Not-so-simple arm pain

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Sometimes the chief complaint is not the problem

It’s a busy night and you’re in “fire fighting mode”, sorting out what is urgent and what can wait. On first pass, the kid in room three seems to fall into the latter category. She’s a 17-year-old girl with right arm pain. Fine. You dispatch the intern to look into it while you take care of a few dozen other things.
The intern emerges some time later to tell you the story. Her arm starting hurting last night. There was no precipitating trauma or event, she just noticed it while she was studying.
She’s here because it isn’t any better. She has no significant past medical history. She smokes, is on no meds, doesn’t do sports and isn’t taking PE class this year. Her exam is reported as diffuse, poorly localizing right upper arm pain. She has good range of motion. The intern wants to offer her something for pain and check an X-ray. Sounds OK. But having supervised a few interns in your day, you ask for the rest of the exam. Nothing to speak of, it turns out. What about the vital signs?
Oops, almost forgot that. The intern pulls up the nurse’s note and does a double take. The BP is 174/100. Wow, that’s got your attention.
You go in to see this kid. She appears fairly comfortable, despite the chief complaint of pain. She denies headache, vision changes, shortness of breath, swelling, palpitations, drug ingestions, h/o urinary tract infections, in short, she feels just fine except for her right arm. She denies ever having had high blood pressure before, but hasn’t seen a doctor in a while. On review of systems, she has had some problems with menstrual irregularity, occasional dizziness and headaches but denies these at the present time. You repeat the blood pressure and it’s 150/100.
That’s still pretty high for a 17-year-old. She’s thin and the cuff size seems adequate. You direct your exam toward identifying any end organ damage, but you don’t find any evidence for CHF and her neurologic and fundoscopic exams are normal. She has a soft flow murmur but no gallop rhythm and her lung fields are clear. She has equal pulses in all four extremeties. You can’t hear any bruit or feel enlarged kidneys. Her arm exam is pretty much what the intern told you and not all that exciting. You decide to recheck her BP again after she’s had something for pain.
OK, this merits some investigation. The list of causes for hypertension is long and distinguished. You decide to hit some of the highlights. You order a pregnancy test to r/o toxemia, a UA and some chemistries to explore the possibility of renal disease, a TSH, a CBC and ESR.
Results are trickling back. Her BP after percocet is not much better. Her urine pregnancy test is negative. Her shoulder film is fine. Her TSH is normal and her ESR unremarkable, her UA is unremarkable. But that’s the end of the good news. Her BUN is 60 and her creatinine is 6.9. And she’s severely anemic with a Hgb of 5. It’s amazing she has so few symptoms, she must have been this way a while.
You call the Pediatric Nephrologist and arrange to admit her. The next day she has a renal ultrasound which shows small, kidneys with loss of corticomedullary differentiation bilaterally. Most likely she has had dysplastic kidneys from birth and has slowly progressed to renal failure. She is started on dialysis. No etiology determined yet for her right arm pain but they’re still working it up.
Looking back, there wasn’t anything in the patient’s story or exam that would have lead you to this diagnosis. It was all in the vital signs – so keep checking! In a patient with mildy elevated BP in the ED, even if pain or anxiety is the likely cause, it might be prudent to have them follow up with their own physician when they’re well just to make sure the BP returns to age-appropriate norms.
Amy Levine, MD is an assistant professor of pediatric EM at UNC Chapel Hill.

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