Megan is a 41 year old charity worker who is midway through the second trimester of her first pregnancy. She conceived after many years of infertility including a failed course of IVF but otherwise has been fit and well and has no other previous medical history.
Megan presented to her GP at 18 weeks because of persistent lower back pain and fatigue. This was interpreted to be induced by her pregnancy, no tests were done and she was told to take paracematol and iron supplements.
Two weeks later, Megan went for her 20 week anomaly scan. There, the midwife noticed her pain and immobility and asked the obstetrician to see her. Megan described her back pain, explaining that it had increased since she saw her GP and that the pain was now aggravated by movement. She also reported new pain in the right pelvis, continuing fatigue and polydipsia.
Concerned by the problems described, the obstetrician ordered further blood and urine tests and an MRI of the lower vertebral column and pelvic girdle.
Blood results revealed:
- Haemoglobin level of 84g/L (range 120 – 160g/L)
- Platelet count of 105 x 109 cells/L (range 150 – 400 x 109/L)
- White blood cell count of 4.8 x 10/L (range 4 – 11 x 109/L)
- Neutrophil count of 2.2 x 109/L (range 2.5 – 7.5 x 109/L)
- Serum protein 74g/L (range 64 – 83 g/L)
- β2-microglobulin (1.91 mg/L (range 0.3 – 1.9 mg/L)
- Albumin levels 40g/L (range 35 – 50 g/L) were all normal
However, corrected serum calcium was raised at 3.2mmol/L (range 2.15 – 2.6 mmol/L) and there was substantial proteinuria (total protein 3.5g/24h) although no evidence of renal impairment (serum creatinine 52.2mmol/L; range 45.0 – 110mmol/L) or elevated blood pressure (120/80).
MRI revealed pathological fractures of the fourth and fifth lumbar vertebrae and significant bone marrow infiltration as shown by extensive alterations in T1- and T2-weighted sequences. There were no neurological symptoms.
Megan was subsequently referred to haematology for further investigation.
A serum free light chain test found κ light chain levels were highly elevated at 7229mg/L (range 3.3 – 19.4 mg/L). All other immunoglobulins were reduced with IgG at 2.58g/L (range 7 – 16g/L), IgA at 0.3g/L (range 0.7 – 4g/L) and IgM < 0.22g/L (range 0.4 – 2.3g/L). A bone marrow biopsy showed 60% plasma cell infiltration and a full body MRI confirmed the fractures, but there were no indications of extramedullary disease.
Megan was diagnosed with k light chain myeloma, Durie-Salmon Stage IIIA and International Staging System (ISS) I.