Clinical Profile and Predictors of Outcome in Patients with Diphtheria in a Tertiary Care Center

DISCUSSION

Vaccination against diphtheria has reduced the mortality and morbidity of the disease dramatically; however, it is still a significant child health problem in developing countries.

In present study, out of 33 cases, only 9 (27.3%) cases were less than 5 years of age and 24 (72.7%) were above 5 years, whereas prior to the vaccination era, children less than 5 years of age were affected more, due to their poor immunity while adolescents and adults were saved because of their developed immune system. However, in the recent years, when the vaccination coverage has been improved, it is noticed that there has been a shift in age for occurrence of disease. It is now seen more in older children and adults. This is probably because of lack of booster doses that are recommended at 18 months and at 5 years of age. Child with missed booster dose becomes susceptible to infection due to fall in antibody titers, whereas infants and younger children are better protected due to initial three doses which are least likely to be missed now a days. Such shift in age group was observed in two other recent studies in India. Basavraja et al.’s¹⁴ study had 25.8% patients who were less than 5 years and 74.1% patients who were over 5 years, while in study by Bandichhode et al.,¹⁵ 33.33% cases were less than 5 years of age, whereas 66.66% were more than 5 years of age.

In present study, males outnumbered females by ratio 1.35:1. Ninety-one percent patients belonged to the rural area, and 94% were from the lower class. This may be attributed to the fact that socioeconomically weaker may have lesser access to the immunization/health facilities compared to economically richer population, also there could be challenges in rural areas to maintain the cold chain. Similar observations were made by Meshram et al.¹⁶ and Maheriya et al.,¹⁷ but male to female ratio was almost similar in the former i.e. 0.95:1. Hindus and Muslims were almost same in number.

We observed, out of 33 patients, 55% cases were unimmunized, 30% patients were partially immunized, and only 15% were completely immunized. Similar observation regarding immunization status was reported by Maheriya et al.¹⁷ and Bandichhode et al.¹⁵ In the study by Bandichhode et al.,¹⁵ 36 patients were taken, out of which 58.33% were unimmunized, 30.55% were partially immunized, and only 11.11% children were fully immunized. This lack of complete immunization may be due to non-availability of immunization services especially in rural/hilly area. Other factors include delaying or postponing vaccination in minor childhood illness, lack of awareness, and illiteracy.

In our study, 83.3% of unimmunized patients had developed complications while 55% of them died. Among 10 partially immunized patients, 80% cases had complications and 30% died. In immunized group, one (20%) out of five patients had complication but all the patients (100%) survived. These data strongly favor the point that prior immunization plays a key role in preventing the complications and fatal outcome of the disease. Disease had run more fulminant course in unimmunized patients. It proves that proper immunization is necessary for the reduction of the mortality associated with the disease.

In total, 24 (72.7%) out of 33 patients had complications, out of which respiratory and cardiac complications were the most common i.e. 45.5%. It was comparable to study by Meshram et al.¹⁶ and Ujjwal et al.,¹⁸ which showed myocarditis as the most common complication, i.e., 42.5 and 63.3%, respectively.

Respiratory distress was seen in 15 cases (45.5%), out of whom 12 patients required supportive intervention in the form of ventilatory support, 6 had undergone tracheostomy. A similar observation regarding respiratory distress was made in study by Jayshree et al.¹⁹

Lab test for Albert stain was positive in 20 (60.6%) cases and negative in 12 (36.4%) cases. Other studies done by Basavaraja et al.,¹⁴ Bandichhode et al.,¹⁵ and Singh et al.¹⁹ observed positive Albert stain in 16.1, 33.33, and 30.63% cases, respectively. Due to low sensitivity rate, we should not depend completely on result of lab test, thereby initiating therapy on clinical suspicion of diphtheria without delay, in form of ADS.

In our study, out of 28 patients who were given ADS, 64.3% survived, 67.8% had complications, and 35.7% died. The cause of occurrence of these complications may be history of incomplete immunization, delay in starting the treatment or inadequate dosage. However, there were five patients who were not given ADS, probably as Albert stain was negative in them. Forty percent of them survived, all of them (100%) had complications and 60% expired, suggesting that prompt antitoxin therapy is important in preventing the fulminant course and lethal outcome. ADS neutralizes free toxin circulating in the blood and can thus reduce complications as well as mortality of diphtheria. This observation implies that we should start the therapy as soon as possible, based on the clinical suspicion.

Out of 33, 14 patients died, making case fatality rate of diphtheria 42.4%, in present study. Similar mortality rate (48%) was seen in study done by Singh et al.²⁰ A higher mortality (56.3%) was noted in study by Jayshree et al.,¹⁹ while in study by Ujjwal et al.,¹⁸ it was 18.18%, and in study by Meshram et al.,¹⁶ it was 21.28%. It indicates that diphtheria remains a potentially fatal disease, even in present times. This high mortality rate could also be due to delay in clinically diagnosing the disease, possibly as clinicians do not suspect diphtheria as the possibility, thereby delaying the treatment in form of ADS. We observed that delay in initiating ADS therapy resulted in high morbidity and mortality.

Therefore, the present study showed that complete immunization, high index of suspicion, early clinical diagnosis, and prompt antitoxin therapy are the essential key factors in preventing the mortality and complications.