Benign Acute Childhood Myositis - medIND

Original Article
Benign Acute Childhood Myositis
Sarala Rajajee, S. Ezhilarasi and K. Rajarajan
Kanchi Kamakoti CHILDS Trust Hospital, Chennai, India.
Abstract. Objective: To describe the clinical and laboratory features of benign acute childhood myositis. Methods : 40 children
of BACM were seen during October 2001 to February 2002, 22 (52%) were male with mean age of 5.3 years. Duration of illness
was 3.97 days. Preceding symptoms included fever, leg pain, vomiting and inability to walk. A provisional diagnosis of viral
myositis was made in 26 (66%). Guillian Barre Syndrome was the most common referral diagnosis. Results: 11 (27.5%)
children had leucopenia with lymphocytic response and 16 (40%) had thrombocytopenia. CRP was negative in 32 (80%). CPK
was markedly elevated (more than 1000 IU/l) in 18 (45%) and more than 500IU/l in 11 (27.5%) remaining between 200 to 500IU/
l. Associated features were hepatitis (elevated SGOT & SGPT) in 28 (70%) and shock in 5 (12.5%).Serological test were
indicative of dengue virus (Elisa PAN BIO) in 20 (50%) of which 8 (25%) were primary dengue and 12 (30%) were secondary
dengue. The outcome of therapy mainly supportive were excellent. Conclusion: Benign acute myositis occurs often in
association with viral infection. In the present study, Dengue virus was positive in 20 (50%) children. Benign acute myositis can
be differentiated from more serious causes of walking difficulty by presence of calf and thigh muscle tenderness on stretching,
normal power and deep tendon reflex and elevated CPK. [Indian J Pediatr 2005; 72 (5) : 399-400]
E-mail : saralarajajee@yahoo.com
Key words : Myositis; Dengue virus; Guillian Barre Syndrome
Benign acute childhood myositis (BACM) was first
described in 1957 by Lundberg 1 under the name of
“Myalgia Cruris Epidemica”. It is characterised by
sudden onset of calf pain and refusal or difficulty to walk.
Viral agents have been implicated. 1,2,3,4 It is followed by
rapid recovery within a week. It is rarely reported in
adults. We report 40 cases of BACM between October
2001 to February 2002.
MATERIAL AND METHODS
Inclusion criteria: (i) Children presenting with fever /
myalgia. (ii) Muscle tenderness demonstrated by straight
leg raising test (iii) Absence of nuchal rigidity. (iv)
Absence of neurological signs such as altered sensorium
or local deficit.
RESULTS
Forty cases of BACM were seen. 22 (55%) were male with
mean age of 5.3 years age. All cases were seen between to
October 2001 – February 2002. Duration of illness was 3.97
days. Preceding symptoms included fever, leg pain,
headache.
A provisional diagnosis of viral myositis was made in
26 (65%). Guillian Barre syndrome was the most common
referral diagnosis in 5 (12.5%). 18 (45%) children were
unable to walk and in those who walked a characteristic
Correspondence and Reprint requests : Dr. Sarala Rajajee, 19 (New
No 28) Second Main Road, CIT Colony, Chennai – 600 004.
pattern were observed, they walked on toes or walked
with wide based, stiff gait. Muscle tenderness was
recorded in 34 (85%) cases. This was well illustrated by
stretching of the muscle by raising the leg. Similar
observations were made by Mackary et al. 5
Eleven children (27.5%) had leucopenia, with
lymphocyte response 16 (40%) had thrombocytopenia.
CRP was negative in 32 (80%). CPK was markedly
elevated (more than 1000 IU/litre) in 18 (45%), and more
than 500 IU/litre in 11 (27.5%) (Fig 1). Serological tests
were indicative of dengue virus (Elisa PAN BIO) primary
Dengue in 8 (25%), secondary Dengue in 12 (30%).
Associated features were hepatitis in 28 (70%)
(elevated SGOT and SGPT) shock in 5 (25.5%).
The outcome of the therapy was excellent, everybody
recovered. Repeat CPK was normal in 10 (25%). Rest of
the children were asymptomatic at review after two
weeks. Therapy was mainly supportive with intravenous
fluids as indicated and paracetamol.
DISCUSSION
After the first reports of BACM in 1957 1 , Middleton et al 2
described cases in 1970 and showed elevated CPK in
association with influenza B. Since then there have been
253 cases reported associated with various virus
infections.
In the present series 55% of patients were boys. In the
report by Mackary et al 84% of patients were boys. This
may be either due to greater levels of activity in boys or a
genetic predisposition.
Indian Journal of Pediatrics, Volume 72—May, 2005 399

No. of cases
20 –
16 –
12 –
8 –
4 –
0 –
12
135-500 500-999 >1000
CPK levels (IU/litre)
Fig 1. Creatine Phosphokinase (CPK)
The mean age of onset of symptoms in our study was
5.3 days. The mean duration of prodromal symptoms in
the present study was 3.97 days. There was associated
clinical features of hepatomegaly in 33 (82.5%) cases.
Shock in 5 (12.5%). Resolution was rapid within as week.
This was similar to the observation of Mackary et al and
Mckinlay et al. Myalgia primarily affected the
gastroneomius and hamstring muscles.
Viruses associated with myositis according to several
authors include Influenza A, adenovirus , Coxsackie and
para influenza. In the present series the Dengue virus was
11
Sarala Rajajee et al
18
MOTHER & CHILD CARE
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associated with 20 (50%) cases of myositis.
Muscle biopsies performed in myositis showed non
specific degenerative changes, focal muscle fibre
vacuolation and muscle necrosis. The elevation of CPK
suggests muscle fibre destruction in keeping with a
myositic component.
Awareness of the possibility of myositis in children
presenting with acute myalgia, difficulty in walking in
association with elevated CPK may lead to streamlining
further tests and unnecessary therapy may be avoided.
Contributions
SR drafted the manuscript. KR collected the data. SE analysed the
data. SR will act as the guarantor of the paper.
REFERENCES
1. Lundberg A Myalgia cruris epidermica. Acta Paediatr 1957;
46 : 18-31.
2. Middleton PJ, Alexander RM. Severe myositis during
recovering from influenza. Lancet 1970; 2 : 533-535.
3. Anthony J H, Procopis PG, Ouvier RA. Benign acute
childhood myositis. Neurology 1979; 29 : 1068–1071.
4. Mckinlay IA, Mitchell I. Transient acute myositis in childhood.
Arch Dis Child 1976, 51; 135-137.
5. Mackay MT, Kornverg AJ, Shield LK, Dennett X. Benign acute
childhood myositis. Neurology 1999; 53 : 70.
6. Mark Barasz. Benign acute myositis. Am J Emerg Med 2000;
18 : 35-37.
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400 Indian Journal of Pediatrics, Volume 72—May, 2005