Wednesday, December 6, 2000

9:30am – 11:30AM 

CASE NO. 1

CHIEF COMPLAINT: Cough and fever for four days

HISTORY: Mr. Alcot is a 68 year old man who developed a harsh, productive cough four days prior to being seen by a physician. The sputum is thick and yellow with streaks of blood. He developed a fever, shaking, chills and malaise along with the cough. One day ago he developed pain in his right chest that intensifies with inspiration. The patient lost 15 lbs. over the past few months but claims he did not lose his appetite. "I just thought I had the flu." Past history reveals that he had a chronic smoker's cough for "10 or 15 years" which he describes as being mild, non-productive and occurring most often in the early morning. He smoked 2 packs of cigarettes per day for the past 50 years. The patient is a retired truck driver who has been treated for mild hypertension, bronchitis, appendicitis (as a young adult), hemorrhoids and a fractured femur and splenic injury. (motorcycle accident).

PHYSICAL EXAMINATION: The patient is an elderly man who appears tired haggard and underweight. His complexion is sallow. He coughs continuously. Sitting in a chair, he leans to his right side, holding his right chest with his left arm. Vital signs are as follows: blood pressure 152/90, apical heart rate 112/minute and regular, respiratory rate 24/minute and somewhat labored, temperature 102.6°F. Examination of the neck reveals a large, non-tender hard lymph node in the right supraclavicular fossa. Both lungs are resonant by percussion with one exception: the right mid-anterior and right mid-lateral lung fields are dull. Auscultation reveals bilateral diminished vesicular breath sounds. Bronchial breath sounds, rhonchi and late inspiratory crackles (are heard) in the area of the right mid-anterior and right mid-lateral lung fields. The remainder of the lung fields is clear. Percussion and auscultation of the heart reveals no significant abnormality. Examination of the fingers shows clubbing.

LABORATORY: WBC 17,000/mm3; neutrophils 70%, bands 15%, lymphocytes 15%.

COURSE OF ILLNESS: Following a chest x-ray PA view and lateral , which revealed an acute pneumonia in the right middle lobe, the patient was treated with antibiotics as an outpatient. During the 10 days of treatment the patient's fever abated and he felt somewhat better. A post-treatment (follow up) chest x-ray reveals a right hilar mass. Sputum cytology demonstrates atypical cells.

1.Identify the problems from the history.

 

 

 

 

2. Identify and explain the significance of physical findings.

 

 

 

 

 

3. Review the lab findings. What is your diagnosis?

 

 

 

 

 

 

4. What do you understand by the terms "hospital acquired" and "community acquired " pneumonia.? Which type of pneumonia does our patient have?

Oropharyngeal colonization is different in the community and hospital setting. This makes a difference in the etiology of pneumonia. This patient has community acquired pneumonia.

 

 

 

 

 

5. What organisms are likely to be causing his pneumonia?

The patient has community-acquired pneumonia.

The most common organisms are

 

 

 

 

 

 

6. List the various host factors, or conditions which predispose a patient to developing pneumonia. What host factors may have predisposed this patient to pneumonia?

Healthy adults have intact pulmonary clearance mechanisms that remove aspirated secretions.

Damaged clearance mechanisms 

 Systemic defects 

Inability to mount an antibody response

Mr. Alcot has the following predisposing factors.

 

 

 

 

 

7. Explain the pathogenesis of pneumococcal pneumonia? What virulence factors are important? What pathologic changes are produced in the lungs because of pneumonia?

S. pneumoniae lives in the nasopharynx, and can be cultured in 5-10% healthy adults, 20-40% children. Nearly all infants are colonized at some point in the first two years of life. In epidemics involving a closed population, 5-10% of all persons carry the epidemic strain.

The major virulence factor is the

 

 

 

 

 

 

 

 

8. How is the specific diagnosis established? What is the primary disadvantage to the examination of expectorated sputum? Describe characteristic morphology/growth of S. pneumoniae.

S. pneumoniae are gram positive diplococci which produce alpha hemolytic colonies on blood agar. It is distinguished from viridans streptococcus by susceptibility to Optochin and by bile solubility.

 

 

 

 

 

 

9. What antimicrobial agents would you prescribe for this patient? Would you use or avoid penicillin, and why? What is the duration of treatment?

The length of treatment will vary with the severity of illness and the presence of underlying disease. 

 

 

 

 

 

 

 

10. What is the mechanism of pneumococcal resistance to penicillin?

 

 

 

 

 

 

11. What are the complications of Pneumococcal pneumonia?

 

 

 

 

 

 

12. Is prevention possible?

Pneumococcal vaccine containing capsular polysaccharide from the 23 serotypes that most commonly cause infection is available.

Mr. Alcot’s enlarged supraclavicular lymph node represents a metastasis (Virchow’s node).

 

 

 

 

A 15 year old female with a history of hay fever develops fever, headache and malaise for 4 days followed by a nonproductive cough and scratchy throat. Despite chicken soup and orange juice, the cough and fever persist, and her mother drags her to your office. On examination, her temperature is 101°, pulse 90 beats/min, BP 110/70, respiratory rate 20 beats/min Physical examination is unremarkable except for scattered rales over the left lower lung, and small bullae in her left tympanic membrane. Chest x-ray reveals a patchy left lower lobe infiltrate. At your request, she makes a heroic effort but is unable to produce sputum

 

 

1. What is the  type of pneumonia this patient is likely to have? 

Atypical pneumonia.

 

 

 

 

 

 

2. What is "atypical pneumonia"?

The term "atypical pneumonia" is applied to non-lobar patchy or interstitial infiltrates on chest x-ray where the causative organism is not identified on gram stain or culture of sputum.

Often they are not toxic, do not have shivers and do not seek medical attention. "Walking Pneumonia"

 

 

 

 

 

3. What is the differential diagnosis of atypical pneumonia?

The pathogens causing atypical pneumonia include 

 

 

 

 

 

 

4. What is the most likely organism in this patient and why?

Mycoplasma pneumoniae

Many of the agents listed above could be responsible for this patient’s pneumonia. Features pointing to Mycoplasma include her 

 

 

 

 

 

5. Describe Mycoplasma pneumoniae.

 

 

 

 

 

 

6. What is the pathogenesis of infection produced by these agents? What pathologic changes are produced in the lungs?

Other pathogens producing atypical pneumonia produce similar pathologic changes.

 

 

 

 

7. How does immunity to Mycoplasma pneumonias develop ? Is reinfection possible?

 

 

 

8. How is the diagnosis established in atypical pneumonia?

Definitive diagnosis is made by isolation of the organism or demonstration of an antibody response. 

Antigen detection and culture of sputum for specific pathogens helps establish the diagnosis in other cases of atypical pneumonia. Serology is useful but acute convalescent titers are needed. 

 

 

 

 

 

9. What antimicrobial agent(s) would you use ?

 

 

 

 

 

 

10. You start the patient on Erythromycin. If he is taking antihistamines, what drug interaction might occur?

 

 

 

CASE NO. 3

A 35 year alcoholic male with a history of seizures is admitted with a three week history of fever, generalized weakness, poor appetite, and cough productive of green, foul - smelling sputum. On physical examination, the temperature is 100.3 degrees P. pulse is 96 beats per minute, respiratory rate is 20 breaths per minute, and BP is 120/80 mm. There are many missing teeth with gingivitis and dental caries. He has rales and decreased breath sounds over the right base. Chest x-ray shows consolidation in the superior segment of the right lower lobe. 

 

 

1. What type of infection is suggested by his foul smelling sputum?

Anaerobic infection.

 

 

 

 

 

 

 

 

2. What organisms could be responsible for this patient's pneumonia?

Many of the infections are polymicrobial. 

Anaerobic bacteria are found in 60% to 85% of the cases.

50% of patients have only anaerobic organisms, while the other 50% have a combination of aerobic and anaerobic organisms with and anaerobic predominance.

Anaerobes that are frequently found include:

Aerobes that my be found in predominant anaerobic infection include:

 

 

 

 

 

 

3. Does a normal person aspirate?

50% of healthy persons aspirate during sleep, usually goes unrecognized, and has few sequelae.

 

 

 

 

 

 

 

4. What then determines who gets infection?

The frequency, volume, and character of the aspirated material will determine whether or not a pulmonary infection will develop.

 

 

 

 

 

 

5.  What are the other predisposing factors for aspiration? What factor/s predisposed this patient to aspirate?

Factors associated with increased frequency of aspiration include.

His alcoholism and seizures probably are the predisposing factors for him. Gingivitis and caries provided a bigger bacterial inoculum for aspiration.

 

 

 

 

 

 

6. Describe the pathogenesis of this pneumonia.

 

 

 

 

 

 

7. What are the common sites for aspiration lung abscess and why ?

The superior segments of RLL, LLL and axillary subsegments of anterior and posterior segments of RUL are common sites for aspiration and will account for 85% of all Lung abscesses. 

Gravitational forces determine the site of aspiration. Position of the patient at the time of aspiration determines the segment the aspiration is most likely to occur. 

 

 

 

 

 

8. What is the normal clinical picture of lung abscess? Does this patient fit that clinical picture?

Most of the patients present with sub acute onset of illness and do not seek medical attention for three to four weeks since the onset of illness. 
Patients complain of cough, low grade fever, anorexia and weight loss of few weeks duration . 
Patients often have cough with large amounts of foul smelling sputum. 
Lack of foul smell does not exclude lung abscess, as 50% of anaerobic infections do not produce a foul smell. 

Our patient has the typical clinical picture.

 

 

 

 

 

 

9. Are there other routes besides aspiration by which anaerobes can reach lungs?

Less common mechanisms by which anaerobic bacteria reach the lung include:

 

 

 

 

 

 

10. What complications are associated with this infection?

If aspiration pneumonia goes untreated, progressive tissue necrosis may ensue. This results in

 

 

 

 

 

 

11. How would you treat this patient?

 

 

 

 

 

 

 

12. What organisms might be the cause of a hospital acquired aspiration pneumonia?

Patients with nosocomial aspiration pneumonia are more likely to have a mixed aerobic-anaerobic infection, in which the aerobic component (gram-negative bacilli) predominates.

Aerobic organisms:

Anaerobic organisms:

Antibiotics