Question 12.2

Created on Wed, 05/13/2015 - 00:09
Last updated on Fri, 04/28/2017 - 19:27
Pass rate: 91%
Highest mark: 9.4

Other SAQs in this paper

Other SAQs on this topic

A 72-year-old man is admitted to ICU post-operatively for multi-trauma following a motor vehicle crash. 10 days post admission he develops a new fever. Septic screen results are pending and the full blood count is as follows:

Parameter

Result

Normal Range

Haemoglobin

76 G/L*

130 – 175

White Cell Count

15.8 x 109/L*

4.0 – 11.0

Platelets

1211 x 109/L*

150 – 450

Reticulocytes

220 x 109/L*

10 – 80

Neutrophils

10.4 x 109/L*

1.8 – 7.5

Lymphocytes

2.06 x 109/L

1.5 – 4.0

Monocytes

2.54 x 109/L*

0.2 – 0.8

Eosinophils

0.48 x 109/L*

0.0 – 0.4

Haematocrit

0.26*

0.4 – 0.52

MCV

92 fl

82 – 98

MCH

29.9 pg

27.0 – 34.0

MCHC

326 g/L

310 – 360

Comment on blood film: Moderate anisocytosis. Moderate polychromasia. Moderate number of target cells. Occasional Howell-Jolly bodies. Increased rouleaux formation. Marked thrombocytosis.

  • What is the explanation for this blood picture?
  • What treatment will you consider to prevent complications of this condition when this man is discharged from hospital?
 

[Click here to toggle visibility of the answers]

College Answer

  • Post splenectomy​
  • Antibiotic prophylaxis with Penicillin or equivalent
  • Immunisation prior to hospital discharge for Haemophilus, Meningococcus and Pneumococcus

Discussion

With this blood picture, one might safely wager that this patient has had a splenectomy. Howel-Jolly bodies are bits of lefteover DNA in the erythrocytes. The rest of the RBC morphologies commented on are essentially just cellular garbage. Normally, the spleen would view these as pollutants of the bloodstream, not to be tolerated; and they would be rapidly destroyed. The asplenic man, therefore, must put up with factory seconds of haematopoiesis.

As for protecting him from complications - one must immunise him, and protect him from the thromboembolic complications of thrombocytosis. Thrombosis after splenectomy has an incidence of about 5%, and can be managed wth either aspirin or (in extreme circumstances) with hydroxyurea.

The vaccinations prevent severe infection by encapsulated organisms - because the encapsulated organisms are poorly opsonised by complement, and the spleen was the only organ which could remove them. Thus, one must protect this patient from these bugs. There has been a 2011 revision of the guidelines for such prophylaxis. The most recent iteration of the immunisation schedule can be found here, at Spleen Australia.

  • The asplenic patients should carry an identifying card
  • They should receive the following vaccinations:
    • Pneumococcal vaccination
    • Haemophilus influenzae type b conjugate vaccine
    • Meningococcal conjugate vaccine (polyvalent)
    • Influenza immunization
  • There may be some role for lifelong prophylactic antibiotics
  • The patient should have a supply of antibiotics for emergency use at home

References

Vaccines recommended for adults (>18 years) with asplenia/hyposplenism  -from Spleen Australia

Corazza, G. R., et al. "Howell‐Jolly body counting as a measure of splenic function. A reassessment." Clinical & Laboratory Haematology 12.3 (1990): 269-275.

Bain, Barbara J. "Diagnosis from the blood smear." New England Journal of Medicine 353.5 (2005): 498-507.

Cadili, Ali, and Chris de Gara. "Complications of splenectomy." The American journal of medicine 121.5 (2008): 371-375.

Di Sabatino, Antonio, Rita Carsetti, and Gino Roberto Corazza. "Post-splenectomy and hyposplenic states." The Lancet 378.9785 (2011): 86-97.

Hirsh, J., J. A. McBride, and J. V. Dacie. "Thrombo-embolism and increased platelet adhesiveness in post-splenectomy thrombocytosis." Australasian annals of medicine 15.2 (1966): 122-128.

Davies, John M., et al. "Review of guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen: Prepared on behalf of the British Committee for Standards in Haematology by a Working Party of the Haemato‐Oncology Task Force." British journal of haematology 155.3 (2011): 308-317.

Khan, Palwasha N., et al. "Postsplenectomy reactive thrombocytosis."Proceedings (Baylor University. Medical Center) 22.1 (2009): 9.