Influenza B myositis, case report, in hospital Roosevelt, Guatemala city

Influenza B myositis is a self-limited process that is typically accompanied by myalgia and muscle weakness, which can be caused by an acute respiratory infection. It occurs in the convalescence phase of the disease. It can usually affect preschool and school children, who present bilateral pain and tenderness in the muscle groups of the lower limbs without alterations in the neurological examination. Being able to generate an alteration in the brand or bipedestation. Its main complication is rhabdomyolysis. In Guatemala is difficult to test for viral respiratory infection and the incidence of viral myositis is unknown, for which we consider the report important because it presents a benign course and is easy to manage with the use of non-steroidal anti-inflammatory drugs, to avoid unnecessary hospitalizations. We present to case report to an 8-year-old male patient, previously healthy, with diagnostic de Influenza B myositis.

Acute myositis is a self-limited process that is typically accompanied by myalgia and muscle weakness, which can be caused by an acute respiratory infection. It occurs in the convalescence phase of the disease. It is important to note that influenza is still a vaccine-preventable disease [1,2].

An 8-year-old male patient, previously healthy, not immunized for Influenza, with no significant background, who 5 days prior to seeking medical care started with a fever of 39 degrees Celsius with the use of paracetamol, a cough developed at non-specific times. He developed weakness in the lower limbs and pain when walking, which is why he went to urgent care. In the physical examination, it is demonstrated that there is pain upon palpation in the gastrocnemius region, and has difficulty supporting his own weight when standing. A rapid Influenza A/B test was performed, coming back positive for Influenza B. Elevation of muscle enzymes CPK: 6160 U/l, CK-MB: 150.3 U/l was documented. He does not present any symptoms compatible with rhabdomyolysis, with which he is followed up for 48 hours, controls are carried out with CPK: 750 U/I, CK-MB: 56 U/I and he was discharged [3,4].

Influenza B myositis occurs during the post-influenza episode, it usually manifests with muscle pain, muscle weakness and, a regular neurological assessment. It is usually associated with an elevation of muscle enzymes, which could be associated with renal failure and myoglobinuria. It is a self-limited process and the treatment is pain management, with complete recovery at around 10 days and usually does not produce any side effects [5,6].

It is a benign disease with outpatient management.

Prior evaluation is important and according to the clinical characteristics, the performance of complementary tests.

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