4.3 Connective Tissue Diseases, Stroke, Epilepsy & Movement Disorders

Systemic Autoimmune and Connective Tissue Diseases

Systemic Lupus Erythematosus (SLE) SLE is a chronic, relapsing, and remitting multisystem autoimmune disease predominantly affecting women of childbearing age (with a notable predilection for women of African and Asian descent). The pathogenesis is fundamentally driven by the loss of self-tolerance, leading to the production of pathogenic autoantibodies and widespread immune complex deposition (a classic Type III hypersensitivity reaction).

Clinical Features:

• Constitutional/Dermatologic: Classic manifestations include profound fatigue, fever, and a distinct photosensitive malar (butterfly) rash that prominently spares the nasolabial folds (differentiating it from rosacea). Discoid lesions, which are raised and erythematous, can cause permanent scarring and alopecia.
• Musculoskeletal: Non-erosive, symmetric polyarthritis and arthralgia (Jaccoud arthropathy).
• Renal: Lupus nephritis is a major cause of morbidity and overall mortality. Patients typically present with heavy proteinuria, microscopic hematuria, and new-onset hypertension. A definitive renal biopsy is required to determine the specific WHO classification (Class IV being the most severe and diffuse) and rapidly guides aggressive immunosuppressive therapy.
• Hematologic: Autoimmune hemolytic anemia, leukopenia, and thrombocytopenia (driven by a Type II hypersensitivity mechanism against blood cells).
• Cardiovascular: Libman-Sacks endocarditis (characterized by sterile, non-bacterial verrucous vegetations on both sides of the cardiac valve, usually the mitral), and fibrinous pericarditis.

Diagnosis and Management: Antinuclear Antibodies (ANA) are highly sensitive (serving as the primary screening test) but lack specificity. Anti-double-stranded DNA (anti-dsDNA) and anti-Smith (anti-Sm) antibodies are highly specific for the disease. Crucially, anti-dsDNA levels often directly correlate with disease activity, particularly signaling impending renal flares. Decreased serum complement levels (C3, C4) indicate active, ongoing immune complex consumption during flares. Virtually all patients with SLE should be placed on Hydroxychloroquine long-term, as it is proven to reduce flare frequency, prevent organ damage, and improve overall survival. Acute mild flares are managed with low-dose corticosteroids and NSAIDs. Severe, organ-threatening manifestations (e.g., diffuse proliferative lupus nephritis or cerebritis) require potent immunosuppressants like Mycophenolate Mofetil or high-dose Cyclophosphamide.

Rheumatoid Arthritis (RA) RA is a chronic, systemic inflammatory disorder that specifically targets the synovial lining of joints. This leads to profound synovial hypertrophy (pannus formation), eventually resulting in irreversible articular cartilage destruction and periarticular bone erosions.

Clinical Features: Patients typically experience symmetric, additive polyarthritis. It classically involves the Metacarpophalangeal (MCP), Proximal Interphalangeal (PIP), and wrist joints, while distinctly and notably sparing the Distal Interphalangeal (DIP) joints (which are frequently involved in Osteoarthritis). A clinical hallmark is prolonged morning stiffness lasting significantly greater than 1 hour, which progressively improves with physical activity throughout the day. Advanced, untreated disease causes classic joint deformities (ulnar deviation of the fingers, swan neck, and boutonnière deformities). Extra-articular manifestations are common and include subcutaneous rheumatoid nodules, interstitial lung disease, and serositis (pericarditis).

Diagnosis and Management: Rheumatoid Factor (RF) is sensitive but can be positive in other conditions; Anti-Cyclic Citrullinated Peptide (anti-CCP) antibodies are highly specific for RA. Acute phase reactants (ESR, CRP) are universally elevated during active disease. Early plain radiographs may only show soft tissue swelling and periarticular osteopenia, but later show characteristic marginal bone erosions. Early and aggressive initiation of Disease-Modifying Antirheumatic Drugs (DMARDs) is imperative to halt structural disease progression and prevent permanent disability. Methotrexate is the undisputed anchor first-line therapy. Biologic agents (e.g., TNF-alpha inhibitors like Adalimumab, Etanercept, or Infliximab) are added for refractory cases, though patients must be screened for latent Tuberculosis before initiation.

Cerebrovascular Accidents (Stroke)

Stroke is characterized by the sudden onset of acute, focal neurological deficits resulting from vascular compromise to a specific region of the brain. It is broadly divided into ischemic stroke (accounting for approximately 85% of cases) and hemorrhagic stroke (approximately 15%).

Acute Management Algorithm: When a patient presents with sudden neurological deficits (e.g., sudden unilateral hemiparesis, facial droop, severe dysarthria, or expressive aphasia), immediate and protocolized evaluation is required. The absolute most critical initial step in management is obtaining a non-contrast CT scan of the head. The primary purpose of this scan is strictly to rule out intracranial hemorrhage, as ischemic strokes may not appear on CT for 12-24 hours. If hemorrhage is present, blood pressure must be carefully and rapidly controlled, and emergency neurosurgical consultation is warranted.

For Acute Ischemic Stroke, determining the precise time of symptom onset (defined as the "time the patient was last seen well") is paramount. If the patient presents within 4.5 hours of symptom onset, they must be rapidly evaluated for intravenous thrombolysis with tissue plasminogen activator (tPA, Alteplase). This is provided there are no absolute contraindications (e.g., recent major surgery, active internal bleeding, history of intracranial hemorrhage, or severe uncontrolled hypertension >185/110 mmHg). Patients presenting with large vessel occlusions (LVO) detected on a subsequent CT Angiography may be candidates for endovascular mechanical thrombectomy, which has an extended therapeutic window of up to 24 hours from onset in select patients.

Secondary, long-term prevention focuses heavily on antiplatelet therapy (Aspirin or Clopidogrel), high-intensity statin therapy, tight blood pressure control, and aggressively evaluating for atrial fibrillation (which would necessitate a shift to long-term oral anticoagulation instead of antiplatelets).

Seizure Disorders and Status Epilepticus

A seizure is a transient, observable occurrence of signs or symptoms resulting from abnormal, excessive, or highly synchronous neuronal activity in the cerebral cortex. Epilepsy is defined clinically by an enduring predisposition to generate unprovoked seizures.

Status Epilepticus Status epilepticus is a profound, life-threatening neurological emergency. It is defined functionally as a continuous clinical or electrographic seizure lasting >5 minutes, or a series of recurrent seizures without a full recovery of baseline consciousness between the episodes. Prolonged, unremitting seizure activity can rapidly lead to irreversible hypoxic-ischemic brain injury, massive excitotoxic neuronal death, hyperthermia, and rhabdomyolysis.

Management protocol (detailed in the algorithm below) revolves around halting the seizure as rapidly as possible while simultaneously stabilizing the airway, breathing, and hemodynamics.

Movement Disorders: Parkinson's Disease

Parkinson's disease is a devastating, progressive neurodegenerative disorder caused directly by the premature loss of dopaminergic neurons in the substantia nigra pars compacta. This leads to a profound depletion of dopamine in the striatum, disrupting the basal ganglia's motor control circuits. Histopathologically, the disease is definitively characterized by the presence of Lewy bodies (abnormal intracellular inclusions primarily containing misfolded alpha-synuclein proteins).

Clinical Presentation (The Classic Tetrad):

• Resting Tremor: Typically an asymmetric, 4-6 Hz "pill-rolling" tremor in the hands that is most prominent at rest and noticeably disappears with purposeful, intentional movement.
• Bradykinesia: Generalized slowness of movement, manifesting as a shuffling, short-stepped gait, micrographia (abnormally small handwriting that worsens across the page), and hypomimia (a masked, expressionless face).
• Rigidity: Increased, uniform resistance to passive movement throughout the range of motion, often described as "cogwheel" (when superimposed on a tremor) or "lead-pipe" rigidity.
• Postural Instability: A loss of normal postural reflexes, leading to frequent falls (usually an important later finding in the disease course).

Management: Treatment is entirely symptomatic and aims to restore dopaminergic tone; it does not halt disease progression. Levodopa/Carbidopa remains the single most effective drug. Carbidopa acts to inhibit peripheral DOPA decarboxylase, ensuring significantly more Levodopa crosses the blood-brain barrier intact, thereby drastically reducing peripheral side effects like severe nausea and orthostatic hypotension. Dopamine agonists (e.g., Pramipexole, Ropinirole) are often utilized as initial monotherapy in younger patients to intentionally delay the onset of debilitating Levodopa-induced motor dyskinesias. Monoamine oxidase-B (MAO-B) inhibitors (e.g., Selegiline) and COMT inhibitors (e.g., Entacapone) are primarily used as adjunctive therapies to prolong the clinical effect of Levodopa and smooth out motor fluctuations.

Spondyloarthropathies

The seronegative spondyloarthropathies share inflammatory back pain, sacroiliitis, and an association with HLA-B27; the SMLE expects differentiation of the four subtypes.

• Ankylosing spondylitis: chronic lower-back pain and morning stiffness in a young man that improves with exercise; radiographic sacroiliitis and late "bamboo spine." First-line is an NSAID; second-line is a TNF inhibitor.
• Reactive arthritis (formerly Reiter syndrome): asymmetric oligoarthritis, urethritis, and conjunctivitis ("can't see, can't pee, can't climb a tree") 1–4 weeks after a GI or GU infection (Chlamydia, Salmonella, Shigella, Campylobacter).
• Psoriatic arthritis accompanies psoriasis; a hallmark is dactylitis ("sausage digit").
• IBD-associated arthritis mirrors inflammatory bowel disease flares (peripheral) or runs independent of bowel activity (axial).

High-yield: all four are rheumatoid-factor negative and HLA-B27 linked, distinguishable from rheumatoid arthritis, which is RF/anti-CCP positive, symmetric, small-joint, and erosive.