PHARYNGITIS

Saturday, August 16, 2008

Essentials of Diagnosis

• Pharyngeal discomfort or pain, pain on swallowing (odynophagia).

• Associated symptoms such as myalgia, fever, rhinorrhea, and lymphadenopathy depend on the etiologic agent.

• Pharyngeal erythema with or without exudate or lymphadenopathy.

• Leukocytosis, GAS RADT, and bacterial culture or other serologies may provide the definitive microbiologic diagnosis.

General Considerations

Pharyngitis is an acute infection of the pharyngeal mucosa caused by a variety of pathogenic microorganisms, the majority of which are viral (Box 9-2). A minority of pharyngitis episodes are bacterial and, of those, group A streptococcus is the most common cause. Viral pharyngitis is caused by respiratory viruses such as rhinoviruses, coronaviruses, adenoviruses, influenza, and EBV. Bacteria causing pharyngitis include group A and non-group A streptococci, Corynebacterium diphtheria, Corynebacterium pseudodiphtherium, Neisseria gonorrhoeae, Yersinia enterocolitica, Arcanobacterium hemolyticum, and anaerobic bacterial species. Persons infected with the human immunodeficiency virus (HIV) may present with an HIV-induced exudative pharyngitis during the acute retroviral syndrome or with Candida-induced pharyngitis. The etiology of pharyngitis remains obscure in 40% of cases. Most pharyngitis occurs as result of respiratory or contact transmission; few cases are foodborne. Outbreaks are common in winter or in crowded living situations, especially in families with children who serve as reservoirs by acquiring infections in daycare centers or school.

Clinical Findings

A. Signs and Symptoms. The severity of the pharyngitis may vary from mild to life threatening depending on the etiologic agent. Symptoms of mild pharyngitis are irritation or sore throat. With increasing severity there may be severe pain that increases on swallowing or talking, plus cervical lymphadenopathy with or without fever. Pharyngitis can be life threatening with inflammatory edema of pharyngeal walls and extension to the larynx leading to respiratory distress.

An erythematous pharynx with or without exudates or cervical lymphadenopathy is the common finding on examination. Because it impacts therapeutic decision-making, it is important to attempt clinical differentiation between viral and bacterial pharyngitis. However, this may be difficult. Associated clinical signs and symptoms provide diagnostic clues to formulate a differential diagnosis. Mild pharyngeal symptoms with rhinorrhea usually suggest a viral etiology. Pharyngeal exudates suggest streptococcal pharyngitis, HIV, or EBV. Presence of vesicles and ulcers is seen with herpes simplex and coxsackievirus. Coxsackievirus-related vesicles often occur on the hard palate. Adenoviral pharyngitis is associated with conjunctival congestion. EBV, HIV, A hemolyticum, and streptococcal toxic shock can present with pharyngitis and a generalized rash. Pharyngitis with elevated transaminases, splenomegaly, and atypical lymphocytosis is the typical manifestation of EBV-induced infectious mononucleosis. Aseptic meningitis along with pharyngitis should suggest an acute HIV or enteroviral syndrome. Systemic viral infections with CMV, measles, and rubella, among others, can present with acute pharyngitis.

Sore throat with cough and signs of pneumonia may suggest influenza, Chlamydia pneumoniae or Mycoplasma pneumoniae. Diphtherial pharyngitis is associated with a grayish pseudomembrane.

GAS (Streptococcus pyogenes) pharyngitis frequently presents with fever of > 38.3 oC, chills, sudden-onset sore throat, painful and difficult swallowing, and tender cervical lymph nodes. Lymphadenopathy is more likely to be anterior and tender in GAS pharyngitis, unlike viral pharyngitis, which is more likely to be generalized and nontender. Exudate with intense pharyngeal and tonsillar pillars erythema is seen. Occasionally patients, especially children, present with systemic symptoms of nausea, vomiting, and headache. Symptoms of non-group A, such as group C or G, streptococcal pharyngitis are very similar to GAS and clinically indistinguishable. These symptoms and signs are nonspecific for GAS pharyngitis. However, absence of fever or presence of other symptoms such as rhinorrhea, cough, oral ulcers, and viral exanthema strongly suggests a viral rather than a GAS pharyngitis.

B. Laboratory Findings. Laboratory values may not be of considerable help. Testing for GAS should be done in all patients in whom GAS pharyngitis cannot be confidently excluded on clinical grounds. Diagnosis of GAS pharyngitis can be made by RADT, which has a sensitivity of 80-95% and specificity of 95%. Use of RADT significantly increases the number of patients receiving appropriate antibiotic treatment. Because of its relatively lower sensitivity, a negative test should be confirmed with a throat culture. Throat cultures taken from the tonsillar fossae and posterior pharyngeal wall are 90-95% sensitive for the diagnosis of GAS pharyngitis. Follow-up cultures are not generally recommended except in patients with histories of acute rheumatic fever or poststreptococcal glomerulonephritis or in outbreaks. Asymptomatic contacts of the patient do not need to be screened unless there is an outbreak or the patient has a history of acute rheumatic fever.

Special culture media for N gonorrhoeae or C diphtheria should be specifically requested when these bacteria are suspected. Serologic testing can establish the diagnosis of EBV, HIV, CMV, influenza, M pneumoniae, and C pneumoniae. During acute HIV retroviral syndrome, HIV RNA polymerase chain reaction, or HIV culture can help make a diagnosis because HIV serology may be negative.

C. Imaging. A lateral neck x-ray should be done if the patient has associated symptoms of stridor or respiratory compromise, to rule out laryngeal obstruction.

Differential Diagnosis

In children, Kawasaki's syndrome can present with a clinical picture similar to an infectious pharyngitis. Noninfectious causes of pharyngitis include chemotherapy-induced mucositis, drug reactions, agranulocytosis, or connective-tissue disorders.

Complications

Local complications of bacterial pharyngitis include peritonsillar or retropharyngeal abscesses or Fusobacterium necrophorum jugular vein thrombophlebitis and its embolic complications (Lemeire's syndrome). In the United States, appropriate and timely antibiotics have decreased nonsuppurative complications of S pyogenes such as rheumatic heart disease or poststreptococcal glomerulonephritis. C diphtheria pharyngitis may become complicated by acute upper-airway obstruction, myocarditis, or neuritis. Viral pharyngitis may be complicated by secondary bacterial infection of the sinuses or lower respiratory tract.

Treatment

In patients with a clinical picture consistent with GAS pharyngitis, empirical therapy should be started to prevent suppurative and nonsuppurative complications, to decrease infectivity and transmissibility, and to induce clinical improvement of symptoms (Box 9-3). Patients with a high index of suspicion for GAS pharyngitis but negative or pending RADT/culture results can be given empirical antibiotics until the results are available. An alternative approach is to withhold antibiotics until the culture is positive for S pyogenes. Delaying therapy against GAS does not increase the incidence of rheumatic heart disease or recurrences with the same strain of S pyogenes. Following the latter course will decrease inappropriate antibiotic use and control the increase in antibiotic resistance.

Antibiotic selection is based on efficacy, ease of administration, cost, compliance, and spectrum of the antibiotic. The treatment of choice is penicillin V or amoxicillin for 10 d to treat and eradicate carriage. Intramuscular benzathine penicillin G may be given in patients unlikely to complete a 10-d course. Shorter courses are not recommended until more definitive studies are available. Erythromycin or other macrolides (such as clarithromycin or azithromycin), or oral cephalosporins are the recommended alternatives for bacterial pharyngitis in patients who are allergic to penicillin. Absence of penicillin-resistant GAS and limited (5%) resistance to erythromycin make it imperative to choose a cheaper alternative to the newer more expensive antibiotics. In some patients with recurrent GAS pharyngitis, penicillin is unable to eradicate nasopharyngeal carriage. In such patients, rifampin, clindamycin, or amoxicillin/clavulanate use may decrease colonization. Patients with negative throat RADT/cultures should have antibiotics discontinued.

Pharyngitis caused by anaerobic bacteria may respond to penicillins, amoxicillin/clavulanate, or clindamycin. A hemolyticum is susceptible to erythromycin. Yersinia pharyngitis requires treatment with a third-generation cephalosporin, an aminoglycoside or trimethoprim-sulfamethoxazole (TMP-SMX). Effective therapies for gonococcal pharyngitis include ceftriaxone, cefixime, or fluoroquinolones such as norfloxacin, ofloxacin, or ciprofloxacin. Treatment of choice for Mycoplasma pharyngitis is either doxycycline or macrolides. Doxycycline is contraindicated in children < 8 y old because it causes discoloration of teeth.

Symptomatic oropharyngeal herpes simplex ulcers, particularly in an immunocompromised host, should be treated with acyclovir for 7-10 d. Influenza type A pharyngitis can be treated with amantadine or rimantadine or the neuraminidase inhibitors if the patient presents within 48-72 h of onset of symptoms. HIV acute retroviral syndrome should be considered for treatment with combination antiretroviral therapy.

General measures for symptomatic relief include fluids, warm saline gargles, and nonsteroidal anti-inflammatory drugs. Aspirin should be avoided in children with viral infections, particularly varicella-zoster virus infection, to prevent Reye's syndrome. Patients that appear toxic or patients with suppurative complications should be hospitalized for parenteral or surgical management.

Prognosis

Uncomplicated pharyngitis results in no sequelae. Prognosis of GAS pharyngitis complicated by rheumatic heart disease or poststreptococcal glomerulonephritis is good with penicillin prophylaxis in rheumatic heart disease and spontaneous remission in poststreptococcal glomerulonephritis. Suppurative complications have minimal long-term adverse effects.

Prevention & Control

Active immunization plays a role in prevention with regard to diphtheria and influenza types A and B (Box 9-4). Tonsillectomy is recommended in selected patients. Penicillin prophylaxis is required in patients at risk for recurrent rheumatic fever.

4 comments:

Arthur said...

I suffered a pharyngitis so can I sill get a Viagra Online Prescription from my doctor ?

DonMchl said...
This comment has been removed by the author.
DonMchl said...

Your article truly helped me in making a proper diagnosis
for my aching throat. I found that in my case relief was quickest obtained when
taking Lortab with Cipro.

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