Denouement Hot Seat #16: Ankle Swelling and Pain

by Naomi Hughes, Children's National
with Jennifer Chapman on the Hot Seat

The Case
This is a case of a 3 year old boy who presents with acute on chronic, intermittent ankle pain and swelling that started while visiting family in Ghana. For complete case presentation click here.

Thank you to Dave, Pavan, Theresa, and Joelle on their perspectives on this challenging case. Please click here to read their comments (scroll up).

Here's how you answered our questions:

1. Which ONE of he following tests would be most useful in determining your management in this case?

One person suggested getting a TB test, presumably a PPD.

Now, you also got his ankle film and is read as "persistent calcinosis of the left ankle."

He has received Toradol and can now walk but with a significant limp. The patient has a readily available PMD and appropriately concerned parents. Orthopedics does not think anything needs to be done tonight. Assume your laboratory evaluation thus far is normal.

2. What is your disposition for this patient?

Four people said their consult would be Infectious Diseases and one each said orthopedics, rheumatology, and oncology. Two people said their disposition depended on consult but did not specify which consult.

Hot Seat Response
by Jennifer Chapman
I am sooo hoping I am on the hot seat because this is a tropical disease. Alas, probably not. The first time I read this through, I was thinking of a differential for sub-acute monoarticular arthritis. But on re-read, the problem is the non-mobile painful mass anterior to the ankle that limits movement, with calcified mass on Xray. The exam helps me quickly dismiss a bacterial abscess because there is no erythema or fluctuance to make me think we should incise and drain. I also see that he is tachycardic and hypertensive for age; so this needs to be repeated before knowing if there is significance to these vitals.

So now the differential I am focused on is the cause of calcinosis with intermittent swelling and pain. What causes calcium to deposit in the skin? Some I knew and some I looked up:
- trauma: blood can calcify in the process of reabsorbing; foreign body such as teeth left behind – these are easy to figure out by history. Not certain why pain/swelling would be intermittent other than reinjury.
- hypercalcemia: finding an abnormally high calcium would only be the beginning of a work-up. The differential would include oncologic causes (NHL, neuroblastoma), endocrinologic causes (hyper PTH), medications (Vit A or D excess, others such as lithium), and chronic renal failure. Clinically, hyperCa presents with fatigue and muscle weakness, bradycardia and sometimes hypertension—so not likely if his exam is otherwise normal.
- as Joelle found, there is tumoral calcinosis: the calcification accumulates near the joint capsule, with normal labs except for sometimes hyperphos. This is a familial disease and usually in more than one place.
- dermatologic disease: scleroderma can cause calcinosis as part of CREST syndrome (calcinosis, Raynaud’s, esophageal dysmotility, sclerodactyly, telangiectasia). Scleroderma is obviously much more common in adulthood, but there are children diagnosed with this autoimmune disease. A careful skin exam and questions about Raynaud’s will help. Not sure if bolded hyperpigmented macule on thigh is significant in pointing to derm diagnosis.
- infections: specific tropical diseases leave calcifications- onchocerciasis (river blindness- not likely with short trip to Ghana); guinea worm (checked Carter Center website and no cases of indigenous guinea worm in Ghana since May 2010- yeah eradication program); cystocercosis (cysts and calcifications found in brain and wouldn’t find their way to anterior ankle). Granulomatous diseases such as TB also need calcifications, but of LNs. Still a possibility given trip to Ghana, brief rash on his right leg (site of infestation), and intermittent nature (cysts dying with skin becoming tender and inflamed).

So, given this differential, I would do the following:
1. check bmp, Ca, phos, PTH—more testing only if these are abnormal
2. discuss with radiologist their differential for this calcified mass. I don’t think other imaging studies are indicated.
3. Agree with previous comments about discussion with Ortho about their thoughts.
4. ask Derm for their input, since a few of these diagnoses fall under their specific expertise. I would not keep him in the ED for this, nor would I admit the child. But I would communicate with the Derm resident to have him scheduled for clinic.

The Denouement
by Naomi Hughes

Patient admitted for 3 days.

Skeletal survey to look for other sclerotic/lytic lesions. – final read negative except for left ankle.

MRI of left ankle: non-aggressive heterogenous mass which appears to arise from the tibial physis. Possible etiologies include osteochondroma or epiphyseal exostosis (trevor’s disease). During hospitalizations, pt improving to where he will walk on left leg, but still dragging left leg behind.

Prior testing from ID and rheum also showed negative inflammatory markers, negative workup for calcium phosphorus abnormalites (LDH, Aldolase, Calcium, phosphorus, magnesium, as well as urine phosphorus and urine calcium), negative titers for ASO, Lyme, Brucella, and mycoplasma. Discharged with plans to follow up with orthopedics for a biopsy as an outpatient.

Ortho note from 3/7 reports – ddx from their standpoint is Trevor’s disease vs intra-articular osteochondroma.
Plan is a CT with thin cuts to determine if it really is as stalk attaching to the anterior tibial epiphysis, as indicated on the MRI.
After the CT – they will decide to excise the lesion vs only biopsy for diagnostic purposes.

So – the saga goes on.

The Hot Seat is a recurrent online case series aimed at facilitating asynchronous sharing of PEM knowledge and experience. Faculty are placed on The Hot Seat and publish their opinions without knowing the case or its outcomes. Cases are written by PEM fellows at Children's National in DC, Johns Hopkins in MD, and INOVA Fairfax in VA. Emily Willner is the faculty advisor on case presentations. We welcome your commentary.