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compartment syndrome involves injury to the nerves , vasculature and muscles by raised pressure within the compartment due to muscle injury , fracture , ischemia , or inflammation.[13 ] however , crush syndrome is characterized by major shock and renal failure following a skeletal muscle injury , as commonly seen with events such as earthquakes , where victims become trapped under collapsed buildings .
these two syndromes can also result in peripheral nerve injury ( pni ) by direct compressive or traumatic nerve injury , or indirect injury from the raised pressure within the compartment .
a patient in a comatose state induced iatrogenically or by drug overdose may also show complications of pni due to compression of parts of body by the body itself following prolonged immobilization , resulting in the formation of a compartment or crush syndrome.[711 ] a longer duration of immobilization would thus seem likely to lead to more severe muscle injury , following a more frequent occurrence of pni in comatose patients following an overdose .
we therefore retrospectively investigated the relationship between duration of the comatose state , severity of rhabdomyolysis , and frequency of pni in comatose patients following psychotropic drug overdose .
our institutional review board approved this study and waived the requirement for informed consent . during the investigation period between october 2004 and february 2010 ,
a total of 199 patients were admitted for treatment following a psychotropic drug overdose , including 45 patients with rhabdomyolysis . in this study ,
rhabdomyolysis was defined as present in a patient who showed creatinine kinase ( ck ) level on admission > 160 iu / l , as the upper limit of normal as defined in our institution .
two patients showing convulsions on arrival and two patients with neuroleptic malignant syndrome on arrival were excluded , as these conditions can also induce rhabdomyolysis .
medical charts were retrospectively reviewed for the 41 patients admitted with disturbance of consciousness induced by psychotropic drug overdose with rhabdomyolysis .
these 41 patients were then subdivided into those with pni ( pni group , n=9 ) and those without ( control group , n=32 ) .
the presence of pni was confirmed by the existence of extremity palsy or sensory disturbance after the patient regained consciousness .
age , sex ratio , psychiatric diseases , physical data on arrival ( glasgow coma scale ( gcs ) , systolic blood pressure , heart rate , and temperature ) , estimated interval between ingestion of the overdosed drugs and arrival , frequency of pressure ulcers ( redness , swelling , or blister formation ) , ck level on arrival , duration of hospitalization , frequency of sequelae , and survival rate were all compared between the pni and control groups . in the pni group ,
the pnis encountered , the drug overdosed , and estimated dose of each drug ingested were analyzed .
statistical analyses were performed using student 's unpaired t - test and a  analysis .
age , sex ratio , psychiatric diseases , and physical data on admission did not differ significantly between the two groups .
the interval of time between drug ingestion , frequency of pressure ulcers and ck levels were all significantly higher in the pni group than the control group .
figure 1 shows a scatter chart representing ck levels on admission . if the cut - off for ck level was set at 10,000 iu / l to predict the existence of pni among patients in a coma due to drug overdose , sensitivity was 77.8% ( 7/9 ) and specificity was 93.8% ( 30/32 ) . background data for subjects scatter chart depicting creatinine kinase ( ck ) values on admission . if the cut - off point for ck was set at 10 000
iu / l to diagnose the presence of pni among patients in a coma following drug overdose , sensitivity was 77.8% ( 7/9 ) and specificity was 93.8% ( 30/32 ) ck level , pnis identified , and treatments provided for the pni group are shown in table 2 .
two of nine patients who demonstrated sensory disturbances without paresis had symptoms that subsided within three months . however , while seven patients who demonstrated motor disturbances displayed improved paresis , none obtained complete recovery .
list of peripheral nerve injury and values of creatinine kinase in the peripheral nerve injury ( pni ) group list of ingested drugs in the peripheral nerve injury group table 4 shows the outcomes for the two groups .
duration of hospitalization was significantly longer and morbidity rate was significantly higher in the pni group that in the control group .
the present results confirm that increased duration of comatose state is associated with increased risk of the development of both pressure ulcers and pni . in crush syndrome
, significant correlations have been observed between the size of muscle injury and the duration of time trapped , peak serum ck level , and duration of hospitalization .
as expected , experimental studies suggest a dose - response curve in which greater duration and amount of pressure result in more significant neural dysfunction . among unconscious patients who were in a comatose state following a psychotropic drug overdose
, a significant positive correlation has been found between the estimated interval between ingestion and admission and the ck level of admission to hospital . in the present study ,
pressure ulcers also develop due to morphological and biochemical changes triggered by the combined effects of mechanical deformation , ischemia , and reperfusion that occur during extended periods of immobilization . accordingly
, direct nerve compression or indirect nerve injury due to raised pressure in the body compartment containing the nerve during prolonged immobilization , resulted in the development of either paresis or sensory disturbances . in terms of treatment for compartment syndrome , immediate fasciotomy is recommended when the compartment pressure exceeds 30 mmhg or when clinical symptoms are overt .
however , these recommendations were made based on clinical experience , and the level of evidence is still not definitive .
conservative treatment has been reported to lead to functionally favorable outcome in at least some cases . while , concerning the treatment of crush syndrome , matsuoka et al . investigated peripheral nerve function two years after the 1995 hanshin - awaji earthquake in 42 patients with crush syndrome . that study found no evidence that fasciotomy had improved patient outcomes . moreover ,
delayed rescue , delayed fasciotomy , and radical debridement may have worsened the physical prognosis .
they therefore concluded that the indications for fasciotomy in crush syndrome during the acute phase require further deliberation , as suggested by huang et al . when describing the chi - chi earthquake .
the present study did not measure compartmental pressure except in one case , as all subjects in the pni group had a delayed diagnosis of compartment or crush syndrome due to their unconscious state on arrival .
the morbidity rate was significantly higher in the pni group than in the control group .
as evidenced - based guidelines concerning fasciotomy for the treatment of either compartment or crush syndrome are lacking , prospective randomized control studies are needed in the future to clarify the details of pni among comatose patients following psychotropic drug overdose .
in patients with a psychotropic drug overdose leading to a comatose state , the longer the comatose state , the more likely that pressure ulcers and pni will occur . in this study
, patients with pni , with paresis due to a comatose state following a psychotropic drug overdose , did not have a complete recovery .
aims : to investigate the relationship between the duration of comatose state , severity of rhabdomyolysis and frequency of peripheral nerve injury ( pni ) in patients following psychotropic drug overdose.materials and methods : medical charts were retrospectively reviewed for 41 patients admitted for disturbance of consciousness induced by an overdose of psychotropic drugs with rhabdomyolysis between october 2004 and february 2010 . 
 subjects were divided into pni group ( n=9 ) and non - pni control group ( n=32).results : mean interval between drug ingestion and arrival , frequency of pressure ulcers , ck level at the time of patient 's arrival and maximum ck level during hospitalization , duration of hospitalization and morbidity rate were all significantly higher in the pni group than in the control group.conclusion:in patients with a psychotropic drug overdose leading to a comatose state , the longer the comatose state , the more likely that pressure ulcers and pni will occur .