RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES
KARNATAKA, BANGALORE
ANNEXURE II
PERFORMA FOR REGISTRATION OF SUBJECT FOR DISSERTATION
(to be submitted in duplicate)
TITLE OF THE TOPIC - VALIDATION OF LRINEC (LABORATORY RISK
INDICATOR FOR NECROTIZING FASCIITIS) SCORING
SYSTEM FOR THE DIAGNOSIS OF NECROTIZING
FASCIITIS IN PATEINTS PRESENTING WITH SOFT
TISSUE INFECTIONS.
6. BRIEF RESUME OF INTENDED WORK:
6.1 NEED FOR WORK –
It has been shown by numerous studies in the past that early recognition and
surgical intervention at the earliest is the sole factor in preventing the morbidity and
mortality in patients with necrotising fasciitis. The paucity of specific cutaneous signs to
distinguish necrotising fasciitis from other soft tissue infections such as cellulitis makes the
diagnosis extremely difficult. So a scoring system which is easy to follow and cost effective
with high positive and negative predictive value is required. One such scoring system is the
LRINEC scoring system devised by Wong. etal in 2005 which claims to have a positive
predictive value of 92.0% and negative predictive value of 96.0%. Hence we would like to
validate this scoring system in our patients and if found to have similar comparable
predictive values, it would prove to be a boon to developing countries like India
where the mortality of the disease reported ranges from 7 to 76% and also where there is
also constraint for resources.
6.2 REVIEW OF LITERATURE:
Necrotizing fasciitis is perhaps the most severe form of soft tissue infection primarily
involving the superficial fascia. This disease has bewildered physicians for centuries.
Hippocrates in the fifth century BC gave the first description of this dreaded disease [1]. The
first report of this disease in the United States was by a Confederate Army surgeon, Joseph
Jones in 1871 and he named this entity ‘hospital gangrene’[2]. Meleney [3] in 1924 reported
an outbreak of hospital gangrene in Beijing and coined the term haemolytic streptococcal
gangrene. The term necrotizing fasciitis was first introduced by Wilson [4] in 1952 and is the
preferred term today describing the most consistent and key feature of this disease, fascia
necrosis. While the understanding of the pathophysiology of necrotizing fasciitis continues
to improve, but the mortality of this disease remains alarmingly high with reported
mortality rates ranging from 6 to 76% [5]. Delayed diagnosis and consequently delayed
operative debridement have been shown in multiple studies to increase mortality
.This is understandable: the greater the delay, the greater the tissue loss and sepsis with
consequent increased mortality. One of the main reasons for the continued high
mortality of patients afflicted by necrotizing fasciitis today is a failure to recognize and
diagnose the condition early because of the paucity of specific cutaneous signs early in its
evolution[5]. It is therefore imperative that the treating physician has a high index of
suspicion and is aware of the armamentarium of diagnostic adjuncts at his disposal when
confronted with such clinical uncertainties.
6.3 OBJECTIVES OF THE STUDY
To validate the LRINEC scoring system for the diagnosis of necrotizing fasciitis among
patients presenting with soft tissue infections to M S Ramaiah Hospitals.
7 MATERIALS AND METHODS
7.1 STUDY SUBJECTS:
All patients presenting to M S Ramaiah Hospital with symptoms suggestive of soft tissue
infections.
7.2 STUDY DURATION - 2 Years
7.3 METHODS OF COLLECTION OF DATA:
Patients presenting with symptoms suggestive of soft tissue infections will undergo clinical
examinations and the below mentioned investigations. Following which information
regarding the demographics & covariates of soft tissue infections will be collected using a
pretested semi- structured proforma cum observational checklist. LRINEC scoring system
will be applied to each of the study subjects. The confirmatory diagnosis for necrotising
fasciitis will be done vide histopathology for all patients, irrespective of the result of the
LRINEC scoring system.
The LRINEC (laboratory risk indicator for necrotizing fasciitis) score
LRINEC score of 6 or greater is considered positive for necrotizing fasciitis
7.4 INCLUSION CRITERIA
Patients presenting to M S Ramaiah Hospital with symptoms suggestive of soft tissue
infections during the study period.
7.5 EXCLUSION CRITERIA
1) Patients below 15 yrs or above 75 yrs of age.
2) Patients who have received antibiotic treatment in the last 48 hours or a minimum of 3
doses of antibiotic prior to presentation.
3) Patient who has undergone surgical debridement for present episode of soft tissue
infection.
4) Patients with boils or furuncles with no evidence of cellulitis.
7.6 Does the study require any investigation or intervention to be conducted on patients or
other humans or animals? If so, describe briefly.
· Haemoglobin
· Total white cell counts
· Random blood sugar
· Serum creatinine
· Serum sodium
· Serum C-reactive protein.
Special investigations:
· Tissue for histopathology
· Tissue for culture and sensitivity
· Tissue fluid for gram staining.
STUDY DESIGN:
Hospital based observational study
STATISTICAL ANALYSIS:
Sample size estimation:
The sample size was estimated based on Positive predictive value of LRINEC as cited in
the below mentioned article, “Wong CH, Wang YS. The diagnosis of necrotizing fasciitis
Current Opinion in Infectious Diseases 2005, 18:101–106”. The study shows a Positive
Predictive Value of 92% of LRINEC system for diagnosis of NF.
Using a Positive predictive value of 92%, precision of 5% and confidence intervals of
95% the sample size was estimated to be a minimum of 113. Assuming an attrition and
non- response of 20%, a final sample size of 140 was estimated.
Descriptive statistics
- All quantitive data like age ,vital signs and investigations will be presented as mean
and standard deviation.
- All qualitative data like sex, symptoms ,examination findings and histopathology will
be presented as frequency and percentages.
Analytical statistics
- Validation of LRINEC scoring system will be analysed vide sensitivity, specificity,
positive predictive value and negative predictive value. Analysis will be done using
SPSS software.
7.7 Has ethical clearance been obtained from your institution? YES
8. LIST OF REFERENCES
1. Descamps V, Aitken J, Lee MG. Hippocrates on necrotizing fasciitis. Lancet
1994; 344:556.
2. Jones J. Investigation on the nature, causes and treatment of hospital
gangrene as it prevails in the confederate armies 1861–1865. In: Hasting
Hamilton F, editor. Surgical memoirs of the war of rebellion. New York:
Sanitary Commission; 1871.
3. Meleney FL. Hemolytic streptococcus gangrene. Arch Surg 1924; 9:317–
364.
4. Wilson B. Necrotizing fasciitis. Am Surg 1952; 18:416.
5. . Wong CH, Khin LW, Heng KS, Tan KC, Low CO. The LRINEC
(Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for
distinguishing necrotizing fasciitis from other soft tissue infections.
Critical Care Med. 2004 Jul;32(7):1535-41