Cystic Fibrosis - Cheat Sheet and Problem List CF PDF

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Cheat Sheet and Problem List CF...

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Cystic Fibrosis Cystic Fibrosis (CF) is the most common life-limiting condition in Caucasian populations. It is a multi-system disorder characterised by recurrent respiratory infections, pancreatic insufficiency, and malnutrition. When CF was first recognised in the 1930s, 70% of babies died within their first year of birth (Andersen, 1938). However, life expectancy has now dramatically improved for those with CF with many living into their 50s (Dodge et. al, 2007). Improvements have been attributed to earlier diagnosis, improved management in infancy and better antibiotics and comprehensive care (Bell et. al, 2008). Aetiology CF is caused by mutations in a single gene called the ‘cystic fibrosis transmembrane conductance regulator (CFTR)’. Defects in the CFTR result in decreased secretion of chloride and water which leads to dehydrated mucus (Koch & Hoiby, 1993). Pathophysiology CF is a systemic disease that affects a range of organs such as the respiratory tract, gastrointestinal tract, and the hepatobiliary tree. Obstruction of the exocrine ducts by viscous secretions plays a role in the pathogenesis of CF. Most studies indicate that babies born with CF have normal lungs at birth (Boucher 2004, Hodson 2000). However, pathological changes occur dramatically with inflammatory markers seen in babies as young as 4 weeks (Khan et. al, 1995). Alterations in electrolyte transport are also seen and these give rise to a decrease in height of the periciliary liquid layer and formation of mucous plaques and plugs, which are adherent to the airway surface (Boucher 2004). Both factors diminish the efficiency of ciliary-dependant mucous clearance which leads to the formation of thickened mucous plaques, this provides an ideal environment for the proliferation of bacterial micro-organisms in the airway (Boucher, 2004). Staphylococcus aureusis most common early in life, however by adulthood 80–90% of patients will be colonized with P. aeruginosa (Robinson 2001, Wilson & Kotsimbos 2004), which is associated with faster deterioration in lung function.

Clinical Features Respiratory Features Most older children and adults with CF cough productive sputum. Breathlessness on exertion is common, along with reduced exercise capacity and diminished physical activity compared to age-matched peers (Rasekaba et al 2013). The clinical course is generally marked my acute exacerbations which are characterised by numerous respiratory and systemic symptoms.

Non-respiratory features As CF is a multi-system disorders, non-respiratory symptoms are important as well. Pancreatic insufficiency causing maldigestion and malabsorption of fats and proteins, occurs in 90% of people with CF by 1 year of age (Orenstein et al 2002). Patients with CF are also at a higher risk of diabetes mellitus (seen in 50% of patients over 30) which increases in incidence and severity during pulmonary exacerbations (Orenstein et al 2002). A high incidence of gastro-oesophageal reflux has also been reported in CF (Ledson et al 1998), which may contribute to deterioration in respiratory function. It is also estimated that 17% of children and 24% of adults with CF have clinically significant liver disease.

Musculoskeletal dysfunction The prevalence of spinal pain in CF patients ranges from anywhere between 43-94% (Botton et. al 2003, Festini et. al 2004, Flume et. al 2009, Haynes et. al 2011), with chest pain ranging from 16-64% (Festini et. al 2004, Haynes et. al 2011). CF arthropathy can affect up to 9% of patients resulting in joint pain, long bone pain and joint effusions which are prevalent during exacerbations (Botton et. al 2003). Joint pain has also been reported in response to some antibiotics used to treat CF. The prevalence of osteoporosis in adults with CF is 23.5% and osteopenia 38% (Paccou et al 2010). Increased rates of long bone, rib and vertebral fractures have also been reported in patients with CF (Hind et al 2008).

Diagnosis and Investigations Newborn Screening In many countries, screening for CF occurs shortly after birth by measuring the newborn’s immunoreactive trypsin in a dry blood heel stick sample. This is followed by genetic testing for the most common CFTR mutations if required. The results of a large RCT have shown that newborns screened for CF reported improved height, weight, and head circumstance.

Other diagnostic methods Not all countries have adopted newborn screening for CF. Newborns that display gastrointestinal abnormalities are often displaying the first signs of CF. Failure to pass meconium (meconium ileus) occurs in 10–15% of cases (Park & Grand 1981). Young children with CF may also display signs of pancreatic insufficiency and an inability to thrive. Older children may present with respiratory co-morbidities such as asthma, and those in adulthood may show signs of infertility linked to CF. Diagnosis is made based on clinical findings supported by two positive sweat test results (Orenstein et al 2002). The results can be confirmed by genetic testing for disease-causing CFTR mutations. Monitoring The progress of CF lung disease is measured by serial measurements of spirometry as FEV is a clear indicator of survival. Measurements of height and weight are also routinely taken at the clinic along with nutritional status.

Medical Management CF is usually treated with several different therapies such as antibiotics, inhaled therapies, nutritional support, and airway clearance. Patients with severe symptoms of CF may be considered for lung transplant surgery. It has also been suggested that CF patients with specialist care such as physiotherapy have greater long-term survival rates. Antibiotic treatment It is routine to treat acute exacerbations of CF with IV antibiotics appropriate to the infecting organism (Orenstein et. al 2002). Treatment often lasts 10-14 days and can be administered in the home if necessary. Eradication therapy for P. aeruginosa is also common where antibiotics are administered upon first detection of the culture in the body (Jones, 2005). Macrolides are a long-term treatment for CF that have both antibiotic and anti-inflammatory properties, resulting in improvement in clinical status and preserved pulmonary function (Equi et al 2002, Saiman et al 2003).

Inhaled therapies Human recombinant dornase alfa (rhDNase) decreases the viscosity of airway secretions and aids clearing of secretion from lungs. Two large scale trials have shown benefits in lung function and exacerbations in those treated with rhDNase compared with a placebo in mild to moderate lung disease (Fuchs et. al 1994, Quan et. al 2003). Nebulized hypertonic saline has been used in CF patients to draw fluid from airways and improve mucociliary clearance. Studies have shown that adults with CF have shown improved lung function and reduction in exacerbations when treated with hypertonic saline. Nutritional support Pancreatic enzyme supplementation is required to ensure adequate fat absorption in 85% of patients with CF (Hodson 2000). If fat absorption strategies are ineffective, high calorie oral supplements are administered or patients may be fed using nocturnal gastrostomy (Orenstein et. al 2002). Physiotherapy Management Airway clearance techniques ACTs are integral to the care of CF patients; studies have shown that mucus transport has short-term beneficial effects in those with CF (van der Schans et. al 2003). Although the evidence is not extensive, ACTs are such an integral part of managing CF that it is unlikely more studies will be conducted anytime soon. Several systematic reviews note that no single ACT is superior, nor is one approach suitable for all patients (Elkins et. al 2006, McKoy et. al 2012).

Problem List Problem Impaired airway clearance

Airflow limitation

Increased WOB

Evidence Increase in the amount of sputum Changes in quality and colour of sputum (yellow/green) Inspiratory crackles or wheezing on auscultation Reduced BS auscultation Silhouette sign CXR Reduced SpO2? Inspiratory wheezing on auscultation Reduced BS auscultation Limited basal expansion Report breathlessness and difficulty clearing secretions

Use of accessory muscles during breathing Increased RR

Pathophysiology People with CF have problems with the CFTR gene which leads to increased production of mucous. This leads to mucous plugging which causes impaired airway clearance.

The formation of thickened mucous plaques provides an ideal environment for proliferation of bacterial microorganisms. This leads to the airways becoming chronically infected causing destruction of the airway walls. Hence, leading to airflow limitation. Due to an abnormal increase of trapped air in the lung after spontaneous expiration. This can cause lung hyperinflation which leads to increased WOB....