Bronchiectasis for USMLE 

Bronchiectasis pathophysiology, etiology/causes, clinical signs and symptoms, investigations and laboratory, management and treatment options for USMLE Step1 and Step 2. Handwritten video lecture presentation for medical students.
Bronchiectasis is an irreversible dilation of larger airways.
PATHOGENESIS OF BRONCHIECTASIS
Weak wall that is easily collapsible due to chronic inflammation and mucous plug. Best way to understand bronchiectasis is to think of it as a cycle of destruction (due to inflammation), impairment (due to decrease mucociliary clearance) and chronic infection. This cycle continues in a chronic fashion leads eventually to bronchiectasis.
ETIOLOGY and CAUSES OF BRONCHIECTASIS
Infectious causes are in immunodeficient stages, such as HIV, CVID, SCID, DiGeorge Syndrome, CGD will lead to recurrent infection that will lead to the cycle continuing over and over again. Pertussis, measles, Adenovirus, Tuberculosis, MAC, and ABPA.
Impairement of mucociliary clearance is due to Cystic Fibrosis, Primary ciliary dyskinesia, Kartagener's Syndrome. Muscular Dystrophy affect the diaphragm so the airway can't be cleared out. Obstruction caused by malacia, stenosis, foreign body and mucoid impaction.
Destruction can be caused by connective tissue disorders such as marfan's syndrome and Ehlor Danlos.
PATHOPHYSIOLOGY OF BRONCHIECTASIS
Airway is dilated with increased thickness of of the wall with increase amount of mucus in the airway. Upper airways is more commonly associated with CF and Sarcoidosis. Middle airway si associated iwth primary ciliary dyskinesia. Lower airway is associated with pneumonia. Central airway associated with Aspergilosis.
CLINICAL SIGNS AND SYMPTOMS of BRONCHIECTASIS
Diagnostic if there is chronic daily cough, sputum production with consistent CT findings. Episodic exacerbations are associated with increase cough and sputum. Sudden fever chest pain and dyspnea. Fatigue is a late finding and correlated with FEV1. Hemoptysis leads to erosion of airway near vessels. Cyanosis may occur in children and leads to severe hypoxemia. V/Q mismatch pulmonary hypertension and cor pulmonale. Physical examination shows crackles wheeze, clubbing.
EVALUATION, WORKUP OF BRONCHIECTASIS
On x-ray there are tram track appearance due to thickened wall. Cystic dilation is also common in patients with bronchiectasis. High Resolution CT (HRCT) is the image of choice and shows airways dilation, wall thickening appearing as signet ring appearance.
LABS OF BRONCHIECTASIS
CBC with diferentials, IgG, IgA, IgM to look for immunodeficiency underlying bronchiectasis. CFTR Mutation analysis to rule out cystic fibrosis. Sputum culture and smear to guide anti-biotic treatment.
PFTs will show obstructive disease and FVC normal and FEV will be low and therefore FEV1/FVC ratio will be very low.
TREATMENT and MANAGEMENT OF BRONCHIECTASIS
Goals consist of controlling infection, decrease inflammation and increase bronchial hygiene.
Treatment undelrying cause of the bronchiectasis such as TB (with chemo) Immunodeficiency (IVIG), Aspergilossis (anti-fungals)
Prevention of exacerbation by giving macrolide to inhibit film of psuedomonas. Inhaled anti-biotics however, this may cause bronchospasm that will require albuterol to prevent. Mucolytic and airway hydration with nebulized hypertonic saline solution or mannitol. Chest P/T such as directed cough, forced expiration, PEP, oscillatory PEP.
Vaccination with PCV to prevent infection.
Treatment of Exacerbation with Anti-Biotics, but must be cultured because high resistance. Common pathogens include H. Influenza, M. Catarrhalis, S. Aureus, S. pneumonia and Psuedomonas. Outpatient treatment is done if stable and afebrile and can be treated with Flouroquinolones until culture is done. But if repiratory rate is higher than 25bpm, hypoxemia hypotension, temperature greater than 38 degree celsius should be treated with anti-psuedomonals and gudied by culture.
Surgery for bronchiectasis can be done if focal resection and if generatlized than lung transplant is an option. If severe hemoptysis than also surgery needs to be done immediately.