Pyomyositis

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Obesity, Sleep & Internal medicine
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Pyomyositis
File:Pyomyositis MRI.jpg MRI showing pyomyositis
Synonyms	Tropical pyomyositis, myositis tropicans
Pronounce
Specialty	Infectious disease, Rheumatology
Symptoms	Fever, muscle pain, swelling
Complications	Sepsis, abscess formation
Onset
Duration
Types
Causes	Bacterial infection, commonly Staphylococcus aureus
Risks	Immunodeficiency, trauma, malnutrition
Diagnosis	MRI, CT scan, ultrasound, blood culture
Differential diagnosis	Cellulitis, osteomyelitis, deep vein thrombosis
Prevention
Treatment	Antibiotics, surgical drainage
Medication
Prognosis	Generally good with treatment
Frequency	More common in tropical regions
Deaths	Rare with appropriate treatment

Pyomyositis is rare bacterial infection of the skeletal muscle (the muscles used for movement).

File:Tropical pyomyositis CT.JPG

File:X-ray of soft tissue swelling of right thigh.jpg

Causes

Approximately 90% of cases are caused by the bacterium, Staphylococcus aureus.

Riskfactors

Risk factors for the condition include strenuous activity, muscle trauma, skin infections, infected insect bites, illicit drug injections, connective tissue disorders, and diabetes.

Signs and symptoms

Signs and symptoms may include pain and tenderness of the affected muscle, fever, and abscess formation. If left untreated, the abscess may extend into the bone and joint or blood poisoning may occur. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Fever
• Myalgia(Muscle ache)
• Myositis(Muscle inflammation)
• Recurrent cutaneous abscess formation
• Subcutaneous nodule(Firm lump under the skin)

30%-79% of people have these symptoms

• Leukocytosis(Elevated white blood count)
• Testicular teratoma
• Weight loss

5%-29% of people have these symptoms

• Renal insufficiency(Renal failure)
• Sepsis(Infection in blood stream)
• Sudden cardiac death(Premature sudden cardiac death)

Diagnosis

• Pus discharge culture and sensitivity
• X ray of the part to rule out osteomyelitis
• Creatinine phosphokinase (more than 50,000 units)
• MRI is useful.
• Ultrasound guided aspiration..

Treatment

Treatment generally includes surgical drainage of the abscess and antibiotics.

Epidemiology

Pyomyositis is mainly a disease of children and was first described by Scriba in 1885. Most patients are aged 2 to 5 years, but infection may occur in any age group.Infection often follows minor trauma and is more common in the tropics, where it accounts for 4% of all hospital admissions. In temperate countries such as the US, pyomyositis was a rare condition (accounting for 1 in 3000 pediatric admissions), but has become more common since the appearance of the USA300 strain of MRSA.