High Altitude Cerebral Edema and High Altitude Pulmonary Edema - Symptoms, Causes, Diagnosis and Treatment

Introduction

As more individuals venture into high-altitude regions for recreational activities such as trekking, mountaineering, and adventure sports, it becomes crucial to understand the potential health risks associated with altitude sickness. High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE) are severe forms of altitude sickness that can pose significant threats to those ascending to elevated altitudes.

What Is High Altitude Cerebral Edema?

High Altitude Cerebral Edema (HACE) is a serious and potentially deadly condition that can occur at high altitudes. At these heights, the air has less oxygen than what the bodies are used to. This shortage of oxygen can make the brain swell, and since the brain is enclosed in the skull, there is not much space for it to expand. This swelling puts pressure on the skull, which is dangerous and affects the body's normal functioning. While it is not very common, HACE can quickly lead to coma and even death within a day if not recognized and treated promptly.

What is High Altitude Pulmonary Edema (HAPE)?

High Altitude Pulmonary Edema (HAPE) is a serious lung condition that can occur when a person is at high elevations. This condition involves the accumulation of fluid in the lungs, a situation known as pulmonary edema. The reduced oxygen levels at high altitudes cause blood vessels to constrict, leading to the buildup of fluid in the lungs. HAPE is one of three forms of altitude sickness, the others being acute mountain sickness (AMS), the most common, and high altitude cerebral edema (HACE). Unlike AMS, where symptoms like nausea and fatigue typically resolve within 12 to 48 hours as the body adjusts to the higher altitude, HAPE presents its symptoms up to five days after reaching a high altitude. It can take two to three days for a full recovery. One must know the potential health risks associated with HAPE when engaging in recreational activities at high altitudes, such as skiing, mountain climbing, or hiking.

What Are the Causes of High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE)?

• Cause of High Altitude Cerebral Edema (HACE): HACE arises due to hypoxia, a condition marked by low oxygen levels or insufficient oxygen in the body's tissues. When vital organs, like the brain, do not receive enough oxygen, it hampers their usual functioning. HACE-related hypoxia occurs when the body is not accustomed to elevations with lower oxygen levels than the norm.

• Cause of High Altitude Pulmonary Edema (HAPE): HAPE develops in response to low oxygen levels at high altitudes, with environmental factors like cold air intensifying symptoms by placing added stress on the lungs. Altitude illness risk is most significant above 8,000 feet (approximately 2,500 meters), particularly if ascent occurs too rapidly without allowing the body to acclimate gradually. While experiencing HAPE at lower altitudes is uncommon, it remains possible, especially for those with a history of HAPE. Additional risk factors encompass the use of sleep medication, excessive salt consumption, and underlying health conditions impacting blood flow to the lungs.

What Are the Symptoms of High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE)?

• HACE- Early signs of HACE encompass:

1. Headache.

2. Fatigue.

3. Dizziness.

4. Vertigo.

5. Nausea and vomiting.

6. Drowsiness.

7. Confusion.

In the event of the following severe symptoms at high altitudes, immediate medical attention is crucial:

1. Severe headache.

2. Loss of coordination (ataxia).

3. Weakness.

4. Slurred speech.

5. Disorientation, memory loss, hallucinations (altered mental status).

6. Loss of consciousness.

7. Seizures.

• HAPE- Symptoms of AMS are sometimes compared to those of an alcohol-related hangover. However, a distinct feature of HAPE is breathlessness. Initially, difficulty in breathing might be noticed during activities like walking or hiking. As symptoms progress, breathlessness can occur even at rest. HAPE symptoms typically emerge within a few days of ascending to high altitudes. Additional signs of HAPE may include:

1. General weakness.

2. Persistent cough.

3. Coughing up white or pink frothy sputum.

4. Chest tightness.

5. Bluish tinge to the lips or skin.

Observing these symptoms necessitates seeking medical assistance.

What Is the Diagnosis of High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE)?

• Diagnosis of HACE- A healthcare provider swiftly identifies HACE for prompt treatment. The diagnostic process includes a neurological examination and a review of symptoms, medical history, and travel history, particularly at high altitudes. While not always essential for diagnosis, tests may be conducted, such as:

1. Blood tests to examine white blood cell count and measure blood salts.

2. An MRI or CT scan.

• Diagnosis of HAPE- Recognizing potential HAPE involves paying attention to certain symptoms. A clinician would consider two or more of these symptoms as indicating HAPE if there is no other clear explanation:

1. Chest tightness or pain.

2. Cough.

3. Shortness of breath while at rest.

4. Decreased ability to exercise.

• To potentially confirm a HAPE diagnosis, a clinician would look for two or more of the following:

1. Bluish or grayish skin or lips.

2. Crackling or wheezing sounds in the lungs.

3. Rapid heart rate.

4. Rapid breathing.

As some symptoms resemble other lung conditions like pneumonia or pulmonary embolism, further tests may be necessary to rule out other possibilities. A chest X-ray, if available, can help confirm HAPE. Additionally, a doctor might order an ultrasound to check for pulmonary edema and an ECG and echocardiogram to explore other potential causes of pulmonary edema aside from HAPE.

What Is the Treatment for High Altitude Cerebral Edema(HACE) and High Altitude Pulmonary Edema (HAPE)?

1. HACE- Managing HACE involves the following steps:

• Descending to a lower altitude, ideally at least 1,000 meters or around half a mile. Travel with a companion for assistance and aim to minimize physical exertion.

• Utilizing supplemental oxygen or a portable hyperbaric chamber.

• Administering medications such as Dexamethasone (a corticosteroid) or Acetazolamide to alleviate brain swelling.

2. HAPE- If HAPE is suspected, an immediate descent is crucial. It is advisable to seek assistance from others, especially medical professionals, to facilitate the descent, as increased physical exertion may worsen symptoms. Supplemental oxygen is a viable treatment option, especially if access to a medical facility is available at a high altitude. Portable oxygen may be necessary if an immediate descent is not feasible. A doctor might prescribe nifedipine, an anti-hypertensive medication, to address HAPE symptoms, including chest tightness and improved breathing. This oral medication is typically prescribed in either 30 mg doses every 12 hours (extended-release) or 20 mg doses every eight hours. After a safe descent, further treatment for HAPE should be sought at the nearest hospital.

What Is the Difference Between High Altitude Cerebral Edema and High Altitude Pulmonary Edema?

Both HAPE and HACE fall under the category of altitude illnesses. HACE is a rare and severe form of acute mountain sickness (AMS), while HAPE can occur with or without AMS symptoms like headache and fatigue. Unlike HACE, HAPE is characterized by noticeable breathing difficulties, even at rest. Although both conditions can be fatal, HAPE tends to progress more rapidly. HAPE affects the lungs, causing distinct symptoms, while HACE impacts the brain, leading to unique signs like hallucinations and loss of coordination. Interestingly, up to 14 percent of individuals with HAPE may also simultaneously experience HACE.

Conclusion

In conclusion, venturing into high-altitude regions for activities like trekking and mountaineering brings the risk of severe altitude sickness, with High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE) posing significant threats. HACE, characterized by brain swelling due to oxygen deprivation, can lead to coma or death if not promptly treated. On the other hand, HAPE, a serious lung condition, manifests with symptoms like breathlessness and requires immediate descent and medical attention. Recognizing symptoms and risk factors, along with swift diagnosis and appropriate treatment, are crucial for ensuring the safety of individuals engaging in high-altitude activities.