Causes of Hypoventilation

Hypoventilation — 

The lung alveolus is a space in which gas makes up 100 percent of the contents. This means that once the partial pressure of one gas rises, the other must decrease. Both arterial (PaCO₂) and alveolar (PACO₂) carbon dioxide tension increase during hypoventilation, which causes the alveolar oxygen tension (PAO₂) to decrease. As a result, diffusion of oxygen from the alveolus to the pulmonary capillary declines with a net effect of hypoxemia and hypercapnia. Because the respiratory quotient (Defined as CO_{2 eliminated}/O_{2 consumed}) is assumed to be 0.8, hypoventilation affects PaCO₂more than O₂.

Hypoxemia due to pure hypoventilation (ie, in the absence of an elevated A-a gradient) can be identified by two characteristics. First, it readily corrects with a small increase in the fraction of inspired oxygen (FiO₂). Second, the paCO₂ is elevated. An exception exists when the hypoventilation is prolonged because atelectasis can occur, which will increase the A-a gradient . Abnormalities that cause pure hypoventilation include:

●CNS depression, such as drug overdose, structural CNS lesions, or ischemic CNS lesions that impact the respiratory center

●Obesity hypoventilation (Pickwickian) syndrome

●Impaired neural conduction, such as amyotrophic lateral sclerosis, Guillain-Barré syndrome, high cervical spine injury, phrenic nerve paralysis, or aminoglycoside blockade

●Muscular weakness, such as myasthenia gravis, idiopathic diaphragmatic paralysis, polymyositis, muscular dystrophy, or severe hypothyroidism

●Poor chest wall elasticity, such as a flail chest or kyphoscoliosis

Bhopalwala. H

Classification Criteria for Adult Still Disease

●Yamaguchi criteria – The Yamaguchi criteria require the presence of five features, with at least two being major diagnostic criteria . In addition, the presence of any infection, malignancy, or other rheumatic disorder known to mimic ASD in its clinical features precludes the diagnosis of ASD, at least for the purpose of research.

The four major Yamaguchi criteria are:

•Fever of at least 39ºC (102.2ºF) lasting at least one week

•Arthralgias or arthritis lasting two weeks or longer

•A nonpruritic macular or maculopapular skin rash that is salmon-colored in appearance and usually found over the trunk or extremities during febrile episodes

•Leukocytosis (10,000/microL or greater), with at least 80 percent granulocytes

The minor Yamaguchi criteria include:

•Sore throat

•Lymphadenopathy

•Hepatomegaly or splenomegaly

•Abnormal liver function studies, particularly elevations in aspartate and alanine aminotransferase and lactate dehydrogenase concentrations

•Negative tests for antinuclear antibody (ANA) and rheumatoid factor (RF)

Bhopalwala. H

HAP and VAP

Pneumonia types — The 2016 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) guidelines distinguish the following types of pneumonia :

●Hospital-acquired (or nosocomial) pneumonia (HAP) is pneumonia that occurs 48 hours or more after admission and did not appear to be incubating at the time of admission.

●Ventilator-associated pneumonia (VAP) is a type of HAP that develops more than 48 hours after endotracheal intubation.

Bhopalwala. H

qSOFA Score for Sepsis

The qSOFA (quick Sequential Organ Failure Assessment) score is easy to calculate since it only has three components, each of which are readily identifiable at the bedside and are allocated one point:

●Respiratory rate ≥22/minute

●Altered mentation

●Systolic blood pressure ≤100 mmHg

Bhopalwala. H

Cogan's Syndrome

●Cogan's syndrome (CS) is a chronic inflammatory disorder that most commonly affects young adults. Clinical hallmarks are interstitial keratitis (IK) and vestibuloauditory dysfunction, and associations between CS and systemic vasculitis, as well as aortitis, also exist. There are a range of pathologic findings, most of which reflect immune-mediated injury of the affected tissues; however, despite an association with systemic vasculitis, eye and inner ear specimens of those with CS do not reveal any evidence of vasculitis. The underlying mechanisms responsible for the eye and inner ear disease in CS are unknown.

●The predominant ocular feature of CS is IK, which typically causes eye redness, pain, photophobia, and blurred vision. Slit-lamp examination commonly demonstrates a patchy, deep, granular corneal infiltrate. IK is not essential for the diagnosis; ocular inflammation may involve other parts of the eye and may lead to iridocyclitis, conjunctivitis, episcleritis, anterior or posterior scleritis, or retinal vasculitis.

●The inner ear manifestations of CS are Ménière-like attacks consisting of vertigo, ataxia, nausea, vomiting, tinnitus, and hearing loss. Vestibular dysfunction may also cause oscillopsia, and caloric testing often reveals absent vestibular function. Recurrent episodes of inner ear disease frequently result in profound sensorineural hearing loss. Noninflammatory down-fluctuations in hearing may be difficult to distinguish from those of inflammatory origin. If hearing loss is associated with eye inflammation or other features of active CS or does not resolve within three to five days, an inflammatory origin is more likely.

●When present, the systemic vasculitis associated with CS is a large- or medium- to small-sized vessel vasculitis or an aortitis. The pattern of vessel involvement may be overlapping. Other systemic manifestations of CS include fever, fatigue, weight loss, lymphadenopathy, hepatomegaly, hepatitis, splenomegaly, pulmonary nodules, pericarditis, abdominal pain, arthralgia, arthritis, myalgia, and urticaria. An association with inflammatory bowel disease has also been observed.

●Evaluation of the patient with possible CS requires ophthalmologic examination to establish the presence of IK, scleritis, or episcleritis and to exclude other diseases and ocular pathology; neurologic and otologic examination to establish the presence of vestibuloauditory abnormalities; and rheumatologic examination to seek evidence of systemic vasculitis. We diagnose CS based upon the presence of characteristic inflammatory eye disease and vestibuloauditory dysfunction. The eye and inner ear are nearly equally likely to be the cause of presenting symptoms, while less than 5 percent of patients initially present with systemic manifestations

Bhopalwala. H

GPA vs MPA Flares

The distinction between GPA ( Granulomatosis with Polyangiitis) and MPA (Microscopic Polyangiitis) is important chiefly because of differential tendencies to flare. Although both diseases may flare after the achievement of remission, GPA is substantially more likely to relapse.

That's all.

Bhopalwala. H

ANCA titers and Disease flare.

Does a rise in ANCA titers predict a disease flare? — This has been a controversial area in the literature almost since ANCA were first identified in the 1980s. However, several rigorous studies have demonstrated that elevations in the titers of ANCA do not predict disease flares in a timely manner . The largest of these studies was performed on a clinical trial cohort of 180 patients (Wegener's Granulomatosis Etanercept Trial [WGET] Research Group, 2005), with serum samples drawn at three-month intervals and ANCA assays performed at the Mayo Clinic . The following findings were observed:
●Among patients who were PR3-ANCA positive compared with negative at baseline, there were no differences in the median time to relapse, disease activity score , or organ involved at relapse. Decreases in PR3-ANCA levels were not associated with a shorter time to remission, and increases were not associated with relapse.
●Relapses occurred among 46 of 101 patients (46 percent) who were mature-PR3-ANCA positive at baseline and achieved remissions of at least six months' duration. However, the proportion of patients who experienced a disease flare within one year of an elevation in ANCA titer was only 40 percent.
Other studies have come to slightly different conclusions, indicating that persistently high or rising titers of ANCA are associated with an increased risk of disease relapse . However, even in those studies, the temporal relationship between a rise in ANCA titer and the occurrence of a disease flare was poor. As an example, in a prospective study of 100 ANCA-positive patients observed over a two-year period, relapse did not occur in 43 and 29 percent of those with a rise in ANCA titers by immunofluorescence and in PR3-ANCA titers by ELISA, respectively .
In addition, a meta-analysis of 18 studies found that neither a rise in ANCA titer nor a persistently elevated ANCA titer were strong predictors of a subsequent disease flare . Therapies for relapsed ANCA-associated vasculitis (often, high doses of glucocorticoids and cytotoxic agents) carry substantial risk, including severe infections, cystitis, bladder cancer, lung fibrosis (rarely), and death. Treating all patients with increases in ANCA titers would result in unnecessary risks of toxicity in a substantial percentage of patients, nearly 30 percent in the study mentioned above. Because of these concerns, using a rise in ANCA titer as the sole parameter to justify altering immunosuppressive therapy cannot be endorsed.
A reasonable recommendation is to closely follow patients with rising ANCA titers but not to alter their therapy unless there are clear clinical signs of active disease.

Bhopalwala. H

POTS Syndrome

●The postural tachycardia syndrome (POTS) is defined as a form of orthostatic intolerance characterized by an excessive increase in heart rate that occurs on standing without arterial hypotension.

●The etiology of POTS is not clear, but the disorder may be heterogeneous. Abnormalities in autonomic regulation that may either be genetic or acquired are described. Proposed mechanisms include partial sympathetic denervation leading to discordant cardiac and vascular sympathetic control, hypovolemia and impairment of the renin-angiotensin-aldosterone system, venous abnormalities and baroreflex dysfunction.

●The clinical symptoms of POTS are varied and nonspecific, and include dizziness, lightheadedness, weakness, blurred vision, and fatigue upon standing. The orthostatic nature of the symptoms is the primary clue to the diagnosis.

●The diagnosis of POTS is established from the history and head-up tilt testing which demonstrates a heart rate increase of >30 bpm over baseline or to >120 bpm. Dehydration, prolonged bedrest, medications, and other dysautonomias should be excluded as etiologies.

●The optimal therapy of POTS is not established. Patients should avoid precipitating factors, and physical activity should be encouraged. We suggest volume repletion and fludrocortisone (0.05 to 0.2 mg per day) as the first line of therapy . Some patients may benefit from midodrine or beta blocking agents. Other therapies remain under investigation, and further confirmation of benefit is needed before they can be recommended.

Bhopalwala. H

Classification of Cryoglobulinemia

●The Brouet classification criteria is the most commonly used system that classifies cryoglobulinemia into three different subgroups based on their Ig composition. These classification criteria are also useful in that the subgroups partly correlate with pathogenicity and clinical manifestations.

•In type I cryoglobulinemia, the cryoglobulins are monoclonal Ig, typically IgG or IgM, and less commonly IgA or free Ig light chains. Type I cryoglobulinemia develops in the setting of protein-secreting monoclonal gammopathies such as a monoclonal gammopathy of undetermined significance (MGUS) or a B-cell lineage malignancy (eg, multiple myeloma, Waldenström macroglobulinemia, or chronic lymphocytic leukemia).

•In type II cryoglobulinemia, the cryoglobulins are composed of a mixture of a monoclonal IgM (or IgG or IgA) with rheumatoid factor (RF) activity and polyclonal Ig. Type II cryoglobulins are often associated with persistent viral infections, particularly hepatitis C virus (HCV) infection, and are associated with the mixed cryoglobulinemia syndrome. Other clinical associations with type II cryoglobulinemia include other infections such as hepatitis B virus (HBV), HIV, autoimmune diseases (mainly systemic lupus erythematosus [SLE] and Sjögren's syndrome), and lymphoproliferative disorders.

•In type III cryoglobulinemia, the cryoglobulins are composed of a mixture of polyclonal IgG (all isotypes) and polyclonal IgM. These cases are often secondary to autoimmune disorders, but can also be associated with infections (mainly HCV).

Bhopalwala. H

Eye Findings in GCA

●Anterior ischemic optic neuropathy – At least 80 percent of cases of vision loss in patients with GCA are caused by AION . The ischemic insult in arteritic AION is typically the consequence of occlusion of the posterior ciliary artery, a branch of the ophthalmic artery from the internal carotid artery, and the main arterial supply to the optic nerve.

Only about five percent of the total occurrences of AION are due to GCA, the majority being nonarteritic and secondary to atherosclerotic disease . About 40 percent of patients who suffer nonarteritic AION regain some amount of visual acuity, in contrast to visual loss due to GCA, which is more often massive and irreversible .

●Central retinal artery occlusion – CRAO is responsible for approximately 10 percent of the cases of visual loss in GCA . On the other hand, approximately two percent of older patients with CRAO have underlying GCA . Bilateral CRAOs in an older adult should prompt evaluation for GCA.

●Posterior ischemic optic neuropathy – PION occurs in less than five percent of patients with GCA . It results from the interruption of blood flow to the retrobulbar portion of the optic nerve. Histopathologic examination typically reveals inflammatory occlusion of the short nutrient posterior ciliary arteries .

●Branch retinal artery occlusion – BRAO is distinctly uncommon in GCA, though it has been described.

●Cerebral ischemia — Homonymous hemianopia is a visual field defect involving either the two right or the two left halves of the visual fields of both eyes. The most common cause in GCA is an occipital lobe infarction resulting from a lesion in the vertebrobasilar circulation. In rare cases, bilateral occipital lobe involvement leads to bilateral homonymous field defects and to the development of cortical blindness.

Bhopalwala. H

Imaging Findings in PMR

Imaging —

As discussed above, there are characteristic features of periarticular structures (eg, bursitis and tenosynovitis) that can be seen on ultrasonography, magnetic resonance imaging (MRI), and positron emission tomography (PET) . Routine radiographs do not show abnormalities in patients with PMR.

Ultrasound (US) and MRI can demonstrate synovitis of the glenohumeral and hip joints and frequent involvement of extraarticular structures, especially the subacromial/subdeltoid bursa, long head of the biceps, and trochanteric bursa. While subdeltoid/subacromial bursitis is a characteristic imaging feature of PMR, it is not specific and is seen in patients with rheumatoid arthritis (RA) and other shoulder pathology .

Bhopalwala. H

How to Diagnose Polymyalgia Rheumatica?

General approach — There is no pathognomonic test or established diagnostic criteria for polymyalgia rheumatica (PMR). We use the presence of all of the following empirically formulated criteria for the clinical diagnosis of PMR in whom another disease to explain the findings is not present :

●Age 50 years or older at disease onset.

●Proximally and bilaterally distributed aching and morning stiffness (lasting at least 30 minutes or more) persisting for at least two weeks. The stiffness should involve at least two of the following three areas: neck or torso, shoulders or proximal regions of the arms, and hips or proximal aspects of the thighs.

●Erythrocyte sedimentation rate (ESR) ≥40 mm/hour.

●Rapid resolution of symptoms with low-dose glucocorticoids. Symptoms are generally 50 to 70 percent better within three days in patients with PMR started on prednisone at a dose of 10 to 20 mg/day, and almost all patients respond completely within three weeks of beginning treatment. The lack of response to initial therapy strongly suggests an alternative diagnosis. Symptomatic improvement with low-dose glucocorticoid treatment can also be seen in patients with rheumatoid disease, psoriatic arthritis, and other inflammatory arthritides.

Bhopalwala. H

Adalimumab (Humira)

Use

Ankylosing spondylitis: Treatment (to reduce signs/symptoms) of active ankylosing spondylitis in adults

Crohn disease: Treatment (to reduce signs/symptoms and to induce and maintain clinical remission) of active Crohn disease (moderate to severe) in adults and pediatric patients ≥6 years of age (Humira only) with an inadequate response to conventional therapy or who have lost response to or are intolerant to infliximab.

Hidradenitis suppurativa (Humira only): Treatment of moderate to severe hidradenitis suppurativa in adults and children ≥12 years of age

Juvenile idiopathic arthritis: Treatment (to reduce signs/symptoms) of active polyarticular juvenile idiopathic arthritis (moderate to severe) in pediatric patients ≥2 years of age (Humira) or ≥4 years of age (Amjevita; Cyltezo); may be used alone or in combination with methotrexate

Plaque psoriasis: Treatment of chronic plaque psoriasis (moderate to severe) in adults who are candidates for systemic therapy or phototherapy, and when other systemic therapies are less appropriate (with close monitoring and regular follow-up)

Psoriatic arthritis: Treatment (to reduce signs/symptoms, inhibit progression of structural damage, and improve physical function) of active psoriatic arthritis in adults; may be used alone or in combination with nonbiologic disease-modifying antirheumatic drugs (DMARDs)

Rheumatoid arthritis: Treatment (to reduce signs/symptoms, induce major clinical response, inhibit progression of structural damage, and improve physical function) of active rheumatoid arthritis (moderate to severe) in adults; may be used alone or in combination with methotrexate or other nonbiologic DMARDs

Ulcerative colitis: Treatment (to induce and sustain clinical remission) of active ulcerative colitis (moderate to severe) in adults who have had an inadequate response to immunosuppressants such as corticosteroids, azathioprine, or 6-mercaptopurine. (Note: Efficacy in patients that are intolerant to or no longer responsive to other TNF blockers has not been established.)

Uveitis (Humira only): Treatment of non-infectious intermediate, posterior, and panuveitis in adults and children ≥2 years of age

Mechanism of Action

Adalimumab is a recombinant monoclonal antibody that binds to human tumor necrosis factor alpha (TNF-alpha), thereby interfering with binding to TNFα receptor sites and subsequent cytokine-driven inflammatory processes. Elevated TNF levels in the synovial fluid are involved in the pathologic pain and joint destruction in immune-mediated arthritis. Adalimumab decreases signs and symptoms of psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis. It inhibits progression of structural damage of rheumatoid and psoriatic arthritis. Reduces signs and symptoms and maintains clinical remission in Crohn disease and ulcerative colitis; reduces epidermal thickness and inflammatory cell infiltration in plaque psoriasis.

Bhopalwala. H

Vision Loss in Giant Cell Arteritis

Causes of vision loss —

Permanent loss of vision in GCA results from arteritic anterior ischemic optic neuropathy (AION), central or branch retinal arterial occlusion (CRAO/BRAO), posterior ischemic optic neuropathy (PION), or, rarely, cerebral ischemia

●Anterior ischemic optic neuropathy – At least 80 percent of cases of vision loss in patients with GCA are caused by AION . The ischemic insult in arteritic AION is typically the consequence of occlusion of the posterior ciliary artery, a branch of the ophthalmic artery from the internal carotid artery, and the main arterial supply to the optic nerve.

Only about five percent of the total occurrences of AION are due to GCA, the majority being nonarteritic and secondary to atherosclerotic disease . About 40 percent of patients who suffer nonarteritic AION regain some amount of visual acuity, in contrast to visual loss due to GCA, which is more often massive and irreversible .

●Central retinal artery occlusion – CRAO is responsible for approximately 10 percent of the cases of visual loss in GCA . On the other hand, approximately two percent of older patients with CRAO have underlying GCA . Bilateral CRAOs in an older adult should prompt evaluation for GCA.

●Posterior ischemic optic neuropathy – PION occurs in less than five percent of patients with GCA . It results from the interruption of blood flow to the retrobulbar portion of the optic nerve. Histopathologic examination typically reveals inflammatory occlusion of the short nutrient posterior ciliary arteries .

●Branch retinal artery occlusion – BRAO is distinctly uncommon in GCA, though it has been described.

●Cerebral ischemia — Homonymous hemianopia is a visual field defect involving either the two right or the two left halves of the visual fields of both eyes. The most common cause in GCA is an occipital lobe infarction resulting from a lesion in the vertebrobasilar circulation. In rare cases, bilateral occipital lobe involvement leads to bilateral homonymous field defects and to the development of cortical blindness.

Bhopalwala. H

Low Alkaline Phosphatase

Subnormal values — Extremely low serum alkaline phosphatase concentrations can be seen in patients with fulminant Wilson disease complicated by hemolysis .
Low values can also occur in patients with hypothyroidism, pernicious anemia, zinc deficiency, congenital hypophosphatemia, and certain types of progressive familial intrahepatic cholestasis in children.

Bhopalwala. H

Old Classification Criteria for Fibromyalgia

The final 1990 ACR FM classification criteria included:

●Symptoms of widespread pain, occurring both above and below the waist and affecting both the right and left sides of the body

●Physical findings of at least 11 of 18 defined tender points

These simple criteria had greater than 85 percent sensitivity and specificity for differentiating patients with FM from those with other rheumatic diseases.

In office practice, the diagnosis of FM can be made even if fewer than 11 of 18 tender points are present, provided that the history is consistent with FM and that the major differential diagnoses have been excluded . The tender points represent heightened pain perception rather than sites of inflammation or tissue pathology. Thus, they are proxies for detecting widespread pain, and the exact number necessary to diagnose FM clinically is somewhat arbitrary. It is important to recognize that the classification criteria were validated for large patient populations and should be used primarily in clinical research and epidemiologic studies of FM

Bhopalwala. H

Beighton Score for Joint Hypermobility

Beighton score for joint hypermobility —

JHM should be evaluated in all patients suspected of JHS. JHM is ascertained by determination of their Beighton score, which depends on the presence of JHM in the hands, elbows, lumbar spine, and knees using specific examination techniques . One point is awarded for the ability to perform each of nine maneuvers (including four maneuvers tested bilaterally and evaluation of the spine). A score of 4 or more points represents generalized hypermobility. The specific maneuvers include:

●Passive apposition of the thumb to the volar aspect of the ipsilateral forearm

●Passive hyperextension of fingers, demonstrated by passive dorsiflexion of the fifth metacarpophalangeal joint to at least 90 degrees

●Hyperextension of the elbow to at least 10 degrees

●Hyperextension of the knee to at least 10 degrees

●Flexion of the spine with placement of the palms flat on the floor without bending the knees

The presence of JHM can be documented by an examination limited to those areas required for calculating the Beighton score, but an examination for JHM and joint stability that is adequate for fuller assessment of the patient and the formulation of treatment plans should also encompass the other joints, including the temporomandibular joints, shoulders, hips, cervical and thoracic spine, ankles, and feet.

In addition to determination of the Beighton score based upon the examination, the presence of generalized JHM, including its presence historically, may also be suspected in patients who answer ‘yes’ to two or more questions in a simple five-part questionnaire :

●Can you now (or could you ever) place your hands flat on the floor without bending your knees?

●Can you now (or could you ever) bend your thumb to touch your forearm?

●As a child did you amuse your friends by contorting your body into strange shapes OR could you do splits?

●As a child or teenager did your shoulder or kneecap dislocate on more than one occasion?

●Do you consider yourself double-jointed?

Bhopalwala. H

Bohan and Peter Criteria for diagnosing DM-PM

Bohan and Peter in 1975 defined DM and PM based upon the following features :

●Symmetric proximal muscle weakness

●Typical cutaneous eruption of DM (the only feature distinguishing DM from PM)

●Elevated serum muscle enzymes

●Myopathic changes on EMG

●Characteristic muscle biopsy abnormalities and the absence of histopathologic signs of other myopathies

Patients with the cutaneous eruption and at least three of the other four criteria met the requirements for definite DM according to these criteria, while requirements for definite PM were met by those with all four criteria other than the cutaneous features . Patients with findings indicating the presence of other disorders that may present similarly were excluded. Patients who did not meet these criteria but who lacked any of the exclusions could potentially have been diagnosed with possible or probable DM or PM, depending upon the number of criteria met.

Skin Findings in Dermatomyositis

Skin findings — Several distinct cutaneous eruptions, which are generally evident at the time of clinical presentation, occur in DM but not in PM . Other skin changes may occur in patients with PM and in patients with DM and are not specific to either disorder. Dermatologic manifestations may be prominent but can be quite subtle in some patients.

Characteristic dermatomyositis findings — Gottron's papules and the heliotrope eruption are the hallmark and likely pathognomonic features of DM. Gottron's sign, photodistributed erythema, poikiloderma, nailfold changes, scalp involvement, and calcinosis cutis are also characteristic and useful in distinguishing DM from PM.

●Gottron's papules – Gottron's papules are erythematous to violaceous papules that occur symmetrically over the extensor (dorsal) aspects of the metacarpophalangeal (MCP) and interphalangeal (IP) joints (picture 1A-C). In addition, these lesions may involve the skin between the MCP and IP joints, particularly when the eruption is prominent. Gottron's papules often have associated scale and may ulcerate. When scaling is present, the lesions may mimic psoriasis or lichen planus.

●Gottron's sign – Definitions used for Gottron's sign have varied in the literature. We define Gottron's sign as the presence of erythematous to violaceous macules, patches, or papules on the extensor surfaces of joints in sites other than the hands, particularly the elbows, knees, or ankles. By contrast, some authors have used the term Gottron's papules to refer to papules in these areas, reserving Gottron's sign for macular or patch-like lesions (picture 2) .

●Heliotrope eruption – The heliotrope eruption is an erythematous to violaceous eruption on the upper eyelids, sometimes accompanied by eyelid edema, which, at times, may be quite marked .

●Facial erythema – Patients may have midfacial erythema that can mimic the malar erythema seen in SLE . In contrast to those with SLE, patients with DM will often have involvement of the nasolabial fold, which can be helpful in distinguishing these two photosensitive midfacial eruptions.

●Photodistributed poikiloderma (including the shawl and V signs) – Poikiloderma refers to skin that demonstrates both hyperpigmentation and hypopigmentation, as well as telangiectasias and epidermal atrophy. In DM, patients may demonstrate poikiloderma in any photo-exposed site; however, classic areas of involvement are the upper back (shawl sign) and the V of the neck and upper chest. The poikiloderma in DM often presents with a violaceous hue. Early in the course of cutaneous disease, these areas may demonstrate only erythema rather than well-developed poikiloderma . The erythema may be macular (nonpalpable) or papular. In rare patients, these lesions become thickened and resemble papular mucinosis. The cutaneous eruption of DM is often associated with significant pruritus, which may assist in distinguishing its photo-exacerbated eruption from that of lupus erythematosus (LE).

●Holster sign – Patients with DM may also have poikiloderma on the lateral aspects of the thighs, referred to as the "Holster sign" . It is unclear why this cutaneous manifestation occurs on this classically photo-protected site.

●Generalized erythroderma – In rare patients, erythroderma may occur, which involves extensive cutaneous surface area, including areas that are less exposed to ultraviolet light.

●Periungual abnormalities – The capillary nail beds in DM may be erythematous and may show vascular changes similar to those observed in other systemic rheumatic diseases (eg, scleroderma and SLE). Abnormal capillary nail bed loops may be evident, with alternating areas of dilatation and dropout and with periungual erythema . In addition, cuticular overgrowth, sometimes termed "ragged cuticles," is characteristic and may be associated with hemorrhagic infarcts within the hypertrophic area . The degree of cuticular involvement is thought to reflect ongoing cutaneous disease activity, representing active vasculopathy .

●Psoriasiform changes in scalp – Changes in the scalp resembling seborrheic dermatitis or psoriasis occur in a high percentage of patients with DM . The scalp involvement in DM is diffuse, often associated with poikilodermatous changes and with prominent scaling. Scalp involvement may result in severe burning, pruritus, and/or sleep disturbance. In addition, severe pruritus may occur in patients without visible disease.

●Calcinosis cutis – The deposition of calcium within the skin, a finding known as calcinosis cutis, occurs commonly in juvenile DM. It is infrequent in adult DM. In children, calcinosis has been associated with a delay in treatment with glucocorticoids and/or immunosuppressive therapy. Calcinosis cutis, which is known to be very challenging to treat, may be seen in a variety of conditions, including SSc, particularly limited cutaneous SSc; SLE (rarely); and overlap connective tissue disorders. It may be more common in patients with DM with the anti-p140/anti-MJ autoantibody

Bhopalwala. H

Antisynthetase Syndrome

Antisynthetase syndrome — Up to 30 percent of patients with DM or PM have a constellation of clinical findings termed the "antisynthetase syndrome" . These findings include relatively acute disease onset, constitutional symptoms (eg, fever and weight loss), myositis, the Raynaud phenomenon, mechanic's hands, arthritis that is generally nonerosive, and ILD . Affected patients have antibodies to aminoacyl-transfer ribonucleic acid (tRNA) synthetase enzymes; the presence of one of these antibodies is highly specific for DM, PM, or ILD .

This syndrome can be further characterized as follows:

●Not all patients with antisynthetase antibodies or even those classified as having the antisynthetase syndrome have all manifestations of this syndrome. The syndrome is generally considered present in patients with an antisynthetase antibody plus two of the following features, which are elements of the syndrome: ILD, inflammatory myopathy, and inflammatory polyarthritis.

●This group of clinical findings or this general clinical picture is not specific for antisynthetase antibodies. Patients with other types of autoantibodies (eg, anti-PM-Scl or anti-U1 ribonucleoprotein [RNP] antibodies) can also present with these types of features. However, patients with antisynthetase antibodies generally have more prominent or severe myositis and ILD, and they usually lack some of the other clinical features seen in patients with these other autoantibodies.

●Some patients with antisynthetase antibodies have relatively little or no myositis, while ILD or other features are more prominent. The absence of myositis is seen more often with some antisynthetase antibodies than with others.

Bhopalwala. H