Case #4 (02-20-2004)

[Andrew_Doan]

CC: 4 y.o. girl with failure to thrive, severe photophobia, and newly diagnosed renal insufficiency.

HPI: Child has always been in the lower 1/3 percentile for growth and development. Parents have noted child becoming increasingly photophobic. Child was recently admitted for "severe illness" and was diagnosed with renal insufficiency.

PMH/POH: No previous ocular or health problems.

Exam:

Vision 20/80 OU with line pictures.
IOP 16 mmHg OU
EOM Full OU
DFE normal OU
SLE notable for crystalline stromal deposits in the cornea from limbus to limbus OU.

Feel free to discuss the following:

What tests should you order (I'll post labs when asked for them)?

What's the differential diagnosis?

What's the diagnosis?

What is the treatment of choice, surgically and/or medically?

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[Kalel]

Diseases to rule out:

Fabry's disease: an X-linked disorder, so as a female, she would have the milder heterozygous form of the disease, making renal insufficiency highly unlikely at such a young age. In males, renal insufficiency in Fabry's disease typically doesn't occur until the patient until the patient reaches young adulthood. Corneal opacities may be present, but these do not cause photophobia. Cardiopulmonary symptoms would typically be more prominent as well.
Avillino Corneal dystrophy: Don't think that this disease is associated with renal insufficiency or failure to thrive/severe illness
Granular dystrophy: Not associated with renal insufficiency, corneal dystrophy typically not seen until adulthood too
Good-pastures: Typically pulmonary-renal disease, with no opthalmologic involvement
Multiple myeloma: extremely rare in young children, typically associated with ages 60+. Can be associated with renal insufficiency/failure, but not the photophobia. More prominent bone symptoms.
Familial hyperlipidemia: Is associated with corneal crystalline deposits, would expect to see a corneal arcus as well. Could be associated with renal insufficiency with renal artery stenosis, but more commonly associated with cardiac manifestations such as aortic stenosis and MI's. Would look for skin xanthomas. Not associated with photophobia.

Most likely diagnosis:

Cystinosis: is associated with renal insufficiency and photophobia during adolescence. Slit lamp exam should reveal corneal and conjuntival cystine crystals, which could be what is being described here.
-would get a chem-7, concern for Fanconi's syndrome
-urinanalysis and urine electrolytes
-would order a cystine level if PMN's or cultured fibroblasts from whatever lab does this test
-renal u/s
-check a TSH

Treatment: cysteamine (oral and ophthalmic drops), indomethacin, growth hormone with electrolyte correction and nutrional supplementation

Thanks for giving me something to do this saturday morning!

 

[Redhawk]

Fabry's (deficient alpha galactosidase A) typically causes a vortex keratopathy unlike that seen here.

Granular dystrophy looks different than this based upon the pictures I've seen. The "granules" are significantly larger and don't look like crystals but more "clumpy" even in the milder form.

Avellino dystrophy is genetically linked (chromosome 5) to both granular and lattice dystrophy and kinda looks like a mixture of the two with both linear opacities and dense sharply demarcated deposits. She doesn't appear to exhibit such features.

Schnyder dystrophy see above.

Multiple myeloma gives a band of punctate flaky opacities in the posterior stroma. These don't look flaky and appear to be present in the anterior stroma. A 4 year old with MM would seem quite unusual.

Cystinosis is associated with severe growth ******ation, renal failure, hepatosplenomegaly and hypothyroidism. Progressive crystal deposition in the conjuctiva and cornea lead to photophobia, blepharospasm and epi erosions. Based on her sx this would be my primary concern. Treatment apparently involves topical cysteamine.

 

[Andrew_Doan]

Do you prefer having a differential diagnosis poll for each case?

I think it's always helpful to think about the differential diagnosis in every case.

What do you think?

 

[Kalel]

I think that it'd be more fun if we weren't given a differential. When given a differential, all I have to do is look up the diseases presented in the differential to find the one that is most consistent with the case. It'd be more realistic without a differential being given too.

 

[Andrew_Doan]

Cystinosis

-Rare autosomal recessive disease, linked to chromosome 17p13.

-Incidence is 1:200-300K

-Cystine deposits in multiple tissues: kidneys, cornea, liver, brain, etc? Unlike Schnyder Corneal Dystrophy, the crystalline corneal deposits are limbus to limbus. In Schnyder Corneal Dystrophy, the crystalline corneal deposits are in the center of the cornea.

-Defect in cystine transporter.

-Treat with oral and eye drops of Cystagon (Cysteamine).

http://www.cystinosis.org/what_is_cystinosis.htm