Primary Care- Respiratory Tract Infections and Asthma

Primary Care: Respiratory Tract Infections and Asthma Tamra N. Fortenberry, MD Department of Ob/Gyn The University of Tennessee Memphis, TN 4/21/2008 1 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. 4/21/2008 2 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. 4/21/2008 3 Differential Diagnosis for Respiratory Tract Infections  Upper respiratory infection (URI)    Viral Rhinitis (Common cold) Sinusitis Pharyngitis      Influenza Pneumonia Bronchitis Tuberculosis Asthma 4 4/21/2008 The Common Cold   An estimated 2 of every 5 Americans are affected each year Some experience multiple episodes in 1 year 4/21/2008 5 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 6 4/21/2008 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 7 4/21/2008 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 4/21/2008 8 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 4/21/2008 9 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 4/21/2008 10 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 4/21/2008 11 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 4/21/2008 12 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 13 4/21/2008 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 14 4/21/2008 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 15 4/21/2008 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 >1 weeks duration  Symptoms may last 10 – 14 days 4/21/2008 16 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?  4/21/2008 17 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 4/21/2008 18 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 Trimethoprimsulfamethoxazole (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 19 4/21/2008 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 4/21/2008 20 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 4/21/2008 21 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 4/21/2008 22 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) 23 4/21/2008 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 4/21/2008 24 Pharyngitis Management/Treatment  Symptomatic treatment – includes saltwater 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. 25 4/21/2008 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 26 4/21/2008 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 4/21/2008 27 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 4/21/2008 28 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 29 4/21/2008 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 4/21/2008 30 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% 31 4/21/2008 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 4/21/2008 32 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) 33 4/21/2008 Pneumonia Diagnosis  Sputum cultures with sensitivities– collected on patients requiring hospitalization  Pulse oximetry on patient with dyspnea – O2 sat should > 93%  Labs: CBC/diff, CMP with LFts  ABGs may reveal hypoxemia, hypocarbia, and respiratory alkalosis 4/21/2008 34 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 <70 may be management as an outpatient) 35 4/21/2008 Pneumonia Indications for Hospitalization of Patients with Community-Acquired Pneumonia (PORT score = 71 or greater) Age > 65 Altered mental status Immunocompromised status Unstable vitals signs Hypoxemia Significant comorbid condition Significant metabolic/hematologic derangement Failure to respond to outpatient therapy 4/21/2008 36 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) 37 4/21/2008 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 4/21/2008 38 Tuberculosis     Approximately 15 million people affected in US Infects an estimated 20 – 43% of the world‟s population Causative agent, Mycobacterium tuberculosis, an acid fast aerobic bacillus –spread by respiratory droplets If adequately treated in pregnancy, fetal complications unlikely 4/21/2008 39 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 4/21/2008 40 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  4/21/2008 41 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; >5mm in immunocompromised pts – get CXR Negative test requires no further evaluation 42 4/21/2008 Tuberculosis Reactive Size > 5 mm Group 1. 2. 3. 4. HIV + pts Recent contacts of people w/active TB Pts w/fibrotic changes on CXR suggestive of prior TB infections Organ transplant/other immunosuppressed pts Recent immigrants HIV neg IVDA Employees/residents of healthcare facilities, nursing homes, correctional facilities Patients w/cormorbidities: silicosis, DM, CRF, leukemias/lymphomas, cancer of head or neck and lung, wt loss >10% of IBW, gastrectomy, jejunoilieal bypass Children <4 yrs or exposed adolescents Any person with no risk factors for TB 43 > 10 mm 1. 2. 3. 4. 5. > 15mm 4/21/2008 1. 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 4/21/2008 44 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    4/21/2008  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 45 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 4/21/2008 46 Objective - Asthma 4. Describe the differential diagnosis of asthma. 5. Treat mild asthma with medications such inhaled betamimetics, corticosteroids, and mast cell stabilizers. 6. Describe the indications for referral of a patient with more severe asthma to a medical specialist. 4/21/2008 47 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 48 4/21/2008 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  4/21/2008 49 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 50 4/21/2008 Asthma Signs and symptoms  Patient may complain of wheezing, SOB especially with inspiration, and cough (dry or productive)  Chest tightness  Difficulty completing sentences 4/21/2008 51 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  4/21/2008 52 Asthma Diagnostic tests  Pulmonary function tests  FEV1 is forced expiratory volume in 1 second; used to evaluate an exacerbation w/peak expiratory flow  Overall decreased in asthma • If >50% of predicted, mild-moderate • If <50% of predicted, severe  Correlates 4/21/2008 53 Asthma Diagnostic Tests  Pulse oximetry Supplemental oxygen should be given to patient awaiting assessment of arterial oxygen tension  Saturation should be maintained at > 90% (>95% in pregnant patients or those with coexisting cardiac disease   Chest xray may show hyperexpansion  used to r/o other causes of obstruction 54 4/21/2008 Asthma Diagnostic tests  Blood gas measurement   Obtain in patients in severe distress and/or FEV1 <30% of predicted values after initial treatment PaO2 of <60 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 55 4/21/2008 Honey, all That Wheezes ain’t Asthma….          4/21/2008 Upper airway obstruction Chronic bronchitis Carcinoid tumors CHF Pneumonias COPD Pulmonary embolus Allergic reaction Croup 56 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 4/21/2008 57 Treatments for Mild Asthma  Inhaled corticosteroids Utilized to reduce airway inflammation and reactivity  All can be administered twice daily  (Aerobid)  Budesonide (Pulmicort)  Fluticasone propionate (flovent)  Triamcinolone (Azmacort)  Flunisolide 4/21/2008 58 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 59 4/21/2008 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  4/21/2008 60 Classification of Asthma Severity Symptoms Nighttime PFTs (FEV1 or symptoms PEF) < 2/month >80% predicted Normal between exacerbations Mild < 2/week Intermittent Mild persistent > 2/ week > 2/month but < 1/day Daily w/daily > 1/week beta agonist use; exacerbations >2/ week Continual; frequent Frequent exacerbations >80% predicted Moderate persistent 60-80% predicted Severe persistent 4/21/2008 <60% predicted 61 References     Williams Obstetrics, 21st Edition, 2001 Washington Manual Up to Date, www.uptodate.com Obstetrics and gynecology, Ling and Duff 4/21/2008 62