Diagnostic algorithm22

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1. Evidence of TMA

Thrombocytopenia

Platelet Count <150,000>3
or >25% Decrease From Baseline

Microangiopathic Hemolysis

Schistocytes
and/or Elevated LDH
and/or Decreased Haptoglobin
and/or Decreased Hemoglobin

2. Symptoms

Cardiovascular Symptoms

Myocardial Infarction
and/or Cardiomyopathy
and/or Heart Failure
and/or Peripheral Gangrene

Neurological Symptoms

Confusion
and/or Seizures
and/or Other Cerebral Abnormalities

Renal Impairment

Elevated Creatinine
and/or Decreased eGFR
and/or Elevated Blood Pressure
and/or Abnormal Urinalysis

Gastrointestinal Symptoms

Diarrhea ± Blood
and/or Nausea/Vomiting
and/or Abdominal Pain
and/or Gastroenteritis

Pulmonary Symptoms

Dyspnea
and/or Pulmonary Hemorrhage
and/or Pulmonary Edema

Visual Symptoms

Pain and Blurred Vision
Retinal Vessel Occlusion
Ocular Hemorrhage

3. Please choose below to show results for:

Differential diagnosis for primary TMAs
(including ADAMTS13)9

Watch this short video to see how presentations can overlap

Patient approach to a TMA associated with a complement-amplifying condition9

Watch this short video to learn about the complement-amplifying conditions associated with aHUS

4. Evaluate ADAMTS13 Activity and Shiga-toxin/EHEC* Test

In the absence of ADAMTS13 results, a serum creatinine level >150–200 μmol/L (>1.7–2.3 mg/dL) or a platelet count of >30,000/mm3 almost eliminates a diagnosis of severe ADAMTS13 deficiency (TTP).

≤10% ADAMTS13 Activity

>10% ADAMTS13 Activity

Shiga-toxin/EHEC Positive

TTP

aHUS

  • Genetic mutations are not identified in 30–50% of patients with aHUS.
  • A diagnosis of aHUS does not require identification of a mutation.

STEC-HUS

* Shiga-toxin/EHEC test is warranted in history/presence of GI symptoms.

ADAMTS13, A Disintegrin and Metalloproteinase with a ThromboSpondin type 1 motif, member 13; eGFR, estimated Glomerular Filtration Rate; EHEC, Enterohemorrhagic E. coli; LDH, Lactate Dehydrogenase; STEC-HUS, Shiga-Toxin-Producing E. coli Hemolytic Uremic Syndrome; TMA, Thrombotic Microangiopathy; TTP, Thrombotic Thrombocytopenic Purpura.

4. Perform panel of TMA tests (to include ADAMTS13 and Shiga-toxin/EHEC tests)*

If CAC is identified (e.g., pregnancy, SLE, MHT, drug-induced)

Treat condition to resolve TMA

If TMA unresolved or reoccurs

ADAMTS13 >10%

Coexisting aHUS

* Shiga-toxin/EHEC test is warranted in history/presence of GI symptoms.

MHT, Malignant Hypertension; SLE, Systemic Lupus Erythematosus.

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