Flashcards in Pulmonology UWorld Deck (110)
What are the two classes of CD4+ T-cells and what cytokines do they secrete?
Th1: IFN-gamma (activates macrophages), IL-2 and other cytokines to activate and CD8+ T-cells.
Th2: IL-4 (promotes B-cell class switching to IgE when associated with IL-13), IL-5 (activates eos and promotes IgA synthesis) and other cytokines to activate B-cells.
Change in venous oxygen content in a patient with cyanide poisoning?
Decreased. Cyanide inhibits Fe3+ in cytochrome C of the electron transport chain, decreasing O2 consumption
A patient has a chronic cough, biopsy reveals well-differentiated mucin-producing dysplastic columnar cells lining the alveolar membrane without invasion. What is the most likely diagnosis?
Adenocarcinoma in situ. These tumors have a tendency to undergo aerogenous spread.
How to differentiate sarcoid from hypersensitivity pneumonitis, cryptogenic organizing pneumonia and lymphocytic interstitial pneumonitis?
CD4:CD8 ratio will be increased > 2 in sarcoidosis.
How is the heart oriented in the thoracic cavity?
Anterior = RV. Inferior = LV and RV. Posterior = LA.
Injured organs if there is a penetrating injury to the left chest at the 5th intercostal space in the midclavicular line.
1st the lung because it is most anterior. 2nd the heart because the apex hides behind the lung at this point.
3 ways aspergillus affects the lungs
1) Colonizes pre-existing cavities 2) Invasive infection in immunocompromised 3) ABPA hypersensitivity reaction in asthmatics that causes high levels of IgE and transient pulmonary infiltrates and later proximal bronchiectasis.
Aspiration when supine
Posterior segment of upper lobes and superior segments of lower lobes.
Ipratropium mechanism of action
Anti-muscarinic that reverses vagally mediated bronchospasm
Theophylline mechanism of action
Inhibits PDE and increases cAMP causing bronchodilation. It also inhibits adenosine-induced bronchoconstriction.
What is the major factor that limits exercise tolerance in patients with COPD?
Dynamic hyperinflation: increased respiratory rate leads to decreased exhalatory time, causing increased air trapping and exercise intolerance.
What makes elastin so stretchy and good for pulmonary compliance? Why does it like alpha-1 AT so much?
The lysine is covalently cross-linked with desmosine by extracellular lysyl hydroxylase, allowing it to return to its original form after being stretched. Alpha-1 antitrypsin prevents elastase from breaking it down.
How does elastin differ from collagen
Few lysine and proline residues are hydroxylated
Elastin does not form a triple helix
A patient on theophylline presents with tremors, arrhythmia and GI symptoms. What drugs could be the cause of his symptoms?
Cimetidine, ciprofloxacin, macrolides and verapamil all inhibit CYP450 and increase serum theophylline levels.
How does the influenza vaccine work?
The killed vaccine induced neutralizing antibodies against viral hemagglutinin. This prevents hemagglutinin binding to sialylated receptors on the host cell. The live vaccine stimulates MHC I receptors and generates CD8+ T-lymphocytes that kill infected cells.
Oseltamivir mechanism of action
It competitively inhibits viral neuraminidase and prevents the virus from cleaving sialic acid residues on glycoconjugate receptors. This inhibits release of new virions from infected cells.
Immunodeficiency with sinopulmonary infections, ataxia and telangectasias.
Immunodeficiency with oculocutaneous albinism, pyogenic infections and progressive neurologic dysfunction.
Immunodeficiency with severe bacterial and fungal infections with granuloma formation.
Chronic granulomatous disease
Immunodeficiency with congenital heart disease, dysmorphic facies and hypocalcemia
Immunodeficiency with severe bacterial and viral infections in infancy, thymic aplasia, chronic diarrhea and mucocutaneous candidiasis.
SCID. Labs show absent CD3+ T-cells and hypogammaglobulinemia.
Immunodeficiency with recurrent Neisseria infections
C5-C9 complement deficiency
Immunodeficiency with recurrent infections that worsen with age, easy bleeding and eczema
Pathophysiology of hyper-IgM syndrome
The normal enzymes that excise the exons that code for other Ig classes makes it so a particular B-cell cannot specialize and produce a specific type of Ig. Also, mutations in the CD40 ligand can cause this because stimulation of this ligand promotes class switching.
Factor that induces class switching to IgA
Weird findings associated with Legionella infection
Hyponatremia, transaminitis, bradycardia despite fever, diarrhea and fever > 102.2.
How to diagnose Legionella
Urinary antigen and growth on buffered charcoal yeast extract with supplement L-cysteine and iron.
Tumor cells with long, slender microvilli and abundant tonofilaments that stain well for pancytokeratin.
Cause of Potter syndrome
Oligohydramnios, commonly secondary to bilateral renal agenesis.