Epidemiology

• Sex: more common in females than males
• Age: usually presents in 30’s-50’s (may be seen in children, particularly those with hypogammaglobulin-emia or AIDS)

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Etiology

• Dysproteinemia
  • Hypogammaglobulinemia
  • Monoclonal or Polyclonal Gammopathy
• Autoimmune
  • Sjogrens Syndrome (see [[Sjogrens Syndrome]])
  • Chronic Active Hepatitis
  • Myasthenia Gravis (see [[Myasthenia Gravis]])
  • [[Primary Biliary Cirrhosis]]
  • Hashimotos Thyroiditis (see [[Hashimotos Thyroiditis]])
  • Pernicious Anemia (see [[Pernicious Anemia]])
  • Autoimmune Hemolytic Anemia (see [[Hemolytic Anemia]])
  • Rheumatoid Arthritis (see [[Rheumatoid Arthritis]])
  • SLE (see [[SLE]])
• Allogeneic Bone Marrow/Stem Cell Transplant (see [[Bone Marrow Transplant]])
• Infection
  • HIV Disease (see [[HIV Disease]])
  • Epstein-Barr Virus (see [[Epstein-Barr Virus]])
  • HTLV-1
  • Tuberculosis (see [[Tuberculosis]])
  • Following Legionellosis (see [[Legionellosis]])
• Celiac Sprue
• Drugs
  • Captopril (see [[Captopril]])
  • Flecainide (see [[Flecainide]])
  • Phenytoin (see [[Phenytoin]])
• Surfactant Protein C Deficiency
• Idiopathic Lymphocytic Interstitial Pneumonia

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Physiology

• Lymphocytic infiltration of interstitium of lung
• Must be differentiated from pseudolymphoma/ primary pulmonary lymphoma/ lymphomatoid granulomatosis/ benign lymphocytic angiitis and granulomatosis/ plasma cell interstitial pneumonia

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Pathology

• Monotonous sheets of lymphocytes infiltrating interstitium and alveolar spaces
• May also have interstitial macrophages, non-caseating granulomas, perivascular amyloid deposits, and germinal lymphoid centers

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Diagnosis

• CXR: reticuar -> mixed alveolar+interstial pattern -> cysts/honeycombing
• HRCT: ground glass

ABG: hypoxemia
PFT’s: restrictive pattern with decreased DLCO
FOB: BAL lymphocytosis (>35%) may be seen (also seen in Sarcoid, Berylliosis, HP, drug-induced ILD, lymphoma)
-Increased plasma cells and macrophages
OLB: required for diagnosis in almost all cases

CXR/Chest CT patterns:
1) ILD: reticulonodular pattern (most common)
2) Mixed alveolar-interstitial infiltrates: due to coalescence
3) Hilar/ mediastinal nodes: in some cases
4) Honeycombing: small cysts (seen best in lower fields) seen late/ radiographic honeycombing correlates well with pathologic honeycombing
5) Pleural effusion: uncommon (suggests presence of complicating lymphoma)

Hypo or hypergammaglobulinemia: may be seen

Serum autoantibodies or immune complexes: may be positive

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Clinical

• Clubbing (common)
• Dyspnea:
• Cough:
• Pleuritic Chest Pain:
• Bibasilar Rales:
• Pulmonary HTN: late

Other System Involvement:
a) Lymphadenopathy:
b) Keratoconjunctivitis sicca:
c) Salivary Gland Enlargement:
d) Hepatosplenomegaly:
e) Fever:
f) Weight Loss:
g) Clubbing:
h) Cyanosis:

Complications:
1) Transformation into Low-Grade Pulmonary or Systemic Lymphoma: may occur in some cases
2) Infection (especially in cases with associated dysproteinemia):

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Treatment

• Steroids: may markedly improve disease (cited in few case reports)
  • Some cases progress to death despite therapy

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Prognosis

• Determined mainly by course of underlying disease

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References

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