Respiratory

Question 1

What are the causes of cludding?

Answer 1

• Resp:
  
  • Bronchial carcinoma
  • lung fibrosis
  • bronchiectasis (suppurative lung disease as in cystic fibrosis)
  • mesothelioma
  • TB
  • lung abscess
• Cardio:
  
  • Atrial myoma
  • infective endocarditis
  • cyanotic heart disease
• GI:
  
  • Cirrhosis
  • inflammatory bowel disease

Question 2

Define pneumonia.

Answer 2

Infection of the lung parenchyma

Question 3

What is the aetiology and risk factors for pneumonia?

Answer 3

• impaired lung defenses
  
  • poor cough/gag reflex (e.g. illness, drug-induced)
  • impaired mucociliary transport (e.g. smoking, cystic fibrosis)
  • immunosuppression (e.g. steroids, chemotherapy, AIDS/HIV, DM, transplant, cancer)
• increased risk of aspiration
  
  • impaired swallowing mechanism (e.g. impaired consciousness, neurologic illness causing dysphagia, mechanical obstruction)
• no organism identified in 75% of hospitalized cases, and >90% of ambulatory cases

Question 4

What are the common organisms that cause community acquired pneumonia?

Answer 4

• Typical Bacteria
  
  • Streptococcus pneumoniae
  • Moraxella catarrhalis
  • Haemophilus influenzae
  • Staphylococcus aureus
  • GAS
• Atypical Bacteria
  
  • Mycoplasma pneumoniae
  • Chlamydophila pneumoniae
  • Legionella pneumophila
• Viral
  
  • Influenza virus
  • Adenovirus

Question 5

What are the common organisms that cause nosocomial pneumonia?

Answer 5

• Enteric GNB (E. coli)
• Pseudomonas aeruginosa
• S. aureus (including MRSA)

Question 6

What are the common organisms that cause aspiration pneumonia?

Answer 6

• Oral anerobes (Bacteroides)
• Enteric GNB (E. coli)
• S. aureus
• Gastic contents (chemical pneumonitis)

Question 7

What are the common organisms that cause HIV associated pneumonia?

Answer 7

• Pneumocystis jiroveci
• Fungi (Cryptococcus)
• Nocardia
• CMV
• HSV
• TB

Question 8

What are the common organisms that cause alcoholic pneumonia?

Answer 8

• Klebsiella
• Enteric
• GNB
• S. aureus
• Oral anaerobes (aspiration)
• TB

Question 9

What are the clinical features of pneumonia?

Answer 9

• cough (± sputum), fever, pleuritic chest pain, dyspnea, tachypnea, tachycardia
• elderly often present atypically; altered LOC is sometimes the only sign
• evidence of consolidation (dullness to percussion, bronchial breath sounds, crackles)
• features of parapneumonic effusion (decreased air entry, dullness to percussion)
• complications: ARDS, lung abscess, parapneumonic effusion/empyema, pleuritis ± hemorrhage

Question 10

What Ix should be done on a pt with pneumonia?

Answer 10

• pulse oximetry to assess severity of respiratory distress
• FBC and differential, electrolytes, urea, Cr, ABG (if respiratory distress), troponin/CK, LFTs, urinalysis
• sputum Gram stain/C&S, blood C&S, ± serology/viral detection, ± pleural fluid C&S (if effusion >5 cm or respiratory distress)
• CXR±CT chest shows distribution (lobar consolidation or interstitial pattern), extent of infiltrate ± cavitation
• bronchoscopy ± washings for:
  
  • (1) severely ill patients refractory to treatment or
  • (2) immunocompromised patients

Question 11

What is the Rx for CAP and HAP?

Answer 11

• Supportive:
  
  • ABCs, O2, IV fluids, consider salbutamol
  • Determine prognosis and need for hospitalisation and Abx
• ABx
  
  • CAP need to assess severity: CURB65 or SMARTCOP
    
    • Mild amoxycillin or doxycycline
    • Moderate: benzylpenicillin IV PLUS doxycycline oral
    • Severe : ceftriaxone IV PLUS azithromycin IV
  • Hospital-acquired pneumonia:
    
    • Mild: amoxycillin + clavulanate PO
    • Moderate: ceftriaxone IV
    • Severe: ceftriaxone
    • High risk of MDR all severities: piperacillin + tazobactam IV

Question 12

What is CURB65

Answer 12

• Used as a diagnostic tool for the severity of pneumonia
• CURB 65: 0-1 outpatient, 2-3 hospitalise, 4-5 ICU admit
  
  • Confusion: Altered mental status = 1
  • Urea/BUN: Urea>7mmol or BUN>20mg/ml = 1
  • Respiratory rate: >30 = 1
  • Blood pressure: Systolic <90 or diastolic <60 = 1
  • Age: 65 or lder = 1

Question 13

What is SMARTCOP

Answer 13

Question 15

What are the pathological stages of pneumonia?

Answer 15

• Congestion in the first 24 hours: characterized histologically by vascular engorgement, intra-alveolar fluid, small numbers of neutrophils, often numerous bacteria. Grossly, the lung is heavy and hyperemic.
• Red hepatization or consolidation: Vascular congestion persists, with extravasation of red cells into alveolar spaces, along with increased numbers of neutrophils and fibrin.
• Grey hepatization: Red cells disintegrate, with persistence of the neutrophils and fibrin. The alveoli still appear consolidated, but grossly the color is paler and the cut surface is drier.
• Resolution (complete recovery): The exudate is digested by enzymatic activity, and cleared by macrophages or by cough mechanism.

Question 16

What are the complications of pneumonia?

Answer 16

• Healing by fibrosis
• PLeuritits
• empyema
• abscess formation
• haematogenous seeding - bacteraemia
• Pleural effusion
• ARDS
• death

Question 17

What is the Lights criteria used for?

Answer 17

Determination of transudate vs exudate source of pleural effusion.

• Fluid is exudate if one of the following Light’s criteria is present:
  
  • Effusion protein/serum protein ratio greater than 0.5
  • Effusion lactate dehydrogenase (LDH)/serum LDH ratio greater than 0.6
  • Effusion LDH level greater than two-thirds the upper limit of the laboratory’s reference range of serum LDH

Question 18

What are the causes of an exudative effusion?

Answer 18

• Abdominal fluid: Abscess in tissues near lung, ascites, Meigs syndrome, pancreatitis
• Connective-tissue disease: Churg-Strauss disease, lupus, rheumatoid arthritis, Wegener granulomatosis
• Endocrine: Hypothyroidism, ovarian hyperstimulation
• Iatrogenic: Drug-induced, esophageal perforation, feeding tube in lung
• Infectious: Abscess in tissues near lung, bacterial pneumonia, fungal disease, parasites, tuberculosis
• Inflammatory: Acute respiratory distress syndrome (ARDS), asbestosis, pancreatitis, radiation, sarcoidosis, uremia
• Lymphatic abnormalities: Chylothorax, malignancy, lymphangiectasia
• Malignancy: Carcinoma, lymphoma, leukemia, mesothelioma, paraproteinemia

Question 19

What the causes of transudative effusions?

Answer 19

• Atelectasis: Due to increased negative intrapleural pressure
• Cerebrospinal fluid (CSF) leak into pleural space: Thoracic spine injury, ventriculoperitoneal (VP) shunt dysfunction
• Heart failure
• Hepatic hydrothorax
• Hypoalbuminemia
• Iatrogenic: Misplaced catheter into lung
• Nephrotic syndrome
• Peritoneal dialysis
• Urinothorax: Due to obstructive uropathy

Question 20

List some exceptions - that is they typically cause exudative effusions, but may cause transudative effusions.

Answer 20

• Amyloidosis
• Chylothorax
• Constrictive pericarditis
• Hypothyroid pleural effusion
• Malignancy
• Pulmonary embolism
• Sarcoidosis
• Superior vena cava obstruction
• Trapped lung