Clinical and biochemical characteristics of suspected ...

Dengue Bulletin – Volume 35, 2011 59

Clinical and biochemical characteristics of suspected dengue fever in an ambulatory care family medical

clinic, Aga Khan University, Karachi, PakistanFirdous Jahan,# Kashmira Nanji, Waris Qidwai, Rozina Roshan & Hira Waseem

Department of Family Medicine (FAMCO), Oman Medical College-Sohar, PO Box 391, PC 321 , Al-Tareef, Sohar, Sultanate Oman.

Abstract

A medical chart review was carried out in an ambulatory family medical clinic attached to the Aga Khan University Hospital, Karachi, Pakistan. The study revealed that all febrile patients the mean fever spike was 39.8°C. The common symptoms were bodyache (46%), nausea (12%) and headache (10%). Other clinical findings were eye pain, backache and anorexia. Out of thirteen patients who had dengue IgM done, nine showed positive results. In laboratory examination, thrombocytopenia was found in 53.4% of patients. Low haemoglobin was found in 51% and leucopenia in 32.9% of patients.

Keywords: Dengue fever; Ambulatory care; Medical chart review; Clinical and biochemical changes; Suspected DF; Aga Khan University Hospital; Karachi, Pakistan.

Introduction

Dengue is a widespread mosquito-borne infection in human beings which, in recent years, has become a major public health concern worldwide.[1] Dengue is re-emerging throughout the tropical world, causing frequent recurrent epidemics.[2,3] In Pakistan, the first major outbreak was recorded in 1994 in Karachi. Since then, Karachi has experienced recurrent outbreaks during 2005, 2006 and 2010. Other cities in Pakistan which recorded major dengue outbreaks were Lahore (2008) and Islamabad (2010). Three serotypes, viz. DENV-1, DENV-2 and DENV-3 (subtype III), have been found circulating in the country.[4]

During 2010, the Dengue Surveillance Cell of the Sind Province of Pakistan reported 563 serologically-confirmed cases at the Aga Khan University Hospital in Karachi. The reported cases were usually complicated or were with haemorrhagic manifestations. However, at an

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60 Dengue Bulletin – Volume 35, 2011

Clinical and biochemical characteristics of dengue fever cases in Karachi, Pakistan

ambulatory care family medical clinic (primary health care centre) attached to the Aga Khan University Hospital, the usual presentation was mild-to-moderate fever, treated as suspected dengue. The present study highlights the clinical and biochemical characteristics of suspected cases as observed at an ambulatory care family medical clinic (ACFMC).

Materials and methods

The primary investigator of this study trained the person who did the chart review and data collection in the clinic. Data were collected through a structured instrument which was developed after brainstorming sessions with the authors.

Demographic information, gender and age were recorded for all patients. Clinical presentation (fever), minimum and maximum rise of temperature, nausea and/or vomiting, rash, abdominal pain, myalgia, headache and haemorrhage were recorded. Results of biochemical tests, which were carried out depending on clinical findings, were recorded.

Thrombocytopenia was defined as a platelet count, 100 000 cells/mm3 blood. A haematocrit value rising by 20% was considered as high. Similarly, leucopenia was defined as a white cell count <5000 cells/mm3, neutropenia as neutrophils <40%, and lymphocytosis as lymphocytes >45%. Alanine aminotransferase (ALT) was considered as raised if it was 55 and 33 IU/L for males and females respectively. Aspartate aminotransferase (AST) was defined as raised if it was 46 and 32 IU/L for males and females respectively.

The Statistical Package for Social Sciences (SPSS) version 15.0 was used for data entry and statistical analysis. Descriptive statistics were calculated. Median (± inter-quartile ranges) were reported for continuous variables such as age, gender, etc. Numbers and percentages were reported for all other categorical variables such as clinical characteristics (fever, headache, bodyache, etc.) and biochemical tests (thrombocytopenia, leucopenia, etc.)

Most developing countries have epidemics of febrile illnesses which can be confused with dengue fever; therefore, other investigations such as blood culture, urine culture, malaria immunochromatography (ICT), typhidot IgM, etc., were done according to clinical symptoms and signs.

Results

The total number of patients who presented with fever in the community health centre (outpatient clinic) during October-November was 125, of whom 78 (62.4%) were male while 47 (37.6%) were female.



The mean fever spike was 39.8 °C. The common symptoms were bodyache (46%), nausea (12%) and headache (10%). Other clinical findings were eye pain, backache and anorexia (Table 1).

Table 1: Clinical features of patients with suspected DF at an ambulatory care family medical clinic, Karachi, Pakistan

Characteristics n %

Age* 32 (±15)

Gender

Male

Female

78

47

62.4

37.6

Bodyache/headache 69 55

Eye pain 4 3.2

Backache 41 32.8

Nausea/Anorexia 11 8.8

*Mean age.

In laboratory investigations, thrombocytopenia was found in 50 out of 92 (54.3%) patients. Low haemoglobin was found in 44 out of 86 (51%) patients, high haemoglobin and haematocrit level was found in 42 out of 86 (48%) patients, leucopenia in 29 out of 89 (32.9%), neutropenia in 9 out of 70 (13%), lymphocytosis 10 out of 69 (14.5%), lymphopenia 26 out of 69 (37.6%), raised ALT 17 out of 41 (41%) and raised AST 25 out of 29 (86%) patients. Raised ALT/AST was found in 5% of the cases (Table 2). Dengue IgM was done in 13 patients and 9 were positive (69.2%). Other investigations done according to clinical presentation revealed significant positive blood culture for Salmonella Typhi and serum Typhidot-IgM.

Severe thrombocytopenia <30 000 was found in 9 (7%) cases, high haematocrit >20 was found in 84 (67%) cases and severe leucopenia <3.0 was found in 12 (10%) cases. Based on these criteria, 52 patients were referred to the Emergency and 9 were hospitalized for platelet transfusion; the rest were sent home after intravenous rehydration and were asked to return for a close follow-up in the ACFMC clinic.



Discussion

The results of this study describe the demographic trends of suspected dengue infections in ambulatory care. As described in available literature, the clinical presentation is somehow classical in most of the suspected DF cases.[5] Dengue virus is now endemic in Pakistan, circulating throughout the year, with a peak incidence in the post-monsoon period. The mean age detected is 32 years (3-78). The median age of dengue patients has decreased and younger patients seem to have become more susceptible.[6]

Clinical presentation in nearly half of the patients was severe bodyache followed by backache, nausea and headache as reported by others.[7] In those who had the diagnosis of suspected DF, the most common biochemical changes were thrombocytopenia and raised AST. Nearly half of the patients had high haemoglobin and haematocrit levels. Dengue IgM was positive in 9 out of 13 patients on whom the test was done. Among patients of DF in other parts of Pakistan, tests revealed similar clinical characteristics, with some variations in symptomatology.[8,9].

Clinical characteristics and biochemical changes, though variable in different parts of the world, show some similarities like thrombocytopenia, high haematocrit, leucopenia, lymhocytosis and lymphonia, that were found in this audit as well.[5,10,11,12] Both ALT and AST levels were high in the biochemical profile but the level of AST was significantly high.[13] Total and differential leukocyte count may be useful for the identification of patients at risk of haemorrhage and their utility needs should be studied further.

Table 2: Laboratory findings of the study participants with suspected DF (n=125)

Tests n=Tests ordered Test positive %

Thrombocytopenia 92 50 54.3

Low haemoglobin 86 44 51

High haemoglobin 86 42 48

Haematocrit level 70 40±5.8

Lymphocytosis 69 10 14.5

Leucopenia 89 29 32.5

Neutropenia 70 9 13

Raised AST 29 25 86

Raised ALT 41 17 41



Other diagnosis in ambulatory care was enteric fever in 34 out of 53 (62%) patients. Although malaria is highly prevalent in this part of the country, but in post-monsoon fever cases, out of 59 tests done, only one malaria ICT was found positive. A significant number of patients were referred to the Emergency room for hospitalization, but most of them were discharged after intravenous rehydration while 9 out of 52 patients needed platelet transfusion. In this study no one had overt bleeding or minor haemorrhage but cases of impending haemorrhage with severe thrombocytopenia were immediately referred for platelet transfusion. Primary care physicians have an active role to play in providing care and support and identifying the signs of impending haemorrhage which has serious consequences. Dengue fever cases need referral to tertiary care for intravenous fluid replacement and platelet transfusion along with supportive care.

Acknowledgements

The authors gratefully acknowledge the help of Sumiara Ihtesham (Head Nurse, CHC Clinic) and Dr Samina Hossien (Assistant Physician In-charge, CHC Clinic).

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Keating J. An investigation into the cyclical incidence of dengue fever. [10] Soc Sci Med. 2001; 53: 1587–1597.

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