An epidural haematoma can arise from trauma to an epidural blood vessel during catheter insertion or removal. Although the incidence of a haematoma occurring is extremely rare, particular care must be taken in patients receiving thromboprophylaxis. Initial symptoms include back pain and tenderness. As the haematoma expands to compress the nerve roots or the spinal cord, symptoms proceed to sensorimotor weakness (Lagerkranser and Lindquist [92]).

This usually occurs when the dura mater is inadvertently punctured during the placement of the epidural catheter. The main symptom is a headache, which arises from leakage of CSF through the dura (Schug et al. [166]).

In extremely rare cases, the catheter may migrate into either a blood vessel or the CSF. If it migrates into a blood vessel, opioid or local anaesthetic toxicity will occur. Opioid toxicity results in sedation and respiratory depression. Local anaesthetic toxicity results in circumoral tingling, numbness, twitching, convulsions and apnoea (Macintyre and Schug [99]). If the catheter migrates into the CSF, the epidural opioids and local anaesthetic agents may reach as high as the cranial intrathecal space. If this occurs, the respiratory muscles are paralysed together with the cranial nerves, resulting in apnoea, profound hypotension and unconsciousness (Macintyre and Schug [99]).

Meningitis is a rare complication of epidural analgesia (Macintyre and Schug [99]). The epidural route is often considered safer than the intrathecal route as the intact dura serves as an effective barrier to the spread of infection to the intrathecal space. The incidence of infection is in the range of 1–5 in 10,000 (Macintyre and Schug [99]). If the patient presents with headaches, fever, neck stiffness or photophobia, they must be reviewed as a matter of urgency by the medical or anaesthetic team; if meningitis is suspected, CSF samples can be obtained and sent to microbiology for analysis, and antibiotic therapy initiated promptly (Schug et al. [166]).

Bos et al. ([25]) note that infection can be introduced into the epidural space from an exogenous source via contaminated equipment or drugs or from an endogenous source, leading to bacteraemia that seeds to the insertion site or catheter tip. Alternatively, the catheter can act as a wick through which the infection tracks down from the entry site on the skin to the epidural or intrathecal space. Symptoms include back pain and tenderness accompanied by redness with a purulent discharge from the catheter exit site (Schug et al. [166]). Effective site care is therefore essential; see Procedure guideline 10.4: Epidural exit site dressing change.