We
presume that this case report has disoriented our colleagues, because one
of the questions was: Do you think this is a case of CMS ?. 1)
Ask yourself if this first chest x-rays shows you something important that
justifies the increased hematocrit. There is a notorious dome
elevation of the right hemidiaphragm. This may suggest hypoventilation
in the right lung.
2)
Do you think that the increased polycythemia will increase with aging or
disease progression ? This is one possibility,
however time has shown that it was not true. Also, aging in this case did
not change significantly the increased polycythemia in twenty four years
of residence in the city of La Paz 3510 m.
3)
If you think the hematocrit will not increase, then try to explain why
not. Even though there is a gradually
evolving ventilatory insufficiency of the right lung and vital capacity
is reduced, there is ventilatory compensation in the left lung.
Oxygen
saturation changes and breath-holding (screen1),(screen2),(screen3), The
breath holding time was 1 min 50 sec . Any comments ? The
first screen shows an average SaO2 of 90 % (a normal value for this altitude
is around 92%) with and ETCO2 of 27 mmHg (normal 30 mmHg for this altitude),
which is explained by a temporary hyperventilation of the subject during
the breath holding test. On the second screen a long breath
holding time is observed (1 min 50 sec) because there is no CO2 retention,
and slight hyperventilation during the test resulting in a post breath
holding ETCO2 of 35 mmHg with CO2 retention which triggers rebreathing.
Note that he is able to tolerate a SaO2 of 78% at the end of the breath
holding.
Spirometry, The
spirometry showed a reduced forced vital capacity of 53%, which confirms
that during inspiration while the left hemidiaphagm goes down the right
side goes up, due to paralysis. Unfortunately we were unable to measure
ventilation and other ventilatory parameters in each lung independently. 4)
What is your diagnostic impression and what should be done ? There
is a right lung hypoventilation secondary to right hemidiaphragmatic paralysis
which is pushed up by the liver, with no resistance. An abdominal sonography
showed no abnormalities in the liver. 5)
Do you think this is a case of CMS ? This case is useful to analyze
because it allows us to show that Chronic Mountain Sickness until now is
not precisely defined since increased polycythemia is a common sign of
many respiratory, cardiac or renal disease of different ethiopathogenesis.
In this particular case, CMS is definitely due to right diaphragm paralysis
in chronic hypoxic conditions.
According to our previous concept:
all disease at high altitude is similar to that at sea level in ethiopathogenesis
and evolution, but with a hypoxic physiognomy. In the present case the
subject had a right side hemidiaphragmatic paralysis, that can also present
at sea level, where comparatively hypoventilation with reduction of the
ventilatory function does not necessarily lead to increased polycythemia,
although there is dyspnea on effort. This due to the fact that the inspired
oxygen tension (at sea level) is more than enough for an adequate saturation
of hemoglobin at rest. In this case, hypoventilation progresses over a
long period of time, decreasing ventilation in the right lung, but at the
same time compensating by increasing ventilation in the left lung gradually
however not completely (SaO2 = 84%) in order to achieve the normal saturation
of blood which is 92 % at 3510 m.
As
can be observed in the first chest x-rays there is an abnormal elevation
of the right diaphragm with a descent of the left diaphragm and shift of
the heart and the mediastinum to the left. The patient has suffered this
alteration for over 24 years with moderate increased polycythemia (Ht =
65%; Hb = 21.7 mg%), that has not increased significantly and if conditions
don’t change we presume that in the future they will remain static At
present this mathematician is active for his age (76 years old), slightly
cyanotic and with his exercise capacity reduced. He is performing respiratory
exercises regularly, since that was the only possible treatment. DIAGNOSIS: Idiopathic paralysis
of the right hemidiaphragm at 3510 m in chronic hypoxia.
Any
further comments or suggestions are welcome. Prof.
Dr. Gustavo Zubieta-Castillo (Sr) & Dr. Gustavo Zubieta-Calleja
High
Altitude Pathology Institute (IPPA) Dear Drs.Gustavo-Zubieta Sr.and Jr.
This case is extraordinaly for me, the resident of
sea level. I can not
4) Paralysis of right side N.phrenics with unknown
cause. I do not think
Michiro Nakashima, MD, JAPAN
We recently received Prof. Nakashima's comments which were: