10 May Flashcards
Pathophysiology of alpha-1 antitrypsin deficiency
This protein is made in the liver and it counters the effects of neutrophil elastase in the lungs and in the skin leading to emphysema, panniculitis, and accumulation of the abnormal protein in the liver leading to cirrhosis.
Disease features of alpha-1 antitrypsin deficiency
Without this protective protein, patients will develop a COPD-like disease. Those who smoke will present in their 30’s, and those who do not in their 40’s. They can also have skin ulceration caused by necrotizing panniculitis most commonly on buttocks and thighs.
How does smoking lead to emphysema?
Smoking directly inhibits alpha-1 antitrypsin activity by a factor of 2000. This leads to neutrophil damage of lung connective tissue by elastase leading to lung destruction and COPD.
How is emphysema different between smoke caused and alpha-1 antitrypsin caused?
Smoking leads to centriacinar (centrilobular) emphysema with destruction primarily in the upper lobes whereas the other causes panacinar (panlobular) emphysema with destruction more in the lower lobes.
When should alpha-1 antitrypsin deficiency be considered in a patient?
1) COPD at a young age (less than 45)
2) COPD without smoking history
3) Liver disease of unknown origin
4) Basilar predominant COPD
How is alpha 1 antitrypsin deficiency diagnosed and treated?
Measure serum AAT levels
Treat with IV human protein
What is a pulmonary shunt?
Perfusion to a portion of the lung that is not ventilated. This is the cause of hypoxemia in pneumonia and pulmonary edema.
What are the goals of ventilation when treating ARDS and how are they achieved? What decreases mortality?
Lung protective measures: use low tidal volume ventilation (LTVV) to prevent barotrauma. 6ml/kg of ideal weight is usually right, this decreases mortality
Adequate oxygenation: Increasing FiO2 helps, but prolonged over 0.6 increases risk of O2 toxicity, Increasing PEEP to 15-20 may be necessary to maintain open airway and this will help improve oxygenation. Goal values are PaO2 55-80 or O2 saturation over 88% (not 92%)
What is the FEV1/FVC ratio in COPD?
usually less than 0.7
What are the most common CAP organisms?
Strep. pneumo, H. flu, Legionella, Mycoplasma pneumo.
What is used to risk stratify patients with pneumonia to decide how and where to treat them?
CURB-65 criteria Confusion Urea nitrogen over 20 Respirations over 30 BP less than 90 (systolic) or 60 (diastolic) Over 65
Score 0: low mortality, treat at home
Score 1-2: intermediate mortality, likely inpatient treatment
Score 3-4: High mortality, urgent admission, ICU if over 4
What are the mainstays of CAP treatment in an admitted patient?
Fluoroquinolone or
Beta-lactam + macrolide
All IV
How is CAP treated in outpatient setting?
In healthy person without comorbidities: macrolide or doxycycline
If comorbidities present: treat like an admitted patient with fluoroquinolones or beta-lactam + macrolide
Patient presents with recurrent sinusitis, saddle-nose deformity, ulceration in ear canal, and bloody nasal discharge. Likely Dx? What other features of the disease?
Granulomatosis with polyangiitis
Granulomas in the lungs
Kidney damage RPGN
Remember that the upper respiratory tract is most commonly involved
What disease can cause false positive ANCA studies?
HIV
