Leptospirosis is the common zoonosis caused by genus Leptospira; it is widespread around the world, particularly in developing nations like India. The pathogenic bacterium is carried by a number of rodents and wild animals and is expelled in their urine [1]. Leptospirosis incidence varies between 0.1 and 1 case per 100,000 people per year in temperate, non-endemic regions and between 10 and 100 cases per 100,000 people per year in humid, tropical, endemic regions, according to WHO estimates. The latest estimates indicate that over 500,000 cases of leptospirosis are recorded annually worldwide [2-3]. Case-fatality rates range from less than 5% to 30%. Other names for it include "mud fever" and "rice field fever."[4] The phrase describes how the disease spreads when individuals, mostly farmers, come into touch with contaminated water. The clinical manifestations of leptospirosis are diverse. About 40% of infected patients seroconvert asymptomatically. About 90% of the remaining 60% experience the milder anicteric type, whereas 10% experience the more severe icteric variant. The severe type has a mortality rate of up to 40% and is linked to multiple organ involvement, particularly hepato-renal [5]. In the first phase, which lasts 4 to 9 days, leptospirosis typically manifests as a sudden onset of flu-like symptoms, including a strong headache, chills, muscle aches, and vomiting. In the second phase, the patient has fever, jaundice, abdominal discomfort, and diarrhea. Because of its varied symptoms, difficulty differentiating it from other feverish conditions, lack of knowledge, or lack of diagnostic procedures, it is often under diagnosed. Many leptospirosis infections may go undetected in the absence of diagnosis, which could result in acute fatalities as well as long-term health consequences like depression, uveitis, migraine, and chronic fatigue. Caution is required in the primary care context due to the early onset of problems such hepatitis [6]. Leptospira infections frequently cause hepatic involvement, which can range from a mild increase in transaminases to severe icteric hepatitis. Some distinguishing characteristics include substantial increases in bilirubin and slightly increased transaminases. According to other research, the prevalence of hepatomegaly ranges from 25% to 76% [7]. A frequent characteristic of both mild and severe forms of leptospirosis is renal involvement. In resource-constrained settings where leptospirosis is common, alternative diagnostic techniques, such as the Leptospira rapid test and ELISA, are commonly available and have the capacity to detect infections in the early stages of the disease. Rapid screening and diagnosis of suspected leptospirosis patients are made possible by the Leptospira fast test, which detects IgM/IgG antibodies to Leptospira bacteria in human plasma, serum, or whole blood specimens [8]. Leptospira-specific IgM and IgG antibodies can be found in the sera of individuals infected with different Leptospira serovars using ELISA, another diagnostic technique [9].

AIMS AND OBJECTIVES: To study the clinico-correlation of Leptospirosis with laboratory parameters with special reference to liver function test and renal function test in the study group. 

Study design: This was a single centric, observational, prospective, descriptive study 

Study Site: This study was conducted in Department of Microbiology of a tertiary care, teaching

Hospital, India.

Study duration: The study was conducted for a period of one year from January, 2016 to December, 2016

Study population: Febrile patients presenting with sign and symptoms suggestive of leptospirosis who willing to give written inform consent for the study

Sample size: Consecutive samples received in the laboratory over a period of one year (n=619)

Data collections: Patients fulfilled the inclusion criteria were enrolled in this study. A detailed history and clinical examination was done for all the study patients.

Test performed for the diagnosis of leptospira were: Rapid IgM Leptocheck Immunochromatography test, Leptospira IgM ELISA and Polymerase chain reaction (PCR).

Other relevant investigations like: complete blood counts, renal and liver function tests were done in every patient. Correlation between seropositivity of leptospirosis and laboratory parameters were measured

Ethical considerations: The study was initiated after obtaining approval from the institutional ethics committee

Statistical analysis: Data was collected and compiled in Microsoft Office Excel version 2013 and a descriptive statistical analysis was carried out. Data was presented using descriptive statistics in the form of frequencies and percentages for qualitative variables, means and standard deviations for quantitative variables. A qualitative variable was compared using (χ2) test while (t) test will be used for comparison of quantitative data. Statistical significance will be considered at p-value ≤ 0.05.

Among 211 seropositive patients, 31 (14.69%) had Hb ≤10 g/dl, whereas the majority (85.3%) maintained Hb between 10–14 g/dl. Leukocytosis (>11,000/mm³) was noted in 21 (9.95%) patients. Thrombocytopenia was present in 26.06% of cases, suggesting its role as an important clinical marker in leptospirosis.

Table 1: Laboratory investigation among seropositive cases [N=211]

Renal impairment was evident with raised BUN in 20.37% and serum creatinine >1.5 mg/dl in 19.9% patients. Electrolyte disturbances included hyponatremia in 11.84% and hypokalemia in 29.85% of cases. These findings indicate that renal dysfunction is a common feature among seropositive patients.

Table 2: Renal function test among seropositive cases [N=211]

A statistically significant association was observed between elevated BUN and creatinine levels with ELISA positivity (p=0.0001). This suggests that renal dysfunction is strongly correlated with disease severity in leptospirosis.

Table 3: Correlating renal function test with cases tested for Seropositivity with ELISA

Among seropositive cases, hyperbilirubinemia was observed in 14.2%, while elevated SGOT and SGPT were found in 16.58% and 13.74% respectively. These results demonstrate hepatic involvement in leptospirosis, though not universal.

Table 4: Liver function test among seropositive cases [N=211]

Hyperbilirubinemia, elevated SGOT, and SGPT were significantly associated with ELISA positivity (p=0.0001). This indicates that hepatic dysfunction has strong correlation with confirmed leptospira infection.

Table 5: Correlating liver function test with cases tested for Seropositivity with ELISA

All seropositive cases presented with fever, followed by headache, vomiting, and abdominal pain, reaffirming the nonspecific but common clinical presentation of leptospirosis.

Figure 1: Clinical Feature among study cases

The reports of an increase in leptospira cases imply knowledge and awareness about leptospirosis. The Centers for Disease Control and Prevention (CDC) defined a suspect leptospirosis illness as fever along with two or more of the following signs: headache, chills, sweats, muscle aches, eye pain, red eyes, dark urine or unusual bleeding [10]

In our study the common clinical features included fever, headache, myalgia, abdominal pain and vomiting. This finding is in concordance with the studies done by Kaustubh D, et al [11] and Holla R, et al [12]. The similarity in clinical presentation and diversity of etiological agents demonstrates the complexity of diagnosis and treatment of acute febrile illness. Therefore serological and laboratory tests thus play an important role in managing a case of febrile illness.

Severe acute respiratory illness was the most frequent complication seen in our study. In 29% of the cases, breathlessness was the most frequent presentation, a study done by Ahmad N, et al [13] reports breathlessness in 33.3% of cases. The pulmonary manifestations in leptospirosis are probably due to vasculitis mediated by toxins and an exaggerated immune response.

Present study demonstrated an association between leptospirosis and impaired host hematological status, including lower hemoglobin and hematocrit concentrations, anemia, and thrombocytopenia, in agreement with the Deodhar D, et al [14] and Adiga DSA, et al [15].

The incidence of leukocytosis among seropositive cases was low in our study. Similar findings reported by D. Deodhar [14] in Punjab and Adiga, et al [15] in their study respectively.

Thrombocytopenia was seen in 26.06 % among seropositive cases in current study, results comparable with the Sethi et al [2] and De Silva, et al [16]. Thrombocytopenia, though frequently occurs in leptospirosis cases, although usually not to the extent that would cause spontaneous hemorrhage. Thrombocytopenia is an important contributory factor in the pathogenesis of bleeding diasthesis in leptospirosis, which is the leading cause of death in this disease. It is important to anticipate and recognize this entity early in the course of leptospirosis so that appropriate steps can be taken to prevent it and to treat it with platelet transfusion.

We have found that the overall renal impairment was seen in ~10% of cases, in accordance to the. Shivakumar, et al [17] found renal failure in 10.6% cases of leptospirosis. Parmar et al [18] in his study also reported renal failure as the most common complication but followed by ARDS and myocarditis.

A study conducted by VC Patil, et al [19] in western Maharashtra reported raised serum creatinine, hypokalemia and hyponatremia; their findings were consistent to the current study.

In our study Altered liver enzymes (SGOT and SGPT), hyperbilirubinemia were the most predominant alterations followed by Leucocytosis, anemia, thrombocytopenia and altered renal parameters. However different studies have reported different variations in their laboratory parameters and findings of Thalva C, et al [20] were almost consistent with our findings.

Renal failure due to leptospirosis commonly presents as a non-oliguric and a hypokalemic state. A wasting sodium and potassium defect has been consistently documented by different studies.

In the present study; Impaired renal function (increased BUN and increased serum creatinine) and impaired liver function test (increased total Bilirubin, increased SGOT and SGPT) was significantly associated with the leptospira seropositive cases, Similar results had been reported by H. Sahira, et al [21], Dwijen D, et al [22], and Bharathi R, et al [23].

Leptospirosis remains a major public health concern due to its varied presentation and diagnostic challenges. Decreased haemoglobin levels, raised WBC count, and low platelet count can be considered in predicting the severity of leptospirosis. Renal failure and hepatic dysfunction are the most common complication associated with the leptospirosis. Therefore, early detection of laboratory abnormalities combined with clinical suspicion can help with timely diagnosis and treatment, which lowers mortality and complications.

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