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Unusual Muscular Injury in an Infant With Severe H1N1 Infection
Pediatric Neurology 47 (2012) 51e54
Contents lists available at ScienceDirect
Pediatric Neurology journal homepage: www.elsevier.com/locate/pnu
Case Report
Unusual Muscular Injury in an Infant With Severe H1N1 Infection Romain Guedj MD a, Isabelle Desguerre MD, PhD b, Anaïs Brassier MD c, Nathalie Boddaert MD, PhD d, Philippe Hubert MD a, Mehdi Oualha MD a, * a
Service de Réanimation Polyvalente et Néonatale, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France b Service de Neurologie et Centre de Références des Maladies Neuromusculaires, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France c Service des Maladies Métabolique, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France d Service de Radiologie Pédiatrique, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France
article information
abstract
Article history: Received 5 January 2012 Accepted 4 April 2012
We report the first well-documented case of unilateral orbital myositis in an 8-month-old boy with life-threatening pandemic H1N1 infection. He presented with status epilepticus and hemodynamic failure associated with unusual right orbital myositis and acute rhabdomyolysis. Because of severe myolysis, metabolic screening was performed to exclude metabolic and genetic etiologies. After corticosteroid administration and symptomatic support, the disease evolution was favorable, without sequelae at hospital discharge. H1N1 influenza infection may be associated with multiple organ failure, and complicated by unusual muscle injury. The presence of intense myolysis should alert practitioners to potential metabolic and genetic etiologies. Ó 2012 Elsevier Inc. All rights reserved.
Introduction
Pandemic influenza H1N1 has been reported in a great number of countries since 2009, and has included the occurrence of certain complications associated with this infection. Among these, myositis has been described, presenting as generally moderate with calf pain and targeting children between 3-14 years of age. We report on a young child with a proven H1N1 infection complicated by severe multiple organ involvement, including unusual orbital myositis and severe myolysis. Case Report An 8-month-old boy was brought to the emergency room after 3 days of fever (39 C), cough, rhinorrhea, diarrhea, and vomiting. The * Communications should be addressed to: Dr. Oualha; Service de Réanimation Polyvalente et Néonatale; Hôpital Necker-Enfants Malades; Assistance Publique des Hôpitaux de Paris; Université Paris-Descartes; 149 Rue de Sèvres; 75743 Paris Cedex, France. E-mail address: [email protected] 0887-8994/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.pediatrneurol.2012.04.006
patient’s previous medical and family histories were unremarkable, and the patient’s developmental milestones were normal. A clinical examination revealed hypovolemic shock associated with dehydration (11% loss of body weight, dry skin, dry mouth, and a sunken fontanel) and altered consciousness. The initial laboratory evaluation revealed hypernatremia (176 mmol/L), acidosis with a normal anion gap (HCO3 , 7 mmol/L; Cl , 149 mmol/L), renal failure with a serum urea level at 36.8 mmol/L, and a serum creatinine level at 313 mmol/L. Serum creatinine kinase was measured at 600 IU/L. After the administration of a 40-mL/kg bolus of saline fluid, the patient was admitted to our pediatric intensive care unit. At admission, a physical examination produced normal results, except for discomfort and reduced mobility. The initial management consisted of slow, intravenous rehydration. The presence of rotavirus was detected by immunochromatography in a stool sample. After 36 hours of management, the patient improved, with a normalization of weight, hydration status, and renal function. His fever resolved, and the diarrhea ceased. However, his limb mobility remained reduced and seemed painful, with muscles tender to palpation. Asymmetric right exophthalmia with lip edema appeared to be associated with his reduced mobility and pain. By the end of day 2, the patient manifested status epilepticus without fever, along with distributive shock. After we controlled the patient’s seizures by successive administrations of clonazepam and phenytoin, a neurologic examination
52
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54
Figure 1. Left: Cerebral and ocular axial T2 magnetic resonance imaging indicates right proptosis with soft-tissue infiltration (dotted arrow). Right: Coronal T1 magnetic resonance imaging after gadolinium injection indicates contrast enhancement of the right inferior rectus muscle (solid arrow).
indicated pyramidal syndrome, coma, and exophthalmia, complicated by right ophthalmoplegia. An electroencephalogram revealed slow and nonspecific disseminated waves. On cerebral magnetic resonance imaging, T2 hyperintensity was detected in the posterior cortical region and basal ganglia, as shown in Fig 1. These findings did not suggest venous thrombosis, but rather acute and nonspecific encephalitis. In addition, significant contrast enhancement and T2 hyperintensity of the orbit muscles were indicative of right orbital myositis. As shown in Fig 2, myolysis was documented on day 5 (creatine kinase, 18,891 IU/L), with a peak of 40,418 IU on day 7 without any increase in the serum level of troponin,
thus excluding myocardial damage. A pandemic influenza H1N1 polymerase chain reaction produced positive results in a nasopharyngeal sample. Cerebrospinal fluid studies revealed normal results, with negative herpes simplex virus and H1N1 polymerase chain reaction assays. The diagnosis therefore involved an H1N1 influenza infection complicated by encephalitis, orbital myositis, severe myolysis, and hemodynamic failure. The child was treated with oral oseltamivir for his pandemic influenza encephalitis, with mechanical ventilation, clonazepam, and phenytoin for his seizures, with fluid resuscitation and vasopressors for shock, and with corticosteroid and
Figure 2. Clinical and biological development. CK, creatine kinase; PICU, pediatric intensive care unit.
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54 hyperhydration for his severe myolysis and orbital myositis. The ophthalmoplegia and exophthalmia dramatically improved on day 3. The patient recovered consciousness on day 4, and was extubated on day 5. No signs of myoglobinuria, renal failure, or electrolytic disorders were evident. The myolysis was treated with hyperhydration. Differential etiologies of myositis were eliminated, including defects in glycogen breakdown, LPIN1 mutations, mitochondrial fatty acid b-oxidation, and oxidative phosphorylation. The level of creatinine kinase slowly decreased, and returned to normal on day 17. The patient was discharged on day 18, with no pain and normal results of a clinical and ophthalmologic examination.
Discussion
We report on a novel case of influenza H1N1 infection complicated by life-threatening organ injury including encephalitis, hemodynamic failure, and severe myolysis, with an unusual localization of myositis. Acute myositis has been described in many epidemics of influenza since 1957 [1]. “Benign acute myositis” has been reported in boys from 3-14 years of age, with acute bilateral pain or weakness in the lower legs resulting in a refusal or inability to bear weight after a period of rest, but without neurologic abnormalities and preceded by influenza-like signs and fever [2]. Cases have been reported in which other muscle groups were affected, although such occurrences are relatively rare [3]. In the present patient, the myositis was unusual because the oculomotor muscles were particularly involved and associated with severe myolysis. Orbital myositis, which is more often observed in adults, comprises a subgroup of idiopathic orbital inflammatory diseases in which one or more of the extraocular muscles are infiltrated by an inflammatory process [4]. Clinical findings of orbital myositis are very heterogeneous, and include pain, ptosis, lid edema and exophthalmia, paresis, and diplopia [5]. Proptosis may constitute the only clinical sign of orbital myositis [6]. The diagnosis is confirmed by computed tomography or magnetic resonance images indicating an enlargement of the extraocular muscles with blurred margins. Our patient manifested clinical and radiologic findings consistent with this diagnosis. Orbital myositis has been associated with systemic disorders [5], along with various infectious processes including streptococcal pharyngitis [7], upper respiratory tract infection, influenza-like viral illness, and infection with Borrelia burgdorferi [6]. Conversely, cases of orbital myositis associated with influenza are rarely described in the literature. Migita et al. [8] reported on a case of influenza with impaired ocular movement and ptosis associated with an increase in creatinine kinase. However, whether the ocular involvement and ptosis were related to encephalitis or to myositis remained unclear, because computed tomography did not reveal an enlargement of the extraocular muscles [8]. Manuchehri et al. [9] described a 6-yearold boy with a family history of influenza-like illness and orbital myositis, preceded by fever a few days earlier. However, no influenza was evident on microbiologic sampling [9]. To our knowledge, the present case is the first to involve a comprehensive diagnosis of orbital myositis associated with H1N1 influenza virus.
53
Because orbital myositis is characterized by swelling that can lead to ischemia or fibrosis, the functional prognosis can be altered, and thus treatment is necessary. In the present case, exophthalmia and ophthalmoplegia rapidly resolved, less than 24 hours after corticosteroid administration. We initially hesitated to implement this treatment, given the benign evolution of the ocular symptomatology. However, corticosteroids have been efficacious in case reports of orbital myositis associated with infection. Systemic corticosteroids have been the treatment of choice in idiopathic orbital inflammatory disease and in orbital myositis in a majority of adult [5] and childhood [4] cases. We think corticosteroid therapy is therefore a reasonable approach to treating orbital myositis in such instances. Viral myositis in young infants has seldom been described, and is probably underdiagnosed because of difficulties in distinguishing pain from other complaints in infants with fever. Our patient was very uncomfortable, probably because of pain in the lower legs. Even if the course of myositis is generally good with complete recovery, the diagnosis must be ascertained for at least two reasons. First, rhabdomyolysis is a rare but life-threatening complication, and can lead to acute renal failure and fatal hyperkalemia. Preventive treatment consists of immediate fluid hydration and biologic monitoring, to determine whether dialysis is necessary [3]. Secondly, rhabdomyolysis can reveal a metabolic disorder such as mitochondrial fatty acid b-oxidation defects, mitochondrial respiratory chain deficiency, or inborn errors of glycogenolysis, some of which involve specific and preventive treatments. These inherited metabolic diseases, often decompensated by viral infections, constitute urgent situations and call for immediate treatment. Michot et al. reported on a high incidence of LPIN1 mutations in a large series of young patients with severe rhabdomyolysis [10]. These mutations appeared to be associated with familiar cases of severe and acute rhabdomyolysis precipitated by febrile illness. We think that metabolic investigations of severe myositis or rhabdomyolysis in young patients should successively include the metabolic investigation of fatty acid b-oxidation defects and a search for intragenic LPIN1 deletions in blood samples, using long-range polymerase chain reaction. Hemodynamic failure, encephalitis, and myolysis associated with H1N1 infection have already been described [11,12], but influenza infection has rarely been associated with so many unusual and severe complications as those observed here. Although we cannot conclusively describe the exact underlying mechanism in the present case, the association of hemodynamic failure, encephalitis, and myositis suggest a probable uncontrolled release of cytokine in a patient without a previous medical history. Finally, all of the complications that appeared secondarily after a short period of improvement cannot be attributed to a rotavirus infection, even if such infections were described as exceptional etiologies of encephalitis or myolysis. In conclusion, we have reported on a novel case of influenza H1N1 infection complicated by unusual organ injury including severe myositis, which can involve all
54
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54
muscle groups and which should, when myolysis is intense, alert practitioners to potential metabolic etiologies. The authors acknowledge Dominique Gendrel, MD, PhD, and Pascale De Lonlay, MD, PhD, for their helpful contributions.
References [1] Lundberg A. Myalgia cruris epidemica. Acta Paediatr Scand 1957; 46:18e31. [2] Rubín E, De la Rubia L, Pascual A, Domínguez J, Flores C. Benign acute myositis associated with H1N1 influenza A virus infection. Eur J Pediatr 2010;169:1159e61. [3] Agyeman P, Duppenthaler A, Heininger U, Aebi C. Influenza-associated myositis in children. Infection 2004;32:199e203. [4] Belanger C, Zhang KS, Reddy AK, Yen MT, Yen KG. Inflammatory disorders of the orbit in childhood: A case series. Am J Ophthalmol 2010;150:460e3.
[5] Yuen SJA, Rubin PAD. Idiopathic orbital inflammation: Distribution, clinical features, and treatment outcome. Arch Ophthalmol 2003; 121:491e9. lu S, Hallaç IK, Poyrazog lu MH. [6] Aydin K, Narin N, Erkiliç K, Kurtog Bilateral proptosis caused by orbital myositis: A case report. Turk J Pediatr 1998;40:135e8. [7] Culligan B. Orbital myositis following streptococcal pharyngitis in a pediatric patient. Optometry 2005;76:250e8. [8] Migita M, Matsumoto T, Fujino O, Takaishi Y, Yuki N, Fukunaga Y. Two cases of influenza with impaired ocular movement. Eur J Paediatr Neurol 2001;5:83e5. [9] Manuchehri K, Lagnado R, Butler L. A case of orbital myositis secondary to orbital cellulitis in a child. Eye 2003;17:434e6. [10] Michot C, Hubert L, Brivet M, et al. LPIN1 gene mutations: A major cause of severe rhabdomyolysis in early childhood. Hum Mutat 2010;31:E1564e73. [11] Davis LE. Neurologic and muscular complications of the 2009 influenza A (H1N1) pandemic. Curr Neurol Neurosci Rep 2010;10: 476e83. [12] Domínguez-Cherit G, Lapinsky SE, Macias AE, et al. Critically ill patients with 2009 influenza A (H1N1) in Mexico. JAMA 2009;302: 1880e7.
Contents lists available at ScienceDirect
Pediatric Neurology journal homepage: www.elsevier.com/locate/pnu
Case Report
Unusual Muscular Injury in an Infant With Severe H1N1 Infection Romain Guedj MD a, Isabelle Desguerre MD, PhD b, Anaïs Brassier MD c, Nathalie Boddaert MD, PhD d, Philippe Hubert MD a, Mehdi Oualha MD a, * a
Service de Réanimation Polyvalente et Néonatale, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France b Service de Neurologie et Centre de Références des Maladies Neuromusculaires, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France c Service des Maladies Métabolique, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France d Service de Radiologie Pédiatrique, Hôpital Necker-Enfants Malades, Assistance Publique des Hôpitaux de Paris, Faculté de Médecine, Université Paris-Descartes, Paris, France
article information
abstract
Article history: Received 5 January 2012 Accepted 4 April 2012
We report the first well-documented case of unilateral orbital myositis in an 8-month-old boy with life-threatening pandemic H1N1 infection. He presented with status epilepticus and hemodynamic failure associated with unusual right orbital myositis and acute rhabdomyolysis. Because of severe myolysis, metabolic screening was performed to exclude metabolic and genetic etiologies. After corticosteroid administration and symptomatic support, the disease evolution was favorable, without sequelae at hospital discharge. H1N1 influenza infection may be associated with multiple organ failure, and complicated by unusual muscle injury. The presence of intense myolysis should alert practitioners to potential metabolic and genetic etiologies. Ó 2012 Elsevier Inc. All rights reserved.
Introduction
Pandemic influenza H1N1 has been reported in a great number of countries since 2009, and has included the occurrence of certain complications associated with this infection. Among these, myositis has been described, presenting as generally moderate with calf pain and targeting children between 3-14 years of age. We report on a young child with a proven H1N1 infection complicated by severe multiple organ involvement, including unusual orbital myositis and severe myolysis. Case Report An 8-month-old boy was brought to the emergency room after 3 days of fever (39 C), cough, rhinorrhea, diarrhea, and vomiting. The * Communications should be addressed to: Dr. Oualha; Service de Réanimation Polyvalente et Néonatale; Hôpital Necker-Enfants Malades; Assistance Publique des Hôpitaux de Paris; Université Paris-Descartes; 149 Rue de Sèvres; 75743 Paris Cedex, France. E-mail address: [email protected] 0887-8994/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.pediatrneurol.2012.04.006
patient’s previous medical and family histories were unremarkable, and the patient’s developmental milestones were normal. A clinical examination revealed hypovolemic shock associated with dehydration (11% loss of body weight, dry skin, dry mouth, and a sunken fontanel) and altered consciousness. The initial laboratory evaluation revealed hypernatremia (176 mmol/L), acidosis with a normal anion gap (HCO3 , 7 mmol/L; Cl , 149 mmol/L), renal failure with a serum urea level at 36.8 mmol/L, and a serum creatinine level at 313 mmol/L. Serum creatinine kinase was measured at 600 IU/L. After the administration of a 40-mL/kg bolus of saline fluid, the patient was admitted to our pediatric intensive care unit. At admission, a physical examination produced normal results, except for discomfort and reduced mobility. The initial management consisted of slow, intravenous rehydration. The presence of rotavirus was detected by immunochromatography in a stool sample. After 36 hours of management, the patient improved, with a normalization of weight, hydration status, and renal function. His fever resolved, and the diarrhea ceased. However, his limb mobility remained reduced and seemed painful, with muscles tender to palpation. Asymmetric right exophthalmia with lip edema appeared to be associated with his reduced mobility and pain. By the end of day 2, the patient manifested status epilepticus without fever, along with distributive shock. After we controlled the patient’s seizures by successive administrations of clonazepam and phenytoin, a neurologic examination
52
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54
Figure 1. Left: Cerebral and ocular axial T2 magnetic resonance imaging indicates right proptosis with soft-tissue infiltration (dotted arrow). Right: Coronal T1 magnetic resonance imaging after gadolinium injection indicates contrast enhancement of the right inferior rectus muscle (solid arrow).
indicated pyramidal syndrome, coma, and exophthalmia, complicated by right ophthalmoplegia. An electroencephalogram revealed slow and nonspecific disseminated waves. On cerebral magnetic resonance imaging, T2 hyperintensity was detected in the posterior cortical region and basal ganglia, as shown in Fig 1. These findings did not suggest venous thrombosis, but rather acute and nonspecific encephalitis. In addition, significant contrast enhancement and T2 hyperintensity of the orbit muscles were indicative of right orbital myositis. As shown in Fig 2, myolysis was documented on day 5 (creatine kinase, 18,891 IU/L), with a peak of 40,418 IU on day 7 without any increase in the serum level of troponin,
thus excluding myocardial damage. A pandemic influenza H1N1 polymerase chain reaction produced positive results in a nasopharyngeal sample. Cerebrospinal fluid studies revealed normal results, with negative herpes simplex virus and H1N1 polymerase chain reaction assays. The diagnosis therefore involved an H1N1 influenza infection complicated by encephalitis, orbital myositis, severe myolysis, and hemodynamic failure. The child was treated with oral oseltamivir for his pandemic influenza encephalitis, with mechanical ventilation, clonazepam, and phenytoin for his seizures, with fluid resuscitation and vasopressors for shock, and with corticosteroid and
Figure 2. Clinical and biological development. CK, creatine kinase; PICU, pediatric intensive care unit.
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54 hyperhydration for his severe myolysis and orbital myositis. The ophthalmoplegia and exophthalmia dramatically improved on day 3. The patient recovered consciousness on day 4, and was extubated on day 5. No signs of myoglobinuria, renal failure, or electrolytic disorders were evident. The myolysis was treated with hyperhydration. Differential etiologies of myositis were eliminated, including defects in glycogen breakdown, LPIN1 mutations, mitochondrial fatty acid b-oxidation, and oxidative phosphorylation. The level of creatinine kinase slowly decreased, and returned to normal on day 17. The patient was discharged on day 18, with no pain and normal results of a clinical and ophthalmologic examination.
Discussion
We report on a novel case of influenza H1N1 infection complicated by life-threatening organ injury including encephalitis, hemodynamic failure, and severe myolysis, with an unusual localization of myositis. Acute myositis has been described in many epidemics of influenza since 1957 [1]. “Benign acute myositis” has been reported in boys from 3-14 years of age, with acute bilateral pain or weakness in the lower legs resulting in a refusal or inability to bear weight after a period of rest, but without neurologic abnormalities and preceded by influenza-like signs and fever [2]. Cases have been reported in which other muscle groups were affected, although such occurrences are relatively rare [3]. In the present patient, the myositis was unusual because the oculomotor muscles were particularly involved and associated with severe myolysis. Orbital myositis, which is more often observed in adults, comprises a subgroup of idiopathic orbital inflammatory diseases in which one or more of the extraocular muscles are infiltrated by an inflammatory process [4]. Clinical findings of orbital myositis are very heterogeneous, and include pain, ptosis, lid edema and exophthalmia, paresis, and diplopia [5]. Proptosis may constitute the only clinical sign of orbital myositis [6]. The diagnosis is confirmed by computed tomography or magnetic resonance images indicating an enlargement of the extraocular muscles with blurred margins. Our patient manifested clinical and radiologic findings consistent with this diagnosis. Orbital myositis has been associated with systemic disorders [5], along with various infectious processes including streptococcal pharyngitis [7], upper respiratory tract infection, influenza-like viral illness, and infection with Borrelia burgdorferi [6]. Conversely, cases of orbital myositis associated with influenza are rarely described in the literature. Migita et al. [8] reported on a case of influenza with impaired ocular movement and ptosis associated with an increase in creatinine kinase. However, whether the ocular involvement and ptosis were related to encephalitis or to myositis remained unclear, because computed tomography did not reveal an enlargement of the extraocular muscles [8]. Manuchehri et al. [9] described a 6-yearold boy with a family history of influenza-like illness and orbital myositis, preceded by fever a few days earlier. However, no influenza was evident on microbiologic sampling [9]. To our knowledge, the present case is the first to involve a comprehensive diagnosis of orbital myositis associated with H1N1 influenza virus.
53
Because orbital myositis is characterized by swelling that can lead to ischemia or fibrosis, the functional prognosis can be altered, and thus treatment is necessary. In the present case, exophthalmia and ophthalmoplegia rapidly resolved, less than 24 hours after corticosteroid administration. We initially hesitated to implement this treatment, given the benign evolution of the ocular symptomatology. However, corticosteroids have been efficacious in case reports of orbital myositis associated with infection. Systemic corticosteroids have been the treatment of choice in idiopathic orbital inflammatory disease and in orbital myositis in a majority of adult [5] and childhood [4] cases. We think corticosteroid therapy is therefore a reasonable approach to treating orbital myositis in such instances. Viral myositis in young infants has seldom been described, and is probably underdiagnosed because of difficulties in distinguishing pain from other complaints in infants with fever. Our patient was very uncomfortable, probably because of pain in the lower legs. Even if the course of myositis is generally good with complete recovery, the diagnosis must be ascertained for at least two reasons. First, rhabdomyolysis is a rare but life-threatening complication, and can lead to acute renal failure and fatal hyperkalemia. Preventive treatment consists of immediate fluid hydration and biologic monitoring, to determine whether dialysis is necessary [3]. Secondly, rhabdomyolysis can reveal a metabolic disorder such as mitochondrial fatty acid b-oxidation defects, mitochondrial respiratory chain deficiency, or inborn errors of glycogenolysis, some of which involve specific and preventive treatments. These inherited metabolic diseases, often decompensated by viral infections, constitute urgent situations and call for immediate treatment. Michot et al. reported on a high incidence of LPIN1 mutations in a large series of young patients with severe rhabdomyolysis [10]. These mutations appeared to be associated with familiar cases of severe and acute rhabdomyolysis precipitated by febrile illness. We think that metabolic investigations of severe myositis or rhabdomyolysis in young patients should successively include the metabolic investigation of fatty acid b-oxidation defects and a search for intragenic LPIN1 deletions in blood samples, using long-range polymerase chain reaction. Hemodynamic failure, encephalitis, and myolysis associated with H1N1 infection have already been described [11,12], but influenza infection has rarely been associated with so many unusual and severe complications as those observed here. Although we cannot conclusively describe the exact underlying mechanism in the present case, the association of hemodynamic failure, encephalitis, and myositis suggest a probable uncontrolled release of cytokine in a patient without a previous medical history. Finally, all of the complications that appeared secondarily after a short period of improvement cannot be attributed to a rotavirus infection, even if such infections were described as exceptional etiologies of encephalitis or myolysis. In conclusion, we have reported on a novel case of influenza H1N1 infection complicated by unusual organ injury including severe myositis, which can involve all
54
R. Guedj et al. / Pediatric Neurology 47 (2012) 51e54
muscle groups and which should, when myolysis is intense, alert practitioners to potential metabolic etiologies. The authors acknowledge Dominique Gendrel, MD, PhD, and Pascale De Lonlay, MD, PhD, for their helpful contributions.
References [1] Lundberg A. Myalgia cruris epidemica. Acta Paediatr Scand 1957; 46:18e31. [2] Rubín E, De la Rubia L, Pascual A, Domínguez J, Flores C. Benign acute myositis associated with H1N1 influenza A virus infection. Eur J Pediatr 2010;169:1159e61. [3] Agyeman P, Duppenthaler A, Heininger U, Aebi C. Influenza-associated myositis in children. Infection 2004;32:199e203. [4] Belanger C, Zhang KS, Reddy AK, Yen MT, Yen KG. Inflammatory disorders of the orbit in childhood: A case series. Am J Ophthalmol 2010;150:460e3.
[5] Yuen SJA, Rubin PAD. Idiopathic orbital inflammation: Distribution, clinical features, and treatment outcome. Arch Ophthalmol 2003; 121:491e9. lu S, Hallaç IK, Poyrazog lu MH. [6] Aydin K, Narin N, Erkiliç K, Kurtog Bilateral proptosis caused by orbital myositis: A case report. Turk J Pediatr 1998;40:135e8. [7] Culligan B. Orbital myositis following streptococcal pharyngitis in a pediatric patient. Optometry 2005;76:250e8. [8] Migita M, Matsumoto T, Fujino O, Takaishi Y, Yuki N, Fukunaga Y. Two cases of influenza with impaired ocular movement. Eur J Paediatr Neurol 2001;5:83e5. [9] Manuchehri K, Lagnado R, Butler L. A case of orbital myositis secondary to orbital cellulitis in a child. Eye 2003;17:434e6. [10] Michot C, Hubert L, Brivet M, et al. LPIN1 gene mutations: A major cause of severe rhabdomyolysis in early childhood. Hum Mutat 2010;31:E1564e73. [11] Davis LE. Neurologic and muscular complications of the 2009 influenza A (H1N1) pandemic. Curr Neurol Neurosci Rep 2010;10: 476e83. [12] Domínguez-Cherit G, Lapinsky SE, Macias AE, et al. Critically ill patients with 2009 influenza A (H1N1) in Mexico. JAMA 2009;302: 1880e7.