A 42-year-old man with a personal history of alcoholism, cocaine abuse and fracture of the right tibial plateau in January 2011 which was treated surgically (osteosynthesis-plate with iliac crest graft). There was an infection of the surgical wound that led to right tibial osteomyelitis after 4 months, requiring several surgical interventions for the removal of osteosynthesis material, debridement and cleaning.
The patient has been hospitalised since 4. He has been treated with the latest generation of intravenous antibiotics administered via a central line, and orally with 2 tablets of distraneurine and bromazepam/12 h since admission (to prevent delirium due to alcohol deprivation); as analgesia: pregabalin 75-0-150, paracetamol 1 g/8 h intravenous, metamizole 2 g/8 h intravenous, tramadol 100 mg/8 h intravenous, Enantyun® 25/8 h orally and morphine 5 mg/6 h intravenous (a total of 20 mg intravenous per day).
At the 8th month of evolution of the process, the patient was referred to the Pain Unit for poor pain control.
On assessing the patient, he was in a depressed mood and in unbearable pain, with an 8 on the visual analogue scale (VAS 8), of a neuropathic type - intense burning and prickling in the right lower limb (DID) - which made it difficult for him to rest at night and even woke him up. At this time he also had fever peaks of up to 39 oC recorded in the nursing chart, with no organic repercussions.
The pain management of this patient was initially straightforward, as he presented mainly with neuropathic pain. We planned to discontinue distraneurine and bromazepam in stages. We switched from intravenous analgesia to oral analgesia, achieving a decrease in symptoms: adding and increasing antineuropathic drugs (1,2): pregabalin (up to 150 mg-0-150 mg) associated with amitriptyline (0-0-25 mg). Discontinuing intravenous morphine and switching to Oxycontin® at equianalgesic doses with morphine (10-0-10 mg) and paracetamol 1 g/8 h, requiring occasional resuscitation with Oxynorm® 5 mg.
On the fourth day of follow-up, the patient started with a significant stupor at night and the following day, without responding to stimuli or obeying orders. After ruling out exogenous opioid consumption, the total opioid dose was reduced to MST® 10-0-10 and Adolonta® 100 mg rescue if pain (requiring one before bedtime at the start of treatment and occasionally throughout the day, and no longer required after 10 days).
On the fifth day, the patient showed significant psychomotor agitation, incoherent speech and disconnection from the environment, compatible with the diagnosis of withdrawal syndrome.
We were forced to make a differential diagnosis. Having ruled out the metabolic origin of the confusional picture (normal blood tests), we thought it was an overdose/abstinence syndrome, for some due to the dose of opioid prescribed and for us due to possible substance abuse (the urine toxicity profile is not conclusive in this regard, The patient was therefore referred to psychiatry to assess the patient and confirm whether there was a pattern of substance abuse (the family denies any drug use by the patient, but they are not always with him) or another origin.
The psychiatrist's diagnostic impression was polymedication, especially opioids, and suggested a short half-life benzodiazepine to control the psychomotor agitation (alprazolam 4 mg v.o./8 h, which was progressively reduced as the symptoms subsided). In this regard, as the opioid had already been tapered, no further action was taken.
In terms of pain control, over the next 15 days, the antineuropathic treatment was very effective, except for a persistence of "shooting" pain, which required a gradual increase of amitriptyline (1.2) to 75 mg at night. This measure achieved a VAS2, with a significant improvement in night-time rest and mood. In addition, the patient no longer requires rescue, as mentioned above.
We could therefore have considered reducing the opioid medication, but the patient continued to present alterations in behaviour and level of consciousness ranging from stupor to psychomotor agitation, with the first repercussion being that the nursing staff did not administer the prescribed opioid, for fear of an opioid overdose leading to respiratory depression, and secondly, he required mechanical restraint after falling and dislocating the spacer placed in the femur.
We insisted that all the prescribed medication should be administered and the total dose of opioid (MST® 10-0-10 and Adolonta® 100 mg rescue) was maintained, so as not to relapse into possible withdrawal syndromes.
Although the patient presented with febrile peaks, the infectologists following the patient did not consider the fever or any other possible complication arising from the osteomyelitis, such as endocarditis or brain abscess, to be responsible for the condition.
As it seemed unlikely that an overdose/abstinence of the prescribed opioids was the origin of the confusional syndrome suffered by this patient for more than 2 weeks, it was decided to rule out organicity by ordering a cranial CT scan after 3 weeks of follow-up.
The cranial CT scan showed a subacute right parietal cerebral infarction.
