Week of 31 August – 6 September 2026¶
Should we perform bone marrow biopsies in patients with ITP?¶
Answer: Bone marrow biopsy is not required to diagnose ITP — this has been shown in multiple studies. However, this is a nuanced decision in patients over 60 years old and should be made on a case-by-case basis, given the higher prevalence of hematological disorders in this population.
- The ASH 2019 ITP guidelines recommend deferring bone marrow examination: a grade 2C recommendation in adults and grade 1B in children.
- More recent Ontario population-based data (ICES) show an increased risk of hematological malignancy — particularly myeloid — in patients over 60 (PubMed). This has not yet changed recommendations on bone marrow sampling, but has altered our own approach: we follow these patients closely and keep a low threshold to biopsy if any atypical features arise.
- For a concise overview, see this in-a-nutshell review (BJH).
Source: American Society of Hematology 2019 guidelines for immune thrombocytopenia
What are the bleeding manifestations of vitamin C deficiency?¶
Answer: Scurvy causes bleeding from capillary and connective-tissue fragility due to impaired collagen synthesis. Manifestations include:
- Perifollicular hemorrhages — corkscrew or "swan-neck" hairs
- Petechiae, ecchymoses, and palpable purpuric lesions — present in ~80% of patients
- Splinter (subungual) hemorrhages
- Spontaneous hematomas and poor wound healing
- Other: gingival and oral bleeding in dentate patients; ophthalmic bleeding (flame-shaped retinal hemorrhages, eyelid/periorbital hemorrhage); musculoskeletal bleeding, reported in children
Onset typically follows 1–3 months of near-absent vitamin C intake, and spontaneous bleeding characteristically ceases within hours to days of repletion. See also Water-Soluble Vitamins: Deficiency and Excess (Pediatrics in Review).
Source: Severe scurvy: an underestimated disease
What data supports the use of sirolimus in refractory ITP?¶
Answer: Sirolimus (an mTOR inhibitor) is an off-label, second-line option for relapsed/refractory ITP, supported by small prospective single-arm trials, retrospective cohorts, and one randomized pediatric trial.
Adult data:
- Prospective open-label single-arm study, 86 patients: ORR 85% at 3 months, 70% at 6 months, 65% at 12 months. Responses were better in patients under 40 or with steroid-dependent disease, and responders showed reduced Th2/Th17 cells with increased Tregs and M-MDSCs.
- Single-center study, 20 patients: ORR 60% at 3 months.
- Multicenter cohort, 45 patients: 38/45 responded, 28 in complete response at end of follow-up.
Pediatric data:
- RCT of sirolimus vs cyclosporine: both produced a significant platelet increase, with a ~50% response rate.
Our experience: better responses in AYA (adolescent and young adult) patients and those with T-cell abnormalities on flow, even if not clonal. Typical dose is 2–4 mg/day, though responses have been seen at doses as low as 1 mg.