LARYNX
CAUSES
A c u t e l a r y n g i t i s i s u s u a l l y c a u s e d b y a v i r a l
i n f e c t i o n , s u c h a s a c o l d . I t c a n a l s o b e d u e
t o
a n
a l l e r g y
o r
s t r a i n i n g
t h e
l a r y n g e a l
m u s c l e s . C h r o n i c l a r y n g i t i s m a y b e c a u s e d
b y o v e r u s i n g t h e v o i c e ; v i o l e n t c o u g h i n g ;
i r r i t a t i o n f r o m t o b a c c o s m o k e o r f u m e s ;
o r d a m a g e d u r i n g s u r g e r y A l c o h o l , p a r t i c -
u l a r l y s p i r i t s , m a y a g g r a v a t e l a r y n g i t i s .
SYMPTOMS
H o a r s e n e s s
i s t h e m o s t c o m m o n s y m p t o m
a n d m a y p r o g r e s s t o l o s s o f v o i c e . T h r o a t
p a i n o r d i s c o m f o r t a n d a d r y , i r r i t a t i n g
c o u g h m a y a l s o o c c u r . L a r y n g i t i s d u e t o
a v i r a l i n f e c t i o n i s
o f t e n a c c o m p a n i e d
b y f e v e r a n d a g e n e r a l f e e l i n g o f i l l n e s s .
TREATMENT
T r e a t m e n t d e p e n d s o n t h e c a u s e . A c u t e
l a r y n g i t i s d u e t o a v i r a l i n f e c t i o n u s u a l l y
d i s a p p e a r s b y i t s e l f . T h e r e
i s n o t r e a t -
m e n t f o r c h r o n i c l a r y n g i t i s o t h e r t h a n
r e s t i n g t h e v o i c e , t a k i n g m i l d a n a l g e s i c
d r u g s
( p a i n k i l l e r s )
i f
n e e d e d ,
u s i n g
s t e a m i n h a l a t i o n , a n d a v o i d i n g t o b a c c o
s m o k e a n d a l c o h o l . I f h o a r s e n e s s p e r s i s t s
f o r m o r e t h a n t w o w e e k s , m e d i c a l a d v i c e
s h o u l d b e s o u g h t i n o r d e r t o
e x c l u d e
t h e p o s s i b i l i t y o f l a r y n g e a l c a n c e r
( s e e
l a r y n x , c a n c e r o f
) . I n s o m e c a s e s , c h r o n i c
l a r y n g i t i s r e s p o n d s t o s p e e c h t h e r a p y .
la ry n g o s c o p y
E x a m i n a t i o n
o f t h e
l a r y n x
( v o i c e b o x )
u s i n g a m i r r o r h e l d a g a i n s t t h e b a c k o f
t h e p a l a t e ( i n d i r e c t l a r y n g o s c o p y ) , o r a
r i g i d o r f l e x i b l e v i e w i n g t u b e k n o w n a s
a l a r y n g o s c o p e ( d i r e c t l a r y n g o s c o p y ) .
L a r y n g o s c o p y i s p e r f o r m e d t o i n v e s -
t i g a t e
p a i n i n t h e
t h r o a t ;
d i f f i c u l t y
i n
s w a l l o w i n g ;
p e r s i s t e n t h o a r s e n e s s ;
a n d
a b n o r m a l n o i s e s d u r i n g b r e a t h i n g ( s u c h
a s
s t r i d o r
).
I n d i r e c t
l a r y n g o s c o p y
c a n
s h o w c l e a r a b n o r m a l i t i e s , s u c h a s i n f l a m -
m a t i o n , p a r a l y s i s o f t h e v o c a l c o r d s ( s e e
l a r y n g e a l n e r v e p a l s y
),
s i n g e r ’s n o d e s
,
o r
t u m o u r s .
D i r e c t
r i g i d
l a r y n g o s c o p y
i s
u s u a l l y p e r f o r m e d u n d e r g e n e r a l a n a e s -
t h e s i a , a n d d i r e c t f l e x i b l e l a r y n g o s c o p y
i s u s u a l l y c a r r i e d o u t u s i n g l o c a l a n a e s -
t h e s i a . T h e s e t e c h n i q u e s e n a b l e d o c t o r s
t o
e x a m i n e
t h e
t i s s u e s
o f t h e
l a r y n x
m
o r e c l o s e l y , a s w e l l a s t o t a k e a
b i o p s y
( s a m p l e
o f t i s s u e )
o r
r e m o v e
f o r e i g n
b o d i e s o r b e n i g n t u m o u r s .
la ry n g o tra c h e o b ro n c h itis
I n f l a m m a t i o n o f t h e
l a r y n x
( v o i c e b o x ) ,
t r a c h e a
( w i n d p i p e ) , a n d
b r o n c h i
( m a i n
a i r w a y s t o t h e l u n g s ) , c a u s e d b y a v i r a l
o r a b a c t e r i a l i n f e c t i o n . T h e d i s o r d e r i s
u s u a l l y m i l d b u t i n s o m e c a s e s c a n b e
l i f e - t h r e a t e n i n g . I t i s a c o m
m o n c a u s e o f
c r o u p
i n y o u n g c h i l d r e n .
la ry n x
T h e o r g a n i n t h e t h r o a t r e s p o n s i b l e f o r
v o i c e p r o d u c t i o n , c o m m o n l y c a l l e d t h e
v o i c e b o x .
I t
l i e s
b e t w e e n
t h e
p h a r y n x
( t h r o a t ) a n d t h e
t r a c h e a
( w i n d p i p e ) .
STRUCTURE AND FUNCTION
T h e l a r y n x c o n s i s t s o f a r e a s o f
c a r t i l a g e
,
t h e l a r g e s t o f w h i c h i s t h e t h y r o i d c a r t i -
l a g e ,
w h i c h
p r o j e c t s
f o r w a r d s
t o f o r m
t h e A d a m ’s a p p l e . B e l o w t h e t h y r o i d c a r -
t i l a g e
i s
t h e
c r i c o i d
c a r t i l a g e ,
w h i c h
j o i n s i t t o t h e t r a c h e a . S i t u a t e d o n t h e
b a c k
o f t h e
c r i c o i d
c a r t i l a g e
a r e
t w o
p y r a m i d - s h a p e d
s t r u c t u r e s
c a l l e d
t h e
a r y t e n o i d c a r t i l a g e s . T h e
i n s i d e
o f t h e
l a r y n x i s l i n e d w i t h m u c o u s m e m b r a n e .
W
i t h i n
t h e
l a r y n x ,
s t r e t c h i n g
b e t w e e n
t h e t h y r o i d a n d a r y t e n o i d c a r t i l a g e s , a r e
t w o f i b r o u s s h e e t s
o f t i s s u e c a l l e d t h e
v o c a l c o r d s
.
T h e c o r d s v i b r a t e t o p r o d u c e
v o c a l s o u n d s w h e n a i r f r o m t h e l u n g s
p a s s e s t h r o u g h t h e m . T h e s e v i b r a t i o n s
a r e m o d i f i e d b y t h e t o n g u e , m o u t h , a n d
l i p s t o p r o d u c e
s p e e c h
.
A t t a c h e d
t o
t h e
t o p
o f t h e
t h y r o i d
c a r t i l a g e
i s
t h e
e p i g l o t t i s
,
w h i c h
i s
a
l e a f - s h a p e d f l a p o f c a r t i l a g e t h a t c l o s e s
L
DISORDERSOFTHE LARYNX
Disorders of the
l a r y n x
(voicebox)
usually cause
h o a r s e n e s s ;
other
symptoms of a disorder include
breathing difficulties,
s t r i d o r
(an
abnormal sound during breathing),
sore throat, and coughing.
Inflammation
L a r y n g i t i s
(inflammation of the
larynx) is the most common
laryngeal disorder in adults.
C r o u p
(inflammation of the airways) is
common in young children, up to
the age of about four. Much rarer
is
e p i g l o t t i t i s
(inflammation of the
epiglottis, the flap of cartilage that
covers the larynx).
Congenitaldefects
Rarely, a baby is born with a soft, limp
larynx and epiglottis, a condition called
laryngomalacia. This defect causes
noisy breathing (see
l a r y n g e a l s t r i d o r ) .
Tumours
Various kinds of noncancerous
tumour may develop on the vocal
cords. The most common is a
p o l y p
(a noncancerous swelling caused by
smoking, an infection such as
influenza, or straining the voice).
Warts and small noncancerous
growths called
s i n g e r ' s n o d e s
can also
occur on the vocal cords. The larynx
may also develop cancerous tumours
(see
l a r y n x , c a n c e r o f ) ,
which may cause
persistent hoarseness.
Other disorders
Lesions, infection, or other disorders
affecting the throat tissues, or surgery
on the throat, may damage the nerves
supplying the larynx. As a result, one
or both of the vocal cords may become
paralysed (see
l a r y n g e a l n e r v e p a l s y
).
INVESTIGATION
Disorders of the larynx are investigated
by
laryngoscopy.
Sometimes a
biopsy
sample is taken.
459
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