Hip disease in a child can present as: (1) A painful hip. (2) A painful hip and a painful, but otherwise normal, knee, due to the referral of pain along the obturator nerve. (3) A painful knee with no pain in the hip. (4) A painless limp. Some hip disease is potentially so serious, that everyone delivering primary care should be on the look out for these four signs, which may be due to several diseases. The most important ones not to miss are the infective ones, especially tuberculosis and septic arthritis, because they need early treatment[md]septic arthritis needs it in the first few hours! The least serious condition is a poorly understood one known as known as ''transient synovitis', which may recover spontaneously, or proceed to Perthes' disease. In the early stages some causes of an irritable hip may be indistinguishable from one another, so observe the child carefully.
A PAINFUL HIP [s7]PARTICULARLY IN CHILDREN DIFFERENTIAL DIAGNOSIS. Don't forget that abdominal and spinal conditions can also cause pain in the hip. Remember also the possibility of disease near the hip (periadenitis, ]]pyomyositis, etc.[md]see Sections 5.12, 7.1). In Zambia the causes of a painful hip in a child are approximately as follows, in decreasing order of frequency
Suggesting transient synovitis[md]no X-ray changes, spontaneous resolution in a few weeks without further episodes. Some cases are viral, notably those due to the parovirus, and several joints may be involved. There may be a history of mild trauma.
Suggesting septic arthritis/osteomyelitis (7.18, 7.10)[md]an acute onset, often in a few hours. His hip is acutely painful, and he cannot move it in any direction. The general symptoms of an acute infection. There are no bony changes for about 2 weeks. If the film is a good one you may see displacement of the fat shadow, or a widened joint space, indicating fluid in his hip joint. Partially treated cases are more difficult to distinguish clinically and by X-ray.
Suggesting sickle-cell disease[md]pain in other parts of the body also. A positive sickle-cell test.
Suggesting rheumatic fever[md]age 5 to 20 years. Transient symptoms and the involvement of other joints.
Suggesting tuberculosis (29.3)[md]any age, but common in childhood and adolescence. Generalized rarefaction of the bone round the joint, localized areas of erosion, a joint space which is either narrowed or widened.
Suggesting Perthes' disease (27.14)[md]age 4 to 9 years (occasionally 2 to 18 years). His hip is slightly painful when you move it, and all movements are slightly to moderately diminished. No general symptoms. X-rays as in Fig. 27-16.
Suggesting rheumatoid arthritis[md]from childhood to 40 years (at the onset). The involvement of several joints is usual, although monarticular disease does occur.
Suggesting gonococcal disease or Reiter's syndrome[md]a urethral discharge, conjunctivitis and/or anterior uveitis. A gonococcal arthritis is usually acute. Reiter's syndrome often follows a chlamydial infection, for which tetracycline may be beneficial.
Suggesting a slipped epiphysis (77.10)[md]age 12 to 18. Usually a history of an acute onset, sometimes with a fall. X-rays show slipping of the upper femoral epiphysis as in Fig. 77-9. A fixed external rotation deformity.
CAUTION ! (1) If you diagnose transient synovitis, follow up the child carefully[md]some of these children develop Perthes' disease later. (2) Pain in the knee is often due to hip disease.
A PAINFUL HIP IN A YOUNG CHILD IS INFLAMMATORY, UNTIL PROVED OTHERWISE