A Case of Serotonin Syndrome in a Patient Receiving Epidural Steroid Injection for Chronic Low Back Pain


Mechanism of action

Drug category

Drug

Reuptake inhibition

Antidepressant
 
• SSRI

Fluoxetine, paroxetine, sertraline, citalopram, escitalopram

• SNRI

Venlafaxine, desvenlafaxine, duloxetine

• DNRI

Bupropion

• TCA

Amitriptyline, nortriptyline, clomipramine, desipramine, doxepin

• Serotonin modulator

Trazodone

Others

1. Antiepileptic—valproate, carbamazepine

2. Antiemetic—ondansetron, metoclopramide

3. Bariatric—sibutramine

4. Muscle relaxant—cyclobenzaprine

5. Amphetamine — dextromethorphan

6. Analgesic—meperidine, tramadol

7. Supplement—St. John’s wort, ginseng

8. Illicit—cocaine, MDMA

Serotonin metabolism inhibition

MAOI
 
• Antidepressants

Phenelzine, selegiline, isocarboxazid

• Antimicrobials

Linezolid

• Others

Methylene blue

Increases serotonin release

Amphetamine

Dextromethorphan, methamphetamine

Parkinsonian

Levodopa, carbidopa-levodopa

Illicit

Cocaine, MDMA

Increases serotonin formation

Amino acid

Tryptophan

Direct serotonin agonist

Antimigraine

1. Triptans—sumatriptan, rizatriptan

2. Ergots—ergotamine, methylergonovine

Analgesic

Fentanyl

Illicit

LSD

Increases sensitivity at postsynaptic receptor

Antipsychotic

Lithium



The clinical presentation is classically described as a triad of cognitive/behavioral changes (confusion, agitation, lethargy, coma), autonomic instability (hyperthermia, tachycardia, diaphoresis, nausea, vomiting, diarrhea, dilated pupils), and neuromuscular changes (myoclonus, hyperreflexia, rigidity, trismus) [13]. It is known to vary on a spectrum ranging from mild to moderate to severe including death [2]. Several sets of diagnostic criteria have been developed to define serotonin syndrome, including the Sternbach criteria [2] and the Hunter Criteria [14] (Box 9.1). In a study of the Hunter Criteria , the clinical findings that have been shown to have a statistically significant association were clonus (inducible, ocular, spontaneous), myoclonus, hyperreflexia, peripheral hypertonicity, and shivering [14]. The onset of symptoms is typically rapid; approximately 75% of patients with serotonin syndrome present within 24 h after initial use of medication, an overdose, or a change in dosing [13]. However, administration of a serotonergic agent within 5 weeks after the discontinuation of fluoxetine has been shown to initiate serotonin syndrome [15]. It does not resolve spontaneously unless the causative agents are discontinued.


Box 9.1 Comparison of Serotonin Syndrome Diagnostic Criteria














Sternbach criteria—1991

Hunter serotonin toxicity criteria—2003

Recent addition or increase in dosage of a known serotonergic agent

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Feb 26, 2018 | Posted by in Uncategorized | Comments Off on A Case of Serotonin Syndrome in a Patient Receiving Epidural Steroid Injection for Chronic Low Back Pain
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