Discussion
Both NF1 and SCD individually may cause unique complications that when
combined can be worsened. Patients with sickle cell disease have an
increased risk of vasculopathies. NF1 has been shown to increase the
risk of peripheral and cerebral vascular abnormalities in the pediatric
patient. Neurofibromatosis type 1-associated vasculopathy is an acquired
condition that can affect all sized vasculature, most notably causing
aneurysms or stenoses of the aortic, renal and mesenteric
circulation6. Therefore, routine screening for
hypertension is recommended due to renovascular disease as well as
coarctation of the aorta7. Additionally, moyamoya
disease and other cerebral vasculopathies have been routinely observed;
therefore, screening with an MRV/MRA brain is recommended for evaluation
of moyamoya, arteriovenous malformation, and
strokes8.
Similarly, SCD increases the risk of micro and macro vasculopathies,
which causes the development of pulmonary hypertension, stroke, leg
ulcerations, priapism, and other organ dysfunctions9.
In this patient, her MRI brain showed a remote infarct in the right
frontal lobe showing a silent stroke. Both her NF1 and SCD increases her
risk of having strokes, pulmonary hypertension, and other vascular
complications that need routine screening9-11.
IH can be caused by cerebral vascular abnormalities including
intracranial venous sinus thrombosis and venous sinus
stenosis12. Several reports have shown occurrence of
cerebral venous and sinus thrombosis in SCD and
NF113-14. Other causes of intracranial hypertension in
NF1 include intracranial mass as well as aqueductal
stenosis3,15. This patient had no vascular or
structural abnormality noted on brain imaging.
Many studies have shown a relationship between IH and
SCD4-5. Hydroxyurea increases fetal hemoglobin, which
has been reported to cause IH and increased risk of cerebral vascular
abnormalities16-17. When hydroxyurea was discontinued,
the IH improved in some patients4-5. In our patient,
after discontinuing hydroxyurea and starting acetazolamide, her OCT RFNL
became normal. Her fetal hemoglobin dropped to 15.7%. We are unable to
determine if hydroxyurea was the cause of IH or if she developed
idiopathic intracranial hypertension, since the increased pressure
resolved with both the discontinuation of hydroxyurea and usage of
acetazolamide. Prospective evaluation of patients such as the one
presented are needed in order to determine if increases in fetal
hemoglobin cause IH or if another etiology may be to blame.
Additionally, more genetic studies are needed to show if there is a link
between NF1 and SCD.