On a medical mission to Central America you spend a day working at a makeshift clinic in a small, impoverished village where hygienic practices are rather primitive and most of the inhabitants are somewhat malnourished. A 19-year-old man arrives at the clinic and complains of painfully sore gums and a foul taste in his mouth. Except for a mild fever (38 C), vital signs are normal. On examination, you note that his gums are reddened and swollen. Some areas are coated by a grayish film that appears to be caused by decomposition of the gum tissue. Crater-like ulcers are present between the teeth, on the gum papillae, and the patient has very noticeable halitosis. Even the slightest pressure on the gums causes them to bleed profusely. The cervical lymph nodes are somewhat swollen. On questioning, you learn that the patient has little knowledge of oral hygiene, does not own a toothbrush, and does not clean his teeth regularly by any other means.

Question 3.1: What is your diagnosis?

The patient appears to be suffering from some form of gingivitis, an inflammation of the gums, which is hardly surprising given his lack of oral hygiene. The painful nature of the gum tissues, their tendency to bleed easily, the crater-like ulcers on the papillae, and the obvious halitosis all indicate a relatively severe form of gingivitis called acute necrotizing ulcerative gingivitis. The disease is also known as Vincent's angina and trench mouth. The "trench mouth" terminology stems from World War I, when the disease was common among the soldiers who spent long periods in muddy trenches, where they were unable to practice regular oral hygiene.

Question 3.2: What are the predisposing risk factors?

The most common risk factor for trench mouth is poor oral hygiene, which undoubtedly played a major role in this case. Malnutrition-another significant risk factor-probably contributed to the development of this case as well. Other risk factors that have been linked to trench mouth include throat, tooth, or mouth infections; smoking; and emotional stress. Relatively severe cases of trench mouth are also seen in association with HIV infection; in fact, in countries where oral hygiene is practiced routinely, the highest incidence of infection is among AIDS patients.

Question 3.3: How was this patient infected?

Poor oral hygiene permits the development of an overabundance of normal mouth bacteria in the oral cavity. This, in turn, increases the likelihood that the gum tissues will be invaded and infected by these bacteria. Minor injuries (e.g., during chewing of certain types of foods) can provide openings in the epithelial surfaces that serve as portals of entry for mouth bacteria. Viruses may also play a role in enabling mouth bacteria to overgrow and invade the gums. Regardless of the details, the result is a rapidly developing, painful inflammation of the gingivae that results in necrosis, ulceration, tissue loss, etc.

Question 3.4: What is the causative agent?

Trench mouth is actually a mixed infection caused by various anaerobic bacteria that are normal members of the human mouth flora (see above). The most important causative agents are Prevotella intermedia, Porphyromonas gingivalis, and various species of spirochetes.

Question 3.5: What complications are possible?

Ulcerative gingivitis occasionally spreads to the buccal mucosa, the teeth, and the mandible and maxilla, resulting in widespread destruction of bone and soft tissue. This infection is referred to as acute necrotizing ulcerative mucositis (sometimes called cancrum oris, or noma). It rapidly destroys tissues, causing the teeth to fall out and large areas of bone, or even the whole mandible, to be sloughed. A strong, putrid odor is frequently detected, although the lesions are not painful. The gangrenous lesions eventually heal, leaving large disfiguring defects. This infection is seen most often following a debilitating illness or in severely malnourished children.

Question 3.6: How is this disease treated?

Therapy with oral penicillin plus metronidazole or with clindamycin alone is usually quite effective. Good oral hygiene is also vital to the treatment of trench mouth. Thorough tooth brushing and flossing must be performed as often as possible, at least twice each day and preferably after each meal and at bedtime. Salt water rinses may be soothing to sore gums. Hydrogen peroxide, used to rinse or irrigate the gums, is often recommended to remove decayed gum tissue.

Question 3.7: How is this disease prevented?

The most effective means of prevention is to practice good oral hygiene. Avoidance of the other risks factors (malnutrition, smoking, etc.) also helps to prevent trench mouth.