Melioidosis of the Parotid Gland: Lessons Learned from a Fatal Case

Abstract

Meliodosis is an infectious disease also called whitemore’s disease that can be fatal and is caused by the bacteria Burkholderia pseudomallei. This facultative intracellular aerobic gram-negative bacterium is typically transmitted through direct contact with contaminated water or soil (Currie et al. in Seminars in Respiratory and Critical Care Medicine 36:111–125, 2015). Endemic and widespread, it often affects individuals with underlying health conditions like diabetes, chronic lung disease, chronic renal disease, chronic liver disease, malignancy, connective tissue diseases, or on immunosuppressive treatment. The most common clinical presentation includes septicaemia, pneumonia, hepatic abscess, splenic abscess, skin and soft tissue infection, urinary tract infection and osteoarticular infection. Isolated parotid gland involvement in meliodosis is rare, particularly in adults, even in endemic regions. While parotid abscesses due to meliodosis are more commonly seen in children, where they account for 30–40% of cases, adult cases are much less frequent (Dance et al. in Journal of Infectious Diseases 159:654-60, 1989). According to a study by Tipre et al., which reviewed literature from 1953 to June 2016, only 4 out of 99 cases reported meliodosis involving parotid gland (Chandrasekaran et al. in International Journal of Medical and Biomedical Studies 22–24, 2020). Similarly, in another study by Mohanty et al., which focused on meliodosis of the head and neck in Eastern India, only three patients with the parotid gland involvement (Mohanty et al. in Infectious Disease Reports 12:36–45, 2020). This emphasize the rarity of this clinical presentation in adults and the limited documentation available in medical literature, even in regions where meliodosis is prevalent. Parotid gland meliodosis can mimic other conditions such as bacterial sialadenitis, or abscesses, making diagnosis challenging. It is critical to recognize this unusual manifestation because a delayed diagnosis can have serious consequences.

Case Presentation

A 50-year-old male, a known diabetic, presented with a history of swelling on the left side of the face and difficulty opening the mouth for 1 week which was associated with fever. Examination revealed a diffuse swelling noted in the left parotid region which was tender (Fig. 1). Laboratory investigations showed hemogram—10.8 gm/dl, total leucocyte count—16,560 cells/mm³ (Neutrophils-95%, Lymphocytes-2.9%, basophils-0.3%, platelets–3.19 lakhs/mm³. Serum urea—83 mg/dl, Serum Creatinine—1.62 mg/dl, Serum Sodium—136 mEq/L, Serum potassium—4.99 mEq/L, Total bilirubin—1.25 mg/dl, Direct bilirubin—0.7 mg/dl, with normal liver enzymes. Ultrasound parotid area showed mild interstitial edema noted over the left parotid region without any obvious collection. In view of acute parotitis, patient was treated empirically with intravenous Clindamycin 600 mg every 8 hourly. But there was no improvement even after 24 h of the treatment. Blood culture was sent in view of persistent high grade fever which grew Burkholderia pseudomallei, sensitive only to Ceftazidime. B.pseudomallei was identified by its characteristic growth on MacConkey agar (small,smooth,non lactose fermenting colonies after overnight incubation, which turned pink with a metallic sheen after 48 h and dry and wrinkled after 96 h of incubation) (Fig. 2). Patient was planned for Contrast Enhanced Computed Tomography(CECT) of the Neck for extension of the disease but was not done as the patient’s condition deteriorated in view of septic shock secondary to disseminated meliodosis and succumbed to death within less than 36 h of admission in hospital.

Fig. 1.

Depicting diffuse swelling on left side of the face extending to left periorbital region

Fig. 2.

Showing non lactose fermenting bacteria colonies on MacConkey agar exhibiting the typical metallic sheen with a pinkish, rugose and dry appearance after prolonged incubation

Discussion

The parotid gland meliodosis is an unusual manifestation of Burkholderia pseudomallei infection, especially in adults. Although septicaemia, pneumonia, or abscess formation in different organs are common presentation of meliodosis, parotid gland involvement is more frequently observed in children in endemic regions, which makes this presentation particularly noteworthy. Melioidosis can affect people of any age, but its incidence is highest between the ages of 40–60 years [5].

The usual clinical symptoms of melioidosis broadly categorizrd into four classes: localised infection, prolonged fever without an obvious site of infection, fulminant septicaemia, and asymptomatic carrier during the latent period [6]. The clinical presentation of parotid meliodosis is nonspecific, often resembling bacterial sialadenitis. In this patient, the symptoms of parotid swelling, pain, and systemic signs like fever and malaise initially pointed to a more common bacterial infection. However, in endemic regions, melioidosis should be included in the differential diagnosis, particularly in individuals with risk factors such as diabetes, which compromises immune function and heightens susceptibility to Burkholderia pseudomallei.

While imaging can provide valuable information, it may not be conclusive in differentiating cellulitis and abscess especially in the early stages of infection. In this present patient, ultrasound findings suggested a soft tissue infection, but a blood culture was essential for confirming the diagnosis. The gold standard for diagnosing melioidosis is microbiological culture, although results can take several days [7]. The indirect hemagglutination assay is also a well-established serological test for detecting melioidosis [8]. Accurate diagnosis of this condition is crucial for guiding appropriate antibiotic treatment. If left untreated, the disease has a mortality rate of up to 95%, and even with proper antibiotic therapy, the mortality rate can still be as high as 50% [8].

The management of meliodosis requires prompt and prolonged antiobiotic treatment to prevent relapse and complications. Treatment can be divided into two phases: the initial acute phase and the eradication phase [9]. The standard regimen involves initial intravenous antibiotics, such as Inj Ceftazidime, followed by an extended course of oral antibiotics, like Cotrimoxazole to prevent relapse rate [10]. Treatment duration depends on the severity of the condition. Initial phase treatment usually continues for more than 10 days. Eradication treatment should be given for atleast 12–20 weeks. In this case, the patient developed septicaemia and did not respond to antibiotics.

This case also illustrates the importance of considering meliososis in the differential diagnosis of atypical infections, even when the presentation is unusual. Failure to recognize and treat meliodosis can lead to systemic dissemination and significant morbidity and mortality. This case report of melioidosis involving the parotid gland emphasizes the distinctive clinical and bacteriological features of this infection. By increasing awareness of this specific presentation of Burkholderia pseudomallei infection, we aim to facilitate accurate diagnosis and timely treatment. It is essential to recognize the infection in patients with underlying risk factors, such as diabetes and not responding to empirical antibiotic therapy. Early diagnosis and appropriate treatment are essential for managing melioidosis, especially in cases involving the parotid gland, where delayed intervention can lead to severe consequences, as exemplified by our patient’s fatal outcome.

Conclusion

In conclusion, parotid meliodosis, though rare, is an important differential diagnosis. Early diagnosis through high clinical suspicion, microbiological confirmation and prompt initiation of appropriate therapy are crucial for a favorable outcome. This patient emphasizes the need for awareness among clinicians to consider meliodosis in patients presenting with parotid gland infections, particularly those with underlying risk factors.

Funding

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Declarations

Conflict of interest

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Ethical Approval

Approved.