Respiratory System Pathopharm

Areas involved in respiratory tract infections

Upper + Lower tract

Upper Respiratory Infections

Common cold, acute rhinitis, sinusitis, acute pharyngitis

Common Cold

#1 most common respiratory tract infection

Viral infection of upper respiratory tract

Rhinovirus most common cause

Common cold episodes

Adult - 3-4 per year

Child: 6-8 per year

How can the common cold be transmitted?

Fingers - greatest source.

Cough, sneeze, nasal mucosa, conjunctival surface of the eyes

Rhinitis

Inflammation of nasal mucosa

Sinusitis

Inflammation of paranasal sinuses

Paranasal sinuses

Frontal, Ethmoid, Nasal, Maxillary, Sphenoid, Pharynx (Throat)

Rhinosinusitis

Inflammation involving the nasal sinuses

Clinical manifestations of Rhinosinusitis

Facial pain, headache, fever, purulent nasal drainage, decreased sense of smell, pain on bending, unilateral maxillary pain, pain in teeth

Acute rhinosinusitis

may be viral, bacterial, mixed

Can last 5-7 days up to 4 weeks

Subacute rhinosinusitis

lasts from 4 weeks to less than 12 weeks

Chronic rhinosinusitis

Lasts beyond 12 weeks

Associated with bacterial or fungal infection

Influenza Rates of infection

highest among children and older adults

serious illness and death highest - 65+

More contagious than bacterial respiratory tract infections

Transmission: inhalation

Pathogenesis of Influenza

Can cause 3 types of infections

Rhinotracheitis - uncomplicated upper respiratory infection

Viral pneumonia

Respiratory viral infection followed by a bacterial infection

Clinical manifestations of Influenza

Early stages, s/s indistinguishable from other viral infections

Rapid onset

Diagnosis and Treatment of Influenza

Goal - supportive care and prevent spread outside upper respiratory tract

Early diagnosis can reduce inappropriate use of antibiotics

Potentially antiviral

Preventative measures

Education of cold and flu at home

do not take longer than 5-7 days, see physician

encourage fluids

encourage rest

read OTC drug labels

OTC analgesics + antipyretics

OTC Cough medications in healthy individuals, may need to refer to physician

Consult pediatrician for infants/ children for dosing and safety

Older adults or those with cardiac dysfunction should consult physician first prior taking OTC medications

Older adult are high risk for sedation, confusion, lightheaded, and dizziness with OTC medications

Pneumonia

Inflammation of parenchymal structures of the lung in the lower respiratory tract, such as alveoli and bronchioles

Classifications of pneumonia based on

Source of infection, Causative organism, Patient risk factors

Types of pneumonia

Typical vs Atypical - normal bacteria vs fungi

Lobular vs Bronchial - lobe of lung or bronchial

Hospital vs Community Acquired

Aspiration - weakened esophageal sphincter

Ventilator Associated

Etiology of Pneumonia

bacterial, virus, fungi, parasite

Pathogenesis of pneumonia

causative agent enters via inhalation, aspiration, or bloodstream shedding and triggering an immune response, exudates fill and consolidate air space resulting in impaired gas exchange

Diagnostic of pneumonia

history, chest x-ray, sputum culture and sensitivity

Treatment of pneumonia

Antibiotic, antiviral, bronchodilators, expectorants, humified oxygen, antipyretics

Preventative treatment is key, pneumococcal pneumonia can be prevented thru immunization

Community Acquired Pneumonia

Infections from organisms in community

Bacterial / Viral

S. pneumonia (Pneumococcal Pneumonia) - most common cause

others - H. influenzae, S. aureus, gram negative bacilli

Treatment - appropriate use of antibiotics, hospitalization if needed

Hospital Acquired Pneumonia

Infections from organisms found in hospital or nursing home

Bacterial

Infection not present or incubating on admission to hospital

Occurs 48 hours + after admission

Second most common cause of hospital acquired infection

Mortality rate of 30-50%

Highly probable for antibiotic resistance

Tuberculosis Pathogenesis

caused by M. tuberculosis

can infect any organ of body, mainly lungs

develops granulomatous lesion, caseous necrosis

Tuberculosis Clinical Manifestations

Low grade fevers, fatigue, and weight loss

Dry cough → productive with purulent and sometimes blood tinged sputum

Dyspnea and orthopnea develop

Night sweats, anemia, rales

Tuberculosis Diagnosis

TB skin test, QuantiFERON-TB Gold, CXR-exposure

Only diagnostic by sputum culture in active infection

Treatment of Tuberculosis

use of multiple drugs for a long period of time

Undergoes high rate of mutation and tends to acquire resistance to any one drug

Lung Cancer

Leading cause of cancer death in US

Etiology of Lung Cancer

Cigarette Smoking

Secondhand smoke

Occupation Exposure

Air Pollution

Genetic

Prior lung disease (COPD, pulmonary fibrosis)

Clinical Manifestations of lung cancer

Chronic cough

Change in cough

Hemoptysis

Dypsnea

Chest pain

Unexplained weight loss

Fatigue

Recurrent pneumonia

Diagnostics of Lung Cancer

Biopsy

Treatment of Lung Cancer

surgery, radiation, chemotherapy, immunotherapy

Viral Croup

Most common

Slight dyspnea but in severe cases may progress to AW obstruction

C/c by inspiratory stridor, hoarseness, barking cough

Spasmodic Croup

Manifests with symptoms similar to those of acute viral croup.

Thought to have an allergic origin

Occurs at night and tends to recur with respiratory tract infections.

Epiglottis

Rapidly progressive and life-threatening condition.

S/S: difficulty swallowing, muffled voice, drooling, fever, extreme anxiety, inspiratory and expiratory stridor, respiratory distress

Dramatic, potentially fatal condition characterized by inflammatory edema of the supraglottic area, including the epiglottis and pharyngeal structures

Acute bronchiolitis

Viral infection of the lower airways, most commonly caused by the RSV.

Older children and adults tolerate bronchiolar edema much better than infants and do not manifest the clinical picture of bronchiolitis

Drugs acting on upper respiratory system

Antihistamines

• Decongestants (sympathomimetic amines)

• Antitussives

• Expectorants

• Mucolytics

Antihistamines

Block the release or action of histamine, a chemical that increases secretions and narrows airways (H1 blockers)

Decongestants

Decrease the blood flow to the upper respiratory tract and decrease the production of secretions

Antitussives

Acts on the cough center in the medulla; block cough reflex

Expectorants

Increase productive cough to clear airways

Mucolytics

Increase or liquify respiratory secretions to aid clearing of airways

URT drugs provide relief for

Allergy/Infectious

• The Common Cold

  • Seasonal Rhinitis

  • Sinusitis Pharyngitis Laryngitis, and Bronchitis

  • Pneumonia

  • Tuberculosis

Ventilation/Gas Exchange Disorders

• Atelectasis

  • Bronchiectasis

  • Asthma

  • COPD

  • Cystic Fibrosis

  • RDS and ARDS

Antitussives Therapeutic action

act on medullary cough center of brain to depress cough reflex

Benzonatate: acts as local anesthetic on respiratory passages, lungs pleura blocking effect to stretch receptors

Antitussives Indications

used as cough suppressant meds

Antitussives Adverse Effects

Drying effect on mucous membranes, CNS adverse effects, nausea, respiratory depression

Antitussives Nursing Considerations

Assess for contraindications, allergy, baseline VS, evaluate orientation to monitor CNS effect of drug, evaluate for respiratory depression

Antitussives Prototype

Dextromethorphan

Expectorants Prototype

Guaifenesin (Mucinex)

Expectorants TA

thins mucous, helps cough up mucous, more productive cough and enhanced airway patency

Expectorants Indications

Anyone who has a productive cough or needs a cough to be productive, COPD, asthma

Expectorants AE

nausea, vomiting, rash, dizziness, headache

Expectorants NC

observe color of secretions - yellow/green infection, antibiotics may be needed, should not be used longer than a week

Nasal Decongestants TA

cause vasoconstriction, decreases edema and inflammation of nasal membranes

Nasal Decongestants I

nasal congestion, common cold, sinusitis, allergic rhinitis

Nasal Decongestants AE

local stinging, burning, rebound congestion, fight or flight response - sympathetic nervous system response

Nasal Congestion Prototype

tetrahydrozoline

Nasal Decongestants NC

Assess for contraindications, skin color, monitor vs, monitor u/o, retention, temperature, sympathetic response

Oral Decongestants TA

shrink nasal mucous membranes, promotes drainage in sinus and improves airflow

Oral decongestants I

nasal congestion r/t cold, sinusitis, allergic rhinitis, pain and congestion of otitis media

Oral Decongestants AE

rebound congestion, sympathetic response, accidental overdose

Prototype Oral decongestants

pseudoephedrine

Oral Decongestants NC

Assess for anxiety, restlessness, headache, dizziness, drowsiness, vision changes, seizures, hypertension, arrhythmias, pallor, nausea, vomiting, urinary retention, respiratory difficulty

Steroid Nasal Decongestants TA

Anti-inflammatory action, blocks reactions responsible for inflammation

Steroid Nasal Decongestants I

allergic rhinitis, inflammation, first line med for nasal congestion

Steroid Nasal Decongestants AE

Local burning, irritation, stinging, dryness of the mucosa, and headache,

suppression of healing can occur in a patient who has had nasal surgery or

trauma

Steroid Nasal Decongestants Prototype

flunisolide (Aerobid)

Steroid Nasal Decongestants NC

Observe for c/o burning, irritation, stinging, dry mucosa, headache, increased

risk of infection

Stimulation of H1 receptor

constricts extravascular smooth muscle including those lining the nasal cavity

Stimulation of H2 receptor

increases gastric secretions (which is a cause of peptic ulcer)

First Gen Antihistamines

sedating

Cause, drowsiness, dry mouths and other anti-cholinergic symptoms

Contained in many OTC cold remedies

diphenhydramine (Benadryl)

Given po, IM, IV

excreted as metabolites in the urine

Short half life

Second gen antihistamines

nonsedating

Fewer anticholinergic effects and a lower incidence of drowsiness

Little or no effect on sedation

Moderate amount of alcohol may be taken with them but it is advised against

Half life 7 to 15 hour

Antihistamines TA

Selectively block effects of histamine at the histamine-1 receptor sites, decreasing

allergic response, anticholinergic and antipruritic effects

Antihistamines I

Helps with allergies, seasonal, etc.

Antihistamines AE

Renal or hepatic impairment, first generation: History of arrhythmias or prolonged QT intervals, agranulocytosis, hemolytic anemia, thrombocytopenia

Antihistamines Prototype

diphenhydramine (Benadryl)

Antihistamines NC

Monitor response

Monitor AE - dryness, GI upset, sedation/drowsiness, thickened secretions, glaucoma, constipation

Avoid driving, CNS depressants

Anticholinergic effects

OTC meds/prescribed

Physiologic Effects of Ventilation and Diffusion Disorders

Hypoxemia, Hypercapnia

Disorders of Lung Inflation

Disorders of pleura, Atelectasis

Obstructive Airway Disorders

Asthma, COPD, Bronchiectasis, Cystic Fibrosis

Chronic Interstitial (Restrictive) Lung Disease

Sarcoidosis

Disorders of Pulmonary Circulation

PE, Pulmonary Hypertension, Cor Pulmonale, Acute Respiratory Disorders, Acute Respiratory Failure

Primary Function of respiratory system

Remove CO2, Addition of O2

Insufficient exchange of gases

Hypoxemia, Hypercapnia

Hypoxemia

reduction in arterial blood O2 levels

Normal Pa O2 levels 80-100mm Hg

Etiology and Pathogenesis of Hypoxemia

Hypoventilation

Impaired diffusion of gases

Inadequate circulation of blood

Mismatch of ventilation and perfusion

Inadequate oxygen in air

Neurologic dysfunction

Clinical Manifestations of Hypoxemia

Lactic acidosis

Increased heart rate

High respiratory rate

Restlessness

Dyspnea

Anxiety

Impaired mental performance

The body compensates for chronic hypoxemia by

Increased ventilation

Pulmonary vasoconstriction

Increase release of erythropoietin

S/s of Chronic hypoxemia

Clubbing and cyanosis

Chronic Hypoxemia Diagnostics

ABGs, VBGs, SPO2 pulse oximetry - least invasive

Chronic hypoxemia treatment

correcting cause of disorder, administration of supplemental oxygen

Hypercapnia

Increase in the carbon dioxide (CO2) content of the arterial blood

PaCO2 >45mm, normal range 35-45 mm

Clinical Manifestations of Hypercapnia

Headache, confusion, lethargy, flushed skin

Respiratory acidosis affecting kidneys, neurological and cardiovascular function

Body compensates by increasing renal bicarbonate (HCO_3) retention (slow) or increased RR

Diagnostics of Hypercapnia

ABG/VBG

Treatment of Hypercapnia

BiPAP, CPAP, ventilator

Pleural Effusion

Abnormal collection of fluid in the pleural cavity

Can be transudate, exudate, purulent, chyle, sanguineous