Primary Care: Respiratory Tract Infections and Asthma

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Primary Care Respiratory Tract Infections and
Asthma

• Tamra N. Fortenberry, MD
• Department of Ob/Gyn
• The University of Tennessee
• Memphis, TN

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Objectives - Respiratory Tract Infections

• 1. List the differential diagnosis for
  respiratory tract infection.
• 2. Obtain a pertinent history in a patient with
  a suspected respiratory tract infection.
• 3. Describe the usual symptoms and signs of
  respiratory tract infection.
• 4. Perform a targeted physical examination to
  confirm the diagnosis of respiratory tract
  infection.

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Objectives Respiratory Tract Infections

• 5. Interpret selected tests to diagnose
  respiratory tract infection
• a. Chest X-ray
• b. Sputum Gram stain and culture
• c. Tuberculin skin test
• d. Serologic tests for viral or bacterial
  infection
• e. Pulse Oximetry
• 6. Treat uncomplicated respiratory tract
  infections.

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Differential Diagnosis for Respiratory Tract
Infections

• Upper respiratory infection (URI)
• Viral Rhinitis (Common cold)
• Sinusitis
• Pharyngitis
• Influenza
• Pneumonia
• Bronchitis
• Tuberculosis
• Asthma

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The Common Cold

• An estimated 2 of every 5 Americans are affected
  each year
• Some experience multiple episodes in 1 year

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The Common Cold

• Rhinoviruses are the most common viral agents
• Over 100 serotypes have been implicated
• Other viruses implicated included coronaviruses,
  influenza C, parainfluenza virus, adenoviruses,
  and respiratory syncytial virus

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The Common Cold

• No specific virus can be identified in 50 of the
  cases
• Highly contagious, respiratory droplets spread by
  sneezing, coughing, or hand contact with the
  nose, eyes, or face
• 75 of patients infected with rhinovirus will
  have symptoms

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The Common Cold

• Is not caused by a change in weather, loss of
  sleep, going outside with wet hair, or fatigue
• Risks for contracting a cold are due to exposure
  to the causative viruses through personal contact

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The Common Cold

• Signs and symptoms
• Has an incubation period of 2 4 days
• Thereafter, sneezing, coughing, malaise may last
  from 6 10 days or possibly up to 3 weeks after
  incubation period

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The Common Cold

• Signs and symptoms
• Patient may complain of headache, nasal
  congestion, and scratchy throat
• Subsequently, may complain of sneezing and
  clear, watery rhinorrhea in association with
  nasal obstruction with general malaise but no
  fever

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The Common Cold

• Signs and Symptoms
• After 2 3 days, nasal discharge becomes
  thicker, cloudy, and yellowish in color as
  systemic symptoms improve
• Hoarseness, cough, and sore throat may last up to
  7 10 days

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The Common Cold

• Diagnosis
• Made on clinical grounds pt symptoms, nasal
  exam showing reddened, edematous mucosa, narrowed
  nasal passages, and watery discharge
• Laboratory and/or imaging only indicated if other
  conditions are strongly suspected
• Viral isolation/culture is not practical

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The Common Cold

• Management/Treatment
• No curative treatment
• Supportive therapy 10 treatment
• Fluids, rest, humidification, and decongestants
• Analgesics, cough suppressants, mucolytics, and
  antihistamines are also helpful
• Short term use of zinc lozenges (zinc gluconate
  10-15 mg q 2 hrs) shown to reduce duration of
  subjective symptoms if begun early in course of
  disease

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The Common Cold

• Inappropriate prescribing of antibiotics is
  common
• Due to patient beliefs/misinformation of cold
  being bacterial in origin
• Rural location
• Female gender
• Patients with purulent secretions
• Antibiotics should be considered if symptoms last
  longer than 10-14 days, due to an 80 chance of a
  secondary infection occurring

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Sinusitis

• Over 35 million people in the US are affected
  each year
• Causative agents are usually normal inhabitants
  of the respiratory tract
• Hemophilus influenzae and Streptococcus
  pneumoniae are the most common causes
• Viral and fungal agents are rare

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Sinusitis

• Signs and symptoms
• Patient may complain of a feeling of fullness
  and pressure over the involved sinuses, nasal
  congestion, and purulent nasal discharge
• Other associated symptoms include sore throat,
  malaise, low grade fever, headache, toothache,
  cough gt1 weeks duration
• Symptoms may last 10 14 days

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Sinusitis

• As part of the history, the physician may inquire
  about the following
• Are symptoms exacerbated by positional changes,
  preceded by air travel, URI, or seasonal
  allergies?
• Exposure to tobacco smoke, cold or damp weather,
  pollution?

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Sinusitis

• Diagnosis
• Based on clinical signs and symptoms
• Physical exam may reveal patient described
  symptoms palpate over sinuses, observe for
  structural abnormalities such a deviated nasal
  septum
• Sinus radiographs may reveal cloudiness and air
  fluid levels
• Limited coronal CT are more sensitive to
  inflammatory changes and bone destruction

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Sinusitis

• Management/Treatment
• 2/3 of untreated patients will improve
  symptomatically within 2 weeks
• Antibiotics may be appropriate in certain
  patients
• Amoxicillin (500mg TID) or Trimethoprim-sulfametho
  xazole (1 double strength tablet BID) for 10
  days, or up to 21 days
• Alternative antibiotic therapy should include
  drugs with activity against beta
  lactamase-producing bacteria

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Sinusitis

• Supportive therapy such as humidification,
  antihistamines, analgesics, and/or
  vasoconstrictors may relieve congestion and
  fullness
• OTC decongestant sprays for use of more than 5
  days duration should be discouraged

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Pharyngitis

• Fewer than 25 of patients with a sore throat
  have true pharyngitis
• Primarily seen in 5 18 year old population, it
  is common in adult women

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Pharyngitis

• May be of bacterial or viral origin
• Most common cause is viral most common agent is
  rhinovirus
• Self-limiting usually lasts 3-4 days
• Group A, beta-hemolytic strep is the primary
  bacterial pathogen, in 1/3 cases - early
  detection reduces incidence of acute rheumatic
  fever and post streptococcal pharyngitis

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Pharyngitis

• Signs and symptoms
• Inflammation of the pharynx and lymphoid tissue
  results in fever, sore throat, malaise, and
  rhinorrhea
• There is usually a lack of cough
• Classic triad of findings for Group A strep
  pharyngitis include
• High fever
• Tonsillar exudates
• Anterior cervical adenopathy (in absence of
  significant cough)

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Pharyngitis

• Diagnosis
• On PE observe throat for tonsillar exudates
  obtain throat swab
• Rapid streptococcal identification tests are
  most commonly used there is a sensitivity of 80
  and a specificity of 95
• Throat cultures may be collected if rapid strep
  screen is negative

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Pharyngitis

• Management/Treatment
• Symptomatic treatment includes salt-water
  gargles, acetaminophen, cool-mist humidification,
  and throat lozenges
• Antibiotics treatment is necessary to treat
  proven strep infections
• Benzathine penicillin G 1.2 million units as a
  single dose, is optimal therapy
• For pen allergic pts, erythromycin 500mg po
  QID x 10 days or Azithromycin 500mg once daily x
  3 days.

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Influenza

• Responsible for over 4 million respiratory
  illnesses each year
• Attributable for up to 40,000 deaths and 200,000
  hospitalizations annually
• Several types including Influenza A and B with
  each having a variety of strains which may vary
  each year
• Susceptibility/incidence in pregnancy varies
• Incubation period 1-5 days contagious 24 hours
  before to 7 days after Sx began

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Influenza

• Signs and symptoms
• Often necessary to differentiate influenza from
  the common cold
• Symptoms include high fever (up to 1040 F)
  exhaustion, generalized aches, and cough
• Patients occasionally report headache,nasal
  congestion, sneezing, and sore throat

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Influenza

• Diagnosis
• Diagnosis is based on clinical signs and symptoms
• Nasopharyngeal swab or aspirate can be obtained
  for a rapid antigen test
• Chest xray usually normal

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Influenza

• Options for the prevention and treatment are
  available
• The vaccine is a inactivated killed form that
  is 70 80 effective in preventing illness or
  reducing severity of symptoms
• ACOG recommends vaccination of all pregnant women
  in 2nd and 3rd trimesters during flu season or
  any trimester if pt at high risk for pulmonary
  complications

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Influenza

• Management/Treatment
• Analgesics and a cough suppressants for
  supportive therapy
• Amantadine and rimantadine (both at doses of 200
  mg/day) have been effective at treating
  Influenza A. Rimantadine is preferred in renal
  failure patients
• Zanamivir and Tamiflu are effective for patients
  with Influenza A and B, but with less side
  effects

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Pneumonia

• Most commonly community-acquired
• Common etiologic agents are Streptococcus
  pneumoniae or Mycoplasma pneumoniae
• Viral and fungal causes have been indicated but
  less common
• Increased incidence of SAB and PTL has been
  reported
• Major cause of nonobstetric maternal death,
  approximately 3.6 8.6

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Pneumonia

• Signs and symptoms
• Fever or hypothermia, cough with or without
  sputum, dyspnea, chest discomfort, sweats, or
  rigors
• Malaise may precede
• Atypical pneumonia associated with headaches,
  diarrhea, nonexudative pharyngitis, bullous
  myringitis, slow onset, myalgias

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Pneumonia

• Diagnosis
• Based on clinical signs and symptoms
• PE may reveal fever, tachypnea, tachycardia.
  Lung exam - altered breath sounds dullness to
  percussion
• Gram stain
• gram positive lancet shaped diplococci (Strep.
  pneumoniae)
• gram negative coccobacilli (H. influenzae)
• PMNs and monocytes no bacteria (Mycoplasma
  pneumoniae)

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Pneumonia

• Diagnosis
• Sputum cultures with sensitivities collected on
  patients requiring hospitalization
• Pulse oximetry on patient with dyspnea O2 sat
  should gt 93
• Labs CBC/diff, CMP with LFts
• ABGs may reveal hypoxemia, hypocarbia, and
  respiratory alkalosis

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Pneumonia

• Diagnosis
• Chest xray essential (AP and Lateral)
• Patchy airspace infiltrates (Mycoplasma)
• Lobar or segmental consolidation (w/air
  bronchogram) (Pneumococcal)
• Diffuse alveolar or interstitial infiltrates
  (viral or Mycoplasma and other)
• Utilize the PORT score to determine if patient
  needs to be hospitalized (score of lt70 may be
  management as an outpatient)

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Pneumonia
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Pneumonia

• Management/Treatment (outpatient)
• Empiric therapy for 10 14 days
• Doxycycline 100 mg po BID
• Fluoroquinolones (Gatifloxacin 400mg po QD,
  Levofloxacin 500mg po QD)
• Macrolides (Azithromycin 500mg po x 1, then 250mg
  QD x4 days)

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Pneumonia

• Prevention
• Polyvalent pneumococcal vaccine may be given at
  same time with influenza vaccine
• ACOG recommends vaccination of pregnant women
  with asplenia metabolic, renal, cardiac,
  pulmonary diseases smokers immunosuppressed

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Tuberculosis

• Approximately 15 million people affected in US
• Infects an estimated 20 43 of the worlds
  population
• Causative agent, Mycobacterium tuberculosis, an
  acid fast aerobic bacillus spread by respiratory
  droplets
• If adequately treated in pregnancy, fetal
  complications unlikely

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Tuberculosis

• Sign and symptoms
• Slowly progressive constitutional symptoms of
  fatigue, anorexia, weight loss, fever, and night
  sweats
• Chronic cough is most common pulmonary symptom
• Dyspnea is unusual, unless extensive disease

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Tuberculosis

• Diagnosis
• Gather detailed history including
• Known exposure to TB infected persons
• Recently traveled from country with high TB
  prevalence
• History of previous disease and treatment
• Recent history of incarceration

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Tuberculosis

• Diagnosis
• Laboratory studies needed for definitive
  diagnosis
• Tuberculin skin test is most important screening
  test
• Should be performed in high risk populations
  especially early in pregnancy
• Positive test induration at site of 10mm or
  more gt5mm in immunocompromised pts get CXR
• Negative test requires no further evaluation

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Tuberculosis
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Tuberculosis

• Diagnosis
• On PE crepitant rales may be auscultated
• Chest xray may reveal multiple bilateral
  infiltrates upper lobes most commonly involved
• Proof of active infection is via sputum cultures
  takes 6 weeks
• Preliminary smear may reveal tubercle bacilli

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Tuberculosis

• Management/Treatment
• Inactive (latent) infection positive skin test
  with chest xray WNL
• Isoniazid (INH) 300mg poQD for 6-12 months
• Active infection oral Rx for minimum of 9
  months
• INH 5mg/kg(max 300mg daily)w/pyridoxine 50 mg
  daily
• Rifampin 10mg/kg daily (max 600mg) substitute
  Rifabutin 300mg QD in HIV pts
• Ethambutol 5-25mg/kg daily (max 2.5g)
• Pregnancy category C

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Objectives - Asthma

• 1.Obtain a targeted history from the
  patient with asthma.
• 2. Perform a focused physical examination to
  detect findings associated with asthma.
• 3. Interpret basic pulmonary function tests, such
  as
• a. Forced expiratory volume in 1
  second (FEV1)
• b. Pulse oximetry
• c. Blood gas assessment

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Objective - Asthma

• 4. Describe the differential diagnosis of
  asthma.
• 5. Treat mild asthma with medications such
  inhaled beta-mimetics, corticosteroids, and mast
  cell stabilizers.
• 6. Describe the indications for referral of a
  patient with more severe asthma to a medical
  specialist.

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Asthma

• Chronic inflammatory condition of airways which
  leads to reversible airway obstruction and
  hyperrsponsiveness
• Prevalence in U.S. adult population is
  approximately 3 7
• Affects approximately 1 of pregnant patients

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Asthma

• Focused history determines presence of
  precipitants
• Respiratory irritants - perfumes, cigarettes,
  detergents, strong odors, dust, areoallergens
• Infections - URI, sinusitis)
• Drugs aspirin, beta blockers, morphine
• Others - GERD, cold air, emotional stress,
  seasonal

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Asthma

• Focused history also inquires about prior
  exacerbations
• Frequency
• Duration
• Severity
• Need for steroid tapers
• ER visits, hospital and/or ICU admissions
• Intubations
• Use of home nebulizer
• Diurnal peak flow variability
• Medications

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Asthma

• Signs and symptoms
• Patient may complain of wheezing, SOB especially
  with inspiration, and cough (dry or productive)
• Chest tightness
• Difficulty completing sentences

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Asthma

• On PE
• Observe for increased WOB, retractions
• Lung exam may reveal wheezing, increased
  expiratory phase, hyperresonance w/chest
  percussion chest becomes more silent as
  obstruction worsens
• Check for nasal polyps
• Pt may be tachycardic

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Asthma

• Diagnostic tests
• Pulmonary function tests
• FEV1 is forced expiratory volume in 1 second
  used to evaluate an exacerbation
• Correlates w/peak expiratory flow
• Overall decreased in asthma
• If gt50 of predicted, mild-moderate
• If lt50 of predicted, severe

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Asthma

• Diagnostic Tests
• Pulse oximetry
• Supplemental oxygen should be given to patient
  awaiting assessment of arterial oxygen tension
• Saturation should be maintained at gt 90 (gt95 in
  pregnant patients or those with coexisting
  cardiac disease
• Chest xray may show hyperexpansion
• used to r/o other causes of obstruction

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Asthma

• Diagnostic tests
• Blood gas measurement
• Obtain in patients in severe distress and/or FEV1
  lt30 of predicted values after initial treatment
• PaO2 of lt60 mmHg (nl 80-105mmHg)
• sign of severe bronchoconstriction or of a
  complicating condition
• PaCO2 of may initially be low due increased
  respiratory rate (nl 35-45 mmHG)
• With prolonged attack, value will increase
  secondary to severe airway obstruction, increased
  dead space ventilation, and muscle fatigue
• A normal or increased value is a sign of
  impending respiratory failure and requires
  hospitalization

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Honey, all That Wheezes aint Asthma.

• Upper airway obstruction
• Chronic bronchitis
• Carcinoid tumors
• CHF
• Pneumonias
• COPD
• Pulmonary embolus
• Allergic reaction
• Croup

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Treatments for Mild Asthma

• Inhaled beta mimetics
• Beta 2 selectivity promotes bronchodilation
• Short acting class - rapid onset, within 5
  minutes and lasts approximately 4-6 hours
• Albuterol MDI w/spacer 2 puffs q 4-6 hr prn
• Levalbuterol (nebulizer soln) BID-QID prn
• Long acting class duration up to 12 hours
• Salmeterol MDI 2 puffq12/diskus DPI 1inhalation
  q 12

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Treatments for Mild Asthma

• Inhaled corticosteroids
• Utilized to reduce airway inflammation and
  reactivity
• All can be administered twice daily
• Flunisolide (Aerobid)
• Budesonide (Pulmicort)
• Fluticasone propionate (flovent)
• Triamcinolone (Azmacort)

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Treatments for Mild Asthma

• Mast cell stabilizing agents
• Alternative choices when initiating preventive
  therapy in mild asthma
• Virtually devoid of side effects
• Well-suited for steroid phobic pts
• Less effective than inhaled corticosteroids
• Inhibits degranulation of sensitized mast cells
  following exposure to specific antigens
• Cromolyn 2-4 puffs QID
• Nedocromil 2 puffsQID

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When to refer.

• Referral to an asthma specialist is recommended
  if
• There are difficulties achieving or maintaining
  control
• Patient meets criteria of moderate or persistent
  asthmatic

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Classification of Asthma
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References

• Williams Obstetrics, 21st Edition, 2001
• Washington Manual
• Up to Date, www.uptodate.com
• Obstetrics and gynecology, Ling and Duff