Pyomyositis — Clinical guidelines — Diagnosis and treatment manual — MSF Clinical guidelines — Médecins Sans Frontières 2026

MSFClinical guideline (chapter)Current edition

From Clinical guidelines — Diagnosis and treatment manual › Chapter 10: Medical and minor surgical procedures · Médecins Sans Frontières, Current online edition, 2026

MSF guidance on diagnosis and surgical management of staphylococcal muscle infections for clinicians in resource-limited settings.

In one sentencePyomyositis, almost always staphylococcal, requires limb immobilisation, systemic antibiotics, 70% alcohol compresses twice daily, and definitive surgical incision and drainage with large drain removal around day 5; needle aspiration alone is insufficient.

Issuer: Médecins Sans Frontières
Edition: Current online edition, 2026
Audience: Clinicians in resource-limited settings
Evidence: Expert consensus
Reviewed: 22 Oct 2026 · GMJ

Read the original on MSF Whole guideline (PDF)

Summary by GMJ Guidelines Desk•Reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD•Record updated 22 Oct 2026•Next check Apr 2027

What this guideline says

GMJ summary

This MSF clinical guideline addresses pyomyositis, a bacterial infection of skeletal muscle almost always caused by Staphylococcus aureus. The condition most commonly affects limb and torso muscles, with risk factors including immunosuppression, concurrent S. aureus infection, malnutrition, trauma and injection drug use. Delayed treatment carries significant mortality risk.

Clinical presentation includes exquisite muscle tenderness, oedema giving muscles a ‘woody’ texture on palpation, regional adenopathy and fever. Psoas muscle involvement presents with a flexed hip and pain on extension, mimicking appendicitis when right-sided. Complications include septic emboli, endocarditis, septic arthritis and septic shock.

The guideline emphasises that definitive treatment is surgical incision and drainage under aseptic conditions, preceded by limb immobilisation, systemic antibiotic therapy and compresses soaked in 70% alcohol applied 2 times daily (maximum 3 times daily to prevent skin burns). The surgical technique involves generous incision along the limb axis, dissection of muscle fibres with non-toothed forceps or round-tipped scissors, evacuation of pus, abundant washing with 0.9% sodium chloride, and insertion of a large drain removed around the 5th day. Needle aspiration alone is insufficient even if pus is evacuated.

Key points

For clinicians — doses and thresholds as stated in the guideline

Pyomyositis is almost always caused by <em>Staphylococcus aureus</em> and carries significant mortality risk if treatment is delayed
Clinical diagnosis: exquisite muscle tenderness, oedema giving 'woody' texture on palpation, regional adenopathy and fever
Immobilise the limb and apply compresses soaked in 70% alcohol 2 times daily (maximum 3 times daily to prevent skin burns) until incision and drainage
Initiate systematic antibiotic therapy as for erysipelas and cellulitis
Definitive treatment is surgical incision and drainage under aseptic conditions; needle aspiration is insufficient even if pus is evacuated
Surgical technique: generous incision along limb axis, dissect muscle fibres with non-toothed forceps (Kelly type) or round-tipped scissors perpendicular to muscle fibres
After evacuating pus, wash abundantly with 0.9% sodium chloride, insert large drain and remove drain around the 5th day
For pyomyositis of the psoas muscle, start antibiotics and refer to a surgeon

From the guideline

Verbatim

“Needle aspiration is insufficient treatment even if pus is evacuated and should be followed by surgical incision and drainage.”

— Médecins Sans Frontières, Pyomyositis — Clinical guidelines — Diagnosis and treatment manual — MSF Clinical guidelines, Treatment section (2026)

Editor’s perspective

Why this matters for Georgia and the region

Prof. Giorgi Pkhakadze, MD, MPH, PhD

Editor-in-Chief, Georgian Medical Journal · Chair, Public Health Institute of Georgia · WHO consultant, health and migration

As Chair of the Public Health Institute of Georgia, I recognise pyomyositis as an underdiagnosed entity in our region, particularly among people who inject drugs and those with HIV-related immunosuppression—populations we encounter regularly in Tbilisi and regional centres. The MSF guideline's emphasis that needle aspiration is insufficient even when pus is obtained is critical for Georgian clinicians who may lack surgical confidence and attempt conservative drainage. The specific technique of dissecting muscle fibres perpendicular to their orientation with Kelly forceps and the clear timeline for drain removal (around day 5) provide practical procedural guidance often missing from standard texts. However, successful implementation requires that district hospitals maintain adequate stocks of large-bore drains and that referral pathways to surgical centres are functional for deep psoas abscesses, which remains a challenge in mountainous areas of Georgia and neighbouring Armenia and Azerbaijan.

ORCID 0000-0001-7609-4515 · Perspective written for the GMJ Guidelines Library, 22 Oct 2026

Applicability

Georgia and the South Caucasus

Pyomyositis is an important consideration in Georgia and the South Caucasus, particularly given the prevalence of injection drug use in the region and the burden of HIV-related immunosuppression. The guideline’s emphasis on surgical drainage is directly applicable to Georgian district hospitals and regional centres equipped with minor surgical capacity. National programmes would need to ensure availability of POCUS training for clinicians, as point-of-care ultrasound assists in abscess characterisation and can rule out deep venous thrombosis. The recommendation for 70% alcohol compresses and specific drain management protocols can be readily integrated into existing infection management pathways in Georgian primary and secondary care facilities, though referral networks to surgical centres for deep psoas abscesses should be clearly defined.

Questions this guideline answers

Quick answers

Is needle aspiration sufficient treatment for pyomyositis?

No. Needle aspiration is insufficient treatment even if pus is evacuated. It may be necessary to locate deep abscesses, but must always be followed by surgical incision and drainage.

How often should alcohol compresses be applied?

Apply compresses soaked in 70% alcohol 2 times daily, with a maximum of 3 times daily to prevent burns to the skin, until incision and drainage is performed.

When should pyomyositis of the psoas muscle be referred?

Start antibiotics and refer to a surgeon. Psoas pyomyositis requires specialist surgical management due to its deep location and potential complexity.

When should the drain be removed after incision and drainage?

Remove the drain on about the 5th day. The drain should be fixed to the edge of the wound using a single suture.

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Pyomyositis — Clinical guidelines — Diagnosis and treatment manual — MSF Clinical guidelines

What this guideline says

Key points

From the guideline