A goiter (alternative spelling: goitre) extending behind
the sternum or breast bone. Referred to as a "retrosternal"
goiter in the UK; it might also be termed "intrathoracic"
(inside the chest), perhaps if its widest part is below the
sternal notch.
The Pemberton maneuver (which see) may
betray the presence of such a goiter. The Valsalva maneuver is worth a try. Lying on the back
with a cushion underneath the shoulders so that the head is back
may produce the goiter into the neck. And the Valsalva maneuver
could be used at the same time to try and "blow" the thing into
the neck - Sporus does not know, but this sounds as though you
could do yourself in - perhaps exercise caution. It is easier
to feel the gland in the neck if water is sipped. An innability
to discover the base of the thyroid gland is suggestive of a
substernal goiter.
It has usually appeared because one of the lower poles of the
gland, which is rather given to enlarging, has, instead of
growing forward to give a conventional goiter, grown backwards
and down the neck into the top of the chest. However other
parts of the gland may enlarge or the gland might be in the
wrong place congenitally. These goiters can become very large,
they may even grow as far down as the diaphragm, weigh several
kilograms and do things like pressing on the heart - which may
make it beat fast - (slow beating
caused by the goiter pressing on the vagus nerve is more
common). Sporus does not know but gets the impression that the
common idea goiters get larger as people get older may be
innaccurate.
It is often diagnosed from a chest X-ray taken for another
reason (Sporus has read: "a history of low dose medical X-rays"
increases the probability of a goiter turning cancerous to
not by 40%). X-rays show the goiter in 75% of cases,
ultrasound scans in 15% of cases, a computerized tomography,
CT, scan is allegedly always successful. The impression is
easily gained that these goiters are heavily under
diagnosed.
Many of the symptoms of a substernal goiter are due to its
pressing on various structures: Pressure on the veins that
drain the head and arms causes their blood supply to be
compromised. This may cause dilation of the veins in the cervix
(neck), face or chest; they may stand out like varicose
veins. Rarely, there may be superior vena cava syndrome
(SVCS). There may be trouble swallowing (dysphagia). The
victim might go blind or feel faint, due to pressure on blood
vessels, when they swallow. Slight hoarseness or a cough are
possible, as are voice problems due to pressure on the
recurrent laryngeal nerve. (In Sporus's view it is perhaps
possible for speech problems to be present due to the voice
competing with the brain for the already compromised blood
supply. In this case speech might be tiring - also a well known
symptom of myasthenia gravis - or might produce a feeling of a
poor blood supply to the head.) The normal symptoms of
a thyroid disorder may occur. Pressure on the trachea, or
even competing with the lungs for space in the thorax, may cause
breathing difficulty (dyspnea): this can become suddenly
severe and dangerous during a respiratory infection or due to
bleeding into a blood filled cyst inside the goiter (or - a
speculation - the stomach may become very full with pabulum,
drink or gas and lift the diaphragm which lift the lungs so
that they compete with the goiter for an even smaller space
inside the thorax. Thus, for example, difficulty inflating the
lungs after a large meal may be suggestive.) Dyspnea may be
present during sleep or when the head is in one particular
position. Other pressure symptoms may vary with the position of
the head, for example faintness when looking upward. There may
be stiffness of the neck.
It is impossible to overstate, in diagnosing this problem and
in everything else, the incompetence and venality of the medical
profession.