A Retrospective Analysis of Altitude Illness at the Himalayan Rescue Association Aid Post Manang (2018-2023)

Area of Science:

• Altitude medicine
• Travel medicine
• Public health

Background:

• The Himalayan Rescue Association (HRA) operates aid posts in Nepal to manage altitude-related illnesses like acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE).
• Understanding the patterns of these illnesses is crucial for improving trekkers' safety in high-altitude environments.

Purpose of the Study:

• To analyze the incidence and characteristics of altitude-related illnesses treated at the HRA Manang aid post between 2018 and 2023.
• To identify risk factors associated with altitude illness, including ascent profiles and demographic factors.

Main Methods:

• A retrospective analysis of medical records from the HRA Manang aid post (2018-2023).
• Data collected included patient demographics, diagnoses, Lake Louise Score (LLS) for AMS, and ascent profiles.
• Comparison of illness frequency between trekkers with and without rapid ascent.

Main Results:

• Out of 2,904 visitors, 337 (11.6%) experienced altitude-related illnesses, predominantly AMS (274 cases).
• Rapid ascent (elevation >500m/day above 2,500m) was noted in 28.2% of cases, with a higher proportion of HACE and concurrent HAPE/HACE.
• Prophylactic acetazolamide use was lower in Nepali patients (36.20% overall).
• Fall season saw 58.8% of cases; most patients were non-Nepali adults.

Conclusions:

• Altitude illness remains a significant concern for trekkers in Nepal's Annapurna region.
• Targeted educational initiatives for high-altitude travelers are essential to mitigate risks and improve health outcomes.