Connective Tissue Disorders Flashcards
What characterizes CT disorders such as LE, scleroderma and dermatomyositis?
They all have a genetic predisposition, an autoimmune pathogenesis, response to systemic steroid (scleroderma less so), and have unknown etiology.
What is lupus erythematosus?
Skin lesion sites in this disease are heterogenous and encompass a range of dermatologic lesions and manifestations. There is a spectrum of LE judging by the skin lesions which can be more or less severe and indicating systemic involvement and the type of lesion whether it is T cell mediated or caused by antibodies.
Histologically LE is easy to recognize as there is an inflammation caused by CD4 T cells at the dermo epidermal junction, called Interface dermatitis pattern. Triggers involve UV light, EBS etc. the most accepted theory is the defect in apoptosis cause the formation of nucleosomes which get attacked and the immunocomplex deposit causing inflammation. There is chronic, subacute and acute LE.
What is chronic lupus?
Also called discoid LE it is the most common form. The lesions look like a circular coin. It is characterized by erythema, hyperkeratosis, scaly plaques, scarring and atrophy. If the lesion involves the scalp you get cicatricial alopecia. There is a possibility in progression to the systemic form. Lesions can occur in the oral mucosa but it is not frequent.
What is subacute LE?
Histopathologically very similar to the chronic state but the clinical presentation is different. We have the psoriasiform typo in which lesions mimic psoriasis and has papulosquamous lesions. We also have the annular type in which lesions are ringed shaped and mainly occur in the trunk and back. Another difference is that lesions in the subacute form are not scarring. Patients usually joint involvement like arthralgias, photosensitivity. Often triggered by drugs such as antihypertensive drugs.
What is acute LE?
Patients have systemic manifestations. Most common lesions are the facial erythema aka butterfly rash and diffused generalized erythema which mimic a viral infection or drug reaction. Lesions on the skin do not scar. There are also non specific cutaneous lesions like Raynaud’s phenomenon, non scarring alopecia and even vasculitis.
How do we diagnose systemic LE and what are some therapies?
We use clinical and immunological criteria. Like if there is non scarring alopecia, renal involvement, leukopenia etc. and if there are anti dna, complement protein etc.
Therapy’s are protection from UV ray, no smoking, topical or systemic steroids, antimalarials.
What is scleroderma?
Scleroderma is a connective tissue disease in which the typical findings are excessive deposition of collagen (sclerosis) that involves the skin and internal organs like kidneys and lungs. There is also the involvement of vessels which contribute to the formation of sclerosis. In addition there is an immune activation of both T and B cells and the end result is fibroblast activation increasing collagen deposition.
What is localized scleroderma?
In this format we only have skin involvement without systemic involvement. Plaque like morphea is the most abundant and it is characterized by sclerotic brownish or whitish plaques surrounded by an erythema called iliac ring, moreover the skin can be hypo or hyperpigmented. Generalized morphea can be generalized which mean it is disseminated. Linear morphea is the second most common type and is more typical of pediatric patients, may involve the limbs and trunk, also the scalp in some cases with hair loss.
What is diffuse systemic scleroderma?
The entire body can be involved, it is more severe than the limited form and Scl 70 are the typical antibodies. Usually starts with Raynaud’s phenomenon which is characterized by three phases : first the fingers become thick and hard, then you loose the pliability and flexibility of the skin and finally severe flexion contracture. Can also have ischemic ulcerations at the tip of the fingers. Same thing can happen at the feet but it is less frequent. The face has pinched nose, thin lips, telangiectasia and mouth furrowing.
What is limited systemic scleroderma (CREST)?
CREST stand for calcinosis-Raynaud-Esophagus-Scleroderma-Telangiectasia. This disease involved upper and lower arms and the face. It is less severe. It can have calcium depositions in the sclerotic tissue. Unlike morphea there are systemic implications with the kidney, lung, esophagus and cardiac. No actual treatment, so we treat the symptoms.
What is dermatomyositis?
A chronic autoimmune inflammatory connec ve ssue disease that involves striated muscles and the skin, it may have a systemic involvement of organs. There is a prevalence in females and Afro-Americans compared to males and Caucasians. It has genetic predisposition but the trigger is unknown, some suggest viral infections causing cell mediate inflammation. There are four main clinical forms :
1- Dermatomyosi s: in which we have the involvement of skin and muscle.
2- Polymyosi s: involvement of only the muscle, with the absence of skin involvement.
3- Amyopathic dermatomyosi s: involvement of only the skin, with the absence of muscle.
4- Paraneoplas c dermatomyosi s: most important one to diagnose, as it could evolve to cancer (especially in older people).
What are some cutaneous manifestation of dermatomyositis?
Involvement of muscles causing inability to walk or lift arms up. Skin can show gottrons sign which is a systemic macular violet lesion on the back of hand, can present with papules. Periorbital heliotrope oedema causing inability to open eyes. There can be erythematous lesions which are photosensitive. Like in scleroderma there is calcium deposition in skin lesions but it is less frequent.
How is dermatomyositis diagnosed?Prognosis?
Clinical history and clinical presentation. Lab exams for muscle enzymes like CPK LDH myoglobin. Skin and muscle biopsy. One important antibodies is anti Jo1 related to lung involvement and other cancer related antibodies. This disease is paraneoplastic, the patients with skin involvement have a higher chance of developing cancers in the ovaries,lung and pancreas.
Prognosis is good when not related to cancer. Steroids improve muscle and skin symptoms. Prognosis is bad in cancer patients and with cardiopulmonary involvement.
