CR - Thoracic & Respiratory Disorders Flashcards
You are viewing the chest x-ray of a patient who is a traveler from overseas that reveals a multifocal pneumonia associated with a moderate unilateral pleural effusion and hilar adenopathy.
What is your diagnosis?
Tuberculosis
Primary TB shows up in the lower lobes. Reactivation TB is characteristically an upper lobe process sometimes with cavitation
Can present as multifocal pneumonia with unilateral pleural effusion and hilar adenopathy
Most commonly affects the right lung
Suspect it in travelers from developing countries, patients with a history of incarceration, HIV patients, or health care workers with exposure.
Most common symptoms in active disease are fever, chest pain, malaise and weight loss.
Suspect in patients with night sweats, hemoptysis, and weight loss
What diagnosis is suggested by abrupt fever, shaking chills, pleuritic chest pain, cough with rust-colored sputum, and a chest x-ray revealing an infiltrate in the right lower lobe
S. pneumoniae (pneumococcal) pneumonia
The most common cause of community-acquired bacterial pneumonia
The classic presentation is more common in younger patients
The rust-colored sputum is due to a mix of red blood cells and hemoglobin in the sputum
A 21 year old male with no PMH presents with headache, dizziness, nausea. He was cooking in his apartment on a charcoal grill earlier because it was raining. his physical exam reveals sinus tachycardia and mild gait instability. Prior to being placed on 100% oxygen, what is his pulse oximetry likely to reveal?
95-100%
This is carbon monoxide poisoning.
Oxygen is replaced by CO, which changes the hemoglobin molecule from oxyhemoglobin to carboxyhemoglobin.
Pulse oximetry measures the percent of arterial hemoglobin in the oxyhemoglobin form, which the pulse oximetry cannot differentiate from CO-Hb. Often presents with multiple victims from same household with similar symptoms (headaches, lightheadedness etc). Treat with 100% high flow O2
A child is Brough in because of an earache. Examination reveals bulls myringitis, as well as rales and wheezing on the chest exam. There is no history of asthma or other reactive airway disease. Chest X-ray demonstrates a unilateral lower lobe infiltrate and a small pleural effusion.
What is the causative organism?
Mycoplasma pneumonia
Is is the most common cause of atypical pneumonia commonly affecting school-age children and young adults. The chest x-ray usually looks a lot worse than the patient’s clinical appearance. Patients present with upper and lower respiratory tract infection, non-productive cough, low grade fever, malaise and wheezing without history of asthma. Extra-pulmonary features include: bulbous myringitis, sinusitis, erythema multiform, aseptic meningitis, may develop Guillain-Barre syndrome and hemolytic anemia
The combination of fever, nonproductive cough, pleuritic chest pain and exertion dyspnea in a patient who is HIV positive with a CD4 count of less than 200 cells/mm3 should suggest what diagnosis?
Pneumocystis jirovecii pneumonia
The most common opportunistic infection in HIV patients (the most common cause of community acquired pneumonia in HIV patients is strep pneumonia)
Patients with PCP may present with subacute onset of nonproductive cough, fever, shortness of breath and weight loss.
Diffuse interstitial infiltrates may be present on chest radiography.
Arterial hypoxemia is common
Tachypnea and tachycardia are usually present
10-20% lack these typical findings
30% will have a normal CXR
May see perihilar infiltrates “bat-wing” pattern and ground glass appearance
What is the initial drug of choice for patients with pneumocystis jirovecii pneumonia?
TMP-SMX is treatment of choice
Usual regiment is 20 mg/kg of TMP and 100 mg/kg of SMX daily in 3 divided doses, for 21 days, PO or IV
For patients allergic to sulfa, pentamidine IV can be given (4 mg/kg)
Steroids should be added for patients with a pO2 <70mmHg or an A-a gradient >35 mmHg, tapered over 21 days
Patients with CD4 < 200 should be on PCP prophylaxis
An elderly debilitated patient with a history of DM, alcoholism, COPD, presents in early spring with a cough and sputum production that has been gradually getting worse. He complains of fever, shortness of breath, and pleuritic chest pain. There are rales but no signs of consolidation on physical exam. What is the most likely etiology?
H influenzae pneumonia
Non-typeable H flu is common in people with acute COPD exacerbations (13-50%) and in immunocompromised patients (including DM and alcoholism). CXR shows patchy, basilar infiltrate.
Other common bacterial causes in acute COPD exacerbations include mortadella catarrhalis and s. pneumoniae
A 25 year old male with history of cystic fibrosis presents with increasing shortness of breath and cough for a couple of weeks. Based on physical examination, CXR, and lab, the diagnosis is pneumonia. What is the most likely causative organism?
Pseudomonas aeruginosa
Most common causative agent of pneumonia in patients with CF. CXR shows patchy infiltrate and occasionally abscess formation.
Also pneumonia associated with hot tubs as well as folliculitis
Also associated with pneumonia in intubated patients.
You have just intubated an asthmatic patient. Half an hour after intubation you notice the patient has become hypotensive. What should be your next step in managing the patient?
Remove the patient from mechanical ventilation and start bagging the patient. Patients may get hypotension from auto-PEEP. These patients need to have adequate exhalation / ventilation. The first step in managing respiratory of hemodynamic instability in a mechanically ventilated patient is to remove them from the ventilator, manually ventilate and reassess the airway. If hypotension does not resolve you may have to press on the chest to help exhalation.
To prevent auto-PEEP in intubated asthma patients, ventilate with low tidal volumes and maintain inspiratory : expiratory ratio of 1:2 or higher. This may require increased sedation or neuromuscular paralysis
A 54 year old man presents with shortness of breath after a recent vacation. He has an infiltrate on his chest X-ray. He has recently traveled to Colorado where he was backcountry skiing and using the hot tub at his resort. What test should be sent to evaluate the cause of his shortness of breath?
Urine legionella antigen
The urine legionella antigen is 80% sensitive and 97% specific. It should be sent on patients who have pneumonia and recent exposure to heated or aerosolized water. Think about this diagnosis in patients on cruises or at conventions.
Unsuspecting hyponatremia can also be associated with legionella
A high ranking government employee presents to you after a week of malaise associated with shortness of breath. On CXR you notice a small pleural effusion and mediastinal widening. What organism should you be concerned about?
Bacillus anthracis
Anthrax can cause mediastinal widening on X-ray due to hilar adenopathy. Other pulmonary findings can include effusions and infiltrates
An ill-looking patient presents with fever, chills and pleuritic chest pain. He had the flu, which was followed by the insidious onset of a productive cough of purulent sputum. Coarse rhonchi and rales are heard on the chest exam.
What is the most appropriate antibiotic to start?
Vancomycin
Recent influenza patients are susceptible to s. aureus pneumonia. Due to the high prevalence of methicillin resistance, vancomycin should be empiric antibiotic of choice, in addition to empiric gram negative coverage, even in the absence of radiographic findings. Although susceptible to s. aureus, the most common cause of post-influenza pneumonia remains s. pneumonia
What are the most common pathogenic causes of lung abscess seen on CXR
Immunocompetent patients:
- Anaerobic bacteria (peptostreptococcus most common)
- Aerobic s. aureus (MRSA)
Immunocompromised patients:
- S aureus, e coli, klebsiella, pseudomonas, and streptococcus
- Fungal causes include cryptococcal, aspergillosis, and histoplasma
What is the presentation of a lung abscess
Lung abscess:
Foul smelling fetid bloody sputum
Fever, chest pain, weight loss
Gingivitis and poor dentition are risk factors
35% of patients over 45 years old with an abscess have neoplasm
Must consider post influenza staph pneumonia (tx vanc)
Treatment for abscess: clindamycin IV until patient afebrile for 5 days, then oral for 6-8 weeks
A 34 year old African-American woman presents with shortness of breath and dyspnea on exertion for 3 weeks. Her CXR shows hilar lymphadenopathy. What is the most likely diagnosis?
Sarcoidosis
The hilar region may be symmetrically enlarged in up to 50% of cases
Sarcoidosis triad: bilateral hilar adenopathy, arthralgia, erythema nodosum
Treat CNS and ocular complications with steroids.
Get pulmonary consult
A slaughterhouse worker presents looking ill, diaphoretic, and febrile. He experienced sudden onset of shaking chills, high fever, myalgias, severe headache, and a nonproductive cough. Chest findings are minimal. Hepatomegaly is present.
What is the most likely diagnosis?
Q fever pneumonia
Caused by coxiella burnetii
Found in cattle, sheep and goats
Abrupt onset, looks ill, febrile, diaphoretic
Causes hepatomegaly with transaminitis but without elevations in bilirubin or jaundice
Doxycycline first line treatment
A 54 year old man presents with acute dyspnea and hypoxia. He is intubated for his respiratory distress. His post-intubation X-ray shows bilateral infiltrates. on 40% FiO2 his PaO2 is 100. He has no history of heart failure.
What settings would you start on the ventilator for this patient?
Low tidal volume ventilation
Patients with ARDS have improved mortality when low tidal volume ventilation is started at 6 ml/kg ideal body weight. This is based on the patients height.
Also consider relatively high PEEP and high respiratory rate to make up for tidal volume loss
A 2 year old girl presents with her mother to the emergency department. The patient states that her daughter has had difficulty breathing an da fever over the last few days. Upon physical examination, the child has labored breathing, inspiratory stridor, and a barking cough. Auscultation of the lungs revels a high-pitched sound over the trachea. What is the most likely diagnosis and what is the most likely radiographic finding?
Croup
Steeple sign
