Pharyngitis, an inflammation of the throat, remains one of the most common reasons for seeking medical care. It is usually caused by a bacterial or viral infection, with group A Streptococcus being the most likely cause. Pharyngitis is not normally serious, but cases related to strep throat can have severe complications.
Instructions
1. Obtain the patient history. Streptococcal pharyngitis has an incubation period of two to five days, and patients typically experience an abrupt onset of symptoms that include chills, fever, headaches and a sore throat. Abdominal pain, nausea and vomiting also are common in children.
2. Conduct a physical examination. The most likely findings include a red, inflamed throat and uvula. Other common sighs of pharyngitis include swollen tonsils with grayish-white patches and swollen lymph nodes.
3. Take a throat culture by swabbing the tonsils and posterior pharynx vigorously, and culture the sample for two days in sheep blood agar. The false negative rate for a properly performed throat culture test is 5 to 10 percent.
4. Run rapid antigen detection tests. These tests are more expensive than throat cultures and can be completed in minutes at the bedside. Rapid antigen detection tests that use chemiluminescent DNA probes have sensitivities and specificities that are comparable to throat cultures.
5. Provide streptococcal antibody testing. Elevated streptococcal antibody levels will confirm a recent group A Streptococcus infection and also may be helpful in diagnosing complications such as acute rheumatic fever. The most common antibodies to test for are antideoxyribonuclease B and antistreptolysin O.
Tags: antigen detection, antigen detection tests, detection tests, group Streptococcus, most common, most likely, streptococcal antibody