Injections and aspirations are generally safe, but complications do occur, and competence means being able to anticipate them, recognise them early and manage them rather than simply listing them at the consent stage. Complications divide usefully into three groups: those that are common and usually self-limiting, such as a post-injection flare and a vasovagal episode; those that are uncommon but serious and time-critical, such as septic arthritis and local anaesthetic systemic toxicity; and those that are specific to the agent injected, such as skin and fat changes or tendon rupture after corticosteroid. For the sport and exercise medicine (SEM) clinician the practical skill is knowing which is which at the point the patient contacts you. This page covers immediate complications and how to manage them, delayed complications and how to distinguish benign from serious, and how complications should be documented and reported.
What can go wrong during or immediately after a procedure?
The most common immediate event is a vasovagal episode, which is a physiological response to the procedure rather than to the drug, and which is under-recognised precisely because it is benign. The patient becomes pale, sweaty and nauseated, with a slow pulse and falling blood pressure, and may briefly lose consciousness. Management is simple and effective: stop the procedure, lay the patient flat and elevate the legs, protect them from falling, and allow recovery before sitting them up slowly. Injecting supine where practical can reduce the risk of fainting and of injury from a fall, particularly if the patient is anxious, has fainted before, or the procedure will be prolonged. The important error is mistaking a vasovagal episode for anaphylaxis, and the discriminator is persistence and the pattern of compromise: anaphylaxis is recognised by sudden airway, breathing or circulation compromise that does not resolve with positioning, and it may occur with or without skin or mucosal changes such as urticaria, angioedema or flushing, so their absence does not exclude it. Anaphylaxis is treated with intramuscular adrenaline, five hundred micrograms in an adult, repeated after five minutes if there is no improvement, with the patient kept lying flat.
Complications separate by time course: vasovagal episodes and local anaesthetic toxicity occur immediately, a flare peaks within a day or two and settles, and septic arthritis, skin and fat atrophy and tendon rupture appear later. A flare settles; infection escalates.
Local anaesthetic systemic toxicity is uncommon but must be recognised, since it can progress rapidly. Early features include numbness around the mouth, a metallic taste, tinnitus and agitation, which may progress to seizures and then cardiovascular collapse; the sequence is not fixed, and toxicity can present suddenly with cardiovascular compromise and no warning symptoms, or with delayed onset. Management follows the national safety guideline: stop injecting, call for help, give oxygen with effective ventilation, control seizures with a benzodiazepine, and give twenty per cent lipid emulsion as a bolus followed by infusion, following an immediately available current local anaesthetic systemic toxicity checklist. Resuscitation is modified to use reduced adrenaline dosing and to avoid further local anaesthetic, beta-blockers, calcium-channel blockers and vasopressin, and it is continued for a prolonged period since recovery can take time. Lidocaine is not used as an anti-arrhythmic in this setting. Other immediate events include bleeding or haematoma, which is usually managed with direct pressure; allergic reaction, which is rare but, if anaphylaxis is suspected, requires immediate intramuscular adrenaline as above; and direct nerve injury, suggested by immediate sharp pain or paraesthesia in a nerve distribution during needle advancement, which should prompt the operator to stop and withdraw rather than continue injecting. Pneumothorax is a specific hazard where a needle is directed close to the chest wall, such as upper thoracic, intercostal and scapulothoracic procedures, and new breathlessness or pleuritic pain after such a procedure needs urgent assessment.
How are delayed complications recognised and handled?
The critical delayed discrimination is between a post-injection flare and infection, and the discriminators are trajectory and systemic features rather than the presence of pain itself. A flare begins within hours, peaks within a day or two, settles with simple analgesia, and leaves the patient systemically well. Septic arthritis escalates: pain increases rather than decreases, the joint becomes hot and swollen with severe pain on any movement, and the patient develops fever, rigors or a general sense of being unwell. Escalating local symptoms or systemic illness at any stage require urgent assessment, aspiration where indicated with fluid sent for cell count and differential, Gram stain and culture, and urgent orthopaedic referral, with antibiotics after cultures where samples can be taken promptly and without delaying treatment in an unstable patient. Agent-specific delayed effects are also worth knowing: corticosteroid can cause depigmentation of the overlying skin and atrophy of the subcutaneous fat at the site, appearing over days to weeks, which may persist for months and can occasionally be permanent, facial flushing, and a transient rise in blood glucose that is most marked in the first one to three days and matters most in diabetes. Rupture risk is increased by intratendinous corticosteroid injection, particularly in load-bearing tendons, which is why injection into tendon substance is avoided, and it presents with sudden loss of function rather than gradual soreness.
The response is clinical management, candour where care has gone wrong and caused or may cause harm, contemporaneous documentation, local incident reporting, a Yellow Card report where a medicine or device meets the criteria, and learning through audit and appraisal.
How a complication is handled afterwards is as examinable as the clinical management. Professional candour applies when something has gone wrong with a patient's care and has caused, or may cause, harm or distress: the patient is told promptly, given an honest explanation of what happened and what will be done, and offered an apology, which is an expression of regret rather than an admission of legal liability. A recognised complication that occurs despite correct care does not automatically mean something has gone wrong, but the patient should still be informed and supported after any significant adverse outcome. The event is documented factually and contemporaneously in the clinical record, including what happened, what was done and what the patient was told. It is reported through the local incident reporting system, because the value of reporting is aggregate rather than individual: a single case reveals little, whereas a pattern can expose a contaminated batch, an equipment fault or a technique problem. Where a medicine or device is implicated and the event meets the reporting criteria, a report is made to the Medicines and Healthcare products Regulatory Agency through the Yellow Card scheme, which covers suspected adverse drug reactions and device incidents. Complications should also feed back into practice through audit, significant event analysis and appraisal, since the purpose of the governance loop is to change what happens next rather than to allocate blame.
Exam Tips
•A vasovagal episode is the most common immediate event and is usually self-limiting: pale, sweaty, nauseated, bradycardic and hypotensive; lay the patient flat and elevate the legs, and injecting supine where practical reduces the risk of fainting and injury.
•Anaphylaxis is recognised by sudden airway, breathing or circulation compromise, with or without skin or mucosal changes, so their absence does not exclude it; treat with intramuscular adrenaline five hundred micrograms in an adult, repeated after five minutes if no improvement.
•Local anaesthetic systemic toxicity may follow perioral numbness, metallic taste, tinnitus and agitation to seizures and collapse, but can present suddenly; follow an immediately available current toxicity checklist, giving oxygen, seizure control and lipid emulsion, with reduced adrenaline dosing and never lidocaine as an anti-arrhythmic.
•The key delayed discrimination is trajectory: a flare peaks and settles with the patient well, whereas septic arthritis escalates with systemic features and needs urgent assessment and referral.
•Corticosteroid-specific delayed effects include skin depigmentation and subcutaneous fat atrophy, which may persist for months and can occasionally be permanent, facial flushing, transient hyperglycaemia most marked in the first one to three days, and increased rupture risk if injected into tendon substance.
•Professional candour applies when care has gone wrong and caused or may cause harm or distress: tell the patient promptly, explain honestly, apologise, document contemporaneously, report through local incident reporting, and use the Yellow Card scheme where a medicine or device meets the reporting criteria.