Endgames Case Review

A curious case of facial swelling in the night-time

BMJ 2015; 350 doi: http://dx.doi.org/10.1136/bmj.h1487 (Published 07 April 2015) Cite this as: BMJ 2015;350:h1487
  1. Joanna Quinn, foundation year 2 trainee1,
  2. Sophie Todd, specialist registrar, haematology1,
  3. Samir Agrawal, consultant2,
  4. Dimitris A Tsitsikas, consultant1
  1. 1Department of Haematology, Homerton University Hospital NHS Foundation Trust, London UK
  2. 2Department of Haematological Oncology, St Bartholomew’s Hospital, London, UK
  1. Correspondence to: J Quinn quinn.j{at}icloud.com

A 57 year old woman presented to the emergency department with swelling of the lips and oropharynx of one hour’s duration. Treatment for anaphylaxis was started but 30 minutes later she was much worse. After intubation, she was taken to the intensive care unit for airway management.

She had attended the emergency department with similar symptoms one month earlier and had been treated with chlorphenamine and discharged home with an EpiPen. A referral to the allergy clinic was made.

Her medical history included hypertension, although she had never received an angiotensin converting enzyme inhibitor. In addition, two years earlier she had been diagnosed with a B lymphoproliferative disorder, which was asymptomatic and under surveillance. She had no history of asthma but had reported facial swelling as a child after a bee sting. She had no known allergies, no family history of note, and took no regular drugs.

Blood tests showed haemoglobin 91 g/L (reference range 130-180), mean cell volume 78.4 fL(80-98), platelets 159×109/L (150-400), total white cell count 21.9×109/L(4.0-11.0), lymphocytes 8.5×109/L (1.0-4.0), and tryptase 1.45 µg/L (0-11.4).

A complement screen showed C1q 49 mg/L (50-250), C2 2.0 mg/L (14-25), C3 0.8 g/L (0.88-2.01), C4 <0.03 g/L (0.16-0.47), and C1 esterase inhibitor 54 mg/L (220-390).

Questions

  • 1. How would you interpret the blood results?

  • 2. What is the diagnosis?

  • 3. What could be the underlying cause?

  • 4. What is the treatment?

Answers

1. How would you interpret the blood results?

Answer

The low C2, C4, and C1q values are indicative of complement C1 esterase inhibitor deficiency. She also had microcytic anaemia.

Discussion

Complement is a major component of innate immunity. It mediates various pathways involved in the immune response, including the classical, alternative, and lectin pathways, which are activated in various inflammatory or infective processes.

C1-C4 are components of the classical pathway and are often low when …

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