Article Type : Research Article
Authors : Snoussi M and Belmekki A
Keywords : Thrombotic microangiopathy; Lupus erythematosus
The term thrombotic microangiopathy (TMA) includes several medical
conditions characterized by the association of mechanical hemolytic anemia and
peripheral thrombocytopenia. There are few studies in the literature focusing
on this pathology, and its causes are dominated by bacterial and viral
infections and systemic disease. Indeed, TMA is a serious complication that can
occur in patients with systemic lupus erythematosus (SLE), adversely affecting
prognosis and increasing mortality. The etiology of TMA in these patients may
be multifactorial and may overlap among different entities. We present the case
of a 22-year-old female who was previously diagnosed with SLE. She was
hospitalized with acute kidney injury, severe bicytopenia, and other features
consistent with her flare of lupus.
The term thrombotic microangiopathy (TMA) includes
several medical conditions characterized by the association of mechanical
hemolytic anemia and peripheral thrombocytopenia [1]. Few studies in the
literature have focused on this condition, and its etiology is dominated by
bacterial and viral infections and systemic disease [2]. Systemic lupus
erythematosus (SLE) is a chronic autoimmune disease of unknown cause. Renal
involvement, usually due to immune complex-mediated glomerular disease, is
common, but vascular disease also occurs and generally has a negative prognosis
and increases mortality [3]. We report his case of a patient diagnosed with
class IV LN presenting with TMA.
A 22-year-old Moroccan women with LN was admitted with acute kidney injury [serum creatinine (SCr): 6.1 mg/dl], bicytopenia (haemoglobin=7.9 g/dl, platelets=64G/L), positive anti-dsDNA. The anemia (hemoglobin = 7.9g/dl) is normocytic (VGM=77.6fl), normochromic (CCMH=35.1g/dl and TCMH=27.2pg), regenerative (reticulocyte rate=143G/L). The rate of schistocytes was 7% (Figure 1). Thrombocytopenia is severe at 64G/L. Hyperleukocytosis was found at 16.1G/L with a predominance of neutrophils (15.5G/L) [4,5].
Figure 1: Microscopic pictures of
the schizocytes found in the patient.
TMA represents a group of syndromes with multiple
etiologies, both inherited and acquired [6]. Globally, TMA classification can
be complex and confusing. One way to classify them is to classify them into
primary and secondary causes. Primary TMAs include TPP (thrombotic
thrombocytopenic purpura) and atypical HUS (hemolytic uremic syndrome).
Secondary TMAs include infectious diseases such as Shiga-toxin producing E.
coli and other conditions such as malignancies or autoimmune diseases as SLE [7].
Clinically detectable TMA is rare in SLE and mostly has a histopathological
nature. It may magnify the renal destruction caused by lupus by causing and
increasing local inflammation with damage to the diseased kidney. Patients with
LN have more severe and active renal disease. The etiology of TMA in LN remains
unclear and may be multifactorial. Since SLE is an immune complex-mediated
disease, activation of the classical pathway has been suggested to play an
important role in the development of TMA (Table 1).
Table 1:
Analytical parameters of the patient.
Analytical parameters |
Value |
Reference value |
Hemoglobin |
7.9 g/dl |
11.5-17.5 g/dl |
VGM |
77.6 fl |
76-96 fl |
CCMH |
35.1 g/dl |
31-36 g/dl |
TCMH |
27.2 pg |
24.4-34 G/L |
Leukocytes |
16.1 G/L |
3.8-11 G/L |
Platelets |
64 G/L |
150-445 G/L |
Several studies have shown that dysregulation of the
alternative complement pathway may also be involved, which is consistent with
low C3 and C4 levels in LN [4,5]. This case reports TMA in an SLE patient. The
patient presented with bicytopenia and other features consistent with lupus
flares. However, the severity of this case was explained by her diagnosis of
TMA, one of the most serious complications in SLE patients. TMA is a complex
process involving imbalances between immunity, coagulation and complement
caused by a variety of factors, in this case a severe lupus flare-up. Local or
systemic complement activation induces endothelial damage that is present in
both primary and secondary causes of TMA. Whatever the cause, TMA is a
devastating condition that results in systemic and renal damage and compromises
patient prognosis and survival [6,7].
Thrombotic microangiopathy (TMA) is a severe renal
vascular injury presenting with progressive life-threatening thrombocytopenia,
microangiopathic hemolytic anemia, and progressive renal failure. Although
rare, TMA is commonly found in patients with Class IV lupus nephritis (LN) and
plays an important role in the progression and exacerbation of LN.