lect 3 Geriatric and Pulmonology

Chronic Obstructive Pulmonary Disease (COPD) Overview

• Definition: COPD is an inflammatory process involving persistent airflow limitation that is progressive and not fully reversible with bronchodilators.

• Pathophysiology: It is characterized by irreversible airflow obstruction due to a loss of elastic recoil and increased airway resistance.

• Primary Branches: Most patients present with mixed symptoms of both subtypes:     * Emphysema: Defined by the destruction of the alveoli resulting in the permanent enlargement of air spaces distal to the terminal bronchioles. It involves decreased protective enzymes and increased damaging enzymes causing alveolar capillary destruction.     * Chronic Bronchitis: Defined clinically as the presence of a productive cough or sputum for at least $3\,months$ during each of $2\,consecutive\,years$. It involves chronic inflammation leading to mucous gland hyperplasia.

• Primary Treatment: The main lifestyle intervention that helps patients is the administration of oxygen.

Clinical Presentation of COPD Subtypes

• Emphysema (The "Pink Puffer"):     * Typical Patient: Older male with a history of smoking; may present with a thin physique.     * Symptoms: Dyspnea (shortness of breath) is the most common symptom.     * Physical Exam Findings: Pink skin, cursed (pursed) lip breathing, use of accessory muscles, decreased breath sounds, and hyperresonance to percussion.     * Atypical Presentation: If emphysema is seen in a young non-smoker, a genetic cause should be suspected, specifically $\alpha\text{-1 antitrypsin deficiency}$.

• Chronic Bronchitis (The "Blue Bloater"):     * Typical Patient: Overweight, older male who may experience cyanotic episodes (turning blue during shortness of breath).     * Physical Exam Findings: Productive cough (hallmark), decreased breath sounds, increased resonance on percussion, and rales or rhonchi/wheezing.

• Accessory Muscle Use: In adults, retracting or using accessory muscles to breathe is concerning but treatable; however, in pediatric populations (peds), these signs are considered way more critical.

Diagnostic Testing and Monitoring in Pulmonology

• Spirometry Criteria: Diagnosis is typically made when the $FEV_1/FVC$ ratio is less than $0.7$ and the $FEV_1$ is less than $80\%$ of the predicted value.

• Blood Work (VBG vs. ABG):     * Venous Blood Gas (VBG) is the standard of care in many settings as Arterial Blood Gas (ABG) "E-sticks" are not commonly performed as a first-line measure.     * VBG Utility: Used to check $CO_2$ levels and acid-base status. In COPD patients, a high $CO_2$ (hypercapnia) indicates they are retaining air.     * Hypercapnia Presentation: Elderly patients may appear stable or lethargic, but can eventually present with Altered Mental Status (AMS). One recorded patient had a $CO_2$ of $117\,mmHg$ and required intubation.

• Lactic Acid (Lactate):     * Should be checked in all sepsis patients.     * A high lactic acid value is greater than $2$.     * High levels should be repeated every $2\,hours$.     * Differential - Mesenteric Ischemia: Consider this in a $65\,year\,old$ patient with intractable belly pain, vomiting, a negative CT scan, and a rising lactic acid level despite fluid resuscitation.

• VBG in Other Conditions: Necessary for diagnosing Diabetic Ketoacidosis (DKA) to monitor pH and electrolyte shifts.

Hospital Procedures and Complications

• Central Lines:     * Purpose: Used for medications that cannot be pushed peripherally for long periods, specifically pressors like $Levofed$ ($Norepinephrine$). Most hospitals require transitioning to a central line after $6\,hours$ of peripheral pressor use.     * Procedure: Unlike peripheral IVs, central lines are a sterile procedure requiring a gown, gloves, mask, and hairnet.     * Locations: Internal Jugular (IJ), Subclavian (considered the best but requires specialized training), and Femoral (easiest but has the highest infection risk; should be replaced within $24\,hours$).     * Confirmation: A chest X-ray must be performed after placing an IJ or subclavian line to confirm placement and ensure no pneumothorax was caused.

• Pneumothorax:     * Characterized by the extravasation of air into the pleural space.     * Most Common Cause: The procedure most likely to cause a hospital-acquired pneumothorax is a Thoracentesis (removal of pleural fluid).     * Imaging: Look for the absence of lung markings. On a normal X-ray, white lines (lung markings) should be visible on both sides.

BiPAP and Non-Invasive Ventilation

• BiPAP (Bilevel Positive Airway Pressure):     * Used to help patients ventilate and "blow off" $CO_2$.     * Patient Experience: Often described as the sensation of sticking one's head out of a fast-moving car window; it is uncomfortable and can cause anxiety.     * Management: To help anxious patients tolerate BiPAP, low doses of $Valium$ ($Diazepam$), $Versed$ ($Midazolam$), or $Ativan$ ($Lorazepam$) may be administered.     * Contraindications: Inability to clear secretions, high aspiration risk, sepsis, hypotension (unstable), facial trauma, upper airway obstruction, or recent craniofacial surgery.

Lung Volume Definitions and Calculations

• Tidal Volume ($V_T$): The volume of air moved in and out of the lungs during quiet breathing.

• Residual Volume ($RV$): The amount of air remaining in the lungs after maximum expiration.

• Expiratory Reserve Volume ($ERV$): The amount of air that can be further exhaled after a normal expiration.

• Inspiratory Reserve Volume ($IRV$): The amount of air that can be further inhaled after a normal inspiration.

• Vital Capacity ($VC$): The maximum air exhaled after a maximum inhale. Calculated as: $VC = V_T + ERV + IRV$.

• Total Lung Capacity ($TLC$): The total volume in the lungs at maximal inspiration.

• Functional Residual Capacity ($FRC$): The volume of gas in the lungs at normal tidal volume and expiration.

• Forced Vital Capacity ($FVC$): Measurement of the volume of air that can be expelled from a maximally inflated lung.

Stages of COPD (GOLD Criteria)

• Stage 1 (Mild):     * Symptoms: Chronic cough and sputum may or may not be present.     * Management: Lifestyle modifications (smoking cessation) and vaccines.

• Stage 2 (Moderate):     * Symptoms: Development of dyspnea on exertion (DOE).     * Management: Addition of a long-acting bronchodilator and pulmonary rehab.

• Stage 3 (Severe):     * Symptoms: Dyspnea at rest, reduced exercise capacity, and significant impact on quality of life.     * Management: Start oxygen therapy.

• Stage 4 (Very Severe):     * Symptoms: Shortness of breath at rest, lung hyperinflation, hypoxemia, and hypercapnia.     * Management: Long-term $O_2$ therapy for chronic hypoxia.

Pharmacotherapy for COPD and Respiratory Conditions

• Bronchodilators:     * Beta-agonists: Promote smooth muscle relaxation (e.g., Albuterol).     * Anticholinergics: Enhance smooth muscle relaxation; Ipratropium ($Atrovent$) is short-acting; main side effect is dry mouth. $DuoNeb$ combines Albuterol and Ipratropium.

• Magnesium ($Mg$):     * Administered IV for smooth muscle relaxation in COPD and asthma exacerbations.     * Clinical Note: Often mixed in Dextrose ($D_5$), so clinicians must monitor fingerstick blood sugars as it can raise glucose levels.

• Corticosteroids:     * Dexamethasone ($Decadron$): Adult dose maxes at $12\,mg$ or $16\,mg$. Pediatric dose is $0.6\,mg/kg$. Can be given as an IM shot to avoid IV placement.     * Methylprednisolone ($Solu-Medrol$): Typically given IV at a dose of $125\,mg$.     * Side Effects: Short-term use can raise blood sugar. Long-term use can cause Cushingoid features.

• Antibiotics: Used prophylactically in COPD exacerbations to prevent secondary infection, rather than treating a primary infectious process.

Pneumonia by Organism

• Streptococcus pneumoniae: Gram-positive diplococci. The number one cause of Community-Acquired Pneumonia (CAP). Vaccine is critical.

• Haemophilus influenzae: Gram-negative. Common in chronic cardiopulmonary disease. Main complication is empyema.

• Staphylococcus aureus: Gram-positive cocci in clumps. Seen most commonly in patients with a recent influenza virus infection.

• Klebsiella pneumoniae: Gram-negative encapsulated rods. Associated with alcoholics and diabetics. Can cause abscesses and necrotic regions on X-ray.

• Moraxella catarrhalis: Seen in the elderly with pre-existing lung disease; can lead to bacteremia.

• CURB-65 Score: Used to determine hospital admission:     * C: Confusion     * U: BUN > 19\,mg/dL     * R: Respiratory Rate $\geq 30$     * B: Blood Pressure (Systolic < 90 or Diastolic $\leq 60$)     * 65: Age $\geq 65$

Tuberculosis (TB)

• Pathogen: $Mycobacterium\,tuberculosis$.

• Symptoms: Fever, weight loss, night sweats, and cough. Hemoptysis (though the #1 cause of blood in sputum is generally pneumonia).

• Gold Standard Test: PPD (Purified Protein Derivative) or QuantiFERON blood test.

• Treatment (RIPE Regimen):     * Rifampin: Side effect of orange-colored secretions and thrombocytopenia.     * Isoniazid ($INH$): Causes hepatitis and peripheral neuropathy. Must be given with Vitamin B6 (Pyridoxine) to prevent neuropathy.     * Pyrazinamide: Causes hepatitis and hyperuricemia (gout flare risk).     * Ethambutol: Causes optic neuritis (monitor vision).

Cor Pulmonale and Pleural Effusion

• Cor Pulmonale: Right-sided heart failure resulting from pulmonary hypertension or lung disease (COPD is the most common chronic cause; PE is the acute cause). Definitive diagnosis requires a right heart catheterization.

• Pleural Effusions: Fluid in the pleural space (Normal volume is $5\,to\,15\,mL$).     * Light's Criteria (Exudative vs. Transudative):         * Transudative: Imbalanced pressures; low protein count. Causes: CHF, Cirrhosis.         * Exudative: High protein/LDH. Causes: Infection, Malignancy, Pneumonia.         * Criteria: Fluid/Serum Protein ratio > 0.5 or Fluid/Serum LDH ratio > 0.6 indicates Exudative.

Environmental Lung Disease and ARDS

• Acute Respiratory Distress Syndrome (ARDS): Acute onset of bilateral infiltrates on X-ray and hypoxia that is refractory to oxygen (doesn't improve with $\text{O}_2$ therapy). Typically triggered by sepsis, trauma, or shock.

• Pneumoconiosis: Chronic occupational lung diseases caused by particle inhalation.     * Coal Workers: Inhaled coal dust (coal macules).     * Silicosis: Silica inhalation; increases risk of TB.     * Asbestosis: Related to asbestos exposure.

• Idiopathic Pulmonary Fibrosis (IPF): Characterized by chronic cough and a "honeycombing" pattern on CT scan. Definitive treatment is a lung transplant.