# Pyomyositis as a rare musculoskeletal complication of chickenpox in a pediatric patient case report

## TL;DR

A child with chickenpox developed pyomyositis, a rare muscle infection, which was successfully treated with surgery and antibiotics.

## Contribution

This case report highlights pyomyositis as a rare musculoskeletal complication of chickenpox in a pediatric patient.

## Key findings

- The patient presented with right thigh pain and limping following chickenpox.
- MRI confirmed pyogenic myositis, which was drained surgically and resolved after 10 days of hospitalization.

## Abstract

Chickenpox is a common viral infection that mostly affects children from 5 to 9 years old, but it can also occur at any age group. Although typically self-limiting, chickenpox can rarely cause a severe disease and serious complications in approximately 2% of patients. Musculoskeletal complications, though less common, may be both life- and limb-threatening. Clinical manifestations include cellulitis, abscess formation, pyomyositis, necrotizing fasciitis, osteomyelitis, septic arthritis, gangrene, and toxic shock syndrome. Pyomyositis occurs when bacteria enter muscle tissue and start proliferating, resulting in inflammation, pus formation, and possibly muscle abscess. Diagnostic factors in pyomyositis consist of clinical presentation and imaging. Ultrasound (US), scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been used for diagnostic imaging in suspected cases. Treatment options can be surgical or nonsurgical (e.g., antibiotics) depending on the stage of the disease.

This case was presented to Prince Ali Military Hospital in march 2024, was diagnosed with chickenpox 5 days ago, 5 days after initial presentation, the patient returned with right thigh pain and limping that gradually became more prominent over the past 2 days. The patient's lab results included a white blood cell count (WBC) of 17,400 cells/µL and a positive C-reactive protein (CRP). The MRI showed Rt lateral compartment pyogenic myositis which was drained in theater, admitted to our hospital for 10 days post operatively, she was improved and completely healed.