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Cystic Fibrosis Module C Chapter 41 Objectives • State the clinical definition for Cystic Fibrosis. Describe the anatomic alterations of the lungs in Cystic Fibrosis. • Describe the etiology of Cystic Fibrosis. • List the clinical manifestations seen in Cystic Fibrosis. • Describe the management of Cystic Fibrosis. • Indicate the lab test used to evaluate a patient for cystic fibrosis and give normal values and values used to identify cystic fibrosis. Definition • Formerly known as Mucoviscidosis. • An inherited disease of the exocrine glands, primarily affecting the GI and respiratory systems, and usually characterized by COPD, exocrine pancreatic insufficiency, and abnormally high sweat electrolytes. Exocrine Glands • Exocrine glands are glands whose secretions pass into a system of ducts that lead ultimately to the exterior of the body. • • • • • • Sweat Glands Pancreatic ducts Intestinal ducts Liver & bile ducts Reproductive glands Lungs (bronchial glands) Incidence • Most common life-shortening disease genetic disease in US • Affects about 30,000 children and adults in US. • 1 in 3,500 live births. • Greater incidence in white births. • 10,000,000 symptomless carriers (1 in 25). • 80% diagnosed by age three; ~10% at age 18 or older. Etiology • Various mutations of a single gene located on chromosome 7. • Gene cells normally produce a protein called Cystic Fibrosis Transmembrane Regulator (CFTR). • A mutation known as DF508 results in deletion of the amino acid phenylalanine at position 508 of the CFTR protein. (70% of all cases) • This results in a defect in chloride transport by epithelial cells (also Na and K). Etiology • Carriers of a single defective gene have no clinical disease. • If both parents are carriers, children who inherit one abnormal gene from each parent will be homozygous and develop CF. • Regardless of sex, the children of two carrier parents will have: • a 25% chance of having CF, • a 50% chance of being carriers, • a 25% of being normal (non-carrier). Pathology • Nearly all exocrine glands are affected in varying degree of severity. • Three types of defects: • Glands become obstructed by viscid material (pancreas, intestines, bile ducts, gallbladder). • Increased secretion of abnormal mucus (bronchial glands) • Histologically normal cells, but increased secretion of Sodium and Chloride (sweat glands). • The lungs may appear normal at birth but abnormal structural changes occur rapidly. Pathophysiology - Pulmonary • Bronchial glands hypertrophy and there is metaplasia of goblet cells. • Impairment of mucociliary clearance. • Mucous plugging leads to hyperinflation and atelectasis. • Retained secretions lead to frequent infections (pneumonia). • Staphylococcus aureus • Haemophilus Influenza • Pseudomonas Aeruginosa (mucoid variant) • Smooth muscle constriction. • Chronic bronchitis, bronchiectasis and lung abscess. • AIRWAYS – NOT GAS EXCHANGE UNITS. Pathophysiology - Intestinal Tract • Meconium Ileus: Obstruction of the small intestine of the newborn caused by impaction of thick, dry tenacious meconium, usually at or near the ileocecal valve. • Deficiency of pancreatic enzymes • Earliest manifestation of CF • Newborns have abdominal distention and fail to pass stool within 12 hours after birth • Intestinal Obstruction occurs in older children and adults Pathophysiology - Pancreas • Pancreatic ducts become plugged with mucous which leads to fibrotic changes. • Cannot digest fats, proteins and cannot break down nutrients. • Deficiency of vitamins A, D, E, K. • Vitamin K deficiency leads to easy bruising and bleeding. • Patients have difficulty gaining weight. • Cachectic • Vitamin D deficiency leads to absorption of Calcium and Phosphorus. • Diabetes Pathophysiology – Sweat Glands • Glands secrete up to 4 times the normal amount of Na and Cl. • The actual volume of sweat does not change. • Sweat Chloride concentration can be used as a diagnostic indicator. • “Kiss a baby” • Greater than 60 mEq/L is diagnostic in children. • In adults, a concentration of greater than 80 mEq/L is usually required for a diagnosis. Pathophysiology – Other • Nasal Polyps and Sinusitis • 20% of patients. • Polyps are multiple and may cause nasal obstruction and distortion of normal facial features. • Sterility • 99% of men and many women are sterile. • Women not likely to carry fetus to term. • Infant will have cystic fibrosis or will be a carrier. Signs & Symptoms • Vital Signs: • • • • Tachypnea Tachycardia Hypertension May have increased temperature if infection present. • Inspection: • • • • • Use of accessory muscles during I & E. Increased A-P diameter of the chest. Pursed lip breathing. Clubbing Cyanosis Signs & Symptoms • Palpation: • Decreased tactile and vocal fremitus. • Percussion • Hyperresonant percussion note. • Auscultation • Diminished breath sounds. • Crackles, rhonchi, wheezing. Cor Pulmonale • Chronic hypoxemia • • • • • • Polycythemia Pulmonary hypertension. Distended neck veins. Enlarged and tender liver. Peripheral edema. Pitting edema. Spontaneous Pneumothorax • 20% greater incidence. • 50% recurrence rate. • Symptoms include: • Pleuritic pain • Shoulder pain • Sudden dyspnea • Can be precipitated by • Excessive exertion • High altitude • Positive pressure breathing Pulmonary Function • Obstructive Picture: • • • • Decreased FVC Decreased flowrates Increased RV, TLC, FRC Flow Volume Loop • Scooped out Arterial Blood Gases • Mild to Moderate CF • Acute alveolar hyperventilation with hypoxemia. • Severe CF • Chronic ventilatory failure with hypoxemia. • Increased shunting. • Watch out for “acute on chronic” condition during exacerbations of disease. Chest X-ray • • • • • • Translucent (dark) Depressed or flattened diaphragms Right ventricular enlargement Areas of atelectasis and fibrosis Pneumothorax Abscess formation Treatment • Oxygen Therapy • Treat hypoxemia ( / , shunt) • Nutritional Support • • • • Pancreatic Enzymes to aid food digestion Increase of calories by 50 – 100% Multivitamins and minerals Salt • Mobilization of Bronchial Secretions • Bronchial Hygiene Protocol • Hyperinflation Protocol • Aerosolized Medication Protocol Bronchial Hygiene • Hydration • Cough Techniques • Active Cycle Breathing, Autogenic Drainage, • Deep Breathing • IS, Flutter, PEP therapy • Chest Physical Therapy • Percussion & Vibration • Postural Drainage • Mucolytic Therapy Active Cycle Breathing Autogenic Drainage PEP Therapy • Used in the management of airway secretions and atelectasis. • Patient is instructed to inhale a volume of air larger than Vt through a one way valve. • Exhale actively through a fixed orifice to a normal level. • Fixed orifice is chosen to achieve a PEP of 10 to 20 cm H2O during exhalation. • Perform 10-20 breaths followed by coughs. PEP Therapy Postural Drainage & Percussion High Frequency Chest Wall Compression • ThAIRapy Vest • Inflatable, personally fitted jacket attached to a large pump that generates variable high frequency oscillations and applies that directly to the chest wall. • Pulse frequency is set for 5-25 Hertz (300 to 1500 cycles/min). Aerosolized Medications • • • • • Mucolytics - Pulmozyme Sympathomimetics Parasympatholytics Xanthines Antibiotics - tobramycin, colisitin Mechanical Ventilation • Treat increased PaCO2 (and low pH) • Use caution with increasing tidal volume. • Increased RV leads to overdistension. • Extend expiratory time. • Auto PEEP • Shorten inspiratory time (increase inspiratory flow rate). • Use respiratory rate to control PaCO2. • Control patient (?) pharmacologically. • Permissive hypercapnia and acidosis. • Treat reduced PaO2 • Usually a result of hypoventilation and / • Responds well to increase in FIO2. imbalance. Home Care • • • • Patient, family education Home oxygen Aerosol therapy CPT/PD Future Therapies • denufosol tetrasodium • denufosol is designed to enhance the lung's innate mucosal hydration and mucociliary clearance through stimulation of the P2Y2 receptor. • HUH? Prognosis • Diagnostic testing for the abnormal gene is now available. • Life expectancy is 37 years of age (CF Foundation) with some patients living past 40 years. Death is usually due to pulmonary complications • Respiratory failure • Heart failure