resp Flashcards

Question

Hypoxemia

Answer 1

5 mechanism 1) Hypoventilation 2) V/Q mismatch 3) Right to left shunt 4) Diffusion limitation 5) Reduced inspired oxygen tension Hypoventilation causes hypoxemia in the following conditions: 1) CNS dpression- drug overdose, structural CNS lesion 2) Obesity hypoventilation syndrome 3) Impaired neuronal conduction-GBS, MND 4) Muscular weakness- myasthenia gravis 5) Poor chest wall elasticity- kyphoscoliosis. Hypoventilation is characterized by: – correction with increase in FiO2. – normal A-a gradient

Answer 2

In the normal lung, there is V/Q mismatch because perfusion and ventilation are heterogenous. Both ventilation and perfusion are greater in bases more than apices. But difference between apical and basilar ventilation is smaller than apical basilar perfusion. V/Q ratio is usually higher in apices than the bases. V/Q mismatch is responsible for the normal A-a gradient. Conditions from V/Q mismatch: – Obstructive lung disease – Pulmonary vascular disease – Interstitial lung disease

Answer 3

– 100% will have HLA DQB1*0602 (HLA DR2) ``` Mx: – scheduled naps – reduce heavy carbo meals – good night’s sleep – psychosocial support ``` – Avoid Prazosin- may induce cataplexy

Answer 4

- Serum neurone specific enolase can be found in 75% of small cell lung cancer – dopa decarboxylase – calcitonin – chromogranin A – CD 56 or neural cell adhesion molecule (NCAM) – gastrin releasing peptide – insulin like growth factor 1

Answer 5

Stage I and II- surgical resection **surgical resection plus adjuvant chemo(For completely resected stage II and III) Stage IIIa- Induction chemotherapy followed by surgery OR chemoradiotherapy Stage IIIb- chemoradiotherapy Stage IV- Chemotherapy AND palliative radiotherapy. – if solitary brain mets consider surgical excision. If patient is not suitable for optimal regimen, treat depending on symptom and performance status. -observation if not symptomatic or palliative management (ie: Palliative radiotherapy for Stage IIIa to IV)

Answer 6

1. Limited disease: Optimal management: - Platinum based chemotherapy combined with thoracic radiotherapy. AND - Prophylactic cranial irradiation for complete responders. If not for optimal management: Palliative chemotherapy +/- radiotherapy. ``` 2. Extensive disease: Optimal management: Combination chemotherapy AND Prophylactic cranial irradiation for complete responders ``` If not for optimal management: Symptom control. DEFINITIONS: Limited disease: (a) disease confined to one hemithorax, although local extensions may be present; (b) no extrathoracic metastases except for possible ipsilateral, supraclavicular nodes if they can be included in the same (radiotherapy) portal as the primary tumour; (c) primary tumour and regional nodes which can be adequately treated and totally encompassed in every (radiotherapy) portal. Extensive disease: Inoperable patients who cannot be classified as having limited disease

Answer 7

Constrictive bronchiolitis or bronchiolitis obliterans is concentric submucosal fibrosis of the bronchiolar airway leading to narrowing and obliteration. Shortness of breath is the most common presenting symptom and early inspiratory crackles are heard by lung auscultation. Pulmonary function demonstrates irreversible airflow obstruction with decreased FEV1:FVC ratio, although a restrictive pattern may be seen. The chest radiograph shows normal lungs or hyperinflation, while the chest CT shows air trapping by the expiratory view, a mosaic pattern, bronchiolectasis and small airway wall thickening. Corticosteroid therapy is effective for the inflammatory component of the illness and for exacerbations. Immunosuppressive agents may be effective in some individuals. Antifibrotic agents may be effective in the future. Lung transplantation is an option for life-threatening, disabling disease.

Answer 8

- Use preventer if asthma symptoms >3x per week or use SABA >3x per week - Start with a low dose of inhaled ICS. Once control is achieved, titrate the dose of ICS to the lowest dose at which effective control of asthma is maintained. Those with moderate persistent asthma will need the addition of a LABA. Little additional improvement in symptoms or lung function is gained by increasing doses above: 800 mcg/day budesonide(Pulmicort), 500 mcg/day fluticasone(Flixotide) In adults, initial therapy with ICS is superior to treatment with a leukotriene receptor antagonist (LTRA), cromone or theophylline for improving lung function and reducing symptoms.

Answer 9

Samter’s triad characterized by presence of aspirin intolerance, asthma and nasal polyposis. The disorder is caused by overproduction of leukotrienes.When prostaglandin production is blocked by NSAIDS like aspirin, the cascade shunts entirely to leukotrienes, causing overproduction of LT-4 and producing the severe allergy-like effects. Treatment is with leukotrienes antagonist(Montelukast) for symptom relief but the preferred treatment is now aspirin desensitization.

Answer 10

Severe H1N1 infection is associated with IgG(2) deficiency, which appears to persist in a majority of patients. Pregnancy-related reductions in IgG(2) level may explain the increased severity of H1N1 infection in some but not all pregnant patients. The role of IgG(2) deficiency in the pathogenesis of H1N1 infection requires further investigation, because it may have therapeutic implications. Association between severe pandemic 2009 influenza A (H1N1) virus infection and immunoglobulin G(2) subclass deficiency.

Answer 11

– major constituents of aspergilus cell wall – released during growth of hyphae – used to diagnose invasive aspergillosis in immunocompromised patients.

Answer 12

predicting the risk of death from any cause and from respiratory causes among patients with COPD - BMI - Obstruction(FEV1) - Dyspnea(MMRC) - Exercise(6MWD)

Answer 13

``` – stage IIIb or IV – FEV1 <1.5 – malignant pleural effusion – tumour near hilum – vocal cord paralysis – SVC obstruction ```

Answer 14

Small cell lung cancer(SCLC) comprises about 20% of lung cancers. This type of lung cancer is the most aggressive and rapidly growing of all the types. SCLC is strongly related to cigarette smoking with only 1% of these tumors occurring in non-smokers. SCLC metastasize rapidly to many sites within the body and are most often discovered after they have spread extensively. infrequently present with: - SVC obstruction - Pancoast syndrome - Paraneoplastic syndrome

Answer 15

1) Low FEV1 2) High CO2 3) High WCC 4) Females

Answer 16

augment the chloride-transport activity of G551D-CFTR protein in vitro. Ivacaftor was associated with improvements in lung function at 2 weeks that were sustained through 48 weeks. Substantial improvements were also observed in the risk of pulmonary exacerbations, patient-reported respiratory symptoms, weight, and concentration of sweat chloride.

Answer 17

``` In primary pneumothorax, risk factors include: – smoking – positive family history in 10% – Marfan’s syndrome – Homocytinuria – Thoracic endometriosis ``` In secondary pneumothorax, risk factors include: – COPD for 70% of cases (Increased risk with worsening obstruction) – PCP – AIDS – CF – TB Management of Primary pneumothorax: – supplemental oxygen (100% humidified oxygen) – simple pleural aspiration or intercostal tube drainage (similar 12 months outcome) – But Simple aspiration is associated with a reduction in hospitalization.

Answer 18

May be classified into 5 WHO groups: Group 1: due to idiopathic,familial or associated dx (ie: connective tissue disease, HIV, portal hypertension, congenital heart disease, schistosomiasis). Group 2: due to left heart disease (LV systolic dysfunction, LV diastolic dysfunction, valvular disease, congenital heart disease) Group 3: due to respiratory disease (COPD, ILD, sleep disordered breathing, alveolar hypoventilation disorders,etc) Group 4: due to chronic thromboembolic HT (CTEPH) Group 5: due to unclear or multifactorial mechanisms (hematological disorders, systemic disorders like sarcoidosis, etc). Three important hormones in pathogenesis of PAH and their function: 1) Prostacyclin causes vasodilation and anti-proliferation. 2) Nitric oxide causes vasodilation and anti-proliferation 3) Endothelin 1 causes vasocontriction of smooth muscle. What happens in PAH? 1) Low prostacyclin production. 2) Low nitric oxide synthesis. 3) High Endothelin 1 and thromboxane production. 4) Impaired voltage gated potassium - calcium 5) Mutation of Bone morphogenetic protein(BMPR) gene resulting in increased smooth muscle proliferation. Other gene mutations: Activin 1 like kinase receptor, serotonin transporter gene. How to treat? Treat the cause.Treatment depends on Group of PAH. Group 1 – treat underlying condition like HIV, scleroderma. – warfarin for IPAH, familial PAH. – lung transplant for IPAH if refactory to medical Rx. Group 2- optimize heart failure therapy. Group 3- oxygen Group 4- warfarin. consider heart lung transplant Group 5- treat underlying condition if possible. Pharmacotherapy: 1) Low prostacyclin- Treat with prostacyclin (Epoprostenol, Treprostinil) 2) Low nitric oxide- Treat with phosphodiesterase Type 5 inhibitor (Sildenafil) 3) High endothelin 1- Treat with endothelin receptor antagonist (Bosentan, Ambrisentan) 4) Calcium blocker-Trial in patients with positive vasoreactivity test but most patient are non-responders (No role for PAH with scleroderma)

Answer 19

– intracranial disease – uncontrolled hypertension – recent major surgery or trauma (within the past 3 weeks). Percutaneous mechanical thrombectomy (thrombus fragmentation and aspiration) and surgical embolectomy should be restricted to high-risk patients with an absolute contraindication to thrombolytic treatment and those in whom thrombolytic treatment has not improved hemodynamic status; percutaneous mechanical thrombectomy is an alternative to surgical embolectomy in cases in which immediate access to cardiopulmonary bypass is unavailable.

Answer 20

PA02 - Pa02 PA02 = [FiO2 x (Patm - PH20) ] - (PCo2 / 0.8) PH20 = 47 Patm at sea level = 760 at room air and sea level PA02 = 150 - 5/4 (PCo2)