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Table 2 Prevalence of symptoms of serotonin syndrome

From: Conundrums in neurology: diagnosing serotonin syndrome – a meta-analysis of cases

  All (n = 299) Rhabdo-myolysis (n = 42) No rhabdo-myolysis (n = 257) Intensive care (n = 114) No inten-sive care (n = 177)
% Mental status changes
Mania 2.7 2.4 2.7 - 4.5
Confusion/consciousness impairment/semi coma 63.9 73.8 62.3 68.4 59.9
Coma 11.4 21.4 9.7 25.4** 2.8
Agitation/restlessness 56.1 45.2 58.0 60.5 53.7
Insomnia 9.7 -* 11.3 2.6** 14.7
% Neurological symptoms
Clonus
 • Spontaneous
 • Inducible
34.1
27.1
7.0
31.0
26.2
4.8
34.6
27.2
7.4
45.6**
38.6**
7.0
27.7
20.9
6.7
Eye clonus/roving eye movements
 • Spontaneous
 • Inducible
7.7
7.4
0.3
11.9
11.9
-
7.0
6.6
0.4
10.5
10.5
-
5.7
5.1
0.6
Myoclonus 41.5 35.7 42.4 43.9 39.5
Tremor 58.5 57.1 58.9 42.1** 70.1
Hyperreflexia 56.5 66.7 54.9 60.5 54.2
Rigidity/hypertonicity 45.4 59.5* 43.2 55.3* 40.6
Incoordination 15.1 4.8* 16.7 8.8* 19.8
% Vegetative symptoms
Diarrhea 15.1 7.1 16.7 13.2 17.5
Fevera 59.7 76.9* 56.0 74.0** 46.6
Hyperthermia > 41.1 °Cb 9.2 20.6* 6.5 17.6* 1.2
Diaphoresis 53.2 52.4 53.3 50.9 54.8
Shiver 15.1 16.7 14.8 19.3 12.4
Mydriasis 34.1 42.9 32.7 36.0 32.8
Tachy/bradycardiac 85.1 88.9 84.3 86.3 84.2
Hyper/hypotensiond 75.8 76.6 75.7 80.7 70.6
Tachy/dyspnea as measured by a breathing rate > 20 or hypoxia 26.4 38.1 24.5 43.9** 15.9
  1. *significant at p ≤ 0.05, **significant at p ≤ 0.01
  2. a221 of all patients, 39 cases with rhabdomyolysis and 182 without, 100 cases with intensive care and 116 without, for whom temperature was explicitly mentioned
  3. b173 of all patients, 34 cases with rhabdomyolysis and 139 without, 85 cases with intensive care and 84 without, for whom actual temperature values were recorded
  4. c221 of all patients, 36 cases with rhabdomyolysis and 185 without, 95 cases with intensive care and 120 without, for whom actual pulse values were recorded
  5. d194 of all patients, 30 cases with rhabdomyolysis, 164 without, 88 cases with intensive care and 102 without, for whom actual blood pressure values were recorded