Chronic Histiocytic Intervillositis (CHI) is a rare placental inflammatory disorder associated with placental insufficiency, fetal growth restriction, and adverse pregnancy outcomes. Diagnosis is typically made retrospectively on placental histopathology, and there are limited clinical markers that may suggest its presence during pregnancy.
Here, we describe a pregnancy complicated by newly diagnosed triple positive antiphospholipid antibodies in which an extreme elevation of alkaline phosphatase (>1000 U/L) prompted investigation. Isoenzyme fractionation confirmed a placental source, and the biochemical abnormality coincided with a decline in fetal growth trajectory. Placental histopathology following delivery demonstrated CHI with characteristic macrophage infiltration of the intervillous space.
In detail, LB is a lady in her 30s, with previously normal pregnancies and deliveries at term. This pregnancy, at 13 weeks, she was found to be triple positive for anti phospholipid antibodies during work up of mild thrombocytopaenia at booking. At 37 weeks, she developed an isolated ALP rise > 1000. She was asymptomatic at the time with no family or past medical history of bone or liver disease. She was vitally intact, other liver enzymes and a coagulation profile were normal. Similarly, growth scans were normal until approximately 30 weeks when a reduction in EFW seen. Postpartum, on histopathology the diagnosis of CHI was confirmed. On a literature review, 80% of cases with ALPs in the 1000s can be a/w preterm delivery, low birth weight. A fall in estimated foetal weight can confirm placental dysfunction. Maternal autoimmune disease can pre-dispose to this condition and lead to high risk pregnancies.