Screening and diagnosis

Classification and risk stratification

Perioperative care

Quality improvement

Patient education

Nonpharmacologic interventions

Therapeutic procedures

Respiratory support

Follow-up and surveillance

Specific circumstances

Preventative measures

Medical management

Surgical interventions

Inpatient care

Diagnostic procedures

Diagnostic investigations

Insufficient evidence to make a recommendation.

Strongly favor this test or intervention.

The Revised Five Factor Score (rFFS) calculator is designed to assess the prognosis of systemic necrotizing vasculitis based on five clinical factors. Each input corresponds to a specific risk factor, which is quantified according to a predefined scoring system. The parameters include age over 65 years, renal insufficiency with a stabilized peak creatinine value of at least 150 micromoles per liter, cardiac insufficiency, gastrointestinal involvement, and absence of ear, nose, and throat (ENT) manifestations. 

The calculator assigns a score of 1 for each positive condition and a score of 0 for negative conditions, resulting in a total score ranging from 0 to 5. This cumulative score indicates the risk severity, with a higher score corresponding to a higher estimated 5-year mortality rate.

| Input Parameter                                                                 | Condition Met Value | Score Contribution |
|---------------------------------------------------------------------------------|---------------------|--------------------|
| Age > 65 years                                                                  | Yes                 | 1                  |
| Renal insufficiency stabilized peak creatinine >= 150 micromol/L                | Yes                 | 1                  |
| Cardiac insufficiency                                                           | Yes                 | 1                  |
| GI involvement                                                                  | Yes                 | 1                  |
| Absence of ENT manifestations                                                   | Yes                 | 1                  |

The scoring system evaluates each factor independently. The calculator then sums these values to produce a total score, which is interpreted as follows:

- A total score of 0 indicates a 5-year mortality rate of 9%.
- A total score of 1 indicates a 5-year mortality rate of 21%.
- A total score of 2 or more indicates a 5-year mortality rate of 40%.

In summary, the calculator assesses various risk factors to compute a score that projects a prognosis for patients with systemic necrotizing vasculitis. By doing so, it provides clinicians with valuable information for patient counseling and management strategies based on quantified risk levels.

The Revised Five Factor Score (rFFS) is a clinical calculator used for prognosis in patients with systemic necrotizing vasculitis. This scoring system is specifically designed for patients diagnosed with this rare autoimmune disease, which causes inflammation and damage to blood vessels throughout the body.

The rFFS is used to predict the likelihood of patient survival at five years following diagnosis. It takes into account five key factors: age over 65 years, cardiac symptoms, gastrointestinal involvement, renal insufficiency, and the absence of ear, nose, and throat symptoms. Each factor is assigned a score, and the total score is used to estimate prognosis.

The rFFS is not applicable to patients without a confirmed diagnosis of systemic necrotizing vasculitis. It also may not be as accurate in patients with other significant comorbidities or in those who have had the disease for a long time before diagnosis, as these factors can influence the course of the disease and the patient's overall prognosis.

Revised Five Factor Score for prognosis of systemic necrotizing vasculitis (rFFS)

This calculator helps diagnose microscopic polyangiitis by evaluating several key clinical indicators and combining their scores to reach a diagnostic conclusion. The process begins with the following set of questions, each assessing a different clinical aspect:

- Is there evidence of small- or medium-vessel vasculitis on imaging?
- Have alternative diagnoses that might mimic vasculitis been excluded?
- Is there any nasal involvement such as bloody discharge, ulcers, crusting, congestion, blockage, or septal defect/perforation?
- Is there a positive test result for perinuclear antineutrophil cytoplasmic antibodies (ANCA) or anti-myeloperoxidase antibodies?
- Does chest imaging show either fibrosis or interstitial lung disease?
- Is there pauci-immune glomerulonephritis present on biopsy?
- Are there positive test results for cytoplasmic ANCA or anti-proteinase 3 antibodies?
- Is the blood eosinophil count ≥ 1×10<sup>9</sup>/L?

Each "yes" response corresponds to a predefined score, which contributes to the total score:

| Criterion | Score |
| --- | --- |
| Evidence of small- or medium-vessel vasculitis on imaging | 20 |
| Exclusion of alternative diagnoses | 20 |
| Nasal involvement | 3 |
| Positive perinuclear ANCA or anti-myeloperoxidase antibodies | 6 |
| Fibrosis or interstitial lung disease | 3 |
| Pauci-immune glomerulonephritis on biopsy | 3 |
| Positive cytoplasmic ANCA or anti-proteinase 3 antibodies | 1 |
| Blood eosinophil count ≥ 1×10<sup>9</sup>/L | 4 |

The total is obtained by adding up the scores for each positive finding. The interpretation of the score is straightforward: 

- A score of 45 or higher indicates the diagnostic criteria for microscopic polyangiitis are met.
- A score below 45 suggests that the diagnostic criteria are not met.

The calculator in question is the ACR/EULAR (American College of Rheumatology/European League Against Rheumatism) Classification Criteria for Microscopic Polyangiitis. This scoring system is used in the clinical setting to classify patients with suspected microscopic polyangiitis, a systemic vasculitis that primarily affects small blood vessels.

The ACR/EULAR criteria are applied to patients who have been identified as having vasculitis, and are used to differentiate microscopic polyangiitis from other forms of vasculitis. The criteria include clinical, serological, and pathological parameters such as organ involvement, ANCA (anti-neutrophil cytoplasmic antibody) status, and histopathological findings.

The clinical utility of this calculator is to aid in the diagnosis of microscopic polyangiitis, which can help guide appropriate treatment strategies. It is also used in research settings to ensure consistent classification of patients in clinical studies.

Exclusion criteria for the use of this calculator include patients with secondary vasculitis due to conditions such as infections, malignancies, or drug exposures, as well as patients with other primary vasculitides.

ACR/EULAR classification criteria for microscopic polyangiitis

Microscopic polyangiitis

Patients with respiratory tract involvement

Patients with respiratory tract involvement (plasma exchange)

Severity assessment

Clinical follow-up

General principles

Induction of remission

Induction of remission, non-severe

Pediatric patients

Pediatric patients (biopsy)

As per SHARE initiative 2019 guidelines, 

Maintenance of remission

Induction of remission, avacopan

Kidney transplantation

Patients with respiratory tract involvement (topical therapy)

Plasma exchange

Management of relapse

Management of relapse, immunosuppressants

Pediatric patients, treatment

Induction of remission, severe

Pediatric patients (diagnostic imaging)

Antineutrophil cytoplasmic antibodies

ANCA

Management of refractory disease

Management of relapse (avacopan)

Induction of remission, IVIG and plasma exchange

Pediatric patients (diagnosis and classification)

Biopsy

Laboratory follow-up

Prophylaxis for Pneumocystis jirovecii pneumonia

Prophylaxis for P. jirovecii pneumonia

Pediatric patients (ANCA testing)

Anticoagulant therapy

Pregnant patients

Serum immunoglobulins

General counseling

Updated 2024 KDIGO guidelines for the diagnosis and management of microscopic polyangiitis


Microscopic polyangiitis

Guidelines

Key sources