Question 7.2
A previously well 54 year old man presents with confusion. On examination a rash is noted (see photograph below). Temperature is 37.10 C. The initial blood results are provided on the next page.
|
Venous biochemistry |
||
|
Test |
Value |
Normal Range |
|
Sodium |
135 mmol/L |
135 -145 |
|
Potassium |
3.8 mmol/L |
3.5 - 4.5 |
|
Urea* |
18 mmol/L |
2.9 - 8.2 |
|
Creatinine* |
177 mol/L |
70 -120 |
|
Bilirubin* |
45 mol/L |
<20 |
|
Haematology |
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|
Test |
Value |
Normal Range |
|
Hb* |
99 G/L |
135 -180 |
|
WBC |
10.8 x 109/L |
4.0 -11.0 |
|
Platelets* |
26 x 109/L |
140 - 400 |
|
Blood film: Schistocytes |
||
|
Coagulation |
||
|
Test |
Value |
Normal Range |
|
PT |
10 sec |
9 -12 |
|
APTT |
29 sec |
24 - 39 |
|
Fibrinogen |
3.0 G/L |
1.7 - 4.5 |
a) What is the most likely diagnosis? Provide 3 reasons.
b) What definitive treatment needs to be instituted urgently?
College Answer
a) What is the most likely diagnosis? Provide 3 reasons.
TTP
Reasons: Low platelets, renal dysfunction, presence of schistocytes suggestive of MAHA and neurological symptoms.
b) What definitive treatment needs to be instituted urgently?
Plasma exchange
Discussion
Thrombotic thrombocytopenic purpura is discussed in greater detail elsewhere.
Characteristic features of TTP are as follows:
- Anaemia
- Thrombocytopenia
- Microangiopathic haemolytic anaemia
- Schistocytosis
- Neurological symptoms
- Fever
- Renal failure
The presence or raised bilirubin suggests that intravascular hameolysis is taking place, and the presence of serious renal failure lends itself to the idea that a haemolytic-uremic syndrome may also be in play here. Those two have been together in the same category before (TTP/HUS). Nowadays, TTP and HUS and HELLP are all recognised as a spectrum of thrombotic microangiopathies.
The definitive treatment for it is plasma exchange, aiming to remove the ADAMTS-13 inhibitor while replacing the missing ADAMTS-13 protein with FFP.
Not much else can be added to this brief answer, the third in a three-part question, which is valued at ten points in total (thus one has 3.333 minutes to dedicate to it).
References
George, James N. "Thrombotic thrombocytopenic purpura." New England Journal of Medicine 354.18 (2006): 1927-1935.
Peyvandi, Flora, et al. "von Willebrand factor cleaving protease (ADAMTS‐13) and ADAMTS‐13 neutralizing autoantibodies in 100 patients with thrombotic thrombocytopenic purpura." British journal of haematology 127.4 (2004): 433-439.
Tsai, Han-Mou. "Advances in the pathogenesis, diagnosis, and treatment of thrombotic thrombocytopenic purpura." Journal of the American Society of Nephrology 14.4 (2003): 1072-1081.
Chapter 97 (pp. 993) Therapeutic plasma exchange and intravenous immunoglobulin therapy by Ian Kerridge, David Collins and James P Isbister
Kakishita, Eizo. "Pathophysiology and treatment of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS)."International journal of hematology 71.4 (2000): 320-327.
Noris, Marina, and Giuseppe Remuzzi. "Hemolytic uremic syndrome." Journal of the American Society of Nephrology 16.4 (2005): 1035-1050.