UNEXPLAINED WEIGHT LOSS
History
Ehsan is seen in the paediatric clinic with his mother, who speaks little English. He is 12 years old, was born in Afghanistan and moved to the UK as a refugee 3 months ago. He was diagnosed with asthma when he was seen in the A&E department 4 weeks ago, on the basis of a chronic nocturnal cough. Today his mother is more worried about the fact that he has been losing weight and has had a poor appetite since coming to the UK. Ehsan is using salbutamol and beclometasone inhalers, which have not improved his cough. He has not yet been to school in the UK. He lives with his mother and three younger siblings in a damp two-bedroom flat and his mother has also been coughing a lot over the last month. His father died last year. They are uncertain which immunizations he has received, but he was healthy before coming to the UK. He has been feeling too tired to play games with his siblings for the last 4 weeks and he finds that his clothes are all much looser than when he arrived in the UK. His mother says that he sometimes feels hot, but she has not measured his temperature.
Examination
He is very thin, his height is 153 cm (75th centile) and his weight is 27 kg (second centile). His heart rate is 80 beats/min, his respiratory rate is 26/min, and oxygen saturation is 97 per cent in air. There is no wheeze but there are bronchial breath sounds in the right upper zone of his chest. There is no lymphadenopathy and his cardiovascular and abdominal examinations are unremarkable.
INVESTIGATIONS
Ehsan’s chest radiograph is shown in Figure 44.1.
Questions
• What further history is required?
• What does the chest radiograph show?
• What is the most likely diagnosis?
• What further tests are needed?
• What is the treatment?
Medicine
A history of weight loss with a chronic cough needs to be fully investigated. It is important to ask about the past medical history, family history and contact history with direct questions about tuberculosis. What happened to this boy’s father? (In fact, he died in Afghanistan after suddenly coughing up a large amount of blood.) Even if the immunization history is unknown, they may know if Ehsan has received the BCG (as this leaves a distinctive scar) and whether he has ever been treated for TB. Ask about the onset of the cough, whether it is productive, whether there is bloodstained sputum and if there is any chest pain or dyspnoea. Ask about exacerbating and relieving factors. Ask when the weight loss started and whether it is associated with abdominal pain, diarrhoea, malabsorptive (bulky, offensive) stools, nausea or vomiting. Also ask about night sweats.
Causes of weight losss
• Inadequate nutrition/neglect
• Gastro-oesophageal reflux
• Coeliac disease
• Inflammatory bowel disease
• Cystic fibrosis
• Anorexia nervosa
• Cardiac failure
• Chronic renal failure
• Diabetes mellitus
• Malignancy
• Infections, e.g. tuberculosis, HIV
The chest radiograph shows dense consolidation and cavitation in the right upper lobe. The most likely diagnosis is pulmonary tuberculosis. Ehsan’s father probably died from pulmonary tuberculosis and Ehsan’s mother probably also has pulmonary tuberculosis. Ehsan will require admission for investigation and treatment, with isolation whilst he may have mycobacteria in his sputum. The possibility of multidrug-resistant TB should be considered in view of his recent immigration from Afghanistan. The gold standard for diagnosis of tuberculosis is culture of the mycobacteria from clinical specimens. Unfortunately this is much more difficult to achieve in children than in adults, and only possible in less than 50 per cent of cases. More often the diagnosis is based on suggestive clinical and radiological features, history of exposure to TB, and results of tuberculin skin testing (TST). Interpretation of the TST is affected by prior BCG vaccination, and new tests based on the release of interferon-gamma from blood mononuclear cells in response to antigens present in TB but not in BCG may aid diagnosis further. Ehsan will require a tuberculin skin test, sputum to be collected for microscopy and culture, erythrocyte sedimentation rate, C-reactive protein, full blood count and liver function tests. It is more likely that his sputum will show acid-fast bacilli on microscopy, because he has cavitating pulmonary disease. Cavities are often teeming with mycobacteria. This presentation would be much rarer in younger children, who rarely have cavitating disease. If he is unable to expectorate sputum by himself, techniques to induce sputum production may be attempted, and gastric aspirates may be sent for mycobacterial culture (but their positive yield is much lower). Drug sensitivity testing will be needed on cultured specimens. Ehsan and his mother should be counselled for an HIV test, because HIV is an important risk factor for development of TB. Standard treatment for pulmonary tuberculosis should commence with four drugs: isoniazid, rifampicin, ethambutol and pyrazinamide. Pyridoxine is often given to adolescents to reduce the risk of isoniazid causing peripheral neuropathy. The rest of the family will need to be screened for evidence of active or latent tuberculosis. Latent tuberculosis occurs when a person has been infected with TB, but, rather than causing disease, the mycobacteria become dormant. Individuals with latent tuberculosis are generally not infectious to others but are at risk of developing active tuberculosis in the future. Chemoprophylaxis (a course of one or two anti-tuberculous drugs) is advised for latent infection. Tuberculosis is a notifiable disease and the incidence has been increasing in the UK. The majority of cases occur in non-UK-born young adults.
KEY POINTS
• Suspicion of tuberculosis should be high in children from high-incidence countries with a compatible clinical history.
• The likelihood of obtaining a positive sputum smear or culture in children with pulmonary tuberculosis is much lower than in adults.
• Diagnosis of tuberculosis is often made on the basis of likelihood of exposure, clinical and radiological findings and tuberculin skin testing.
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