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What is Pyomyositis: Causes, Symptoms, Treatment, Prognosis, Diagnosis

What is Pyomyositis?

Pyomyositis which is also known by the name of Tropical Pyomyositis is a rare pathological condition of the musculoskeletal system in which there is development of muscle abscess as a result of bacterial infection, especially staphylococcus aureus. Pyomyositis usually affects people within the age range of 10 to 40 years who may be otherwise in a very healthy state.

It tends to affect both males and females but males tend to get Pyomyositis more than females. A muscle abscess may develop resulting in Pyomyositis due to a muscle trauma from an injury. IV drug abuse is yet another condition which may cause muscle abscess resulting in Pyomyositis.

IM injections given for many medical conditions can also result in development of a muscle abscess causing Pyomyositis. Additionally, certain nutritional deficiencies, diabetes mellitus, and most commonly people with HIV are more at risk than others for developing Pyomyositis.

What is Pyomyositis?

What Causes Pyomyositis?

As stated, Pyomyositis is basically a bacterial infection which results in development of abscess of muscles. The primary bacterium responsible for Pyomyositis has been identified to be Staphylococcus Aureus which constitutes to about 95% of cases of Pyomyositis.

Apart from this, Group A streptococcus also is responsible for development of Pyomyositis in around 10% of cases.

Gram negative bacillus is yet another type of bacterium which is responsible for a few cases of Pyomyositis. The most recent bacterium which has been added to the list is methicillin resistant Staphylococcus Aureus or (MRSA) has been identified as causing Pyomyositis.

What are the Symptoms of Pyomyositis?

Abscess formation in the muscles is the classic presenting feature of Pyomyositis. There can be a single abscess or multiple abscesses around various muscle groups. Pyomyositis is mostly seen in abdominal muscles, muscles of the spine, the gluteal muscles, quadriceps, pectoralis major, serratus anterior muscle, biceps muscle, iliopsoas muscle along with the gastrocnemius muscle.

The symptoms of Pyomyositis develop over a period of time depending on the stages of the condition. In the first stage which is also called as the invasive stage the affected individual may experience a couple of weeks of diffuse muscle pain which may be accompanied at times by low grade fever.

As the condition advances and reaches the second stage which is called the suppurative stage there is development of a mass like lesion in the muscle which grows with the passage of time and gradually becomes hard and painful. The area of the mass may be tender to palpation. It may be accompanied by high fever along with nausea and vomiting in some cases.

If left untreated, Pyomyositis advances to the third and the most severe stage in which the abscess may infiltrate into other bone and joints surrounding it or may cause septicemia which is a life threatening condition and may cause renal failure and other severe complications. It may endanger the life of the affected individual.

How is Pyomyositis Diagnosed?

Since Pyomyositis is a rare medical condition, hence diagnosing it is a bit difficult and the initial presenting features of this condition resembles many other medical conditions. The formation of an abscess may also be hidden due to overlying muscles. To confirm a diagnosis of Pyomyositis, blood tests will be done to look at the levels of ESR and CRP which will be elevated in cases of bacterial infection.

An analysis of the blood will help in identifying the offending bacteria. Muscle enzymes may also be checked which may be elevated in cases of Pyomyositis. An ultrasound of the affected muscle will clearly show collection of fluid indicative of Pyomyositis. Advanced radiological studies in the form of CT or MRI scan will definitively confirm the diagnosis of Pyomyositis.

How is Pyomyositis Treated?

The best possible way to treat Pyomyositis is by way of surgical drainage of the abscess accompanied with wound closure to allow for faster healing. Post drainage, antibiotics will be prescribed which will eliminate the offending bacteria from the system and prevent recurrence. For HIV patients, broad spectrum antibiotics will be utilized due to their immune compromised state. A typical course of antibiotics is for about a week to 10 days depending on the stage of the condition for treatment of Pyomyositis.

What is the Prognosis of Pyomyositis?

Pyomyositis is definitely curable if it is diagnosed in its early stages. A delay in diagnosis may lead to potential complications some of which may be quite serious and life threatening. Thus it is recommended if there is a suspicion of Pyomyositis then to contact the primary care physician who can help identify the cause of the condition and formulate a treatment plan to treat Pyomyositis.


  1. Ameh EA, Dogo PM. Surgical treatment of tropical pyomyositis. In: Surgical Infections in the Tropical World. Springer, Berlin, Heidelberg; 2011. pp. 225-230.
  2. Del Pozo JL, Patel R. Clinical practice. Infection associated with prosthetic joints. N Engl J Med. 2009;361(8):787-794. doi: 10.1056/NEJMcp0905029.
  3. Gianfaldoni S, Tchernev G, Wollina U, et al. Tropical Dermatology: Tropical Pyomyositis (Myositis Tropicans) – Historical Perspective and Current Status. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821161/
  4. John TJ, Desikan KV. Pyomyositis. J Trop Pediatr. 2000;46(1):55-56. doi: 10.1093/tropej/46.1.55.
  5. Tong SY, Steer AC. Pyomyositis in tropical Australia. J Infect. 2001;42(1):49-54. doi: 10.1053/jinf.2000.0733.

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Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:August 3, 2023

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