What is a sore throat?
Sore throat, termed pharyngitis by medical practitioners, is a common cause of patient discomfort and visits to the doctor’s office. Though many people equate sore throat with strep throat, in reality there are many infectious and noninfectious causes of this symptom. Sore throat can even be a sign of disease in another part of the body. The sensation, which may be described by sufferers as scratchy, raw, tight, burning, or achy, may last from minutes to months, depending on the underlying cause, and may be accompanied by related complaints such as fever, runny nose, hoarseness, or difficulty swallowing.
Most sore throats are caused by infection in the upper respiratory tract, including the ears, nose, and sinuses as well as the throat and tonsils. Research has demonstrated that more than half of these infections are caused by common viruses. Epstein-Barr virus, which causes mononucleosis, accounts for less than 10 percent. Most of the remainder are caused by various bacteria. Of the bacterial causes, strep, more specifically group A beta-hemolytic Streptococcus , is the most common pathogen. Additional bacterial causes include species of Staphylococcus , Hemophilus, Mycoplasma, non-group A streptococcus, and others. More rarely, fungi may account for a larger portion of throat infections in patients with weakened immune defenses.
Noninfectious causes of sore throat are quite varied. Although most are self-limited (resolving over time without treatment), some represent serious illness. These come into consideration especially if the duration of symptoms is longer than usual and if other aspects of the patient’s health history suggest the likelihood of secondary causes.
Traumatic causes of throat discomfort include swallowing foreign objects, such as fish bones; thermal injury from a hot beverage; chemical injury from an ingestion, such as bleach; and external force from a blow to the neck. Environmental irritants, such as smoke and solvent fumes or allergies to dusts and pollens, cause symptoms in susceptible, exposed persons. Regurgitated stomach acid, such as from acid reflux disease, causes discomfort, which may be more pronounced when the patient is lying down. Enlargement of the thyroid gland or the salivary glands, cysts arising from embryonic structures such as the thyroglossal duct, or inflammation of lymph nodes can exert local pressure on the throat itself or on adjacent nerves, thereby eliciting symptoms. Cancer is the most ominous cause of sore throat symptoms, and it needs to be considered in patients with risk factors such as smoking and excessive alcohol consumption.
Considering this expansive list of possibilities, which does not include every possible cause of sore throat, it is evident that the expedient diagnosis of sore throat is challenging. Though most sore throats resolve without treatment or complication, the practitioner must consider the possibility of rarer but potentially life-threatening diseases. The initial history and physical examination are sufficient in most cases to separate those patients who are likely to have an infectious cause from those who are unlikely to have one. Since most patients are initially concerned about the possibility of strep throat and the need for antibiotics, clinical algorithms, such as the Centor score, have been developed to assist this process. By tallying associated signs, symptoms, and patient characteristics, the practitioner may increase diagnostic accuracy. In some cases, additional testing, such as a rapid streptococcal antigen throat swab or a culture, is needed.
The search for noninfectious causes often begins when the patient returns with persisting symptoms. Since most throat infections resolve within a week or two, lingering discomfort suggests the need for further evaluation. In many cases, additional historical information from the patient and a follow-up physical examination will significantly narrow the list of possibilities. Clues such as weight loss, hoarseness, and a history of cigarette smoking and alcohol consumption increase the probability of throat cancer. Occupational information may uncover exposure to noxious dust or vapors. In difficult cases, diagnosis may require examination and biopsy of the throat during a procedure called laryngoscopy.
The treatments of noninfectious sore throat are as varied as the diagnoses themselves. The treatment of infectious sore throat depends on the underlying cause, ranging from rest, fluids, and analgesics (painkillers) for viruses to antibiotics for certain bacteria and fungi. Penicillin has been the mainstay of strep throat treatment since the mid-twentieth century. Before the discovery of penicillin, throat infection sometimes resulted in serious complications, such as rheumatic fever (which damages the heart valves) and glomerulonephritis (which damages the kidneys). Although group A Streptococcus pyogenes has remained remarkably sensitive to penicillin, reports have suggested that the treatment of strep throat is becoming more complex. The presence of other bacteria in the throat, some of which have developed the ability to inactivate penicillin, may actually protect the strep bacteria from the antibiotic. Interestingly, some research suggests that antibiotic treatment very early in the course of disease may even increase the likelihood of subsequent recurrence. Infections by bacteria other than strep or by fungi are treated with other antibiotic and antifungal drugs.
Given this scenario, one may wonder why doctors do not treat everyone with antibiotics, rather than going to the trouble and expense of diagnosing strep throat. Antibiotic treatment is complicated by many factors, including cost, drug interactions, and the potential for allergic reactions. Widespread use has led to the development of antibiotic-resistant strains of “super bacteria,” which are very difficult if not impossible to treat.
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