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2.15 · Nystagmus
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125
2
(CN6). So during head movement, the right semicircular
canal sends inputs regarding the position of the head in
space to the right vestibulocochlear nerve. e right
vestibular nerve sends crossed inputs to the le PPRF,
which in turn sends neural inputs to the le abducens
nucleus. e le abducens nucleus sends two neural
outputs: (1) to the lateral rectus to move via the le
abducens nerve and (2) to the medial rectus to move to
the right oculomotor nucleus via the right MLF. e past
neural pathway is known as the vestibulo-ocular re ex ,
. Fig. 2.15.2 Axial T1W MR illustration demonstrates the normal
location of the medial longitudinal fasciculus on MRI (yellow nuclei)
which is important to stabilize gaze while the head is
moving.
8 . Vestibulochochlear nerve (CN 8) : the vestibular nerve
projects its neural input from the semicircular canals to
the contralateral abducens nucleus a ecting the gaze via
the vestibulo-ocular re ex .
9 . Semicircular canals : the semicircular canals send inputs
regarding the position of the head in space to the right
vestibulocochlear nerve, which in turn a ect gaze via the
vestibulo-ocular re ex .
Nystagmus Subtypes
1 . See-saw nystagmus : it is an uncommon form of
nystagmus characterized by synchronous alternating
elevation and intorsion of one eye, with simultaneous
depression and extrusion of the other eye, followed by
reversal of the vertical and torsional movement in the
next half cycle. On MRI , sea-saw nystagmus can arise
due to (1) suprasellar masses, (2) Chiari
malformations, (3) midbrain lesions involving the
interstitial nucleus of Cajal (
(4) lesions involving the medial and lateral
vestibulospinal tracts , and (5) the absence of the optic
nerve decussation ( achiasma ).
2 . Periodic alternating nystagmus : it is a rare disorder where
the patient complains from the acquired periodic
alternating nystagmus and o en complains of increasing
or decreasing oscillopsia for speci c time intervals. On
. Figs. 2.15.1 and 2.15.3 ),
. Fig. 2.15.3 An illustration
that demonstrates lesion
locations of some nystagmus
subtypes
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Chapter 2 · Neurology
MRI , periodic alternating nystagmus can be caused by
vestibular lesions, cerebellar degeneration, brain stem
infarctions, and intoxications (e.g., lithium ).
2
3 . Horizontal nystagmus : it is an abnormal eye movement
that is restricted to the horizontal axis. On MRI ,
horizontal nystagmus can be caused by vestibular
neuritis, otoliths, and superior oblique myokymia.
Superior oblique myokymia is a rare disorder
characterized by recurrent attacks of oscillopsia and
double vision with oblique images due to monocular
oscillations due to trochlear nerve (CN4) disorder. On
MRI , SOM is classically caused by vascular compression
over CN4 or a lesion in the region CN4.
4 . Torsional nystagmus : it is a rare condition characterized
by torsional eye movement. On MRI , torsional
nystagmus can be caused by a lesion involving the
riMLF or the interstitial nucleus of Cajal (. Fig. 2.15.1 ).
5 . Downbeat nystagmus syndrome (DNS) : it is a disease
characterized by nystagmus with downward pupil
displacement. It can be associated with oculomotor
palsy, bilateral ptosis, and hypersomnolence. On MRI ,
there is a lesion involving the cerebellum ( involving the
bilateral lesion of the occulus or para occulus lobes )
and/or midbrain (e.g., Arnold–Chiari malformation ,
Basilar invagination , hypomagnesemia , etc. )
(
. Fig. 2.15.3 ).
6 . Upward gaze-evoked nystagmus (UGEN) : it is an
uncommon condition reported with organoarsenic
compound poisoning characterized by nystagmus when
the patient is asked to look upward due to gaze-holding
failure, in association with cerebellar ataxia, involuntary
movements ( tremors and myoclonus ), attention and
memory de cits, and sleep disorders. On MRI , there is a
lesion in the midbrain involving the interstitial nucleus
of Cajal (. Fig. 2.15.1 ).
7 . Pendular nystagmus : it is a rare disorder characterized
by monocular or binocular sinusoidal oscillations with
a predominant horizontal, vertical, or oblique
trajectory. On MRI , pendular nystagmus can be caused
by optic chiasma lesions, blindness ( <6 months of age ),
oculopalatal tremor syndrome (myoclonus), and
Pelizaeus–Merzbacher diseases.
8 . Gaze-evoked nystagmus : it is a rhythmic oscillation of
the eyes produced by the attempted maintenance of an
extreme eye position probably due to a defective neural
integrator. On MRI , cerebellar lesion is typically found.
9 . Opsoclonus and ocular utter (dancing eye syndrome) :
opsoclonus is characterized by repetitive bursts of fast,
high-frequency conjugate saccadic oscillations without
intersaccadic intervals. e oscillations may have
horizontal, vertical, and torsional components and are
o en triggered by saccades, pursuit, eye closure, and
convergence. On MRI , dancing eye syndrome can be
caused by (1) cerebellitis ( post-viral , e.g. , coxsackie B37 ;
post-vaccine ) and (2) paraneoplastic cerebellar syndrome
( infants , neuroblastoma ; adults , carcinoma of the lung ,
breast , uterus , or ovary ).
10. Caloric nystagmus : it is a term used to describe
physiologically induced nystagmus via tilting the head
back and irrigating the ear with warm water ( causes
nystagmus in the same direction of the ear irrigated ) or
cold water ( causes nystagmus in the opposite direction of
the ear irrigated ).
11. Spasmus nutans : it is an acquired form of nystagmus
that typically presents between 6 and 12 months of age.
e classic triad of spasmus nutans includes (1) head
nodding , (2) torticollis , and (3) motor nystagmus .
Spasmus nutans typically disappears by age 4 years and
is associated with normal vision.
References
Sami DA, etal. e achiasmia spectrum: congenitally reduced
chiasmal decussation. Br J Ophthalmol. 2005;89:1311–7.
Swash M, et al. Periaqueductal dysfunction (the Sylvian
aqueduct syndrome): a sign of hydrocephalus? J Neurol
Neurosurg Psychiatry. 1974;37:21–6.
ompson L, etal. e visually impaired child. Pediatr Clin
North Am. 2003;50:225–39.
2.16 Erectile Dysfunction
Erectile dysfunction is de ned as the inability to achieve or
maintain an erection of su cient rigidity to allow vaginal
penetration. Impotence can be psychological or physical.
Physical impotence can be arterial in origin (e.g., atheroscle-
rosis ) or venous in origin (e.g., venous leak ).
Neural Control Human Sexual Behavior
1 . Frontal lobe : the frontal lobe sends tonic inhibitory
signals to the periaqueductal gray matter (PAG) , which
causes social inhibition of sexual activity.
2 . Temporal lobe : the temporal lobe mediates sexual drive/
libido .
3 . Higher centers : other higher cortical functions that are
involved in sexual behavior include the insula and
somatosensory region.
4 . Hypothalamus : it a ects human sexual functions via the
medial preoptic area (MPO) and the paraventricular
nucleus (PVN) . e PVN contains large neurosecretory
cells which secrete vasopressin and oxytocin. e
hypothalamus mediates sexual drive/libido and penile
erection .
5 . Amygdala : it mediates sexual drive/libido ( in temporal
lobes ).
6 . Midbrain : it a ects human sexual functions via the
periaqueductal gray matter (PAG) and the ventral
2.16 · Erectile Dysfunction
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127
2
tegmental area (VTA) . e VTA has an important role
in rewarding behavior .
7 . Sympathetic nervous system (T
–L
) : the hypogastric
10
2
nerve, which arises from the hypogastric plexus at the
aortic bifurcation at (L5–S1), supplies the corpora,
bladder neck, and prostate. Stimulation of the
parasympathetic sacral nerves causes detumescence.
–S
8 . Parasympathetic nervous system (S
) : stimulation of
2
4
the parasympathetic sacral nerves causes erection.
9 . Pudendal nerve : it originates from the (S2–S4) sacral
nerve roots ( Onuf’s nucleus ), travels into the ischiorectal
fossa ( Alcock’s canal ), and transmits autonomic (30 %),
sensory (50 %), and motor (20 %) impulses. e
pudendal nerve gives sensory and motor bers to the
ischiocavernosus muscle, bulbospongiosus muscle, and
penile and perianal skin. In females, it supplies the
clitoris.
10. Neuroendocrine hormones : gonadal hormones a ect the
sexual behavior via modifying the cerebral control of
lower re exive mechanisms. e gonadal hormones
a ect sexual performance rather than sex drives.
Multiple gonadal hormone receptors are found within
the midbrain, hypothalamus, and amygdala.
from congenital excessively large venous channels
through the corpora cavernosa, venous shunts between
the cavernosa and the spongiosum, and inadequate
compression of the subtunical and emissary veins and
may occur with aging or Peyronie’s disease.
III. Neurologic erectile dysfunction : neurological disease
accounts for the second most common cause of
erectile dysfunction in older men. It results from
disorders of the parasympathetic sacral spinal cord or
peripheral e erent autonomic bers to the penis,
which impairs penile smooth muscle relaxation and
prevents the vasodilation needed for erection.
Common neurological causes of erectile dysfunction
in older men include autonomic dysfunction from
diabetes mellitus, stroke, Parkinson’s disease, cauda
equina syndrome (. Fig. 2.16.2 ), and injury to
autonomic nerves from radical prostatectomy or
proctocolectomy.
I V. Psychogenic erectile dysfunction : a classic psychogenic
cause in older men is the Widower’s syndrome , where
the older man involved in a new relationship feels guilt
and develops erectile dysfunction as a defense against
perceived unfaithfulness to his dead spouse.
Pathophysiology
Penile erection depends on a complex interaction of psychological , neural , vascular , and endocrine factors. Erectile dys-
function can arise from abnormalities in one or more of the
previous four components:
I . Arterial erectile dysfunction : it typically has a gradual
onset and is most commonly the result of progressive
systemic arteriosclerosis. Arterial erectile dysfunction can arise in patients with hypertension, hypercholesterolemia, and diabetes mellitus and who are
smokers.
II. Venous erectile dysfunction : venous erectile dysfunction
due to venous insu ciency in the presence of adequate
arterial in ow is called veno-occlusive dysfunction or
venous leakage . Venous leakage (
. Fig. 2.16.1 ) can result
Erectile Dysfunction Diff erential Diagnoses
1 . Neurological causes : spinal cord lesion (e.g., cauda equina
syndrome ), diabetic neuropathy, and multiple sclerosis
2 . Endocrinological causes : diabetes mellitus,
hypogonadism, and hyperprolactinemia
3 . Vascular causes : peripheral vascular disease and
veno-occlusive disease
4 . Drug-induced causes : alcohol, cigarette smoking,
marijuana, heroin, antidepressants, spironolactone, H
blockers, statins, amiodarone, opiates, β-blockers, and
+2
b l o c k e r s
Ca
5 . Local penile causes : Peyronie’s disease, priapism, and
penile fracture
6 . Myofascial causes : can arise due to trigger points a ecting
the pyramidalis muscle
2
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Chapter 2 · Neurology
. Fig. 2.16.1 T1W,
postcontrast, fat-sat,
reconstructed MR image of a
2
37-year-old male patient erectile
dysfunction due to venous
leakage investigated by MR
cavernosography technique; the
left mid- and deep periprostatic
venous plexus shows venous
leakage ( arrowheads ), 1 min after
intracavernous gadolinium
injection
2.16 · Erectile Dysfunction
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a
129
b
c
d
2
. Fig. 2.16.2 Sagittal T2W ( a ), coronal T2W ( b ), MR myelographic ( c ), and axial T2W ( d ) images of a 53-year-old female patient with cauda
equina syndrome seen as intervertebral disk protrusion that impinges over the thecal dural sac causing moderate spinal canal stenosis
( arrowheads )
References
Argiolas A.Male erectile dysfunction: chemical pharmacol-
ogy of penile erection. Drug Discov Today er Strateg.
2005;1(2):31–6.
Basson R, etal. Sexual sequelae of general medical disorders.
Lancet. 2007;369:409–24.
Bhasin S, etal. Sexual dysfunction in men and women with
endocrine disorders. Lancet. 2007;369:597–611.
Carey JC.Pharmacological e ects on sexual function. Obstet
Gynecol Clin North Am. 2006;33:599–620.
De Silva P.Paraphilias. Psychiatry. 2004;2(1):33–6.
Giuliano F, etal. Neural control of erection. Physiol Behav.
2004;83(2):189–201.
Khan SA, etal. An unusual case of neurogenic sexual dys-
function due to lead exposure. Open Androl J. 2011;3:6–7.
Levin R, et al. e physiology of human sexual function.
Psychiatry. 2007;6(3):90–4.
Ramage M. Female sexual dysfunction. Psychiatry.
2007;6(3):105–10.
Rao DS, etal. Vasculogenic arterial and venous surgery. Urol
Clin North Am. 2001;28(2):309–19.
Riley A. e physiology of sexual function. Psychiatry.
2004;3(2):3–7.
Shamloul R, et al. Erectile dysfunction. Lancet. 2013;381:
153–65.
Steers WD.Neural pathways and central sites involved in
penile erection: neuroanatomy and clinical implications.
Neurosci Biobehav Rev. 2000;24:507–16.
Wylie KR.Male sexual dysfunction. Psychiatry. 2007;6(3):
99–104.
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Endocrinology andMetabolism
3.1 Graves’ Disease (Hyperthyroidism) – 132
3.2 Hyperparathyroidism – 133
Di erential Diagnoses andRelated Diseases – 134
3.3 Growth Hormone Diseases – 138
Growth Hormone Insu ciency (Hypopituitarism) – 139
Acromegaly andGigantism – 140
Growth Hormone Insensitivity (Laron Syndrome) – 143
Carney’s Complex – 143
3.4 Osteoporosis – 145
Primary Osteoporosis – 145
Secondary Osteoporosis – 148
Regional Migratory Osteoporosis oftheHip (Bone Marrow
Edema Syndrome) – 148
3
3.5 Rickets andOsteomalacia – 149
Di erential Diagnoses andRelated Diseases – 150
3.6 Scurvy – 152
3.7 Fluorosis – 154
3.8 Lead Poisoning (Plumbism) – 156
3.9 Adrenal Glands Abnormalities – 157
Cushing’s Syndrome – 157
Conn’s Syndrome (Hyperaldosteronism) – 158
Addison’s Disease – 159
Pheochromocytoma – 160
Neuroblastoma – 161
X-Linked Adrenoleukodystrophy – 161
Testicular Adrenal Rest Tumors – 162
3.10 Sex Hormone Abnormalities – 162
Polycystic Ovary Disease (Stein–Leventhal Syndrome) – 163
Precocious Puberty – 163
Van Wyk and Grumbach Syndrome – 164
Gynecomastia – 165
Intersex Disorders – 166
Di erential Diagnoses andRelated Diseases – 168
3.11 Sheehan Syndrome (Postpartum Hypopituitarism) – 170
© Springer International Publishing Switzerland 2017
J.A. Al-Tubaikh, Internal Medicine, DOI10.1007/978-3-319-39747-4_3
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Chapter 3 · Endocrinology andMetabolism
3.1 Graves’ Disease (Hyperthyroidism)
Signs on US and Doppler Sonography
Graves’ disease (GD) is an autoimmune disorder character-
ized by hyperthyroidism, thyroid goiter, and ophthalmopa-
thy. e disease arises due to the production of autoantibodies
3
that auto-stimulates the thyrotropin receptors in the thyroid
gland to secrete thyroid hormones.
GD clinical manifestations are mainly due to hyperthy-
5 The gland is diffusely hypoechoic and enlarged in
size.
5 On color Doppler scan, the gland shows bilateral
diffuse increase duplex signal due to
hypervascularity. This sign is characteristic for GD
and is called “thyroid inferno” sign (. Fig. 3.1.1 ) .
roidism (thyrotoxicosis). Patients are commonly females
between the third and h decades presenting with thyroid
goiter. e thyroid is hypervascular, with venous humming
that can be heard by stethoscope in some cases.
Systemic manifestations of hyperthyroidism include
rapid weight loss (>10 % of body weight in less than 6
months), profuse sweating and heat intolerance, increased
appetite (85 %), anorexia (15 %), increased bowel motion and
diarrhea, oligomenorrhea in females, gynecomastia in males
due to increased sex hormone-binding proteins, and proximal muscle weakness and muscle wasting due to increased
basal metabolic rate. Skin manifestations include skin moisture due to sweating, vitiligo, and pretibial skin thickening
due to mucin deposition in the dermis (myxoedema).
Graves’ ophthalmopathy is the most characteristic sign of
this disease. GD is the most common cause of exophthalmos
(abnormal prominent eye) and proptosis (protrusion) of
. Fig. 3.1.1 Color Doppler (Duplex) scan of the thyroid in a
patient with Graves’ disease shows marked vascular signal due
to bruit (thyroid inferno sign)
globe in adults. It occurs in 35 % of cases. e proptosis can
precede the actual thyroid abnormalities or occur a er the
disease has been brought under control. Proptoses are commonly bilateral and symmetrical; unilateral proptosis is
uncommon.
Proptosis in GD can be explained by:
5 I n ltration and deposition of mucopolysaccharidosis
(hyaluronic acid) into orbital muscles. e muscles’
bellies are characteristically increased in size, while their
Signs of Graves’ Ophthalmopathy on CT andMRI
5 Bilateral, symmetrical increase in orbital muscles
bellies width with spares tendons causing the
orbital muscles to have fusiform appearance. The
inferior rectus and the medial rectus muscles are
characteristically affected (. Figs. 3.1.2 and 3.1.3 ).
tendons are spared (fusiform enlargement). e inferior
rectus and the medial rectus muscles are the most
commonly involved. e lateral rectus is the last muscle
to be involved. Hypertrophy of the lateral rectus only can
be seen in orbital pseudotumor, and hypertrophy of the
superior rectus only can be seen in orbital lymphoma.
5 Increased volume of the retrobulbar fat which will push
the globe anteriorly.
Clinical signs of Graves’ ophthalmopathy include widened palpebral ssure ( Dalrymple’s sign ), staring expression
with infrequent blinking ( Stellwag’s sign ), lid lag on down-
ward gaze ( von Graefe’s sign ), and poor convergence ( Möbius’s
sign ). Up to 5 % of patients with Graves’ ophthalmopathy
develop optic neuropathy due to compression of the nerve in
its canal because of backward herniation of the retro-orbital
fat through the optic canal or from hypertrophied ocular
muscle belly at the orbital apex.
. Fig. 3.1.2 Axial ophthalmic CT image of a patient with
Graves’ ophthalmopathy shows marked thickening of the medial
rectus muscle of the left eye. Notice the di erence in the medial
rectus belly thickness ( 2 ) in comparison with the right eye ( 1 )
3.2 · Hyperparathyroidism
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5 Increases in the retrobulbar fat size.
5 CT evidence of proptosis is defined as globe
protrusion exceeding the interzygomatic line by
21mm or more on axial images at the level of the
lens (. Fig. 3.1.4 ).
5 GD optic neuropathy can be detected if
retro-orbital fat is seen extending 4mm beyond
the boundary of the superior orbital ssure or if the
optic nerve is seen compressed by a hypertrophied
ocular muscle belly at the orbital apex.
5 Uncommonly, isolated dilatation of the superior
ophthalmic vein may occur in patients with GD,
and it can be easily mistaken for carotid–
cavernous fistula. CT angiography can confirm the
absence of carotid–cavernous fistula.
133
Further Reading
Arslan H etal. Power Doppler sonography in the diagnosis of
Graves’ disease. Eur J Ultrasound. 2000;11:117–22.
Babcock DS. yroid disease in pediatric patient: emphasiz-
ing imaging with sonography. Pediatr Radiol. 2006;36:
299–308.
Birchall D etal. Graves ophthalmopathy: intracranial fat pro-
lapse on CT images as an indicator of optic nerve compression. Radiology. 1996;200:123–7.
Charkes ND etal. MR imaging in thyroid disorders: correla-
tion of signal intensity with Graves disease activity.
Radiology. 1987;164:491–4.
Greer MA etal. Hyperthyroidism. Dis Mon. 1967;13:1–45.
Nugent RA etal. Graves orbitopathy: correlation of CT and
clinical ndings. Radiology. 1990;177:657–82.
Ralls PW etal. Color- ow Doppler sonography in Graves
disease: “thyroid inferno”. AJR Am J Roentgenol.
1988;150:781–4.
Rawson RW.Hyperthyroidism. Dis Mon. 1955;1:3–43.
Reed Larsen P.Hyperthyroidism. Dis Mon. 1976;22:1–30.
3
. Fig. 3.1.3 Coronal sinus and orbital CT illustration shows a
di erential diagnosis of recti muscles enlargement; the letter G
stands for Grave’s disease, L for lymphoma, and P for orbital
pseudotumor
. Fig. 3.1.4 Axial ophthalmic CT illustration demonstrates
the interzygomatic line. A globe that protrudes >21mm or
more across this line is considered proptosis
3.2 Hyperparathyroidism
Hyperparathyroidism is a metabolic disease characterized by
the metabolic triad of high serum calcium level (hypercalcemia), low serum phosphorus level (hypophosphatemia), and
increased calcium and phosphorus renal excretion (hypercalciuria).
Hyperparathyroidism can be caused by increased parathyroid hormone (PTH) release due to parathyroid adenoma
or hyperplasia (primary type), chronic renal failure or parathyroid glands insensitivity to elevated serum calcium level
(secondary type), or chronic renal failure with autonomous
PTH release even a er correction of the renal failure (tertiary
type). Chronic renal failure causes reduction in serum calcium level, which induces hypersecretion of PTH to elevate
serum calcium level. PTH increases serum calcium by increasing osteoclastic activity, promoting vitamin D renal hydroxylation, and promoting tubular renal absorption of calcium.
Hyperparathyroidism generally arises in those endocrine
phases of life when endocrine glands are most active or rapidly changing like puberty, during the active phase of sexual
life, or a er menopause. us, hyperparathyroidism is rare
before puberty and less commonly starts in later decades.
Symptoms and clinical presentation of hyperparathyroidism are related to its complications. Renal stone formation is
one of the most common presentations of hyperparathyroidism. Increased renal excretion and serum calcium level promotes renal calculi formation. Peptic ulcers may occur in
association with hyperparathyroidism for unknown reasons.
It is speculated that changes in the calcium ion concentration
may play a role in parasympathetic nervous system tone,
which predisposes to increased secretions of gastric acids by
increased vagal activity.
Episodes of acute pancreatitis are commonly associated
with hyperparathyroidism for unknown reasons. irst and
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Chapter 3 · Endocrinology andMetabolism
urinary frequency are common symptoms. Muscle fatigue
and low back pain are also common complaints, and they are
independent of bone changes.
e most common metabolic changes in hyperparathy-
roidism are observed in the skeletal system. Di use osteopo-
3
rosis and bone resorption are commonly seen in primary
hyperparathyroidism. In contrast, di use or focal osteosclerosis is observed in secondary hyperparathyroidism.
Subperiosteal, subchondral, and subligamentous bone
resorptions are the most common ndings radiologically.
Brown tumor is an eccentrically located, expansile bony
lesion uncommonly seen in secondary hyperparathyroidism.
In severe hyperparathyroidism, large areas of bone marrow
cavity are lost due to bone resorption. is bony resorption
leads to microfractures and bleeding in the resorbed areas,
which will create a mass-like e ect within the trabecular
bone. is mass-like structure has a brown pigment in gross
section due to hemosiderin content. Gradually, this mass
undergoes cystic changes. As the severity of the disease
increases, these changes can progress to severe and di use
type of bone expansion, cystic changes, and bone marrow
brosis, a condition which is known as osteitis brosa cystica .
Brown tumor mimics giant cell tumor ( osteoclastoma ) radio-
logically and histologically. Di erentiation between the two
clinical conditions depends on the presence or absence of
hyperparathyroidism manifestations. Osteitis brosa cystica
is a rare complication of hyperparathyroidism that is seen in
advanced stage disease. It is usually seen in young patients
<20years.
Nephrocalcinosis is a condition characterized by calci ca-
tion and calcium deposition within the renal parenchyma,
either in the cortex or in the medulla. Cortical nephrocalcinosis
occurs due to prior insult to the renal cortex like in tuberculosis, ischemia, and glomerulonephritis. Usually it a ects one
kidney, and the a ected kidney is small with global atrophy.
Medullary nephrocalcinosis , on the other hand, arises due to
calci cation of the medullary pyramids due to deposition of
calcium within the renal tubules. Medullary nephrocalcinosis is the most common type of nephrocalcinosis (95 %) and
is caused by systemic hypercalcemic states like in hyperparathyroidism, distal renal tubular acidosis, malignancy, and
acute sarcoidosis. Typically, it a ects both kidneys in a bilateral and symmetrical fashion, because the cause usually is a
systemic disease.
Primary hyperparathyroidism can be a part of multiple
endocrine neoplasia (MEN) syndrome . MEN syndrome is
characterized by the occurrence of tumors involving two or
more endocrine glands within a single patient. ere are two
major types of MEN: MEN type 1 (MEN1, Wermer’s syndrome) and MEN type 2 (MEN2, Sipple’s syndrome). Both
syndromes are inherited as autosomal dominant. MEN1 is
characterized by the combined occurrence of parathyroid
tumors, pancreatic islet cell tumors (e.g., gastrinoma), and
anterior pituitary tumors (e.g., prolactinoma). Associated
tumors include adrenal tumors, carcinoid tumors, and
lipoma. Although not part of the original description,
meningioma has been reported to occur in patients with
hyperparathyroidism due to MEN type 1. MEN type 2, on the
other hand, is divided into three subtypes: MEN2a, MEN2b,
and MTC only. MEN2a describes the association of medullary thyroid carcinoma (MTC), pheochromocytoma, and
parathyroid tumors. MEN2b describes the association of
MTC, pheochromocytoma, marfanoid body habitus, mucosal neuromas, and megacolon. Lastly, MTC only is a variant
in which MTC is the sole manifestation of this syndrome.
In up to 2 % of normal people, an ectopic parathyroid tissue may be found within the mediastinum. e ectopic parathyroid tissue is commonly located within the anterior
mediastinum. An ectopic parathyroid adenoma is rare and
should be suspected in a patient with hyperparathyroidism
who was operated and the signs and symptoms of
hyperparathyroidism persisted (5–10 % of cases). Other areas
where ectopic parathyroid tissue may be found include the
neck (45 %), upper cervical area (8 %), or along the aortic
arch (5 %).
D i erential Diagnoses andRelated Diseases
5 Hyperparathyroidism–jaw tumor syndrome is a rare,
autosomal recessive disease characterized by
hyperparathyroidism (90 %), ossifying broma of the
maxilla and/or mandible (30 %), renal cysts and/or
tumors (10 %), and uterine tumors. Ossifying broma is a
benign lesion that arises from cells in the periodontal
ligament and is mainly restricted to the tooth-bearing
areas of the jaw. e lesion is visualized as a
well-demarcated bony lesion composed of brocellular
tissue and mineralized material. e tumor is typically
painless and located at the posterior region of the
mandible. Patients are o en >35years old. However, a
juvenile form (<20years) may be seen.
5 Hungry bone syndrome ( HBS ) is a rare complication of
parathyroidectomy manifested by severe, prolonged,
sometimes life-threatening hypocalcemia. e
hypercalcemia in hyperparathyroidism is mainly due to
increased bone turnover with predominant osteoclastic
bone resorption and increased renal tubular absorption
of calcium. A er parathyroidectomy, the PTH stimulus
over the osteoclasts is suddenly removed, stopping the
osteoclastic activity, but the osteoblastic activity
continues at its high rate, resulting in marked increase in
bone uptake of calcium to facilitate bone remodeling.
e excessive osteoblastic bony remodeling causes severe
hypocalcemia. HBS is seen in 12 % of parathyroidectomy
cases, and it is suspected in patients who had
parathyroidectomy and presented with persistent
hypocalcemia and hypophosphatemia. Predisposing
factors for HBS include parathyroid adenoma >5cm in
diameter, high preoperative PTH, calcium, and alkaline
phosphatase levels, advanced age, and osteitis brosa
cystica.
3.2 · Hyperparathyroidism
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Signs on Plain Radiographs
5 On chest radiograph, tracheal shift due to enlarged
parathyroid adenoma may be the first sign
detected in an asymptomatic patient.
5 On abdominal radiographs, urinary tract calcium
calculi are seen as radio-opaque lesions in the
renal area or the urethral course.
5 Cortical nephrocalcinosis is often detected as a
unilateral renal “eggshell calcification,” while
medullary nephrocalcinosis is detected as
multiple, punctuated calcification seen within the
kidney shadows in a bilateral symmetrical fashion
(. Fig. 3.2.1 ) .
. Fig. 3.2.2 A lateral plain radiograph of the skull shows mild
salt and pepper skull lesions in a patient with primary
hyperparathyroidism
. Fig. 3.2.1 A plain radiograph of the kidneys in a patient
with medullary nephrocalcinosis shows bilateral, almost
symmetrical, punctuated calci cation within the renal shadow
Signs on Skeletal Radiographs
5 Diffuse osteoporosis and lytic bony lesions are
commonly found in primary hyperparathyroidism.
5 Widening of sacroiliac joints due to subchondral
bone resorption can be seen.
5 Salt and pepper skull appearance : this occurs due to
resorption of the trabecular bone in the skull and
replacement of the resorbed bone by a newly
formed connective tissue causing loss of integrity
in the shape of the skull bones (. Fig. 3.2.2 ).
5 The vertebral bodies in secondary
hyperparathyroidism show sclerosis of the end
plates (Rugger–Jersey spines) (. Fig. 3.2.3 ).
5 Subperiosteal cortical resorption typically occurs in
the hand, especially at the radial aspect of the
middle phalanx, which is a specific sign seen in
both primary and secondary hyperparathyroidism
(. Fig. 3.2.4 ).
5 Brown tumor is seen as a well-circumscribed cystic
bony lesion which can cause bone expansion.
. Fig. 3.2.3 A lateral spine radiograph of a patient with
secondary hyperparathyroidism shows di use vertebral end
plate sclerosis (Rugger–Jersey spines)
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