Bronchitis

Bronchitis

Description

· Hyperemia and edema of the mucous membranes

· Production of mucopurulent exudates

· Impairment of the productive function of the cilia, lymphatics, and phagocytes

· Airway obstruction from:

o Edema

o Secretions

o Bronchial muscle spasm

Etiology

• Viral infections are the primary cause of bronchitis:
• Parainfluenza
• Influenza A and B
• Respiratory syncytial virus
• Human meta pneumovirus
• Echovirus
• Coronavirus
• Adenovirus
• Coxsackievirus
• Rhinovirus
• Measles and herpes viruses (can cause severe viral bronchitis)
• Particularly severe or long-lasting bronchitis:
• Mycoplasma pneumoniae
• Chlamydia pneumoniae
• Bordetella pertussis:
• Rates of pertussis are increasing, even in the fully immunized population (little protection remains after 10 years).
• Other bacteria have not been conclusively proven to cause bronchitis except in those with chronic lung disease.

Diagnosis

Signs and Symptoms

History

• Complaints that may precede upper respiratory tract infection (URTI) symptoms:
• Malaise
• Chills
• Myalgias
• Coryza
• Sore throat
• Onset of URTI symptoms:
• Mile dyspnea
• Cough, initially dry and nonproductive
• Cough, later becomes mucoid or mucopurulent
• Chest pain or burning related to cough
• Initial symptoms improve after 3-5 days, with 1-3 weeks of residual cough and malaise

Physical Exam

• Fever, not usually above 102°F (38.5°C)
• Tachypnea
• Mild hemoptysis
• Wheezing
• Rales
• Scattered rhonchi
• Pulmonary function tests are frequently abnormal

Essential Workup

• The diagnosis is clinical
• Pulse oximetry
• Influenza A and B testing if identification of these organisms is required for treatment or reporting
• Evaluate for pertussis:
• Acute cough illness lasting 14 days or more in a person with paroxysmal cough, posttussive vomiting, or inspiratory whoop
• 14 days or more of cough within an outbreak setting

Tests

Lab

• Influenza A and B testing may help immediately confirm clinical suspicion.
• In most cases, no specific test will help make the diagnosis immediately.
• Viral or bacterial cultures are rarely helpful.
• CBC may show leukocytosis, but this is a nonspecific finding.
• Pertussis may be confirmed using polymerase chain reaction (PCR) testing, but diagnosis will be delayed.

Imaging

Chest radiograph:

• No evidence of consolidation
• Indications:
• Shortness of breath
• Hypoxia
• Chest pain
• Heart rate >100 beats/minute
• Respiratory rate 24 breaths/minute
• Temperature 38 °C
• Focal findings on chest examination
• Elderly patient with multiple comorbid conditions
• Hypoxia
• 14 days or more of cough

Diagnostic Procedures/Surgery

None specific

Differential Diagnosis

• Acute and subacute <8>
• Pneumonia
• Reactive airway disease
• Aspiration
• Acute sinusitis
• Bacterial tracheitis
• Occupational exposure
• Chronic >8 weeks:
• Asthma
• Gastroesophageal reflux disease
• Chronic bronchitis
• Bronchiectasis
• ACE inhibitor use
• Bronchogenic carcinoma
• Carcinomatosis
• Sarcoidosis
• Left ventricular failure
• Aspiration syndrome
• Psychogenic/habit

Pediatric Considerations

• Aggressive initial management of these patients is seldom required.
• Administer oxygen if the patient is hypoxic.
• Fluids may be administered if the patient is dehydrated.

Treatment

Pre Hospital

• Maintain adequate oxygenation
• Bronchodilators if wheezing is present

Initial Stabilization

• Aggressive initial management of these patients is seldom required.
• Administer oxygen if the patient is hypoxic.
• Fluids may be administered if the patient is dehydrated.

ED Treatment

• Bronchitis is usually a viral process; treatment is symptomatic.
• Cough suppressants may be considered.
• β-adrenergic inhaler for patients with severe cough or wheezing
• Amantadine may be used in known outbreaks of influenza A.
• Oseltamivir (Tamiflu) and zanamivir (Relenza) may be considered in patients with recent onset of influenza.
• Antibiotics:
• Generally, antibiotics are not indicated (even when secretions are purulent).
• Antibiotics do not improve overall illness duration, activity limitation, or work loss in healthy patients with no underlying lung disease.
• Consider use in those patients who have recurrence of fever after initial improvement.
• Symptomatic control with antipyretics and analgesics
• Although patients should be encouraged to stop smoking, the use of tobacco is not an indication for antibiotics unless the patient has a known history of emphysema.

Medication (Drugs)

• Albuterol: 0.5 mL in a 0.5% solution nebulized q6h
• Amantadine: 100 mg PO per day, must be given within 48 hours of symptom onset
• Oseltamivir (Tamiflu) and zanamivir (Relenza) within 48 hours of symptom onset for influenza-related bronchitis:
• Zanamivir: 10 mg inhalation q12h — 5 days (no pediatric dosing)
• Oseltamivir: 75 mg PO b.i.d. (peds: 2 mg/kg) — 5 days
• Erythromycin should be given to proven cases of pertussis and to household contacts of those with proven pertussis.
• Yearly influenza vaccinations should be encouraged in health care providers and in the high-risk population (elderly, immunocompromised, chronic lung disease).

Pediatric Considerations

• Use of acetaminophen rather than aspirin for analgesia.
• Repeated bouts in children should lead to referral for complete evaluation of the respiratory tract.

Follow-Up

Disposition

Admission Criteria

• Underlying significant cardiopulmonary compromise
• Significant hypoxia
• Ill patient with unclear diagnosis

Discharge Criteria

• No pulmonary compromise should be present.
• Instruct patients, particularly high-risk patients, to return if no improvement or worsening of symptoms occurs.
• Bed rest
• Fluids
• Aspirin or acetaminophen

References

1. Aagaard E, Gonzales R. Management of acute bronchitis. Infect Dis Clinic N Am. 2004; 18:919-937.

2. Gonzoles R, Sande MA: Uncomplicated acte bronchitis. Ann Intern Med. 2000;133:981-991.

3. Hirschmann JV: Antibiotics for common respiratory tract infections in adults. Arch Intern Med. 2002; 162:256-264.

4. Linder JA, Sims I: Antibiotic treatment of acute bronchitis in smokers. A systemic review. J Gen Inern Med. 2002;17:230-234.

5. Stephens MM, Nashelsky J: Do inhaled beta-agonists control cough in URIs or acute bronchitis? J Fam Prac. 2004;53:662-663.

6. Ward MA: Emergency department management of acute respiratory tract infections in adults. Sem Resp Infec. 2002:17:65-71.

Miscellaneous

SEE ALSO: Cough; Shortness of Breath

Codes

ICD9-CM

466

490

ICD10

J40

Asthma, Adult

Asthma, Adult

Description

• Increased expiratory resistance:
• Bronchospasm
• Airway inflammation
• Mucosal edema
• Mucous plugging
• Consequences:
• Air trapping
• Increased dead space
• Hyperinflation
• Risk factors for life-threatening disease:
• Prior intubations
• Intensive care unit admissions
• Chronic steroid use
• Hospital admission for asthma during the past year
• Inadequate medical management
• Increasing age
• Ethnicity (African Americans)
• Lack of access to medical care

Etiology

Mechanism

• Pollen
• Dust mites
• Molds
• Animal dander
• Other environmental allergens
• Viral upper respiratory infections
• Occupational chemicals
• Tobacco smoke
• Environmental change
• Cold air
• Exercise
• Emotional factors
• Drugs:
• Aspirin
• NSAIDs
• Beta-blockers

Diagnosis

Signs and Symptoms

• Wheezing
• Dyspnea
• Chest tightness
• Cough
• Tachypnea
• Tachycardia
• Respiratory distress:
• Posture sitting upright or leaning forward
• Use of accessory muscles
• Inability to speak in full sentences
• Diaphoresis
• Poor air movement
• Altered mental status

Essential Workup

• Primarily a clinical diagnosis
• Measure and follow severity with peak expiratory flow rate (PEFR)
• Assess for underlying disease
• Pneumonia:
• Pneumothorax

Tests

Lab

• Arterial blood gas:
• Not helpful during the initial evaluation
• The decision to intubate should be based on clinical criteria.
• Mild-moderate asthma: respiratory alkalosis
• Severe airflow obstruction and fatigue: respiratory acidosis
• Pulse oximetry:
• Less than 90% is indicative of severe respiratory distress
• Patients with impending respiratory compromise may still maintain saturation above 90% until sudden collapse.
• WBC:
• Leukocytosis is nonspecific
• Pneumonia
• Chronic steroid use
• Stress of an asthma exacerbation
• Demargination occurs after administration of epinephrine and steroids.

Imaging

• Peak expiratory flow rate:
• Estimates the degree of airflow obstruction:
• Normal peak flow in an adult is 400–600
• Between 100 and 300 indicates moderate airway obstruction.
• <100>
• Use serially as an objective measure of the response to therapy
• Forced expiratory volume (FEV):
• More reliable measure of lung function than PEFR
• More operator dependent
• Difficult to use as a screening tool
• Often unavailable in the ED
• Severe airway obstruction: FEV₁ less than 30–50%
• Chest radiograph:
• Indications:
• Fever
• Suspicion of pneumonia
• Suspicion of pneumothorax or pneumomediastinum
• Foreign body aspiration
• First episode of asthma
• Comorbid illness
• Diabetes
• Renal failure
• AIDS
• Cancer
• Findings:
• Hyperinflation
• Scattered atelectasis
• ECG:
• Indicated in patients at risk for cardiac disease:
• Dysrhythmias
• Myocardial ischemia
• Transient changes in severe asthma:
• Right axis deviation
• Right bundle branch block
• Abnormal P waves
• Nonspecific ST-T wave changes

Differential Diagnosis

• Congestive heart failure
• Myocardial ischemia
• Pulmonary embolus
• Pneumonia
• Bronchitis
• Bronchiolitis
• Croup
• Foreign body aspiration
• Upper airway obstruction
• Angioedema
• Allergic reaction
• Chronic obstructive pulmonary disease
• Chronic cor pulmonale
• Chemical pneumonitis
• Carcinoid tumors
• Smoke inhalation
• Immersion injury
• Venous air embolus

Treatment

Pre Hospital

• Recognize the ‘quiet chest’ as respiratory distress.
• Supplemental oxygen
• Continuous nebulized β2-agonist
• Administration of subcutaneous epinephrine
• Severe disease with decreased breath sounds

Initial Stabilization

• Immediate initiation of inhaled β2-agonist treatment
• Intubate for fatigue and respiratory distress.
• Steroids

ED Treatment

β2Adrenergic Agonist

• Mild-moderate asthmatic:
• Administer every 20 minutes
• Severe asthmatic:
• Continuous nebulized treatment
• Selective β2-agonists (albuterol)
• Subcutaneous β-agonist:
• Severe exacerbations
• Limited inhalation of aerosolized medicine
• More side effects because of systemic absorption:
• Tachycardia
• Tremors
• Relative contraindications: age >40 years and coronary disease
• Corticosteroids:
• Reduce airway wall inflammation
• Administered early
• Onset of action may take 4-6 hours
• Administer intravenously or orally
• IV Solu-Medrol in the treatment of severe asthma exacerbation
• Mild-moderate exacerbations may be treated with oral prednisone.
• Inhaled corticosteroids are currently not recommended as initial therapy.
• Oxygen:
• Maintain an oxygen saturation above 90%
• Aminophylline:
• Rare utility in acute management
• Toxicity:
• Nausea
• Tremor
• Anxiety
• Palpitations
• Tachycardia
• Anticholinergic agents:
• If minimal response to initial β2-agonist treatment
• Severe airflow obstruction
• Inhaled anticholinergic agents should be used in conjunction with β2-agonists.
• Magnesium sulfate:
• No benefit in mild-moderate asthma
• Benefit of magnesium remains unclear in severe asthma
• Heliox:
• Mixture of helium and oxygen (80:20, 70:30, 60:40)
• Less dense than air
• Decrease airway resistance.
• Decrease in respiratory exhaustion
• Not currently recommended for routine use:
• Consider in severe asthma
• Ketamine:
• Bronchodilator and an anesthetic agent
• Useful as an induction agent during intubation
• Contraindications:
• Hypertension
• Coronary disease
• Pre-eclampsia
• Increased intracranial pressure
• Halothane:
• Inhalation anesthetics are potent bronchodilators.
• Refractory asthma in intubated patients
• Intubation of the asthmatic patient:
• Rapid sequence intubation:
• Lidocaine to attenuate airway reflexes
• Etomidate or ketamine as an induction agent
• Succinylcholine should be administered to achieve paralysis.
• A large endotracheal tube >7 mm should be used to facilitate ventilation.
• May need to mechanically exhale for the patient
• Permissive hypercapnia

Medication (Drugs)

• β2-agonists
• Albuterol: 2.5 mg in 2.5 mL normal saline q20min inhaled (peds: 0.1-0.15 mg/kg/dose q20min [minimum dose 1.25 mg])
• Epinephrine: adult: 0.3 mg (1:1,000) SC q0.5h-q4.0h × three doses (peds: 0.01 mg/kg up to 0.3 mg SC)
• Terbutaline: 0.25 mg SC q0.5h × two doses (peds: 0.01 mg/kg up to 0.3 mg SC)
• Corticosteroids:
• Methylprednisolone: 60-125 mg IV (peds: 1-2 mg/kg/dose IV or PO q6h × 24 hours)
• Prednisone: 40-60 mg PO (peds: 1-2 mg/kg/day in single or divided doses)
• Anticholinergics
• Ipratropium bromide: 0.5 mg in 3 mL NS q1h × three doses
• Magnesium: 2 g IV over 20 minutes
• Aminophylline: 0.6 mg/kg/h IV infusion
• Rapid sequence intubation:
• Etomidate: 0.3 mg/kg, or ketamine: 1-1.5 mg/kg
• Lidocaine: 1-1.5 mg/kg
• Succinylcholine: 1.5 mg/kg

Follow-Up

Disposition

Admission Criteria

• Persistent respiratory distress
• PEFR <100>
• Intubated patients

Medical Wards or Observation Unit

• PEFR <40%>
• Patients without subjective improvement
• Patients with continued wheeze and diminished air movement
• Patients with moderate response to therapy and no respiratory distress:
• Factors that should favor admission
• Prior intubation
• Recent ED visit
• Multiple ED visits or hospitalizations
• Symptoms for more than 1 week
• Failure of outpatient therapy
• Use of steroids
• Inadequate follow-up mechanisms
• Psychiatric illness
• Complications:
• Pneumothorax
• Pneumomediastinum
• Pneumonia
• Fatigue

Discharge Criteria

• Patient reports subjective improvement
• Clear lungs with good air movement
• PEFR or FEV₁ greater than 70% of predicted
• Peak flow should be greater than 300.
• Adequate follow-up within 48–72 hours

References

1. Corbridge TC, Hall JB. The assessment and management of adults with status asthmaticus. Am J Respir Crit Care Med. 1995;151:1296-1316.

2. Guidelines for the diagnosis and management of asthma: National Asthma Education Program Expert Panel Report. Bethesda, MD: Department of Health and Human Services; 1991. NIH 91-3042.

3. Jagoda A, Shepherd SM, Spevitz A, et al. Refractory asthma, part 1: epidemiology, pathophysiology, pharmacologic interventions. Ann Emerg Med. 1997;29:262-274.

4. Jagoda A, Shepherd SM, Spevitz A, et al. Refractory asthma, part 2. Airway interventions and management. Ann Emerg Med. 1997;29:275-281.

5. Manthous CA. Management of severe exacerbations of asthma. Am J Med. 1995;99:298-308.

Codes

ICD9-CM

493

ICD10

J45.9

Acidosis

Acidosis

Description

Respiratory Acidosis

• Reduced pH owing to alveolar hypoventilation with elevated PaCO₂
• Defined as PaCO₂ >45 mm Hg or higher than expected for calculated respiratory compensation for metabolic acidosis
• Divided into three broad categories:
• Primary failure in central nervous system drive to ventilate:
• Sleep apnea
• Anesthesia
• Sedative overdose
• Primary failure in transport of CO₂ from alveolar space:
• Chronic obstructive pulmonary disease
• Myasthenic crisis
• Severe hypokalemia
• Guillain-Barre syndrome
• Primary failure in transport of CO₂ from tissue to alveoli:
• Severe heart failure

Metabolic Acidosis

• Process that reduces serum pH by decreasing plasma bicarbonate levels
• Primarily caused by:
• Gain of a strong acid through ingestion or metabolism
• Loss of bicarbonate from the body
• Metabolic acidosis is clinically evaluated by dividing into two main groups:
• Elevated anion gap metabolic acidosis:
• Bicarbonate reduced through buffering of added strong acid
• Anion gap is increased owing to retention of the unmeasured anion from the titrated strong acid.
• Normal anion gap metabolic acidosis owing to:
• Kidneys fail to reabsorb or regenerate bicarbonate.
• Losses of bicarbonate from gastrointestinal tract (diarrhea)
• Ingestion or infusion of substances that release hydrochloric acid
• No anion gap is observed owing to the absence of any unmeasured anion of a titrated acid and secondary chloride retention with HCO₃^- loss.

Etiology

Anion Gap Acidosis

To remember possible causes, use mnemonic A CAT MUD PILES:

• Alcohol ketoacidosis
• Carbon monoxide or cyanide
• Aspirin
• Toluene
• Methanol
• Uremia
• Diabetic ketoacidosis
• Paraldehyde
• Iron/isoniazid
• Lactic acidosis
• Ethylene glycol
• Starvation

Increased Osmolar Gap

To remember possible causes, use mnemonic ME DIE:

• Methanol
• Ethylene glycol
• Diuretics (mannitol; no acidosis)
• Isopropyl alcohol (no acidosis)
• Ethanol

Non-Anion Gap Metabolic Acidosis

• Gastrointestinal losses of bicarbonate:
• Diarrhea
• Villous adenoma
• Removal of small bowel, pancreatic or biliary secretions
• Tube drainage
• Small bowel/pancreatic fistula
• Anion exchange resins (i.e., cholestyramine):
• Ingestion of calcium chloride or magnesium chloride
• Renal loss of bicarbonate
• Renal tubular acidosis:
• Type I (distal): hypokalemic hyperchloremic metabolic acidosis:
• Decreased ability to secrete hydrogen
• Serum HCO₃ <15>
• Potassium low
• Renal stones common
• Type II (proximal): hypokalemic hyperchloremic metabolic acidosis:
• Decreased proximal reabsorption of HCO₃^-.
• Acidosis limited by reabsorptive capacity of proximal tubule for HCO₃^-
• Serum HCO₃ typically 14–18 mEq/L
• Low/normal potassium.
• Type IV (hypoaldosteronism): hyperkalemic hyperchloremic acidosis:
• Aldosterone deficiency or resistance causing decreased H⁺ secretion
• Serum bicarb >15 mEq/L
• Normal/elevated potassium
• Carbonic anhydrase inhibitors
• Tubulointerstitial renal disease
• Hypoaldosteronism
• Addition of hydrochloric acid such as:
• Ammonium chloride
• Arginine hydrogen chloride
• Lysine hydrogen chloride

Diagnosis

Signs and Symptoms

• Nonspecific findings
• Vital signs:
• Tachypnea or Kussmaul respirations with metabolic acidosis
• Hypoventilation with respiratory acidosis
• Tachycardia
• Somnolence
• Confusion
• CO₂ narcosis
• Myocardial conduction and contraction disturbances

Essential Workup

• Electrolytes, BUN, creatinine, glucose:
• Decreased bicarbonate with metabolic acidosis
• Hyperkalemia and hypercalcemia with severe metabolic acidosis
• Arterial blood gases:
• pH
• CO₂ retention in respiratory acidosis
• CO level
• Calculate anion gap: Na⁺ - (HCO₃^- + Cl^-):
• Correct anion gap for hypoalbuminemia:
• For every 1 g/dL decrease in albumin (from 4.0 g/dL), add 2.5 points to calculated anion gap.
• Normal range = 5-12 ± 3 mEq/L
• Anion gap >25 mEq/L is seen only with:
• Lactic acidosis
• Ketoacidosis
• Toxin-associated acidoses
• Calculate the degree of compensation:
• Expected PaCO₂ = 1.5[HCO₃^-] + 8
• If PaCO₂ inappropriately high, patient has a concomitant respiratory acidosis and inadequate compensation
• Respiratory acidosis:
• Acute: expected HCO₃^- increased by 1 mEq/L for every 10 mm Hg increase in PaCO₂
• Chronic: expected HCO₃^- increased by 4 mEq/L for every 10 mm Hg increase in PaCO₂
• Evaluate the delta gap:
• For every one-point increase in anion gap, HCO₃^- should decrease by 1 mEq/L in simple acid/base disorder.
• Evaluate by comparing the change in the anion gap (ΔAG) with the change in the HCO₃^- (ΔHCO₃^-) from normal:
• If ΔAG > ΔHCO₃^-, then patient has a concomitant metabolic alkalosis.
• If ΔHCO₃^- > ΔAG, then patient has concomitant non-anion gap acidosis.

Tests

Lab

• Urinalysis for glucose and ketones
• Measure serum osmolality:
• Calculated serum osmolality = 2 Na + glucose/18 + blood urea nitrogen/2.8
• Osmolal gap = difference between calculated and measured osmolality:
• Normal = <10
• Toxicology screen:
• Methanol, ethylene glycol, ethanol, and isopropyl alcohol if increased osmolality gap
• Aspirin or iron levels for suspected ingestion
• Co-oximetry for CO exposure
• Serum ketones or β-hydroxybutyrate level
• Serum lactate

Alert

• Failure to appreciate acidosis in mixed acid/base disorders
• Failure to appreciate inadequate respiratory compensation for metabolic acidosis and need for ventilatory support

Differential Diagnosis

• Anion gap acidosis:
• To remember possible causes, use mnemonic A CAT MUD PILES:
• Alcohol ketoacidosis
• Carbon monoxide or cyanide
• Aspirin
• Toluene
• Methanol
• Uremia
• Diabetic ketoacidosis
• Paraldehyde
• Iron/isoniazid
• Lactic acidosis
• Ethylene glycol
• Starvation
• Increased osmolar gap:
• To remember possible causes, use mnemonic ME DIE:
• Methanol
• Ethylene glycol
• Diuretics (mannitol)
• Isopropyl alcohol
• Ethanol

Treatment

Initial Stabilization

Airway, breathing, circulation (ABCs):

• Early intubation for severe metabolic acidosis with progressive/potential weakening of respiratory compensation
• Naloxone, D₅₀W (or Accu-Chek) and thiamine if mental status altered

ED Treatment

• Respiratory acidosis:
• Treat underlying disorder.
• Provide ventilatory support for worsening hypercapnia.
• Identify and correct aggravating factors (pneumonia) in chronic hypercapnia.
• Metabolic acidosis:
• Identify if concurrent osmolal gap.
• Treat underlying disorder:
• Diabetic ketoacidosis
• Lactic acidosis
• Alcohol ketoacidosis
• Ingestion
• Correct electrolyte abnormalities.

IV Fluids

Rehydrate with 0.9% normal saline if patient hypovolemic.

Medication (Drugs)

• Dextrose: D₅₀W 1 amp (50 mL or 25 g); (peds: D₂₅W 4 mL/kg) IV
• Naloxone (Narcan): 2 mg (peds: 0.1 mg/kg) IV or IM initial dose
• Thiamine (vitamin B₁): 100 mg (peds: 50 mg) IV or IM

Follow-Up

Disposition

Admission Criteria

• Worsening metabolic acidosis
• ICU admission if pH <7.1>
• Respiratory acidosis

Discharge Criteria

Resolving or resolved anion gap metabolic acidosis

References

1. Adrogue HJ, Madias NE. Management of life-threatening acid-base disorders. New Engl J Med. 1998;338:26.

2. Swenson ER. Metabolic acidosis. Respir Care. 2001;46:342.

3. Whittier WL, Rutecki GW. Primer on clinical acid-base problem solving. Dis Mon. 2004;50:122.

Codes

ICD9-CM

276.2 Acidosis

ICD10

E87.2