Title : Submandibular abscess caused by salmonella in patient with diabetes mellitus: A case report and review of literature
Abstract:
Salmonellosis typically manifests as gastrointestinal symptoms, but rarely may also present as focal infection via the hematogenous spread of the bacteria. The incidence of neck abscess caused by Salmonella is low and there have been few cases reported among patients with uncontrolled blood sugar control. Herein, we describe a case of a newly diagnosed diabetic patient presenting with enlarging submandibular area associated with abscess on computed tomography scan. As mainstay treatment, the patient underwent surgical drainage and Salmonella was isolated from the specimens obtained. Antimicrobial therapy, most commonly Ciprofloxacin by sensitivity, was also provided.
Case presentation: A 29-year-old Filipino female was admitted to the hospital due to a 1-week history of enlarging right submandibular area that was associated with body malaise, cough, colds, and diarrhea. There were no fever, chills, night sweats, dysphagia, nor dyspnea noted. The patient was diagnosed with Polycystic Ovarian Syndrome, maintained on Cyproterone acetate + Ethinylestradiol and with family history of Type 2 diabetes mellitus (mother). She was an occasional alcoholic beverage drinker and never a smoker.
Upon presentation to the Emergency Department, the patient appeared to be in pain with stable vital signs. Physical examination revealed a 10x10cm firm, non-movable, non-erythematous, warm to touch, tender mass in the right mandibular area extending to the anterior neck. Neck ultrasound showed a heterogeneous, septated and fluid-filled structure measuring 8 x 7.7 x 3.9 cm (LxWxAP) and matted, enlarged right cervical lymph node measuring up to 1.6 x 1.4 x 1.3 cm. Computed tomography (CT) scan of the neck revealed a peripherally-enhancing, multiloculated-appearing predominantly hypodense lesion in the right side of the neck spanning from the submandibular region down to the supraclavicular region (C7 level) measuring approximately 7.1 x 5.8 x 8 cm. The right carotid space is effaced, compressing and displacing the tracheo-laryngeal structures to the left of midline, as well as effacing and possibly infiltrating the right sternocleidomastoid. Routine laboratory tests included complete blood count demonstrating hemoglobin 11.5 g/dl, hematocrit 35.4%, white blood count 14250- neutrophils 80, lymphocytes 10, platelet count 566,000 and creatinine 0.56 eGFR137ml/min/1.73m2. Her HbA1C was 11 mg/dl, hence was newly diagnosed with Type 2 Diabetes Mellitus and subsequently started on Metformin, Sitagliptin, and Insulin Glargine.
The patient was initially given empiric antibiotics including Clindamycin and Ceftazidime. She then underwent ultrasound-guided aspiration of the submandibular mass with a total of 60cc of purulent fluid aspirate.
Histopathology showed chronic granulomatous inflammation with suppuration. Specimens were also sent for cultures, which then tested positive for Salmonella. Negative results were yielded for MTB-PCR, Fite faraco stain for AFB, KOH, and Gomori methenamine silver stain for fungal elements. The Salmonella spp was sensitive to Ciprofloxacin to which the antibiotics were shifted.
During the admission, the patient developed dysphagia, aspiration episodes to liquids, and hoarseness of voice that was associated with persistent swelling of the submandibular area. Thus, she was given hydrocortisone. A transnasal flexible endoscopy was also performed where abundant cobblestoning along the hypopharyngeal mucosa and lingual tonsillar hyperplasia were found. The patient subsequently underwent incision and drainage of the neck abscess where 180cc purulent discharge was expressed from the incision site. She was able to tolerate the procedure well and eventually discharged stable with Ciprofloxacin for completion until 1 month.
Discussion: Salmonella is a Gram-negative, flagellated, facultative anaerobic bacilli that causes a spectrum of infection, namely gastroenteritis, enteric fever, focal disease, and a chronic carrier state (Gianella, 1996). Typically, Salmonella infection is mediated via the feco-oral route with subsequent blood stream invasion. It is through this hematogenous spread that in some cases, extraintestinal distant metastasis has been observed, including that of urinary tract infection, pneumonia, central nervous system infection, and bone and soft tissue infections. The incidence of Non-typhoidal Salmonella has been estimated at about 2 million individuals per year, a small minority of which developed extra-intestinal illness (Pastagia, 2013). Patients with underlying medical conditions such as diabetes mellitus, connective tissue disorders, HIV and malignancy acquire higher predisposition to infection. Individuals who underwent gastrectomy, with intake of antacid medicines, with achlorhydria and impaired bowel motility were also believed to be at risk for Salmonella disease due to increased susceptibility to bacterial entry and survival (Pastagia, 2013).
Head and neck infection caused by Salmonella is rare, as normally it arises mainly from Streptococcus, Staphylococcus, Haemophilus, or other anaerobic species (Kwon, 2010). Case reports of submandibular abscess as listed in Table 1 were reviewed. The range of age affected by the disease was 18 to 60 years old. Of the 8 patients, 5 are males and 3 are females. All of them had underlying diabetes mellitus with uncontrolled glucose control as revealed by HBA1C levels of 8-14 mg/dl, and one was reported to have liver cirrhosis. Majority of the patients underwent incision and drainage and antimicrobial treatment with Ciprofloxacin based on sensitivity.
In this report, another case of submandibular abscess from Salmonella in a newly diagnosed diabetic patient was presented. The patient belonged to the age group 20-60s which was commonly observed among those with head and neck infection by Salmonella. She manifested with some gastrointestinal symptoms, and eventually developed the submandibular abscess. The mechanism proposed to have predisposed these diabetic patients to Salmonellosis is the decreased gastric acidity, reduced intestinal motility, and prolonged gastrointestinal transit time due to the autonomic neuropathy of the small bowel (Pastagia, 2013). Moreover, Salmonella clearance can be impaired due to compromise of humoral and cell-mediated immunity from underlying conditions like diabetes and liver cirrhosis (Kwon, 2010). Primary gastrointestinal infection and bacteremia were thought to precede seeding of the microorganism to lead to a more focal disease as such to the soft tissues of the head and neck. Conventional treatment for infected neck abscess includes prompt incision and drainage and antibiotics for a minimum of 3 weeks. By culture as demonstrated in the studies, Salmonella remains sensitive to Ciprofloxacin.
Conclusion: Salmonellosis rarely manifests as focal infection as such in the case of neck abscess among patients with poorly controlled blood glucose levels. The proposed mechanism by which diabetes mellitus increases the risk for Salmonella infection is the development of autonomic neuropathy of the gastrointestinal tract (i.e decreased gastric acidity, prolonged gastrointestinal transit time). The standard treatment of neck abscesses arising from Salmonella remains surgical drainage accompanied by antibiotics.
