Hyperbaric oxygen treatment in a rare complication of intramuscular injection: four cases of Nicolau syndrome.

Intramuscular injections are one of the most common clinical procedures. The objectives of this case series are to analyse the role, timing and efficacy of hyperbaric oxygen treatment (HBOT) in the management of Nicolau syndrome (NS), an extremely rare complication of this common intervention. Clinical, demographic, laboratory and microbiological data extraction were performed through retrospective analysis of the medical records of all patients with NS who were referred for HBOT over a 10-year period with wounds, ischaemia, infection or necrosis at the injection site following drug injection; four patients with NS were included. All injections were made via the intramuscular route; three adult cases followed a non-steroidal anti-inflammatory drug, diclofenac sodium and one in a child followed penicillin injection. The time between diagnosis/injection and HBOT ranged from five to 33 days. NS can develop despite all preventive measures based on injection technique guidelines. HBOT appeared beneficial to healing of NS when administered with other therapeutic approaches. Due to the missing pieces of the puzzle in pathogenesis, NS is rarely completely reversible; keeping the awareness high for undesirable complications stands out as the most effective approach.