Sjögren Disease: Sicca, Systemic Features & Lymphoma Risk
Sicca opens the case; kidneys, lymphoma, and the fetal heart raise the stakes
Overview and pathogenesis
Autoimmune exocrinopathy. Sjögren disease is a chronic systemic autoimmune disorder in which lymphocytes infiltrate and gradually destroy the lacrimal and salivary glands, producing keratoconjunctivitis sicca and xerostomia. Women outnumber men about 9:1, usually in middle age. Persistent B-cell hyperactivity explains the autoantibodies, hypergammaglobulinemia, cryoglobulins, and lymphoma risk.
Primary vs secondary. Primary disease stands alone; secondary Sjögren accompanies another connective tissue disease—rheumatoid arthritis most often, but also SLE and systemic sclerosis. Other exocrine surfaces dry out too, causing dry cough, dry skin, and vaginal dryness.
Sicca features and diagnosis
Eyes. Burning, grittiness or a sandy foreign-body sensation, redness, and photophobia. A Schirmer strip wetting ≤5 mm in 5 minutes documents aqueous tear deficiency (nasolacrimal duct obstruction produces the opposite—overflow tearing), and fluorescein or lissamine green staining shows damaged ocular surface epithelium.
Mouth and glands. Patients need water to swallow dry food and notice altered taste. Losing saliva's acid buffering and antimicrobial action causes rampant gum-line (cervical) caries despite good hygiene, oral candidiasis, and angular cheilitis. Episodic or chronic bilateral parotid and submandibular swelling is common.
Serology. Anti-Ro/SSA, with or without anti-La/SSB, is the key antibody. A speckled ANA, rheumatoid factor (positive even without RA), and polyclonal hypergammaglobulinemia (high ESR and total protein) are frequent. Anti-Scl-70 and anti-centromere instead point to systemic sclerosis, and anti-Smith to SLE.
Labial gland biopsy. Minor salivary glands from the inner lower lip show focal lymphocytic sialadenitis; a focus score ≥1 (at least one cluster of ≥50 lymphocytes per 4 mm² of gland) is the key finding when anti-Ro is negative.
| Item | Positive result | Points |
|---|---|---|
| Labial gland biopsy | Focal lymphocytic sialadenitis, focus score ≥1 | 3 |
| Anti-Ro/SSA | Positive (anti-La alone does not score) | 3 |
| Ocular staining score | ≥5 in at least one eye | 1 |
| Schirmer test | ≤5 mm in 5 minutes in at least one eye | 1 |
| Unstimulated salivary flow | ≤0.1 mL/min | 1 |
Mimics to exclude
| Mimic | Clue | Confirm with |
|---|---|---|
| Anticholinergic drugs | TCAs, first-generation antihistamines, oxybutynin | Improvement off the drug |
| Hepatitis C | Sicca with mixed cryoglobulinemia | HCV RNA |
| HIV | Large parotids with CD8+ infiltrates (diffuse infiltrative lymphocytosis syndrome) | HIV testing |
| IgG4-related disease | Firm, persistent gland enlargement, milder sicca, anti-Ro negative, IgG4 often raised; brisk steroid response, rituximab for relapse | Biopsy: storiform fibrosis, IgG4+ plasma cells, obliterative phlebitis |
| Sarcoidosis | Bilateral parotid swelling, hilar adenopathy | Biopsy: noncaseating granulomas |
Extraglandular disease
- Joints, skin, vessels. Fatigue, nonerosive arthralgia or arthritis, and Raynaud phenomenon. Palpable lower-leg purpura with very low C4 signals mixed (type II) cryoglobulinemic vasculitis—monoclonal IgM with rheumatoid-factor activity bound to polyclonal IgG—a marker of severe disease and lymphoma risk.
- Kidney. Lymphocytic tubulointerstitial nephritis impairs distal H+ secretion, causing distal (type 1) RTA: normal anion gap acidosis, hypokalemia (weakness, even paralysis), urine pH >5.5 despite acidemia, nephrocalcinosis, and calcium phosphate stones. Proximal RTA differs because urine can still be acidified once bicarbonate falls below its threshold. Alkali (potassium citrate) corrects both the acidosis and hypokalemia.
- Lung. Dry cough, small-airway disease, and interstitial lung disease—classically lymphocytic interstitial pneumonia (ground glass with thin-walled cysts) or NSIP.
- Nerves. Painful small-fiber neuropathy; sensory ganglionopathy from dorsal root ganglion inflammation, producing sensory ataxia; mononeuritis multiplex when vasculitis is present.
Lymphoma risk
Mechanism. Chronic autoantigen drive within the glands expands rheumatoid factor–producing B-cell clones, which can transform. B-cell non-Hodgkin lymphoma develops in roughly 5–10% of patients—most often extranodal marginal zone (MALT) lymphoma of the parotid; diffuse large B-cell lymphoma is the main aggressive type.
Red flags: persistent (especially unilateral) gland enlargement, lymphadenopathy, splenomegaly, palpable purpura, cryoglobulins, low C4, or a monoclonal protein. A gland that stays enlarged for months needs biopsy—not antibiotics or more sialogogues.
Pregnancy: neonatal lupus and heart block
Maternal IgG anti-Ro/SSA and anti-La/SSB cross the placenta. Neonatal lupus causes an annular photosensitive rash, cytopenias, and transaminitis that fade by about 6–8 months as maternal antibody clears. Injury to the fetal conduction system causes congenital complete heart block, which is permanent—about 1–2% of anti-Ro–positive pregnancies, rising to about 15–20% after a previously affected child.
- Before or early in pregnancyStart or continue hydroxychloroquine, which lowers the risk of heart block
- About 16–26 weeksSerial fetal echocardiography measuring the mechanical PR interval during the highest-risk window
- DeliveryNeonatal ECG; pacing for complete block
Management
Eyes. Preservative-free artificial tears first, then topical cyclosporine or punctal plugs. Stop anticholinergic drugs that worsen dryness.
Mouth. Saliva substitutes, sugar-free gum, topical fluoride, and frequent dental care; treat candidiasis. The muscarinic agonists pilocarpine and cevimeline stimulate residual gland tissue; they cause sweating, flushing, and urinary frequency and are avoided in uncontrolled asthma and narrow-angle glaucoma.
Systemic disease. Hydroxychloroquine for arthralgia and rash; glucocorticoids plus rituximab for cryoglobulinemic vasculitis or severe organ involvement.