Ep 124: A 64-Year-Old with Worsening Dyspnea and Cough

This episode discusses a 64-year-old man who develops acute respiratory symptoms while climbing Mt. Kilamanjaro. The discussion focuses on the likely diagnosis, pathophysiology and treatment.

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 124: 

a 64-year-old with 

worsening dyspnea and cough. 

Cathy, today, I'm taking you out 

of the hospital and the clinic, 

and I'm utilizing your medical 

knowledge in the field. 

[Dr. Handy] Ah, let's see how this goes. 

[Dr. Wiener] I know you're 

an avid outdoorswoman. 

As a celebration of an 

important life event, 

you join an expedition going to the summit 

of Mount Kilimanjaro. 

One of the group members is Gene, 

a 64-year-old well-trained man 

with a past history 

only for hyperlipidemia. 

His only medication is atorvastatin. 

Your group entered the park 

and is in the first night 

of camping at 3,000 meters, 

or about 9,800 feet. 

On day two of your 

ascent, at 4,000 meters, 

Gene begins having some worsening dyspnea, 

then develops a worsening 

cough that's blood-tinged. 

Fortunately, you have your stethoscope. 

[Dr. Handy chuckles] 

Obviously, I'd never leave 

home without it, although I don't know 

that I would've been 

summiting Mount Kilimanjaro. 

[Dr. Wiener] Okay, well, you 

did bring your stethoscope 

in this case, and when you listen, 

you hear inspiratory crackles. 

Amazingly, you also brought 

your point-of-care ultrasound 

and you see about 25 comet 

tails on lung imaging. 

[Dr. Handy] Glad I was really 

prepared for this hike. 

Gene sounds sick. 

I will recall that 15 to 30 

comet tails on ultrasound 

is a sign of moderate excess 

extravascular lung water 

or pulmonary edema. 

[Dr. Wiener] Okay, so that's 

going to lead us to the question. 

The question is asking, 

which of the following diagnoses 

is he most likely suffering from? 

And the options are A. 

acute mountain sickness; 

B. acute myocardial infarction; 

C. decompression sickness; 

D. high-altitude pulmonary edema; 

or E. a pulmonary embolism. 

[Dr. Handy] All right, we're 

talking about altitude illness here. 

[Dr. Wiener] So, I know 

the summit of Kilimanjaro 

is almost 6,000 meters 

or around 20,000 feet, 

but what are we talking about 

when you say altitude illness? 

[Dr. Handy] Altitude 

illness is likely to occur 

above 2,500 meters or 8,000 feet, 

but it's been documented at lower altitude 

at even 1,500 meters or 5,000 feet. 

The unifying mechanism 

is hypobaric hypoxia, 

and altitude illness may be 

exacerbated by dehydration 

or severe respiratory alkalosis. 

[Dr. Wiener] Okay, so we're 

talking about altitudes 

that are common here even 

in the United States, 

but many groups live their 

entire lives at altitude. 

Do they have any genetic 

advantage over us, low-landers? 

[Dr. Handy] Yeah, 

hypoxia-inducible factor, 

which acts as a master switch 

in high-altitude adaptation, 

controls transcriptional 

responses to hypoxia 

throughout the body, and 

it's involved in the release 

of vascular endothelial growth 

factor, VEGF, in the brain, 

erythropoiesis, 

and other pulmonary and cardiac 

functions at high altitudes. 

In particular, the gene EPAS1, 

which codes for 

hypoxia-inducible factor 2-alpha 

appears to play an important 

role in the adaptation 

of Tibetans living at high altitude, 

resulting in lower 

hemoglobin concentrations 

than are found in Han Chinese 

or South American highlanders. 

Other genes implicated 

include EGLN1 and PPARA, 

which are also associated 

with hemoglobin concentration. 

Some evidence indicates 

that these genetic changes 

occurred within the past 3,000 years, 

which is very fast in evolutionary terms. 

An intriguing question is whether 

the Sherpas' well-known 

mountain-climbing ability 

is partially attributed 

to their Tibetan ancestry 

with overrepresentation of 

variance of the EPAS gene. 

[Dr. Wiener] Thank you for 

mentioning hypoxia-induced factor. 

You know that is my favorite 

transcription factor- 

[Dr. Handy chuckles] 

[Dr. Wiener] -but what 

about our patient, Gene, 

not the genes in the Sherpas? 

What's going on with him? 

[Dr. Handy] So he is 

most likely developing 

high-altitude pulmonary edema or HAPE, 

so the answer is D. 

He has pulmonary edema on exam 

with my stethoscope and 

ultrasound, which I took hiking, 

and he could be having an 

acute MI with cardiac failure, 

but I think that HAPE is more likely. 

[Dr. Wiener] One of the other options is 

acute mountain sickness. What's that? 

[Dr. Handy] Acute mountain sickness 

is actually the most common 

of the altitude illnesses. 

It's a neurologic syndrome 

characterized by non-specific symptoms, 

such as headache, nausea, 

fatigue, and dizziness. 

It typically develops 6-12 hours 

after ascent to an altitude, 

and it's a clinical diagnosis. 

Now, it must be distinguished 

from just exhaustion, 

dehydration, hypothermia, 

and alcoholic hangover, and hyponatremia. 

At the other end of 

the neurologic spectrum 

of acute mountain sickness is 

high-altitude cerebral edema, 

which is an encephalopathy 

whose hallmarks are ataxia 

and altered consciousness with 

diffuse cerebral involvement, 

but generally without 

focal neurologic deficits. 

So, that's obviously a medical emergency. 

[Dr. Wiener] And tell me a little bit more 

about high-altitude 

pulmonary edema or HAPE. 

[Dr. Handy] So, unlike 

high-altitude cerebral edema, 

HAPE, which is the pulmonary edema, 

is primarily a pulmonary problem 

and therefore is not necessarily preceded 

by acute mountain sickness. 

It develops within 2-4 days 

after arrival at high altitude, 

and it rarely occurs 

after four or five days 

at the same altitude, 

probably because of 

remodeling and adaptation 

that render the pulmonary vasculature 

less susceptible to 

the effects of hypoxia. 

A rapid rate of ascent, a history of HAPE, 

respiratory tract infections, 

and cold environmental 

temperatures are risk factors, 

and men seem to be more 

susceptible than women. 

[Dr. Wiener] What's the 

pathophysiology of HAPE? 

Why does it happen? 

[Dr. Handy] So, it's a 

non-cardiogenic pulmonary edema 

with normal pulmonary 

artery wedge pressure. 

It's characterized by patchy 

pulmonary hypoxic vasoconstriction 

and that leads to 

overperfusion in some areas. 

This abnormality leads to 

capillary stress failure. 

The exact mechanism for this 

hypoxic vasoconstriction 

is not known. 

It can happen to any climber, 

but people with abnormalities 

of the cardiopulmonary 

circulation leading to 

pulmonary hypertension 

- so examples of that 

would be mitral stenosis, 

or primary pulmonary hypertension, 

or unilateral absence of 

the pulmonary artery - 

they can be at increased risk of HAPE, 

even at moderate altitudes. 

And it's also a clinical emergency, 

so should not go untreated. 

[Dr. Wiener] And what are 

the clinical findings? 

You mentioned that you've found it 

on your stethoscope and 

your POCUS, but what else? 

[Dr. Handy] The initial manifestation 

may be a reduction in exercise tolerance 

greater than what would be 

expected at that given altitude. 

Although a dry, persistent 

cough may precede HAPE, and may 

be followed by the production 

of blood-tinged sputum, 

cough in the mountains is almost universal 

and the mechanism is poorly understood. 

Tachypnea and tachycardia, even at rest, 

are important markers 

as illness progresses. 

Crackles can be heard on auscultation 

but are not diagnostic. 

Point-of-care ultrasound 

findings of comet tails, 

which are consistent with pulmonary edema, 

that has been useful in 

detecting subclinical 

or clinical HAPE. 

[Dr. Wiener] Okay, well, before we finish, 

tell me why pulmonary embolism 

and decompression illness 

were not viable answers for you. 

[Dr. Handy] Well, you can never 

rule out pulmonary embolism, 

and it's true there is some 

hemoconcentration at altitude, 

but given his activity and the 

presence of the pulmonary edema, 

that led me away from PE. 

Decompression illness is the 

medical term for the bends, 

which are seen in hyperbaric 

or diving condition. 

Maybe we'll talk about 

that in a future episode. 

[Dr. Wiener] The teaching 

point in this case is that 

altitude illness runs a spectrum 

from acute mountain sickness 

to high-altitude cerebral edema. 

High-altitude pulmonary edema or HAPE, 

is a distinct clinical entity from those. 

HAPE is a medical emergency 

that requires descent 

and the administration of oxygen quickly. 

[Dr. Handy] Check out this 

question and questions like this 

on Harrison's Review Questions, 

or you can read more about this 

in the chapter on altitude illness. 

[Dr. Wiener] Maybe we should do a 

future episode on the treatment. 

[Dr. Handy] Stay tuned. 

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. 

[upbeat outro music]