**IMACS Core Set Measures -- Case examples**

**Myositis Disease Activity Assessment Tool (MDAAT)**

The purpose of this exercise is to provide some guidelines in scoring
the specific items of the MDAAT. These cases were prepared by David
Isenberg, Fred Miller and Lisa Rider. The scores provided in the cases
are suggestions for your consideration and there may be some differences
of opinion.

# 

# MDAAT Case A 

Clinic visit 1:

Mr RS, a 56 year old Caucasian male, had developed myositis at age 53
with proximal muscle weakness in his arms and legs, a CK \> 10x the
upper limit of normal, a myopathic EMG and a biopsy consistent with
idiopathic inflammatory myopathy. His weakness was reasonably well
controlled by steroids and cyclosporin (he had developed a low white
blood cell count on azathioprine and raised liver function tests on
methotrexate). His CK values were never normal (2 weeks ago the CK had
been 1,302 IU/L; nl\<173) and he had persistent 'low level' weakness
with some myalgia. His CK at this visit was 1337 IU/L. His muscle
weakness had been accompanied for the past 3 months by fatigue and aches
in the joints and muscles of his hands and feet which are not
significantly changed in the past month. There are no other clinical
features.

# First Assessment Score 

\(3\) Fatigue 2

\(14\) Arthralgia 2

\(25\) c. Mild muscle inflammation 2

\(26\) Myalgia 2

Clinic visit 2:

In the next month his fatigue got worse, his appetite was poor and his
weight fell from 70 to 65 kg. His joint pains, muscle pain and muscle
weakness are worse, but functionally he was little changed. He was also
complaining of mild but persistent abdominal pain which seemed to mirror
his general symptom exacerbation.

# Second Assessment Score 

\(2\) Weight loss 4

\(3\) Fatigue 3

\(14\) Arthralgia 3

\(16\) c. Mild abdominal pain 4

\(25\) b. Moderate muscle inflammation 3

\(25\) c. Mild muscle inflammation 3

\(26\) Myalgia 3

Clinic visit 3:

Four weeks later his muscle weakness became much more of a problem as it
became difficult to get up from his bed and his muscle pain had
increased. His CK increased to 6,100 IU/L and his abdominal pain had
become so severe that a laparotomy was undertaken -- no major structural
problem was found, but a biopsy of the gut wall demonstrated vasculitis.
His weight dropped further to 60 kg and his fatigue was much worse
although his joint pains, while persistent, had not changed.

# Third Assessment Score 

\(2\) Weight loss 2

\(3\) Fatigue 3

\(14\) Arthralgia 2

\(16\) a Severe abdominal pain 4

\(16\) b Moderate abdominal pain 4

\(16\) c Mild abdominal pain 4

\(25\) a. Severe muscle inflammation 4

\(25\) b. Moderate muscle inflammation 3

\(25\) c. Mild muscle inflammation 3

\(26\) Myalgia 3

# MDAAT Case B 

Clinic visit 1:

Miss DM had developed 'classic' juvenile dermatomyositis as a child at
age 6 and for 29 years she had been on prednisolone before finally
stopping. For a year or so the persistent muscle weakness (unchanged
previously in 10 years) was unaltered. Her rash had long since gone and
she was able, with some life-style adjustments (avoids stairs at all
costs) to continue her job in publishing. However, during the month
prior to the assessment her muscle weakness and muscle ache began to get
a little worse, her CK was noted to be 270 IU/L (nl\<173) and she was
referred by her 'local' consultant for a further opinion. An MRI scan
showed extensive replacement of many muscle groups by fat but in her hip
adductors and shoulder flexors edematous changes were reported
'compatible' with some disease activity. There were no other
changes/features.

# First Assessment Score 

\(25\) c. Mild muscle inflammation 3

\(26\) Myalgia 3

Clinic visit 2:

She was given the 'benefit of the doubt' and for 2 months given
methotrexate 15 mg/week. Her CK dropped to 195 IU/L and she was
convinced that her weakness and myalgia was a little better.

# Second Assessment Score 

\(25\) c. Mild muscle inflammation 1

\(26\) Myalgia 1

Clinic visit 3:

Following a nasty viral illness 2 months later, she developed a cough
and shortness of breath on exertion, together with fatigue. Her muscle
weakness and myalgia was unchanged.

# Third Assessment Score 

\(25\) c. Mild muscle inflammation 2

\(26\) Myalgia 2

MDAAT Case C

Clinic visit 1:

Mrs VK, born in Ghana, presented at age 23 with polyarthritis,
pleuritis, a strongly positive ANA (\>1:640 speckled pattern) with
antibodies to Ro, Sm and RNP. She was leucopenic and lymphopenic. Her C3
was low at 0.67 g/L (normal 0.9-1.8). A diagnosis of SLE was made and
she responded well to Plaquenil and low dose prednisolone (5→10 mg/day
on average).

Two years after her initial presentation she was in clinical remission,
but 6 months later she complained of increasing weakness in her upper
arms and legs. Her CK was 2,107 IU/L (n\<170); her EMG clearly myopathic
and her muscle biopsy confirmed that she had now developed idiopathic
myositis. Her original lupus features no longer troubled her.

Her steroid dose was initially maintained and her CXR and lung function
tests done as a baseline were normal. However, in a 1 month period
(about 6 months after the diagnosis of myositis) she deteriorated
rapidly. She was significantly weak (MRC scale 4→4^+^ in most proximal
muscles), finding it a problem to climb stairs and take a book off a
shelf although she is still at work (as a secretary). In addition she is
troubled by fatigue and shortness of breath, which are both new. A
repeat CXR shows slight but definite bi-basilar shadowing, her lung
function tests now show FVC 75%, normal, DLCO 70% normal. She has no
muscle ache or joint problems however.

# First Assessment Score 

\(3\) Fatigue 4

\(18\) a. Dyspnea due to ILD 4

\(18\) b. CXR changes 4

\(18\) c. PFTs - 10% change 4

\(25\) b. Moderate muscle inflammation 4

\(25\) c. Mild muscle inflammation 4

She is given 3 x 1g IV methylprednisolone and her oral steroids
increased to 40 mg/day.

Clinic visit 2:

During the next month her fatigue improves (but does not disappear). Her
dyspnea remains much the same but a HRCT scan is done and shows
significant 'ground-glass' shadowing. Her CK is 1870 IU/L and anti-Jo-1
antibody testing is positive. Her lung function tests 4 weeks later are
virtually the same (FVC 78%; DLCO -- 68% normal). Her muscle strength is
unchanged. There are no other clinical features.

# Second Assessment Score 

\(3\) Fatigue 1

\(18\) a. Dyspnea due to ILD 2

\(18\) b. HRCT changes 4

\(18\) c. PFTs 2

\(25\) b. Moderate muscle inflammation 2

\(25\) c. Mild muscle inflammation 2

Clinic visit 3:

In spite of adding an increasing oral dose of methotrexate (5→15 mg per
week during the month), her muscle weakness gets much worse in the next
4 weeks. She is now hardly able to rise from bed and now complains for
the first time of aching in her muscles and slight difficulty in
swallowing solid food. In contrast her fatigue and dyspnea are
unchanged. Her lung function tests remain static. A repeat CXR is also
unchanged.

# Third Assessment Score 

\(3\) Fatigue 2

\(15\) b. Dysphagia 4

\(18\) a. Dyspnea 2

\(18\) b. CXR 2

\(18\) c. PFTs 2

\(25\) a. Severe muscle inflammation 4

\(25\) b. Moderate muscle inflammation 3

\(25\) c. Mild muscle inflammation 3

\(26\) Myalgia 4

MDAAT Case D

Clinic visit 1:

Ms VC presented with myositis in her early 20s. She developed severe
proximal muscle weakness, myalgia, interstitial lung involvement, a high
CK (\>6,000 IU/L n\<173) at onset, with a myopathic EMG and major
inflammatory change on biopsy. During the next 7 years she was tried on
combinations of oral steroids with azathioprine, methotrexate,
cyclosporin, tacrolimus and IVIG. She invariably showed a mild to modest
improvement with each change of therapy but she was poorly compliant
(she blamed part of this on her job, selling insurance which meant that
she travelled a great deal) and invariably other forms of treatment were
considered. She was offered the chance of B cell depletion. She
accepted. She was admitted to hospital and says that in the past month
she has got much weaker. She can rise from a bed and get in and out of
her car (with some difficulty) and manage the housework at home. She has
had long standing shortness of breath on exertion which has not changed
in several years. Likewise her CXR and lung function tests, while
showing a low FVC and DLCO, have not really altered in 3 years. However,
in the past 4 weeks she has developed some painful swelling of the MCP
and PIP joints with slight loss of function (e.g. "it's been a bit
difficult to make a cup of tea"). On examination she has clear wasting
of her deltoid and gluteus maximus. Her CK 1,300 3 months ago is now
3,200 units. She has no fatigue or other features.

# First Assessment Score 

\(13\) b. Moderate arthritis 4

\(13\) c. Mild arthritis 4

\(14\) Arthralgia 4

\(25\) b. Moderate muscle inflammation 3

\(25\) c. Mild muscle inflammation 3

Clinic visit 2:

She is re-assessed 1 month after she was given 1 g rituximab. Her muscle
weakness has not altered but her joint swelling and pain are much
improved. The swelling went down 2 weeks after the infusion and
functionally she has also improved but is not quite back to normal.
There are no other changes/new features.

# Second Assessment Score 

\(13\) b. Moderate arthritis 1

\(13\) c. Mild arthritis

\(14\) Arthralgia 4

\(25\) b. Moderate muscle inflammation 2

\(25\) c. Mild muscle inflammation 2

Clinic visit 3:

During the next 4 weeks she has no functional problems from her
arthritis though the fingers remain a little swollen and painful. Her
muscle symptoms still seem unchanged though her CK has dropped a little
(it's now 2,400 IU/L). She has, however, developed a sinus tachycardia
(pulse 104/min) and her weight dropped from 55 to 50 kg. Investigations
reveal that her thyroxine level (FT4) is 36.2 pmol/L (n \<22) and her
TSH is 0.15 mIU/L (n 0.27→4.2).

# Third Assessment Score 

\(2\) Weight loss ≥ 5% 0

\(13\) b. Moderate arthritis 0

\(13\) c. Mild arthritis 1

\(14\) Arthralgia 1

\(25\) b. Moderate muscle inflammation 2

\(25\) c. Mild muscle inflammation 2

**NOTE:** Her weight loss and tachycardia are due to her thyrotoxicosis
and not due to her myositis -- thus they do not score in the MDAAT.