives a figure of 0.22–0.27/100 000.4 Possibly, as in adults, a significant proportion of cases are asymptomatic and remain undiagnosed.
Muscle involvement in sarcoidosis is well recognised in adults. Symptomatic muscle involvement is reported to be between 0.5 and 1.4% of known cases of sarcoidosis.5,6 However, only two reports of muscle involvement in childhood sarcoidosis have been published. The clinical spectrum of muscle involvement in adult sarcoidosis can range from an asymptomatic state to a nodular myopathy (where lesions can be detected by MRI and gallium scintigraphy).7 Non-caseating granulomas have been detected in 20–75% of muscle biopsy specimens in adult patients with sarcoidosis, despite the absence of muscle symptoms.8–10
Our patient exhibited myopathic symptoms at presentation which improved with treatment. We believe that a diagnosis of sarcoidosis should be entertained in any child with unexplained muscle weakness and associated systemic symptoms.
We feel that muscle biopsy is useful in establishing the diagnosis of sarcoidosis and should be considered in children with sarcoidosis even if they have no muscle involvement (as sarcoid granulomas are seen in the skeletal muscle of 50% of adults with sarcoidosis with no muscle involvement).
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