Friday, December 28, 2007

X Marks the Spot

On your last day of pediatric preceptorship, you see a 13 year old boy complaining of "weird spots" on his lower abdomen and butt. He also says that since a few years ago, he often has burning pain in his hands and feet, especially when he has a fever. This pain radiates proximally and is sometimes relieved with rest. On exam, you notice the following two findings (the second is seen by the slit-lamp):

When you ask the patient about his family history, he tells you that his uncle on his mother's side recently received a kidney transplant. This uncle also has skin lesions and extremity pain.

Challenge: What is your diagnosis?

Related Questions:
1. What is the skin finding?
2. What is the eye finding?

This case written by Kate Dinh.
Both images shown under fair use.

5 comments:

Future doctor scientist said...

xeroderma pigmentosum
not sure about eye finding?

Alex said...

don't have an answer this time.

thought skin looked like ACTH

thought eye looked like copper ring in Wilson's Disease.

since neither of them matched, I would guess it's one of those metabolic disorders I don't know (looked up hemochromatosis but it didn't match) or a vasculitis that I don't know.

Craig said...

This one is harder. Hint: it's one of those biochem diseases, and since UCSF doesn't really teach biochem, it's not covered in the curriculum (but other schools teach it!).

Alex said...

doesn' it involve angiokeratomas?

Craig said...

X Marks the Spot

This is Fabry disease, an X-linked lysosomal storage disorder due to a mutation in lysosomal hydrolase alpha-galactosidase A that results in accumulation of globotriaosylceramide. This is a deficiency in the breakdown pathway of globoside, a glycosphingolipid in the red cell membrane and the kidney. It is metabolized in lysosomes, and in the absence of degradation, it can accumulate in the vascular endothelium, ganglia, renal glomerular and tubular cells, cardiac muscle cells, valvular fibrocytes, and the cornea.

Clinical manifestations include severe neuropathic or limb pain precipitated by stress, temperature extremes, and physical exertion; telangiectasias and angiokeratomas (characteristic of this disease, shown in the first image, commonly in the groin, hip, and periumbilical areas); asymmetric corneal deposits (cornea verticillata, shown in the second image, do not affect visual acuity); renal failure with polyuria or polydipsia; cardiac involvement including LV hypertrophy, heart failure, coronary artery disease, valve abnormalities, and conduction abnormalities; and CNS involvement with TIAs and stroke.

Sources: Kate Dinh; UpToDate; NEJM; Washington University in St. Louis (neuro.wustl.edu).