Coughing and swollen joints
Thabisa, a 10 year old girl, living in rural South Africa, is brought to the local district clinic by her mother with a 4 month history of swollen ankles and a swollen left elbow. Her mother has noted that the joints are warm and tender on movement. The joints are more painful in the mornings with stiffness lasting about 40 minutes after getting out of bed.
Thabisa has had increasing difficulty keeping up with the other girls when walking the 2 kilometres to the farm school every day. She is also more tired than usual, has lost weight over the past months and has developed a cough for the past few weeks. Even though it is cold at night in the house where the family lives together, her mother has remarked how she is sweating sometimes at night.
She is the third child of five in her family. She was previously a healthy child and had been growing normally. She has received all her routine vaccinations and she only suffered from the occasional cold and flu as a child. Even though the family is not well off, the parents are both employed on the farm where they live, they have a stable income and no shortage of food.
On examination, Thabisa walks with a slight limp and she is underweight for age. She is apyrexial and her general examination is otherwise unremarkable. Her chest is clear on auscultation. On musculoskeletal examination both ankle joints are mildly warm and swollen. There is some swelling of the left elbow. She can move all joints freely but she has restricted range of movement of the ankles and she can cannot fully extend her elbow.
What is the diagnosis?
This is likely Poncet's disease - i.e., a form of reactive arthritis related to Tuberculosis (TB).
The high index of suspicion or diagnosis of TB is made from the history, clinical presentation, a positive mantoux or Tuberculin Skin Test and radiographic changes. Confirmation of diagnosis relies on culture of the organism from sputum, biopsy or fine needle aspirate from bone or synovial fluid.
Remember that patients who have TB may also have co-existent infection with Human Immunodeficiency Virus [HIV].
Suspecting TB requires a thorough history to include questions about:
- Loss of weight, night sweats, chronic cough for more than 2-3 weeks, chronic abdominal distention, lethargy or reducing activity/energy levels; these may suggest disseminated TB.
- Social circumstances including history of overcrowding, poor ventilation, positive TB or symptomatic contacts that have primary, secondary or multi-drug resistant TB.
- Previous history of TB (and management thereof), on past medical history.
- Human Risk factors for HIV exposure (sexual, vertical transmission from mother, intravenous drug use, contaminated blood products) or confirmed HIV testing of the child and treatment thereof.
More information is available from the Centre for Disease Control and Prevention
Further information about TB is also available in the Investigations, Limping Child and Arthritis modules of pmm.