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child is seriously ill, is delirious at night, develops bed-sores over
the sacrum and, it may happen that, not being expected to recover, the
legs are allowed to assume contracture deformities with ankylosis or
dislocation at the hip and flexion ankylosis at the knees; should the
child survive, the degree of crippling may be pitiable in the extreme;
prolonged orthopaedic treatment and a series of operations--arthroplasty,
osteotomies, and resections--may be required to restore even a limited
capacity of locomotion.

#Pneumococcal affections of joints#, the result of infection with the
pneumococcus of Fraenkel, are being met with in increasing numbers. The
local lesion varies from a _synovitis_ with infiltration of the synovial
membrane and effusion of serum or pus, to an _acute arthritis_ with
erosion of cartilage, caries of the articular surfaces, and
disorganisation of the joint. The knee is most frequently affected, but
several joints may suffer at the same time. In most cases the joint
affection makes its appearance a few days after the commencement of a
pneumonia, but in a number of instances, especially among children, the
lung is not specially involved, and the condition is an indication of a
generalised pneumococcal infection, which may manifest itself by
endocarditis, empyema, meningitis, or peritonitis, and frequently has a
fatal termination. The differential diagnosis from other forms of
pyogenic infection is established by bacteriological examination of the
fluid withdrawn from the joint. The treatment is carried out on the same
lines as in other pyogenic infections, considerable reliance being
placed on the use of autogenous vaccines.

In #measles#, #diphtheria#, #smallpox#, #influenza#, and #dysentery#,
similar joint lesions may occur.

The joint lesions which accompany #acute rheumatism# or "rheumatic
fever" are believed to be due to a diplococcus. In the course of a
general illness in which there is moderate pyrexia and profuse sweating,
some of the larger joints, and not infrequently the smaller ones also,
become swollen and extremely sensitive, so that the sufferer lies in bed
helpless, dreading the slightest movement. From day to day fresh joints
are attacked, while those first affected subside, often with great
rapidity. Affections of the heart-valves and of the pericardium are
commonly present. On recovery from the acute illness, it may be found
that the joints have entirely recovered, but in a