Ep 126: A 60-Year-Old with Fever, Purulent Sputum, and Chest Pain

This episode presents a 60-year-old man with acute respiratory symptoms and a cavitary lesion on chest CT. The discussion focuses on the likely etiology and appropriate therapy.

Transcript

[upbeat intro music]

[Dr. Handy] Hi, everyone. Welcome

back to Harrison's Podclass.

We're your co-hosts. I'm Dr. Cathy Handy.

[Dr. Wiener] And I'm Dr.

Charlie Wiener and we're joining

you from the Johns Hopkins

School of Medicine.

[music continues]

Welcome to episode 126:

a 60-year-old with fever,

purulent sputum, and chest pain.

Hi, Cathy. Today's patient

is a 60-year-old man

with a past medical history of alcohol use

who presents with 10 days of fever,

cough productive of purulent sputum

and right-sided pleuritic chest pain.

On physical examination,

the patient's cachectic,

and he appears short of breath.

His temperature's 38 degrees Celsius,

his blood pressure is 107/72,

his respiratory rate is 18 per minute,

his heart rate's 95,

and his oxygen saturation

on room air is 86%.

He has multiple oral caries.

His lungs show distant

breath sounds throughout,

and cavernous breath sounds are noted

on the right lower lobe area.

[Dr. Handy] Okay, so we

have a chronically ill man

with an acute febrile respiratory illness.

Let's discuss a few notable things

on his physical examination.

You point out the poor dentition,

which can contribute to his

risk of respiratory infections.

I'm also concerned with

his pleuritic chest pain,

which suggests that there is

some pleural inflammation,

and I'd be worried about an effusion.

He's also hypoxic, so we do

need to put him on oxygen.

[Dr. Wiener] Okay, so his

oxygen saturation increases

to 93% on nasal oxygen.

I mentioned cavernous breath sounds.

You want to talk a little bit about those?

[Dr. Handy] Yeah, so they

are what they sound like,

low-pitched blowing sounds

as if you're hearing air move in a cavern.

They're also called amphoric.

[Dr. Wiener] Are they specific

to any lung pathology?

[Dr. Handy] They typically arise

when there's a large

non-functional airspace

that is in proximity to the chest wall

likely transmitting sounds

from the larger airways.

So you can hear them in lung abscesses

or if there are large blebs or cysts

or extensive bronchiectasis.

Can we do some imaging of his chest?

[Dr. Wiener] Sure. He

receives a contrast chest CT,

which shows no pulmonary embolism,

but does show a large

seven-centimeter cavity

in the posterior right upper lobe

with an air/fluid level and

adjacent pleural thickening.

There's also some scattered consolidation

in the right lower lobe.

There's no notable pleural effusion though

and the left lung is clear.

It has no infiltrate.

[Dr. Handy] Okay, given his

history and these findings,

we most likely have a

primary lung abscess.

It's reassuring that there's

no effusion or empyema.

What's the question?

[Dr. Wiener] It's a therapy

question. The question asks,

which of the following

therapies should you initiate?

And the options are A.

ampicillin-sulbactam;

B. cefepime;

C. metronidazole;

D. rifampin, isoniazid,

pyrimethamine, and ethambutol;

or E. vancomycin.

[Dr. Handy] The answer is

A. ampicillin-sulbactam.

That's the best initial therapy

for a presumed primary lung abscess.

Primary lung abscesses

are thought to originate

when chiefly anaerobic bacteria

and microaerophilic streptococci

in the gingival crevices

are aspirated into the lung parenchyma

in a susceptible host.

Pneumonitis develops initially,

exacerbated in part by tissue

damage caused by gastric acid,

and then over a period of

about one to two weeks,

the anaerobic bacteria produce

parenchymal necrosis and cavitation

whose extent depends on

host-pathogen interaction.

Anaerobes are thought to

produce more extensive tissue

necrosis in polymicrobial infections

in which virulence factors of

the various bacteria can act

synergistically to cause more

significant tissue destruction.

Primary lung abscesses

are typically indolent,

as in this patient, with

symptoms for many days

or even a few weeks before presentation.

[Dr. Wiener] You mentioned

susceptible hosts.

And do you want to

comment on the location?

This one's in the

posterior right upper lobe.

Is that typical?

[Dr. Handy] As I mentioned,

patients with poor dentition

or gingival disease have greater

levels of oral colonization

with the anaerobes and

microaerophilic streptococci.

Combine that with loss of consciousness

and loss of protection of the airways,

such as in intoxication or seizures,

and you have a susceptible host.

As far as location, since most

aspiration events take place

when the patient is supine,

the usual areas for

development of lung abscess

are the most dependent lung regions,

specifically, the superior

segment of the right lower lobe,

the posterior segment

of the right upper lobe,

and the posterior segment

of the left lower lobe.

The right lung is more frequently affected

because the left mainstem

bronchus takes off

at a more acute angle from the carina.

[Dr. Wiener] Okay, so we already

discussed the antibiotics.

Let's discuss that part a little bit more.

[Dr. Handy] Primary lung abscesses

are typically polymicrobial with organisms

and the microaerophilic

streptococci predominating.

The recommended regimens are clindamycin

or an IV-administered

beta-lactam/beta-lactamase combination,

followed, once the patient's

condition is stable,

by orally administered

amoxicillin-clavulanate.

However, as clindamycin is associated

with a high risk of C.

difficile infection, that's why

this question is advocating

using ampicillin-sulbactam.

And this therapy should be continued

until imaging demonstrates that

the lung abscess has cleared

or regressed to a small scar.

So treatment duration may

range from three to four weeks

to as long as 14 weeks.

[Dr. Wiener] Do you want to go

through the other choices briefly?

[Dr. Handy] Well, option B. was cefepime,

which does not cover anaerobes

and we're not really worried

about a pseudomonal infection,

which is what cefepime would add.

Now, Pseudomonas can absolutely cause

a necrotizing lung infection,

but that would be a consideration

in a different host.

[Dr. Wiener] Option C. was metronidazole

and that has activity

for anaerobes, right?

[Dr. Handy] Yes, but

metronidazole is not effective

in this type of polymicrobial infection.

Studies have demonstrated

a high failure rate

for metronidazole when used

to treat lung abscesses.

[Dr. Wiener] Option D.

is the initial therapy

for non-resistant tuberculosis, right?

[Dr. Handy] Yes, while tuberculosis

can cause a cavitating lung infection,

it's typically in the upper lobes

and, given the history, is

far less likely in this case.

[Dr. Wiener] And finally, vancomycin?

Staph can cause lung abscesses, right?

[Dr. Handy] Yes, Staph aureus is common,

possibly the most common cause

of secondary lung abscesses

due to bacteremia. They're often multiple

due to the systemic spread into the lungs.

This patient does not seem to

have a fulminant presentation

consistent with Staph aureus infection.

Also, vancomycin has poor

coverage of anaerobic organisms

so that would be a poor choice here.

[Dr. Wiener] Great. The

teaching points in this case

are that this patient presents

with a primary lung abscess

probably related to his susceptibility

as someone who is often intoxicated

and has bad oral dentition.

Primary lung abscesses are

typically polymicrobial

infections that predominate with anaerobes

and the best initial therapy

targets those organisms.

[Dr. Handy] So you can find

this question and more questions

like it on Harrison's Review Questions

and read more about this topic

in the Harrison's chapter

on lung abscesses.

Visit the show notes for

links to helpful resources,

including related chapters

and review questions from Harrison's.

And thank you so much for listening.

If you enjoyed this episode,

please leave us a review

so we can reach more

listeners just like you.

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