140

Annals of Burns and Fire Disasters - vol. XXXIV - n. 2 - June 2021

ASSESSMENT OF CREATINE PHOSPHOKINASE (CPK)CHANGES IN PATIENTS WITH HIGH-VOLTAGE BURNS

EVOLUTION DES CONCENTRATIONS SANGUINES DE CPK CHEZ LESÉLECTRISÉS PAR HAUT VOLTAGE

Tien N.G.,* Chi L.D., Lam N.N.

National Burns Hospital, Vietnam

SUMMARY. The aim was to evaluate change in creatine phosphokinase (CK) enzyme in high-voltage burn patients. A retrospective study was conducted of 104 patients (aged from 16 to 83 years old) who suffered from burns due to high voltage and were treated as inpatients at the National Burns Hospital. Patients were divided into two groups: patients with limb amputations in group A and patients without limb amputations in group B. Analysis was conducted on medical records of testing for plasma CK level immediately upon admission and during treatment. Testing of CK plasma enzyme was performed on an AU480 machine man-ufactured by Beckman Coulter. Data were processed using SPSS 20.0 software. Average plasma CK index increased on the first day of admission. In group B, plasma CK enzyme index increased from 5.5 to 22.4 times, and in group A this index increased from 5.6 to 46.5 times compared with the plasma CK index of normal people (170 U/l). The mean plasma CK enzyme index in the amputation group (n=20) was higher than in the non-amputation group (n=84). In patients with limb amputations, CK levels significantly de-creased after deep necrosis incision and after amputation (p=0.00001). In patients with burns due to high voltage, plasma CK levels rise in the first days after burns. Increased plasma CK enzyme levels are directly proportional to total burn surface area (TBSA) and burn depth. After escharotomy and amputation, plasma CK levels decreased significantly compared to preoperation levels.

Keywords: high-voltage injury, burns, creatine phosphokinase level, extremity amputation

RÉSUMÉ. Cette étude rétrospective a pour but d’évaluer les variations des concentrations de CPK cez 104 patients (de 16 à 83 ans) hospitalisés dans l’hôpital brûlologique national après une électrisation par haut voltage. Ils ont été répartis en 2 groupes, selon qu’ils aient subi (groupe A, 20 patients) ou non (groupe B, 84 patients), une amputation de membre. Nous avons récupéré dans les dossiers et étudié les analyses de CPK, faites par le AU480 de Bekman- Coulter (normale ≤170UI/L), effectuées à l’entrée et durant le séjour. L’analyse statistique a utilisé SSPS 20.0. La concentration de CPK était multipliée par 5,6 à 46,5 chez les amputés, par 5,5 à 22,4 chez les autres. Les concentrations de CPK diminuaient significativement après aponévrotomies et amputations (p=0,00001), comparativement à leur niveau pré- opératoire. Les CPK aug-mentent dans les jours qui suivent l’électrisation et sont proportionnel à la surface atteinte ainsi qu’à la profondeur des lésions.

Mots-clés: brûlure, électrisation, haut voltage, CPK, amputation

___________

* Corresponding author: Nguyen Gia Tien, MD, PhD, President of Viet Nam Burns Association, Director of Viet Nam National Burns Hospital/Viet Nam Military MedicalUniversity, 263 Phung Hung, Ha Dong, Ha Noi, Viet Nam. Tel.: +84 24 3688 1383; fax: +84 24 3688 3375; email: nguyengiatien@yahoo.comManuscript: submitted 14/09/2020, accepted 23/04/2021

Annals of Burns and Fire Disasters - vol. XXXIV - n. 2 - June 2021

141

Introduction

Creatine phosphokinase (CK or CPK) is an en-zyme that catalyzes the chain of reactions betweenATP and creatine phosphate and plays a key role incontrolling the flow of energy to various tissues inthe body, especially muscle tissue. CK concentrationincreases in myocardial infarction, tetanus, multipletrauma causing crush syndrome, electrical injuries,insect bites and rhabdomyolyses syndrome. Rhab-domyolysis is a syndrome that occurs when dam-aged skeletal muscle releases a series of substancesin muscle cells into the bloodstream, including cre-atine kinase (CK), accompanied by symptoms ofmyalgia and the appearance of myoglobinuria (rhab-domyolysis releases intracellular enzymatic contentinto the bloodstream that leads to systemic compli-cation. The classic presentation of this condition ismuscle pain, weakness, black-tea colored urine-pig-menturia and a marked elevation in serum creatinekinase-CK five to ten times above the upper limit ofnormal serum level, with development of life-threat-ening complications such as acute kidney injury).This syndrome can be life threatening when causingelectrolyte imbalance and acute kidney damage. Intrauma and severe burns, up to 50% of patients haverhabdomyolysis syndrome.1,2,3 Gabow et al. pro-posed to take CK values 5 times compared to normalas diagnostic criteria for rhabdomyolysis.4Burns caused by high-voltage currents cause

damage to skin, tendons, muscles, bones, blood ves-sels, brains, organs... (injured tissue situated underthe skin: tendon, muscles, bones, blood vessels andso on) corresponding to the path of the electricitycurrent in the body.5 The extent of damage shown onthe skin surface is only a “floating iceberg”. Damageto the tendon, muscle, joints etc. is common, with ahigh amputation rate from 18.5 to 44% and the riskof acute kidney injury (AKI).1,4,6 Jurgen et al. studied42 patients with electric burns that showed that theplasma CK index increased in the first 10 days afterburns, proportional to the length of hospital stay andcomplications of renal failure and limb amputation.7Assessing CK index in patients with electric burnshas a predictive value for degree of muscle damage,the risk of amputation, and the prevention of renalfailure complications in the first days after burns.5,8

We conducted this study with the desire to under-stand the correlation between plasma CK enzymelevels and the level of muscle damage in high-volt-age burn patients.

Materials and methods

A retrospective study was conducted betweenJanuary 2018 and December 2018 on 104 patientsin Viet Nam National Burn Hospital who sufferedburn injury caused by high-voltage electricity. Pa-tients were divided into two groups: patients withlimb amputations in group A (n=20) and patientswithout limb amputations in group B (n=84). Thecollected data were processed using SPSS 20.0 soft-ware. All cases were tested for plasma CK enzymeimmediately after admission to the inpatient hospitaland/or one day after amputation surgery. The CK en-zyme index of patients was compared between thetwo groups and with the index in normal people. Theaverage values of plasma CK were compared beforeand after limb amputation. Testing of CK plasma en-zyme was conducted on an AU480 machine manu-factured by Beckman Coulter.

Results

In total, the data of 104 patients were analyzed. CKlevel was recorded and increased on day 1 to day 2after a high-voltage burn. There were 97 males and 7females, with an average age of 37.1 years (range 16-83 years). The common burn area was 12.90±0.97%of total burn surface area (TBSA) and deep burn areawas 5.89±0.55% of TBSA. All patients had a changein color of urine, oliguria. The percentage of amputa-tion of the limb was 13.8%. Seven patients died, thecause of death being multiple organ failure in 6 pa-tients and septic shock in 1 patient (Table I).In the group of patients with amputation in group

A (n=20), the plasma CK index increased to veryhigh levels, from 15.6 to 46.5 times compared withnormal CK index. The CK level increased from thefirst day of inpatient stay to the 4th day post-opera-tion, average 6.5 days. The deeper the burn area, thehigher the plasma CK levels. One day after limb am-

Annals of Burns and Fire Disasters - vol. XXXIV - n. 2 - June 2021

142

putation surgery, the plasma CK enzyme index wasexamined and found to have decreased significantlyfrom 52931.21±4200.94 U/l to 733.97±432.01 U/l(p=0.00001). In group B-without amputation pa-tients (n=84), plasma CK index increased for allgroups of burn area, from 5.5 to 22.4 times com-pared with plasma CK in normal subjects (Table II).

Discussion

In 2018, the number of electrical burn patients re-ceiving inpatient treatment in our hospital was 196,of which men accounted for 96.4%. The statisticaldata showed that self-employed workers and farmerswho do not have safety knowledge and protectiveequipment are at higher risk of high-voltage burnscompared to workers in the electricity industry. Thepatients with high-voltage burns were mainly work-ers working under high-voltage lines using a labortool touching electric lines, or holding a conductorthat touched a high-voltage electrical line. Therefore,the entry wound is usually observed on the upperlimb and the exit wound is on the lower limb. Elec-trical burn defects involve multiple tissues, deepnecrosis reaches to fasciocutaneous tissues, damagesblood vessels, nerves, tendons and muscles, and

leads to anaerobe and compartment syndrome. Theratio of limb amputation in our study was 13.8%. Inthese cases, the muscles in the upper or lower limbswere damaged completely. Dry necrosis and theplasma CK enzyme index increased dramatically atthe beginning of admission. The average number of days of inpatient treat-

ment was 36,88±1,73 days. In severe cases, second-ary progressive necrosis commonly occurs after 2-3weeks. The depth of the injury is not consistent sotangential excision must be conducted several times,and the exposed tendons, joints or muscles requirecovering up by pedicle flaps. In this study, 47 caseswere observed to have defects on a combination ofupper limb, lower limb and other position, which ac-counted for 45.1%. This was a consequence of theentry, exit and path of the current when entering thebody, and is also consistent with previous studies.2,8In patients who suffered high-voltage electrical

burn injury, especially in the amputated patientsgroup, plasma CK enzyme levels increased signifi-cantly in the first days after admission, about 5.6times to 46.5 times compared to the CK index innormal people (170 U/l). It proved that the deeperthe burn area, the greater the plasma CK concentra-tion (Fig. 1). In these patients, the color of urine wasdark, oliguria and sometimes signs of rhabdomyol-ysis appeared immediately in 24-48 hrs after burns.According to some authors, an understanding of themechanism of rhabdomyolysis syndrome will helpphysicians take measures to promptly treat and pre-vent possible complications.5,9

Fig. 1 - Correlation between deep burn area and CK enzyme concen-tration in plasma in high-voltage burn patients

Table I - Clinical characteristics of patients

Table II - Changes in plasma CK enzyme levels at the beginning of hos-pital admission in amputation (A) group and without amputation (B) group

Annals of Burns and Fire Disasters - vol. XXXIV - n. 2 - June 2021

143

In a study on multivariate regression methodson 157 patients with acute rhabdomyolysis, Wardet al.10 showed: CK index from 1000-6000 U/l =there is a risk of rhabdomyolysis syndrome, CKindex from 6000-16000 U/l = high risk of rhab-domyolysis syndrome and CK index >16000 U/l =very high risk of rhabdomyolysis syndrome. Theresults of the study show that muscle resorptionsyndrome can be seen in all patients with high-volt-age burn even if the burn area is not large. Espe-cially in the group of patients with deep burn andassigned amputation, the enzyme CK plasma con-centration was very high (52679.82±27403 U/l). Inthese cases, the skin was damaged completely, themuscle and vessels were exposed and the limbcould not be preserved. According to Gabow et al.,4 plasma CK levels

increased to 23800 U/l in patients with rhab-domyolysis syndrome. The plasma CK level in-creased the highest in the group with severe acuterenal failure at 40246.3±47231.8 U/l. Elevatedplasma CK enzyme indicates great muscle dam-age.7,9 Given the high degree of variability asso-ciated with the course of the pathology, multipleattempts are needed to assess the extent of rhab-domyolysis.6 Therefore, plasma CK test resultsare valuable for diagnosis and prognosis of rhab-domyolysis syndrome in patients with high-volt-age burns.Ahrenholz et al.11 in a study on patients with

electric burns have suggested that elevated plasmaCK index is associated with prolonged hospitalstay and indications for surgical intervention, withrisk of amputation of limb when CK enzyme is>4000 U/L. The study also found a link betweenelevated CK enzyme in the first 2 days after burnsand amputation and death. Thus, in our hospital,we suggested the time for performing amputationsurgery was on day 2 or day 3 after high-voltageburns or immediately when the CK level exceeds4000 U/L. When the patient underwent escharo-tomy, the limb was saved in patients with high-voltage burns with a burn area <40% of body area.Escharotomy within the first 4-6 hours after theburn prevented progressive tissue necrosis. Thehalf-life of CK enzyme is 1.5 days and it will bereduced by 40-50% compared to the first value. If

this indicator does not decrease, it means that mus-cle cells continue to be damaged or compartmentsyndrome is progressing. The plasma CK enzymeis a factor that directly reflects muscle breakdownwith high sensitivity. It is suggested that patientswith high-voltage burns should use plasma CKindex as a prognostic indicator to make an indica-tion for intervention for early limb compression re-lease, proactive necrosis removal surgery andprevention of complications.12 In our opinion, theoperation to remove necrosis of deep burns or am-putation has eliminated the cause of rhabdomyoly-sis syndrome and significantly decreased plasmaCK enzyme index. It was proved by the reductionof the plasma CK index significantly withp=0.00001 (Table III).

This study has faced several limitations. Firstly,our retrospective study lacked a monitoring ofchanges in CK enzyme from highest to normal levelin several patients in the group without amputation,because of transferring department for treatment.Secondly, the number of patients with major limbamputation operation was not separated from thosewith minor amputation. This will be clarified in ournext study.

Conclusion

In patients with burns due to high voltage, CKserum index increased significantly on the first dayafter the burn. The plasma CK enzyme index washigher in the group of patients with assigned am-putation compared to the patient group withoutamputation. Increased plasma CK enzyme ratiowas directly proportional to the area of burn andthe extent of deep burn injury. After escharotomyand amputation, the plasma CK enzyme index de-creased significantly compared to pre-operationvalues.

Table III - Changes in plasma CK enzymes after interventions in theamputation group

BIBLIOGRAPHY

Houssinger TA, Green L et al.: A prospective study of myocardial1damage in electrical injuries. J Trauma, 25: 122-124, 1985.Marc LM: Causes of rhabdomyolysis, 2016. http://www.upto-2date.com/content/causes-of-rabdomyolysis.Brumback RA, Feeback DL, Leech RW: Rhabdomyolysis fol-3lowing electrical injury. Semin Neurol, 15(4): 329-334, 1995.Gabow PA, Williams DK, Stephen PK: The spectrum of rhab-4domyolisis. Medicine, 61(3): 141-151, 1982.John DH, Kathy G, Zeharali D: Rhabdomyolysis. Continuing Ed-5ucation in Anaesthesia. Critical Care and Pain, 6(4): 141-143, 2006.Oh RC, Arter JL, Tiglao SM, Larson SL: Exertional rhabdomy-6olysis: a case series of 30 hospitalized patients. Mil Med, 180(2):201-207, 2015.

Kopp J, Loos B, Spilker G, Horch RE: Correlation between7serum creatinine kinase levels and extent of muscle damage inelectrical burns. Burns, 30(7): 680-683, 2004. Vanholder R: Rhabdomyolysis. The American Society of8Nephrology, 11: 1553-1561, 2000.Ward M: Factors predictive acute renal failure in rhabdomyoly-9sis. Ach Yolisis, Muscle and Nerve, 6: 793-810, 2015.Jessiaca RN, Andrew LM: Diagnostic evaluation of rhabdomy-10olysis. Muscle and Nerve, 2015: 793-810, 2015.Ahrenholz DH, Schubert W, Solem LD: Creatine kinase as a11prognostic indicator in electrical injury. Surgery, 104(4): 741-747, 1988.Demos MA, Gitin EL: Acute exertional rhabdomyolysis. Arch12Intern Med, 133(2): 233-239, 1974.

144

Annals of Burns and Fire Disasters - vol. XXXIV - n. 2 - June 2021