Varieties. — The  chief  varieties  of  the  disease  depend  on  the  age  at  which
it  commences,  and  on  the  condition  of  the  muscles,  whether  they  are  large
or  small.  In  rare  cases  a  single  muscle  may  be  large,  and  the  rest  small,  as
in  Fig.  146,  in  which  only  the  vasti  were  increased  in  size.     Or  everywhere


PSEUDOHYPERTROPHIC    FORM.
387


and  from  the  first  the  muscles  are  smaller  than  normal,  and  they  progressively-
waste.  Such  cases  are  not  uncommon  ;  in  the  first  group  of  cases  described
(by  Meryon),  enlargement  of  muscles  was  inconspicuous.  Many  cases  in
which  all  muscles  are  small  belong  properly  to  the  form  considered  in  the
next  section.  The  cases  described  by  Meryon  are  generally  regarded  as
examples  of  pseudo-hypertrophic  paralysis,  but  they  present?  many  points  of
resemblance  to  the  "simple  atrophy  "  described  further  on.
Complications. — Congenital  mental  weakness,  due  apparently  to  defective
development  of  the  brain,  sometimes  complicates  pseudo-hypertrophic
paralysis.  In  rare  cases  there  have  been  indications  of  some  other  morbid
condition  of  the  central  nervous  system,  such  as  epilepsy.  It  is  uncertain
in  what  light  the  slight  occasional  affection  of  the  bladder  is  to  be  regarded,
whether  as  an  invasion  of  the  vesical  muscles  or  as  a  central  complication.
Fig.  147.
Gastrocnemius  muscle ;  muscular  fibres,  irregularly  narrowed  and  in  part
degenerated,  lie  among  tracts  of  nucleated  fibrous  tissue,  separated  by
adipose  tissue.
Vigoroux  has  recorded  a  case  in  which  the  symptoms  of  pseudo-hypertrophic
paralysis  were  combined  with  the  peculiar  rigidity  of  Thomsen's  disease.
Of  course  the  subjects  of  the  disease  are  liable,  like  other  children,  to  various
diseases  of  the  nervous  system,  such,  for  instance,  as  chorea,  which  brought
one  well-marked  case  under  my  notice,  but  these  are  merely  accidental
complications.
