Psoriasis

Look at the back before you promise a block - the classic distribution is extensor surfaces, scalp, and lumbosacral skin, so plaques over the lumbar spine are the rule rather than the exception. Inspect the intended interspace: plaques are sterile, but fissured, scaling skin is colonized and is not what you want to push a needle through. Pick a clear interspace, or plan a general if the whole field is involved.

Koebner phenomenon - trauma to previously unaffected skin produces new lesions clinically and histologically identical to the underlying disease. Needle sticks, tourniquets, and aggressive adhesive stripping can all seed a plaque later. Minimize skin trauma and lift tape rather than pulling it.

Ask what they are on and when they last took it - serious infection is the most feared complication of biologic response modifiers, which is why they require screening before initiation and monitoring during therapy. The National Psoriasis Foundation guidance on perioperative management of systemic immunomodulatory agents (in the suggested readings) is the document the surgical and rheumatology teams should be using for hold-and-restart decisions. Do not improvise that at the board.

Methotrexate - an antimetabolite used as an immunosuppressant in autoimmune disease. Get current values rather than last year's: CBC, liver function tests, and renal function before an elective case, particularly when significant blood loss or a regional technique is planned.

Immunosuppression raises your sterile threshold - these patients are on drugs whose defining complication is serious infection. Full barrier technique for neuraxial and central lines, and a low threshold to defer an elective case when an active infection is present.

A guttate flare means active streptococcal infection - guttate psoriasis is classically triggered by streptococcal pharyngitis or perianal infection. A new drop-like eruption with a sore throat is an untreated infection sitting in front of an elective anesthetic.

Erythrodermic flare is a systemic problem - erythroderma is diffuse erythema and scaling over 90% of body surface area and can be life-threatening. With that much barrier gone, expect insensible fluid loss and impaired thermoregulation. Warm the room before the patient arrives, use forced-air warming and warmed fluids, and put a temperature probe on from the start.

Monitoring on abnormal skin - thick scale and dystrophic psoriatic nails degrade both ECG contact and pulse oximetry. Put electrodes on clear skin and move the oximeter to an ear or forehead when the nail beds are involved.

Psoriatic arthritis rides along - it is present in about 20% of psoriasis patients and shares clinical features with the spondyloarthropathies and rheumatoid arthritis, which is where the airway, cervical spine, and joint-positioning questions come from. See the psoriatic arthritis entry for those.

Psoriasis is the most prevalent immune-mediated inflammatory disease: a chronic proliferative and inflammatory condition of the skin marked by well-demarcated erythematous plaques under silvery scale, classically over the extensor surfaces, scalp, and lumbosacral region. Plaque psoriasis is the common form. Guttate (drop-like lesions triggered by streptococcal pharyngitis or perianal infection), pustular, generalized pustular, nail, and palmoplantar variants also occur.

It is not confined to skin. It involves nails and joints, psoriatic arthritis appears in about 20% of patients, and the disease is associated with abnormalities of other systems. Two features drive the anesthetic. The lumbosacral distribution puts plaques exactly where a neuraxial needle goes, and control of the disease requires systemic immunomodulation with methotrexate, biologic response modifiers, or JAK inhibitors, so the patient in front of you is immunosuppressed.