title: The effect of epidural methylprednisolone acetate injection on the hypothalamic-pituitary-adrenal axis.
abstract: OBJECTIVE
  To evaluate the effect of an epidural corticosteroid injection of 80 mg and 40 mg of methylprednisolone acetate on the hypothalamic-pituitary-adrenal axis and on back pain.
  
  
  METHODS
  Randomized, single-blinded prospective study.
  
  
  METHODS
  Operating room of a university-affiliated hospital.
  
  
  METHODS
  42 patients with low back pain due to radiculopathy.
  
  
  METHODS
  Group 1 received an epidural corticosteroid injection of 80 mg of methylprednisolone acetate, and Group 2 received an epidural corticosteroid injection of 40 mg of methylprednisolone acetate. All study patients underwent a stimulation test of one μg of adrenocorticotropin hormone (ACTH), and their pain levels were graded just prior to and following the epidural corticosteroid injection on weeks one, 3, and 4.
  
  
  METHODS
  Serum cortisol of the ACTH stimulation tests and back pain levels were rated using a visual analog scale (VAS). Serum cortisol levels lower than 18 ng/mL 30 minutes following the ACTH stimulation test were considered to be secondary adrenal insufficiency.
  
  
  RESULTS
  21 patients were enrolled in each group. The rate of secondary adrenal insufficiency in Group 1 was ~86%, ~ 22%, and ~17% of patients versus ~53% (P = 0.024), 15% (P = 0.874), and ~12% (P = 0.715) of Group 2 patients at weeks one, 3, and 4, respectively. About 62%, 56%, and 39% of Group 1 patients had a favorable clinical response as opposed to ~47% (P = 0362), 35% (P = 0.21), and ~6% (P = 0.049) of Group 2 patients at weeks one, 3, and 4, respectively.
  
  
  CONCLUSIONS
  Epidural corticosteroid injection of methylprednisolone acetate in both groups was associated with very high rates of secondary adrenal insufficiency, but significantly more so in Group 1 at week one. This suppression was transient, with recovery of the gland in most patients noted over the ensuing weeks. An epidural corticosteroid injection of 80 mg had higher rates of favorable clinical response than a 40 mg injection, but significantly more so at week 4 only. This favorable response waned over a few weeks in both groups.
authors.affiliation: Rheumatology Clinic, Nazareth Hospital, Nazareth 16000, Israel; Deputy, Department of Medicine, Carmel Medical Center, Haifa, Technion Faculty of Medicine, Haifa 34362, Israel. Electronic address: gshabib@gmail.com.
authors.forename: George
authors.initials: G
authors.lastname: Habib
authors.affiliation: Central Laboratory, Nazareth Hospital, Nazareth 16000, Israel.
authors.forename: Adel
authors.initials: A
authors.lastname: Jabbour
authors.affiliation: Department of Anesthesiology, Nazareth Hospital, Nazareth 16000, Israel.
authors.forename: Jameel
authors.initials: J
authors.lastname: Salman
authors.affiliation: Department of Orthopedics, Nazareth Hospital, Nazareth 16000, Israel.
authors.forename: Geries
authors.initials: G
authors.lastname: Hakim
authors.affiliation: Department of Anesthesiology, Nazareth Hospital, Nazareth 16000, Israel.
authors.forename: Henry
authors.initials: H
authors.lastname: Haddad
mesh_terms: D000309:Adrenal Insufficiency / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D000324:Adrenocorticotropic Hormone; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004305:Dose-Response Relationship, Drug; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000503:physiopathology; D007268:Injections, Epidural; D017116:Low Back Pain / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000077555:Methylprednisolone Acetate; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000503:physiopathology; D011446:Prospective Studies; D016037:Single-Blind Method; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D000077555:Methylprednisolone Acetate; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone; D008775:Methylprednisolone
keywords: Back pain; Corticosteroids; Epidural analgesia; Hypothalamic-pituitary-adrenal axis; Methylprednisolone acetate; Secondary adrenal insufficiency; chronic