From the Guidelines
High altitude cerebral edema (HACE) symptoms include severe headache, confusion, altered mental status, ataxia, hallucinations, and decreased consciousness that can progress to coma, as noted in the context of high-altitude illnesses 1. These symptoms typically develop after spending time at altitudes above 4500 m, as suggested by the study on high-altitude illnesses 1. The condition is a life-threatening form of high-altitude illness associated with a 50% mortality when untreated, emphasizing the need for prompt recognition and intervention 1. Key points to consider in the diagnosis and management of HACE include:
- The risk of AMS steeply rises when unacclimatised individuals are exposed to increasing altitude, affecting more than 50% of them at altitudes above 4500 m 1
- HACE represents a life-threatening form of HAI associated with a 50% mortality when untreated, highlighting the importance of immediate descent and medical management 1
- The activation and sensitisation of the trigemino-vascular system by both mechanical and chemical factors may cause headaches, and in rare cases, HACE may result from dysfunction or disruption of the blood–brain barrier 1 Immediate descent is the most critical treatment for HACE, and medical management may include supplemental oxygen, hyperbaric therapy, and potentially other interventions to reduce intracranial pressure and manage symptoms. Given the high mortality associated with HACE when untreated, immediate descent and prompt medical attention are crucial for anyone experiencing symptoms of HACE at high altitude.
From the Research
Symptoms of High Altitude Cerebral Edema
The symptoms of high altitude cerebral edema (HACE) include:
- Disturbances of consciousness that may progress to deep coma 2
- Psychiatric changes of varying degree 2
- Confusion 2, 3
- Ataxia of gait 2, 4
- Severe headache 4, 3
- Vomiting 4
- Visual disturbances 4
- Altered mental status 3
- Seizures (in rare cases) 3
- Coma (in severe cases) 2, 3
Clinical Manifestations
HACE typically follows acute mountain sickness (AMS) and poses a significant risk to life 3, 5. Clinical manifestations mainly include ataxia, alterations of behavior, and impaired consciousness, with severe cases progressing to coma 3.
Imaging Findings
Imaging shows reversible white matter lesions, with microbleeds being a significant and persistent imaging marker over time 3.