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A previously healthy 10-year-old girl presents with a 5-month history of a non-productive, worsening cough.
Two months before, she was taken to her pediatrician, and a chest radiograph (CXR) was done. Concerns for an atypical pneumonia prompted a 5-day course of azithromycin, with no improvement of symptoms. Subsequently, a 1-week trial of a short-acting bronchodilator 4 times a day for a possible diagnosis of asthma failed to show any improvement.
More recently, she has had early satiety and a 15-pound weight loss over the last 2 months. Her mother has noticed her looking pale. She denies fever, chest pain, palpitations, orthopnea, wheezing, extremity swelling, hemoptysis, or syncope. There is no animal exposure, foreign travel, camping, or sick contacts. She was born full term and had no significant birth complications.
Physical examination reveals a normally developed child in mild respiratory distress, with a height of 154 cm (98th percentile); weight of 46 kg (92nd percentile), despite weight loss; body mass index of 19.4 kg/m2 (80th percentile); and a respiratory rate of 47 breaths per minute. At rest, oxygen saturation is 95%, but with minimal exertion it is found to be 65% and associated with oral cyanosis.
What are you thinking?
The diagnosis of asthma seems unlikely, given that she has been on a trial of a short-acting bronchodilator without any clinical improvement.1 The absence of fever, lack of improvement after treatment with azithromycin, and a 5-month duration of symptoms make community-acquired pneumonia less likely. Tuberculosis is a possibility, but on further questioning there are no risk factors elicited.
Other concerns include immunodeficiency, predisposing her to atypical fungal infections. A human immunodeficiency virus (HIV) screening test is sent and subsequently found to be normal. Other secondary immunodeficiency causes, such as malignancy, come into consideration.
Knowing that she has weight loss and progressive respiratory symptoms, Hodgkin's lymphoma seems possible. However, the CXR is not suggestive of a large mass in the mediastinum, and a lack of significant lymphadenopathy or night sweats is reassuring.
Another chronic condition that comes to mind is cystic fibrosis. It is less likely, given that she only started showing symptoms 6 months ago, but one must consider a sweat chloride test for evaluation. A sweat chloride test is performed on our patient and found to be normal.
In general, because she has never had any prior significant infection, any type of immunodeficiency is less likely. If present, structural abnormalities such as arteriovenous malformations (AVM) typically present with hemoptysis, mucocutaneous telangiectasia, nodules on CXR, and dyspnea. Of all these listed, she only has the dyspnea.
Family history of hereditary hemorrhagic telangiectasia would raise concern for AVM, but you confirm that her family history is negative for this condition. There is no swallow dysfunction or choking episode that would suggest an aspiration injury. With a normal neurologic exam and no peripheral weakness, a neuromuscular disease causing respiratory distress seems unlikely.