Acute altitude illnesses

This summary is based on a recent BMJ review:

Acute altitude illnesses include:

- high altitude headache
- acute mountain sickness
- high altitude cerebral edema
- high altitude pulmonary edema

Typical scenarios in which such illness occurs include:

- a family trek to Everest base camp in Nepal (5,360 m)
- a fund raising climb of Mount Kilimanjaro (5,895 m), shown in the map below
- a tourist visit to Machu Picchu (2,430 m)


View Larger Map

High altitude headache and acute mountain sickness often occur a few hours after arrival at altitudes over 3,000 meters.

Occurrence of acute mountain sickness is reduced by slow ascent. Severity can be modified by prophylactic acetazolamide.

Mild to moderate acute mountain sickness usually resolves with:

- rest
- hydration
- halting ascent
- analgesics

Occasionally people with acute mountain sickness develop high altitude cerebral oedema with confusion, ataxia, persistent headache, and vomiting.

Severe acute mountain sickness and high altitude cerebral edema require urgent treatment with:

- oxygen if available
- dexamethasone
- possibly acetazolamide
- rapid descent

High altitude pulmonary edema is a rare but potentially life threatening condition that occurs 1-4 days after arrival at altitudes above 2,500 meters. Treatment includes oxygen if available, nifedipine, and rapid descent to lower altitude.

What do extreme athletes who can summit the peaks of Mt. Everest have in common with people with heart failure? This Mayo Clinic video explains it:



References:

Clinical Review: Acute altitude illnesses. BMJ 2011; 343:d4943 doi: 10.1136/bmj.d4943

Road office in a box (video)

An “office in a box briefcase, with a place for everything and everything in its place". Check it out, by ePatient Dave:

Worldwide number of new TB cases is higher than any other time in history

From the 2011 Lancet review:

The worldwide number of new TB cases is more than 9 million - higher than at any other time in history.



22 low-income and middle-income countries account for more than 80% of the active cases in the world.



Due to the devastating effect of HIV on susceptibility to TB, sub-Saharan Africa has been disproportionately affected and accounts for 4 of every 5 cases of HIV-associated tuberculosis.



Management problems include:



- In highly endemic areas, TB diagnosis continues to rely on century-old sputum microscopy



- No vaccine with adequate effectiveness (although BCG works to some extent). According to a recent report, BCG vaccination not only protects against tuberculosis but the number needed to treat (NNT) is 11.



- TB treatment regimens are protracted and have a risk of toxic effects



- Increasing rates of drug-resistant tuberculosis in eastern Europe, Asia, and sub-Saharan Africa

Promising progress includes improved tuberculosis diagnostics with biomarkers of disease activity. New and improved drugs, biomarkers, and vaccines need to be developed.

Diagnosing tuberculosis with cytokines IL-15, IL-10 and MCP-1, in addition to interferon-gamma

A pattern of two cytokines, called MCP-1 and IL-15, was reasonably good at differentiating between persons sick with TB and persons infected but not sick.

Monocyte chemotactic protein-1 (MCP-1) is a small cytokine belonging to the CC chemokine family. According to the new nomenclature, MCP-1 is called chemokine (C-C motif) ligand 2 (CCL2).

A third cytokine called IP-10 also showed promise at differentiating between people who are infected and those who are not.

Interferon gamma-induced protein 10 kDa (IP-10) is also known as C-X-C motif chemokine 10 (CXCL10). It belongs to the CXC chemokine family.

These 3 cytokines could form the basis of a new test to quickly detect whether tuberculosis is dormant or active and infectious.

52 chemokines from 4 families have been described. They interact with 20 receptors (click here for a larger image).

References:



Tuberculosis. Stephen D Lawn MRCP, Prof Alimuddin I Zumla FRCP. The Lancet, Volume 378, Issue 9785, Pages 57 - 72, 2 July 2011.

Immune system could be used to test for TB. Reuters.

Immunology Made Simple: "What are These People Talking About?"

Cytokines

Xpert MTB/RIF is a rapid diagnostic test for tuberculosis with high sensitivity (90%) and specificity (99%). Lancet, 2011.

Image source: PPD, CDC, public domain.

Comments from Twitter:

@sdietrich17: How discouraging. We just keep going backwards with so many infectious diseases...

A microscopic look at hotel hygiene makes a microbiologist travel with an impervious mattress cover

From CNN:

The microbiologist Philip Tierno doesn't feel comfortable staying in hotels. He knows too much. He travels with an impervious mattress and pillow cover to protect against the unseen debris that guests leave behind. When humans sleep they shed about 1.5 million cells an hour.

While the covers were developed for allergy sufferers, Tierno encourages everyone to use them at home and on the road.

And definitely ditch the bedspread, he advises. Hotel bedspreads became a hot topic when one featuring bodily fluids from several sources was introduced in boxer Mike Tyson's 1992 rape trial.


How hotels clean drinking glasses

An Atlanta TV station used hidden cameras to monitor how the drinking glasses in hotel rooms were cleaned. In one case, a housekeeper appeared to clean a toilet and the glasses wearing the same gloves. In multiple hotels, the glasses were rinsed in the sink and dried for the next guests, in violation of health codes.

The Health Magazine lists the 12 germiest places in America or the so called "dirty dozen":

1. Kitchen sink
2. Airplane bathroom
3. A load of wet laundry
4. Public drinking fountain
5. Shopping cart handle
6. ATM buttons
7. Playgrounds
8. Bathtub
9. Office phone
10. Hotel-room remote
    
    

References:
A microscopic look at hotel hygiene, CNN, 2011.

Low risk of transmission of influenza on the plane: 3.5% if sitting within 2 rows of infected passengers

This BMJ study assessed the risk of transmission of pandemic A/H1N1 2009 influenza (pandemic A/H1N1) from an infected high school group to other passengers on an airline flight and the effectiveness of screening and follow-up of exposed passengers.

The design was a retrospective cohort investigation using a questionnaire administered to passengers and laboratory investigation of those with symptoms.

The setting was in Auckland, New Zealand, with national and international follow-up of passengers. The participants were passengers seated in the rear section of a Boeing 747-400 long haul flight that arrived on 25 April 2009, including a group of 24 students and teachers and 97 (out of 102) other passengers in the same section of the plane who agreed to be interviewed.

9 members of the school group were laboratory confirmed cases of pandemic A/H1N1 infection and had symptoms during the flight. Two other passengers developed confirmed pandemic A/H1N1 infection. Their seating was within two rows of infected passengers, implying a risk of infection of about 3.5% for the 57 passengers in those rows.

A low but measurable risk of transmission of pandemic A/H1N1 exists during modern commercial air travel. This risk is concentrated close to infected passengers with symptoms.

Video: "How to Sneeze" Demonstrated by the U.S. Health and Human Services Secretary Kathleen Sebelius. She shows NBC’s Chuck Todd the “Elmo way” to sneeze.

Don't forget to get your influenza immunization (flu shot or spray) this season. The CDC video embedded below clearly explains why this is extremely important.


CDC video: Why Flu Vaccination Matters: Personal Stories from Families Affected by Flu.

References:

Transmission of pandemic A/H1N1 2009 influenza on passenger aircraft: retrospective cohort study. BMJ 2010; 340:c2424 doi: 10.1136/bmj.c2424 (Published 21 May 2010).

Diagram of influenza virus nomenclature. Image source: Wikipedia, GNU Free Documentation License.

In-flight exercises help during plane travel

Prolonged immobilization can cause circulatory stasis which is one of the predisposing factors for DVT described by Virchow in his famous triad: endothelial injury, stasis and hypercoagulability.

In a trial of previously healthy patients who traveled at least 8 hours per flight (median duration 24 hours), duplex ultrasound showed an asymptomatic DVT in 10 % of participants. In other studies, the reported risk of symptomatic DVT after flights of more than 12 hours was 0.5%. According to a 2006 Lancet study, activation of coagulation occurs in some individuals after an 8-hour flight.

This Chicago Tribune article lists some useful in-flight exercises:

In-flight exercises for beginners

- Shoulder shrugs, shoulder rolls. Ten each.
- Short sets of bending and straightening the elbows and knees.
- Walk through the plane every two hours.
- March your knees up and down in your seat.
- Lift and lower your feet on tiptoes to work the calves.

Advanced In-flight exercises

- Neck stretches; hold on each side for 15 to 20 seconds.
- If you can find space (near an exit), work the core with yoga stretches. Pigeon pose — an intermediate move of folding one leg under the body while stretching the back leg out — is an in-flight favorite of hers.
- In your seat, lift your arms over your head, grip your hands together and lean from side to side for a few seconds on each side. Repeat.
- Walk the length of the plane every hour, incorporating deep lunges. Unless you want air marshals on your case, it might be wise to notify a flight attendant.
- Put a small flight pillow in small of back to keep posture upright.

References:
Midair exercise makes for happier landings. Chicago Tribune, 10/2010.

Prolonged immobilization increases risk of DVT -- how do you define prolonged immobilization?

"Avoiding Airport Germs and Healthy Plane Travel Tips" by WebMD http://goo.gl/rLO2h

The risk of VTE (blood clots) is 3 times higher in passengers on long-distance flights than in the general population http://goo.gl/Tk45Z
Exercises for air travel — Cleveland Clinic Journal of Medicine, 2011.

Will Airplane Air Make Me Sick? No, but proximity to the other passengers very well might. WebMD, 2011.

Australian grandmother beats off attacking shark - BBC

From BBC:

"An Australian grandmother has survived a shark attack by repeatedly punching and kicking the animal after it "ripped off" part of her body.

Surgeon Mark Flanagan said: "We can estimate that she lost about 40 per cent of her blood volume from the degree of shock that she had when she came in, and the fact that we required to give her several units of blood."

Mrs Trumbull said she was happy to be alive."


Shark Tunnel and Aquarium at Omaha Zoo, Nebraska.

Health experts' tips for safe international travel

CDC video: Health experts suggest that you take several key steps to be protected against injury or illness when travelling to developing nations. This includes packing a health kit, bringing medications, and getting immunizations for safe and healthy travel.

Distracted Walking: Using a Cell Phone and Walking Is Risky

From the NYTimes:

"Distracted driving has gained much attention lately because of the inflated crash risk posed by drivers using cellphones to talk and text.

But phones aren't just distracting drivers; they make pedestrians inattentive too.

Distracted walking combines a pedestrian, an electronic device and an unseen crack in the sidewalk, the pole of a stop sign, a toy left on the living room floor or a parked (or sometimes moving) car.

Examples include a 16-year-old boy who walked into a telephone pole while texting and suffered a concussion; a 28-year-old man who tripped and fractured a finger on the hand gripping his cellphone; and a 68-year-old man who fell off the porch while talking on a cellphone, spraining a thumb and an ankle and causing dizziness."





References:
Forget Gum. Walking and Using Phone Is Risky. NYTimes.
Video: Stop texting while driving. Terrifying. All drivers should watch this.

Image source: OpenClipArt.org, public domain.

AT&T Don't Text While Driving Documentary (video).

African trypanosomiasis - killer coma - the evolving story of sleeping sickness (Lancet review)

Human African trypanosomiasis (sleeping sickness) occurs in sub-Saharan Africa. It is caused by the protozoan parasite Trypanosoma brucei, transmitted by tsetse flies.

With 12,000 cases of this disabling and fatal disease reported per year, trypanosomiasis belongs to the most neglected tropical diseases.

Life cycle of the Trypanosoma brucei parasites. Source: CDC, Wikipedia, public domain.

The clinical presentation is complex, and diagnosis and treatment difficult. The available drugs are old, complicated to administer, and can cause severe adverse reactions.

Imagine a disease that starts with a fly's bite and ends in death. The first stage of this disease causes non-specific symptoms such as itching and joint pains. If left untreated, it progresses to the second stage weeks, months, or even years later in which the affected person displays dramatic neurological and psychiatric symptoms before slipping into a fatal coma.

New diagnostic methods and safe and effective drugs are urgently needed. There is no field-friendly diagnostic test.  Until recently, the most effective treatment for the second stage as almost as dangerous as the disease.

Vector control, to reduce the number of flies in existing foci, needs to be organised on a pan-African basis.

References:
[Seminar] Human African trypanosomiasis. Reto Brun, Johannes Blum, Francois Chappuis, Christian Burri. The Lancet, Jan 2010.
Killer coma: the evolving story of sleeping sickness treatment. The Lancet, Volume 375, Issue 9709, Page 93, 9 January 2010.