ABSTRACT

Serotonin sendromu serotonerjik aşırı etkinlik sonucu oluşan bir ilaç yan etkisidir. Hafif şiddette olup gözden kaçabildiği gibi hayatı tehdit eden ciddi sonuçları olabilmektedir. Serotonerjik etkili bir veya daha fazla ilacın bir arada kullanılması bu sendroma yol açar (Dokuz Eylül). Buradaki olgu 25 yaşında kadın hasta olup intihar amaçlı yüksek doz 60 adet 100 mg Faver (Fluvoxamine), 20 adet 50 mg Setral (Setraline), 10 adet 20 mg Paxil (Paroxetine) almıştır.

Keywords: SSRI overdose, myoclonus, Serotonin syndrome

Introduction

Sertraline is a selective serotonin (5-Hydroxytryptamine, or 5-HT) reuptake inhibitor (SSRI) (1). This group of drugs reversibly blocks reuptake of 5-HT in the synaptic range (1). It is effective in the treatment of sertraline depression, obsessive-compulsive disorder, and eating and personality disorders. It is widely reported that sertraline is efficacious and well-tolerated (2). Fluvoxamine acts as an antiobsessional and antidepressant by selectively affecting the presynaptic gaps (3). Like Fluvoxamine and sertralin, paroxetine is also an SSRI.

The therapeutic index of SSRIs is considerably wide. Mortality brought about by SSRIs only is rare (4). Our case is a 25-year-old female patient who attempted suicide by ingesting an overdose of her prescription medications: 60 units of 100-mg Faver (Fluvoxamine), 20 of 50-mg Setral (Setraline), and 10 of 20-mg Paxil (Paroxetine).

Case Report

A 25-year-old female patient diagnosed with obsessive-compulsive disorder and depression was brought to the emergency room of Nusaybin State Hospital after informing her relatives she did not feel well as a result of having attempted suicide a half hour earlier by ingesting an overdose of her prescription medications: 60 units of 100-mg Faver (Fluvoxamine), 20 of 50-mg Setral (Setraline), and 10 of 20-mg Paxil (Paroxetine).

In her physical exam when she was first admitted, her general condition was moderate, with a BP of 160/90 mmHg, a pulse of 150/min. a temperature of 36.5 °C, tachypnea, and sweating. She was conscious and exhibited restlessness and mild apathy and agitation; she was partially cooperative and occasionally established eye contact. She suffered no neck stiffness and showed no signs of meningeal irritation. At irregular intervals the patient was observed to repeatedly turn her head to face first one side then the other. Her speech was normal, albeit reduced. Jerky eye movements were present in the form of horizontal spasmodic vibrations. Her pupils were slightly dilated and responded weakly to direct and indirect light. In addition, there was clearly no extraocular muscle weakness as spontaneous eye movements in all directions were observed. She had full muscle strength in all extremities. The upper (biceps, stiloradial, and triceps) deep tendon reflexes were slightly increased, while lower ones (patella and Achilles) were lively, with a few cycles of clonus. Myoclonus was present in the lower extremities. The patient’s plantar reflexes were extensor responses (Babinski signs). Due to the patient’s mental state, it was impossible to evaluate the sensory examination. Examination of the extrapyramidal system revealed mild rigidity in the patient’s upper and lower extremities. All other systemic examinations were normal. The hemogram and biochemical parameters of her first laboratory tests were: albumin 5.58 g/dL, Na 147 mmol/L, Cl 113 mmol/L, Ca 11.7 mg/dL, and WBC 12.5 (x10) K/µL; all other values were within normal reference ranges. It was impossible to measure the blood levels of the drugs she had taken. We were likewise unable to measure the patient’s blood gases.

The patient was hydrated intravenously in the emergency room. Gastric lavage performed by nasogastric tube revealed residues of 6 unknown drugs. Activated charcoal (1 mg/kg) was administered. Upon completion of initial intervention, the patient was admitted to Intensive Care to be monitored for serotonin syndrome. Activated charcoal treatment was continued in ICU with a second dose (1 mg/kg). The patient was sedated for the first 24 hours with an infusion of Demizolam. I and O were monitored. The patient was treated twice (3 mg and 2 mg) with ampules of Beloc (metoprolol) for tachycardia. In spite of the fact that the treatment administered prevented elevated body temperature, the patient complained of fever; yet her temperature remained between 36.5 °C and 37.2 °C. BP ranged from 98/67 to 160/94 mmHg. The patient’s blood glucose level fell to 80 mg/dL, so she was administered 5% dextrose in the 4th hour. Lower extremity myoclonus lasted 16 hours. No abnormality was observed in laboratory parameters. The patient was discharged on the 3rd day of hospitalization in good general condition. Evaluation of the patient on the 2nd and 4th days following discharge revealed no symptoms.

Conclusion

Serotonin syndrome is a toxic condition resulting from postsynaptic serotonin hyperstimulation of neurons (5,6). This side effect occurs most often in patients prescribed single or multiple medications increasing the serotonin level in postsynaptic gaps (6,7). The Hunter serotonin toxicity criteria, the Sternbach criteria, and the Radomski criteria are used for diagnosis of serotonon syndrome (8-10) (Table 1). Serotonin syndrome consists of cognitive behavioral changes, neuromuscular hyperactivity, and autonomic activation. Our reasons for considering serotonin syndrome in this case were the patient’s suicidal overdose on SSRIs; coupled with the presence of such pyramidal irritation and extrapyramidal neurologic findings as changes in mental state (fluctuations in consciousness), acute onset myoclonus, ocular clonus, rigidity, increased deep tendon reflexes, Achilles clonus, and Babinski signs, all of which are major symptoms included in diagnostic criteria; as well as the occurrence of autonomic symptoms like tachypnea, perspiration, sinus tachycardia, weak pupil response, dilation of the pupils, and hypertension. In the differential diagnosis, the infectious, metabolic, and toxic causes necessitating this view must also be taken into account (11). In our case, infectious reasons were not considered, most especially because of the multiple overdoses of serotonergic agents specified in the patient’s history, but also due to the absence of neck stiffness despite all of these clinical findings, as well as to the presence of a multifocal and quickly improved clinical picture that simultaneously affected the central, peripheral, and autonomic nervous systems, such as the occurrence of pyramidal, extrapyramidal, and autonomic signs coincidental with changes in mental state.

Physical examination and medical history hold an important place in the differential diagnosis of Neuroleptic Malignant syndrome (NMS), malignant hyperthermia, and serotonin syndrome. NMS is an idiosyncratic reaction to antipsychotic drugs like butyrophenones and phenothiazines (12). It is thought to be caused by dopamine receptor blockers. It usually begins with altered consciousness and hyperthermia followed by muscle rigidity. Only dopaminergic drugs cause NMS. It develops after several days, in contrast to serotonin syndrome. Patients improve days or weeks later (12). The onset of and recovery from symptoms of serotonin syndrome, on the other hand, both occur within hours. Whether ingestion of the drug is suicidal or therapeutic, symptoms occur in the first 6 hours in most cases. In our case, too, the myoconus appeared within the first few hours and lasted 16 hours.

Malignant hyperthermia is a syndrome resulting from a genetic predisposition to neuromuscular blockers such as succinylcholine and anesthetic agents like halothane (13). This syndrome occurs within minutes after exposure to anesthetic agents. A hypermetabolic state characterized by muscular rigidity and increased oxygen consumption and carbon dioxide production, metabolic acidosis, and hyperthermia are all characteristic features of malignant hyperthermia (14). We believe the reason malignant hyperthermia did not develop on our case was because it was averted by early diagnosis and treatment and by the patient’s resultant early recovery.

There is no specific antidote or treatment for serotonin toxicity. Early diagnosis and supportive treatment are important. Avoiding the potential drug reaction between two serotonergic drug therapies is a basic factor in prevention of this syndrome (15-17). When initiating treatment of serotonin syndrome, the first priority is to discontinue the medication causing this condition. Nonspecific serotonin receptor blockers such as benzodiazepines, propranolol, chlorpromazine, ciproheptadin, and methysergide may be used in the treatment of serotonin syndrome (18). Although there are cases of overdose on single serotonergic drugs, generally symptoms in every age group – young, elderly, and even neonatals-appear when two or more such medications are taken together, even if each is taken in therapeutic doses (19). In our case, the patient overdosed on three serotonergic drugs; serotonin syndrome was the result.

Informed Consent: Consent form was filled out by all participants, Concept: Yavuz Orak, Sevgi Akbulut, Design: Yavuz Orak, Data Collection or Processing: Yavuz Orak, Sevgi Akbulut, Analysis or Interpretation: Yavuz Orak, Sevgi Akbulut, Literature Search: Yavuz Orak, Writing: Yavuz Orak, Hakem Değerlendirmesi: External and Internal peer-reviewed, Conflict of Interest: No conflict of interest was declared by the authors, Financial Disclosure: The authors declared that this study has received no financial support.