Upper respiratory infections case file

Upper Respiratory Infections Case File

Eugene C. Toy MD, Donald Briscoe, MD, FA  AFP, Bruce Britton, MD, Joel J. Heidelbaugh, MD, FA  AFP, FACG

Case 19

A 45-year-old man presents to the clinic with a cough productive of purulent sputum of 3-week duration. He says that he had just gotten over a cold a few weeks prior to this episode. He occasionally has fevers and he coughs so much that he has chest pain. He reports having a mild sore throat and nasal congestion. He has no history of asthma or of any chronic lung diseases. He denies nausea, vomiting, diarrhea, and any recent travel. He denies any smoking history. On examination, his temperature is 98.6°F (37.0°C), his pulse is 96 beats/min, his blood pressure is 124/82 mm Hg, his respiratory rate is 18 breaths/min, and his oxygen saturation is 99% on room air. Head, ears, eyes, nose, and throat (HEENT) examination reveals no erythema of the posterior oropharynx, tonsillar exudates, uvular deviations, or significant tonsillar swelling. Neck examination is negative. The chest examination yields occasional wheezes but normal air movement is noted.

⯈ What is the most likely diagnosis?

⯈ What is your next step?

⯈ What are some common noninfectious causes of cough?

ANSWER TO CASE 19:

Upper Respiratory Infections

Summary: A 45-year-old man, who has no history of lung disease and does not smoke, with 3 weeks of productive cough following an upper respiratory infection.

• Most likely diagnosis: Acute bronchitis.
• Next step: Bronchodilators, analgesics, and antitussives. Antibiotics have not been consistently shown to be beneficial. The illness is usually self-limited.
• Common noninfectious causes of cough: Asthma, chronic obstructive pulmonary disease (COPD), malignancy, postnasal drip, gastroesophageal reflux disease (GERD), medication side effect (eg, angiotensin-converting enzyme [ACE] inhibitors), congestive heart failure.

ANALYSIS

Objectives

1. Develop a differential diagnosis of cough persisting for 3 weeks or more.
2. Understand that most upper respiratory infections are self-limited illnesses.
3. Develop an approach for rational prescription of antibiotics for respiratory infections.

Considerations

The patient described in the case is a 45-year-old man with no prior history of lung disease, immunocompromised state, or tobacco use. These risk factors are important considerations since respiratory complaints in the setting of COPD or HIV or a smoking history require a higher index of suspicion of lower respiratory tract infections such as pneumonia. As with any respiratory complaint, the ABCs should be considered; that is airway, breathing, and circulation. In the ambulatory setting, a very quick assessment of the patient's distress level, respiratory use or nonuse of accessory muscles, anxiety level, stridor, and ability to speak sentences helps to triage to acute emergency versus more relaxed assessment. The individual described is afebrile, has a normal respiratory rate, and appears to be comfortable. The lung examination reveals some slight wheezes, but otherwise normal breath sounds and air movement. The most likely diagnosis in this setting is acute bronchitis. Chest radiograph is not necessarily indicated; however, since the complaint has persisted for 3 weeks, any other abnormal finding such as dullness on percussion of the chest, history of fever, or clinical suspicion would be sufficient reason for chest x-ray. Most acute bronchitis is caused by viruses and antibiotic therapy is not helpful. It is important to remember that acute bronchitis is a diagnosis of exclusion and by definition should not be made in the presence of clinical or radiographic evidence of pneumonia and only after ruling out other etiologies such as GERD, asthma, and the common cold. This patient with true acute bronchitis is best treated by bronchodilator therapy such as albuterol and antitussive agents and follow-up in 2 to 3 weeks.

Approach To:

Upper Respiratory Infections

DEFINITIONS

ACUTE BRONCHITIS: Inflammation of the tracheobronchial tree.

PNEUMONIA: Inflammation or infection of the lower respiratory tract, involving the distal bronchioles and alveoli.

CLINICAL APPROACH

Acute Bronchitis

Acute bronchitis refers to inflammation of the tracheobronchial tree. The inflammatory response to the trigger, whether infectious, allergic, or irritant, leads to increased mucous production and airway hyperresponsiveness. As bronchitis most commonly occurs in the setting of an upper respiratory illness, it is seen more frequently in the winter. Influenza, parainfluenza, adenovirus, rhinovirus, other viruses, Mycoplasma pneumoniae, and Chlamydia pneumoniae have been implicated as causes.

As the primary symptoms are nonspecific, other etiologies can be mistakenly diagnosed as acute bronchitis. In one study, one-third of patients who had been determined to have recurrent bouts of acute bronchitis were eventually identified as having asthma. Occupational history may be important in determining whether irritants play a role.

There are no specific diagnostic criteria for acute bronchitis, although cough productive of purulent sputum is the most common presentation. Other symptoms are often present, including fever, malaise, rhinorrhea or nasal congestion, sore throat, wheezing, dyspnea, chest pain, myalgias, or arthralgias. The sputum produced can be of variable color and consistency; the color of sputum is not diagnostic of the presence of a bacterial infection.

The physical examination in bronchitis is typically nonspecific and, frequently, is normal. The presence of fever, tachypnea, tachycardia, and blood pressure abnormalities should be noted. In persons with underlying pulmonary or cardiac conditions, or in persons with more severe symptoms, oxygen saturation by pulse oximetry may be warranted. Examination of the lungs may reveal rales, rhonchi, or wheezes, but in most cases is unremarkable.

Occasionally, findings on examination may suggest a particular etiology or an alternate diagnosis. Prolonged fever, tachycardia, tachypnea, hypotension, and signs of consolidation on pulmonary examination may suggest a diagnosis of pneumonia. When pneumonia is suspected, a chest radiograph should be obtained to confirm the diagnosis. Conjunctivitis and adenopathy suggest adenoviral infection, although these findings are not specific.

There is no requirement for obtaining viral cultures, serologic testing, or sputum analyses in a suspected case of acute bronchitis as the organism responsible is rarely identified, and more importantly, these tests have no effect on the subsequent management.

Bronchitis is nearly always self-limited in an otherwise healthy individual. Although most acute bronchitis lasts for less than 2 weeks, in some cases the cough can last for 2 months or more. Severe cases occasionally produce deterioration in patients with significant comorbid conditions.

Treatment

The use of antibiotics has not been shown consistently to alter the natural history of acute bronchitis, except in the case of infection with Bordetella pertussis. Patients with abnormal vital signs (pulse >100 beats/min, respiration >24 breaths/min, temperature >100.4°F [38.0°C]) and examination findings consistent with pulmonary consolidation should be evaluated further for the diagnosis of pneumonia and treated appropriately, if confirmed. Pneumonia may present atypically in the elderly and in persons with chronic lung disease. Physicians must have a higher index of suspicion in these populations.

As some of the symptoms of bronchitis are caused by airway hyperreactivity, bronchodilator therapy has been shown in some studies to offer benefit in reducing symptoms. Antitussives, such as dextromethorphan and codeine, may have modest benefits in reducing the cough associated with this illness. Mucokinetic agents have not shown to be of benefit and are therefore not recommended.

OTHER INFECTIONS OF THE UPPER RESPIRATORY TRACT

The most common cause of chronic cough in healthy, nonsmokers with a normal chest x-ray is the encompassing diagnosis of upper airway cough syndrome (UACS). This diagnosis encompasses a variety of upper respiratory conditions, which are distinguished from one another by physical examination findings, signs and symptoms, and sometimes after a trial of therapy. Some conditions under this umbrella diagnosis are allergic rhinitis and bacterial sinusitis.

Rhinosinusitis

Rhinosinusitis is the inflammation/infection of the nasal mucosa and of one or more paranasal sinuses. Sinusitis occurs with obstruction of the normal drainage mechanism. It is traditionally subdivided into acute (symptoms lasting <4 weeks), subacute (symptoms lasting 4-12 weeks), chronic (symptoms lasting >12 weeks), recurrent acute rhinosinusitis (four or more episodes of acute rhinosinusitis per year, with interim resolution of symptoms), and acute exacerbation of chronic sinusitis.

The signs and symptoms of rhinosinusitis are nonspecific and similar to other general upper respiratory tract infection symptoms. As most viral upper respiratory tract infections improve in 7 to 10 days, expert opinion suggests considering a diagnosis of bacterial rhinosinusitis after 7 days of symptoms in adults and 10 days in children. The diagnosis is suggested by the presence of purulent nasal discharge, maxillary tooth or facial pain, unilateral maxillary sinus tenderness, and worsening of symptoms after initial improvement.

Streptococcus pneumoniae and Haemophilus influenzae are the organisms most commonly responsible for acute bacterial sinusitis in adults; S pneumoniae, H influenzae, and Moraxella catarrhalis are most common in children. In chronic sinusitis, the infecting organisms are variable, with a higher incidence of anaerobic organisms seen ( eg, Bacteroides, Peptostreptococcus, and Fusobacterium species).

Treatment of acute sinusitis should be directed at the likely causative agents. Amoxicillin and trimethoprim-sulfamethoxazole are widely used first-line agents, typically for 10- to 14-day regimens. Second-line antibiotics, for those who fail to improve on the initial regimen or who have recurrent or severe disease, include amoxicillin-clavulanic acid, second- or third-generation cephalosporins (cefuroxime, cefaclor, cefprozil, and others), fluoroquinolones, or second-generation macrolides (azithromycin, clarithromycin). Adjunctive therapy with oral or topical decongestants may provide symptomatic relief. Topical decongestants should not be used for more than 3 days to avoid the risk of rebound vasodilation with resultant worsening of symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen may provide symptomatic relief of pain and fever.

Pharyngitis

Pharyngitis is an inflammation or irritation of the pharynx and/ or tonsils. In adults, the vast majority of pharyngitis is viral. It can also be bacterial or allergic in origin; trauma, toxins, and malignancy are rare causes. As most cases of pharyngitis in adults are benign and self-limited, a focus of the examination of a patient with symptoms of pharyngitis should be to rule out more serious conditions, such as epiglottitis or peritonsillar abscess, and to diagnose group A β-hemolytic Streptococcus (GAS) infection.

Pharyngitis occurs with much greater frequency in the pediatric population, with a peak incidence between 4 and 7 years of age. M pneumoniae, C pneumoniae, and Arcanobacterium haemolyticus are common causes of pharyngitis in teens and young adults. GAS causes 15% of all adult pharyngitis and approximately 30% of pediatric cases.

The cause of pharyngitis cannot always be distinguished based on history or examination. Sore throat associated with cough and rhinorrhea is more likely to be viral in origin. The presence of tonsillar exudates does not distinguish bacterial from viral causes, as GAS, Epstein-Barr virus (infectious mononucleosis), mycoplasma, Chlamydia, and adenoviruses, among others, can all cause exudates. Findings frequently associated with GAS infections include an abrupt onset of sore throat and fever, tonsillar and/ or palatal petechiae, tender cervical adenopathy, and absence of cough. GAS can also cause an erythematous, sandpaper-like (scarlatiniform) rash.

Infectious mononucleosis, caused by infection with Epstein-Barr virus, is extremely difficult to distinguish clinically from GAS infection. Exudative pharyngitis is prominent. Features suggestive of mononucleosis include retrocervical or generalized adenopathy and hepatosplenomegaly. Atypical lymphocytes can be seen on peripheral blood smear. The associated splenomegaly can be significant, as it predisposes to splenic rupture in response to trauma (even minor trauma). A patient with splenomegaly from mononucleosis should be restricted from activities, such as sports participation, in which abdominal trauma may occur.

On examination, the patency of the airway must be addressed first. The presence of stridor, drooling, and a toxic appearance suggest epiglottitis. Patients with epiglottitis are sometimes seen leaning forward on their outstretched arms, the so-called tripod position. Patients with suspected epiglottitis need to be managed in a setting where the airway can be emergently secured, via intubation or cricothyroidotomy. Epiglottitis is a rare infection and is becoming even rarer, with near universal immunization for H influenzae, type B.

Swelling of the peritonsillar region, with the associated tonsil pushed toward the midline and with contralateral deviation of the uvula, is consistent with a peritonsillar abscess. This can be seen either as the initial complaint of sore throat, frequently with associated trismus (pain with chewing), or as a complication of streptococcal pharyngitis. Suspicion of peritonsillar abscess should prompt immediate referral for surgical drainage of the abscess.

The diagnosis of GAS infection can be made by rapid antigen testing or throat culture. Rapid antigen tests can be conducted in a few minutes in the office or emergency department setting. They are highly specific but have a lower sensitivity than throat culture. A positive rapid antigen test would prompt antibiotic treatment; a negative test should be followed by a throat culture. Throat cultures are considered the gold standard for diagnosis of GAS infections. Cultures can take 24 to 48 hours; this is acceptable in most instances, as the risk of complication from GAS infections is low if treatment is instituted within 10 days of onset of symptoms.

Several clinical guidelines have been proposed to aid in the rapid diagnosis and management of patients presenting with pharyngitis. One of the most widely used is the modified Centor criteria. In this guideline, a patient is given a point for each of the following criteria: absence of cough; enlarged/tender anterior cervical adenopathy; fever of 100.4°F or higher; and tonsillar swelling/exudates. One point is also awarded if the patient is age 3 to 14 and one point deducted for the age of 45 or higher. Based on the number of points assessed, the following decision guidelines are proposed:

Complications from untreated GAS infections are rare, but include rheumatic fever, glomerulonephritis, toxic shock syndrome, peritonsillar abscess, meningitis, and bacteremia. Rheumatic fever, which may complicate up to one in 400 untreated cases of GAS pharyngitis, can cause permanent cardiac and neurologic sequelae. Glomerulonephritis results from antigen/ antibody complex deposition in the glomeruli. Poststreptococcal glomerulonephritis may occur whether or not the patient receives appropriate antibiotic treatment.

Penicillin is the antibiotic of choice for GAS pharyngitis. Oral therapy requires a 10-day course of penicillin V. Intramuscular therapy of penicillin G benzathine for adults and children weighing greater than 27 kg is 1.2 million units. Children who weigh less than 27 kg can receive 600,000 units of penicillin IM. In penicillin allergic patients, treatment options include cephalosporins and macrolides.

Other Common Causes of Chronic Cough

Asthma remains a significant cause of chronic cough across all age groups, but especially in the pediatric population. The pathophysiology of asthma is characterized by reversible airflow obstruction as well as inflammation and hyperreactivity of the airway. Symptoms besides cough include chest tightness, exacerbation by particular triggers, and improvement with inhaled bronchodilators and corticosteroids, which remain the mainstay of treatment. Spirometry must be done to diagnose asthma, and management is based on the variant determined by factors such as duration of symptoms, nighttime occurrences, and medication requirement to keep symptoms at bay.

Another leading cause of a chronic cough is GERD. The afferent limb of the cough reflex is activated by the acid interfering with the upper respiratory system. GERD presents with a cough that gets worse in a supine position, heartburn and increased symptoms after meals. Although the definitive test is 24-hour esophageal pH monitoring, GERD is usually a clinical diagnosis. A trial of proton pump inhibitor is both diagnostic and therapeutic.

ACE Inhibitor-Related Cough

It is important to mention this etiology as medication-related cough could be an easily overlooked cause of a nonproductive cough. ACE inhibitor-related cough usually appears 1 week to 6 months from initiation of therapy. The management is quite simply to discontinue the medication and assess response. Because it may take several weeks for the cough to go away after discontinuation of medication, response should be at the 4-week mark at the earliest. A good substitute for ACE inhibitor is an angiotensin receptor blocker (ARB).

INFECTIONS OF THE EAR

Otitis externa (OE) is an infection of the external auditory canal. Patients with OE complain of ear pain and, sometimes, itching. The pain from OE can be severe. Examination shows an inflamed, swollen, external ear canal, often with exudates and discharge. Movement of the external ear is usually quite painful. The tympanic membrane may be uninvolved. The most common pathogens include staphylococci, streptococci, and other skin flora. Some cases have been associated with the use of swimming pools or hot tubs. This infection (swimmer's ear) is usually caused by Pseudomonas aeruginosa. Irrigation and administration of topical antibiotics, frequently combined with steroid, is usually successful. Patients with diabetes mellitus are at risk for an invasive external otitis (malignant OE) caused by P aeruginosa. Treatment for this condition involves surgical debridement of necrotic tissue and 4 to 6 weeks of IV antibiotics, if cranial bones are involved.

Otitis media (OM) is an infection of the middle ear seen primarily among preschool children, but occasionally in adults as well. Infection of the middle ear space, caused by upper respiratory tract pathogens, is promoted by obstruction to drainage through edematous, congested eustachian tubes. Viral infection with serous otitis may predispose to acute bacterial otitis media. Fever, ear pain, diminished hearing, vertigo, and tinnitus are common presenting symptoms. On examination, the tympanic membrane may appear red, but the presence of decreased membrane mobility or fluid behind the tympanic membrane is necessary for the diagnosis. S pneumoniae, H influenzae, and M catarrhalis are the most common bacterial pathogens. Most cases of acute OM will resolve spontaneously. Indications for treatment with antibiotics include prolonged, recurrent, or severe symptoms. Numerous antibiotics can be used for treatment. Amoxicillin remains the recommended initial therapy. Alternative treatments include amoxicillin-clavulanic acid, trimethoprim-sulfamethoxazole, or second- and third-generation cephalosporins. Complications are uncommon, but include mastoiditis, bacterial meningitis, brain abscess, and subdural empyema.

CASE CORRELATION

• See Cases 2 (Dyspnea, COPD) and 6 (Allergic Disorders).

COMPREHENSION QUESTIONS

19.1 A 30-year-old woman with no past medical history presents with a productive cough of 2-week duration. She states she also has a runny nose, body aches, congestion, and fevers for the past week. In office she is normotensive, with a normal pulse, and temperature of 101.2°F. Her physical examination

is significant for sinus tenderness, boggy nasal turbinates, and crackles in the left lower lobe lung fields. Which one of the following is the best initial step in management?

A. Reassure the patient that she likely has a viral infection and it will resolve on its own.

B. Order a rapid strep test and treat if positive

C. Prescribe amoxicillin for a likely bacterial infection

D. Order chest x-ray to rule out possible pneumonia

19.2 A 55-year-old man with history of hypertension and diabetes presents with intermittent nighttime cough for a few months. He states he often has a "weird taste'' in his mouth a couple of hours after eating and is afraid of eating dinner because he gets terrible heartburn during the night. He states he has tried over the counter antacid and this has worked to somewhat alleviate his symptoms; however, his nighttime cough is still very bothersome. His vitals in office are within normal limits and physical examination is positive for epigastric tenderness upon palpation. Which one of the following is true regarding the most likely etiology of this patient's cough?

A. It is the second leading cause of chronic cough.

B. The most sensitive and specific test for this condition is a 24-hour esophageal pH monitoring.

C. The first line of treatment for this condition is a trial of 4 weeks of H2 blocker.

D. This condition always requires a diagnostic test for confirmation and should not be diagnosed clinically.

19.3 A 13-year-old adolescent girl presents with fever and sore throat of 48-hour duration. She has a temperature of 101°F in office and is tachycardic with a pulse of 118 beats/min. Her physical examination is positive for tender, enlarged left cervical lymphadenopathy and tachycardia. Her pharynx is erythematous but without tonsillar enlargement or exudate. She has had no

cough. What is the best step in management?

A. Treat empirically with antibiotics.

B. Order rapid strep test and, if positive, treat with antibiotics.

C. Neither further testing nor antibiotics.

D. Order throat culture and, if positive, treat with antibiotics.

ANSWERS

19.1 D. Acute bronchitis is a diagnosis of exclusion in the absence of clinical or radiographic findings concerning for pneumonia. In this patient with fevers, productive cough, and rales on lung examination, it is important to rule out pneumonia. If there is a strong clinical suspicion of community-acquired pneumonia, a chest x-ray is not necessary, and outpatient treatment with antibiotics can be initiated. The diagnosis of streptococcal pharyngitis is made with rapid strep test or throat culture and the decision to order these in office is guided by modified Centor criteria based on the following factors: age, presence of tonsillar exudates, fever, absence of cough.

19.2 B. This patient's cough is most likely secondary to GERD. The most definitive test to diagnose this condition is a 24-hour pH monitoring test, however, this is not required for diagnosis. GERD is almost always a clinical diagnosis and a 4-week trial of proton pump inhibitor is both diagnostic and therapeutic. Lastly, GERD is the third leading cause of chronic cough, after upper airway cough syndrome and asthma.

19.3 A. Management of strep pharyngitis is frequently guided by modified Centor criteria, which calculates a probability of strep throat based on a scoring system (presented earlier in the chapter). This patient gets one point for the presence of fever, tender cervical adenopathy, absence of cough, and age. You could reasonably consider an empiric antibiotic treatment for GAS in her.

CLINICAL PEARLS

⯈ The main concerns with pharyngitis are to rule out more serious conditions, such as epiglottitis or peritonsillar abscess, and to diagnose group A β-hemolytic streptococcal infections.

⯈ Upper airway cough syndrome (UACS) is an umbrella term that encompasses a variety of upper respiratory conditions including rhinitis and sinusitis.

⯈ A tonsillopharyngeal exudate does not differentiate viral and bacterial causes .

⯈ Asthma and GERD are the second and third leading cause of chronic cough, respectively, after UACS, which is the most common cause of cough.

REFERENCES

Aring AM, Chan MM. Acute rhinosinusitis in adults. Am Fam Physician. 2011 May 1;83(9):1057-1063. 

Benich JJ, Carek PJ. Evaluation of the patient with chronic cough. Am Fam Physician. 2011 Oct 15;84(8):887-892. 

Choby BA. Diagnosis and treatment of streptococcal pharyngitis. Am Fam Physician. 2009 Mar 1;79(5):383-390. 

Gonzales R, Bartlett JG, Besser RE, et al. Principles of appropriate antibiotic use for treatment of uncomplicated acute bronchitis: background. Ann Intern Med. 2001;134(6):521-529. 

Irwin RS, Baumann MH, Bolser DC, et al. Diagnosis and management of cough executive summary: ACCP evidence-based clinical practice guidelines. Chest. 2006 Jan;129(suppl 1):1-S23. 

Knutson D, Braun C. Diagnosis and management of acute bronchitis. Am Fam Physician. 2002;65: 2039-2044, 2046. 

Rosenfeld RM, Andes D, Bhattacharyya N, et al. Clinical practice guideline: adult sinusitis. Otolaryngol Head Neck Surg. 2007;137(suppl 3):Sl-S31.

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