Dermatomyositis; Behcet's; Ehlers-Danlos Syndrome

Question 1

Describe the pathophysiology of dematomysositis [1]

Answer 1

Polymyositis and dermatomyositis are autoimmune disorders causing muscle inflammation (myositis). Both present with proximal muscle weakness.

Question 2

Describe the typical presentation of dermatomyositis

Also what is the difference in presentation between polymyositis vs dermatomyositis?

Answer 2

Skin features
* photosensitive
* macular rash over back and shoulder
* heliotrope rash in the periorbital region
* Gottron’s papules - roughened red papules over extensor surfaces of fingers
* ‘mechanic’s hands’: extremely dry and scaly hands with linear ‘cracks’ on the palmar and lateral aspects of the fingers
* nail fold capillary dilatation

Other features:
- Proximal muscle weakness - difficulty standing off chairs
- Myalgia
- Raynaud’s
- ILD

NB: polymyositis doesnt present with skin features

Question 3

Describe the investigations used for dermatomyositis [4]
Which antibody is most associated with polymyositis? [1]

Answer 3

• the majority of patients (around 80%) are ANA positive
• Elevated CK
• Skin and muscle bx can confirm dx
• EMG - to distinguish from neuropathy
• TOMTIP - anti-Jo1 antibodies are associated with polymyositis

Question 4

Mx for dermatomyositis? [1]

Answer 4

1st line: Prednisolone

Question 5

Which specific lung pathologies are caused by dermatomyositis / polymyositis? [2]

Answer 5

fibrosing alveolitis or organising pneumonia

Question 6

Describe what is meant by Behcet’s disease [1]

Answer 6

Behçet’s disease is a complex inflammatory condition affecting the blood vessels and tissues. The main features are recurrent oral and genital ulcers.

Question 7

Behcets is associated with which gene? [1]

Answer 7

There is a link with the HLA B51 gene.

Question 8

Describe the basic pathophysiology of Behcets

Answer 8

The initial trigger for Behcet’s syndrome remains elusive. However, it is believed that an environmental agent such as a bacterium or virus may instigate the onset in genetically predisposed individuals

Upon exposure to the triggering agent, there is activation of both innate and adaptive immune responses.

Mucosal ulceration seen in this condition can be attributed to increased levels of matrix metalloproteinases that degrade extracellular matrix leading to tissue injury.

Question 9

Describe a typical patient suffering from Behcets. [1]

Describe the possible presentation of Behcets [+]

Answer 9

A typical presentation of Behcet’s syndrome might involve a patient in their twenties or thirties presenting with recurrent oral and genital ulcers, accompanied by uveitis

Oral & genital ulceration
- typically painful, round or oval, with a yellow-grey pseudomembrane surrounded by a red halo.

Uveitis
- can lead to blindness

Skin lesions

VTE/arterial thrombosis

GI symptoms:
- abdominal pain, diarrhoea or gastrointestinal bleeding

CNS:
- aseptic meningitis and cerebral venous sinus thrombosis

Question 10

Describe what is meant by the pathergy test

Answer 10

The pathergy test:
- involves using a sterile needle to make multiple pricks on the forearm.
- The area is reviewed 24-48 hours later to look for erythema (redness) and induration (thickening), indicating non-specific skin hypersensitivity.
- A positive result can indicate Behçet’s disease, Sweet’s syndrome or pyoderma gangrenosum.

PassMed:
- +ve result: puncture site following needle prick becomes inflamed with small pustule forming)

Question 11

Describe the treatment of Behcets

Answer 11

Topical treatments:
* For oral and genital ulcers, topical corticosteroids are frequently employed.
* Topical anaesthetics may also be used for pain relief.

Corticosteroids:
* Systemic corticosteroids are administered in cases with severe manifestations such as ocular disease or vascular involvement.
* Prednisolone is often the first-line treatment.

Disease-modifying anti-rheumatic drugs (DMARDs):
- Methotrexate, azathioprine, and cyclosporine can be used as steroid-sparing agents or in patients unresponsive to corticosteroids.

Biologic therapy:
- Anti-TNF agents like infliximab and adalimumab have shown efficacy in refractory cases or those with major organ involvement. Interferon-alpha may be considered for refractory uveitis.

Cytotoxic agents:
- Cyclophosphamide may be employed for severe vasculitis or neurological involvement.

Question 12

Describe what is meant by Neuro-Behcet’s syndrome (a nervous system complication of Behcets) [2]

Answer 12

Meningoencephalitis symptoms such as headache, fever, stiff neck and neurological deficits.
It may also present with parenchymal lesions or cerebral venous sinus thrombosis.

Question 13

Answer 13

anterior uveitis

Question 14

Answer 14

genital ulcers

Question 15

Answer 15

Multiple painful genital ulcers, not sexually active

Question 16

Answer 16

thrombophlebitis and deep vein thrombosis

Question 17

Define Ehler-Danlos syndrome [1]

Answer 17

Ehler-Danlos syndrome is an autosomal dominant connective tissue disorder that mostly affects type III collagen.

This results in the tissue being more elastic than normal leading to joint hypermobility and increased elasticity of the skin.

Question 18

Describe the different types of Ehlers-Danlos syndromes [4]

Answer 18

Hypermobile Ehlers-Danlos syndrome
- is the most common and least severe type of Ehlers-Danlos syndrome (although it still causes significant disability and psychosocial issues).
- The key features are joint hypermobility and soft and stretchy skin.
- A single gene for hypermobile EDS has not been identified. It appears to be inherited in an autosomal dominant pattern.

Classical Ehlers-Danlos syndrome
- features remarkably stretchy skin that feels smooth and velvety.
- There is severe joint hypermobility, joint pain and abnormal wound healing.
- Lumps often develop over pressure points, such as the elbows. Patients are prone to hernias, prolapses, mitral regurgitation and aortic root dilatation. Inheritance is autosomal dominant.

Vascular Ehlers-Danlos syndrome
- is the most severe and dangerous form of EDS, where the blood vessels are particularly fragile and prone to rupture.
- Patients have characteristic thin, translucent skin. Other features include gastrointestinal perforation and spontaneous pneumothorax.
- Patients are monitored for vascular abnormalities and told to seek urgent medical attention for sudden unexplained pain or bleeding. Inheritance is autosomal dominant.

Kyphoscoliotic Ehlers-Danlos syndrome
- is characterised initially by poor muscle tone (hypotonia) as a neonate and infant, followed by kyphoscoliosis as they grow.
- There is significant joint hypermobility. Joint dislocation is common.
- Inheritance is autosomal recessive.

Question 19

TOM TIP: It is worth being familiar with relatively common hypermobile Ehlers-Danlos syndrome and remembering some key features of the other types to spot them in your exams.

Which features are typical for classic EDS? [2]

Which features are typical for vascular EDS? [1]

Answer 19

Classical EDS:
- Extremely stretchy skin
- Severe joint hypermobilitiy

Vascular EDS:
- Thin translucent skin
- Blood vessel rupture

Question 20

Hypermobile Ehlers-Danlos syndrome is associated with which pathology? [1]
Describe the symptoms [3]

Answer 20

Postural orthostatic tachycardia syndrome (POTS)
- Significant tachycardia occurs on sitting or standing, and symptoms include presyncope (lightheadedness), syncope (loss of consciousness), headaches, disorientation, nausea and tremor.

Question 21

TOM TIP: It is worth learning and remembering to use the [] score to assess patients for hypermobility.

Answer 21

TOM TIP: It is worth learning and remembering to use the Beighton score to assess patients for hypermobility.