Introduction
High altitude sickness is characterized by a triad of life-threatening
disorders; Acute Mountain sickness, High Altitude Pulmonary Edema
(HAPE), High Altitude Cerebral Edema (HACE) [1].
It happens because of the
physiologic respiratory failure of the body to adapt the high altitude
environment [2]. It affects individuals who ascends rapidly from low
altitude to high altitude [3]. This phenomenon occurs at an altitude
above 2500 meters the illness worsens with a longer stay of two to four
days on the high altitude [4].
HAPE is non-cardiogenic pulmonary edema that occurs as a result of
pronounced pulmonary vasoconstriction as one adapts to high altitude
hypoxic state [5]. It is the severe presentation of the High
altitude sickness [6]. Prolonged vasoconstriction leads to damaged
blood vessels endothelium and production of free oxygen radicals, which
can result into accumulation of fluids in the lungs [3].
Pulmonary embolism (PE) is a rare entity but is increasingly noted in
high altitude sickness as it coexists with HAPE and can present with
identical symptoms and signs of HAPE [7]. A number of studies have
suggested that high altitude predisposes to thrombosis [4,7–11].
These have shed light on the pathogenesis of pulmonary embolism and HAPE
at high altitude that these entities can coexist in one patient and
early diagnosis and treatment may improve the outcome of the patient.
Another study reported up to 30 times the risk of spontaneous vascular
thrombosis on long-term stay at high altitude in Indian soldiers exposed
above the altitude of 5000 meters [12]. This is explained by the
increase in hypercoagulative state and in a long run In a prolong stay
in the high altitude develop hyper fibrinogenic state complicating the
condition [12].
In light of the above evidences, consideration of pulmonary embolism as
a diagnosis must be kept in mind especially when HAPE symptoms and signs
don’t improve within 48 hours of descent. Many approaches may be
considered in diagnosing the condition, however none of which is
considered as a gold standard. Chest tomography with angiography (CT-PA)
has been used mostly with the ability to show changes in the pulmonary
vasculature.