Because steroids are lipophilic, they diffuse easily through the cell membranes, and therefore have a very large distribution volume. In their target tissues, steroids are concentrated by an uptake mechanism which relies on their binding to intracellular proteins (or " receptors ", see below). High concentration of steroids are also found in adipose tissue, although this is not a target for hormone action. In the human male, adipose tissue contains aromatase activity, and seems to be the main source of androgen-derived estrogens found in the circulation. But most of the peripheral metabolism occurs in the liver and to some extent in the kidneys, which are the major sites of hormone inactivation and elimination, or catabolism (see below).
A diagnosis is normally made on the basis of first excluding other causes of spinal pain (like bone or soft tissue infections, immune-mediated joint disease, infections) by obtaining a blood sample and performing radiographs. Then, cerebro-spinal fluid (CSF) analysis is performed by obtaining a sample of CSF from the neck or lower spine (or both) in a sterile manner under general anaesthesia . Your pet will have dedicated one-to-one care during their CSF tap by one of our nurses from the prep nursing team who are trained and experienced in anaesthesia and sedation . The demonstration of inflammation and the presence of a specific type of inflammatory cell facilitate a presumptive diagnosis. Although infection is very unlikely, we will normally run a panel of various blood and urine tests to exclude this possibility.
References: 1. Bikowski J, Pillai R, Shroot B. The position not the presence of the halogen in corticosteroids influences potency and side effects. J Drugs Dermatol . 2006;5(2):125-130. 2. Del Rosso J, Friedlander SF. Corticosteroids: options in the era of steroid-sparing therapy. J Am Acad Dermatol . 2005; 53(1 Suppl 1):s50-s58. 3. US Food and Drug Administration NDA 017765. Promius Pharma, LLC, Princeton, NJ: Aug 1977. 4. Rosenthal AL. Clocortolone pivalate: a paired comparison clinical trial of a new topical steroid in eczema/atopic dermatitis. Cutis . 1980;25(1):96-98. 5. Kircik LH. A study to assess the occlusivity and moisturization potential of three topical corticosteroid products using the skin trauma after razor shaving (STARS) bioassay. J Drugs Dermatol . 2014;13(5):582-585. 6. Cloderm [package insert]. Princeton, NJ: Promius Pharma, LLC; 2017.