When a Cold Turns the Eyes Yellow
When a Cold Turns the Eyes Yellow
Infection-triggered hemolysis in cold agglutinin disease
By William C. Aird, MD
Case Presentation
A 74-year-old woman with longstanding cold agglutinin disease (CAD) presents with three days of fatigue, jaundice, and dark urine.
Her CAD was diagnosed in 2010 after evaluation of mild scleral icterus and laboratory evidence of hemolysis.
Testing at that time showed:
- direct antiglobulin test: strongly positive for C3
- weakly positive for IgG
- cold agglutinin identified as anti-I
Strong C3 positivity with weak IgG reactivity can still be seen in CAD because IgM antibodies activate complement and then dissociate from the red cell surface, leaving complement detectable on testing.
Over the following 12 years, her disease has been characterized by:
- chronic compensated hemolysis
- mild anemia
- persistent scleral icterus
- intermittent hemolytic flares triggered by respiratory infections
She has required only one transfusion in the past, during hip replacement surgery.
Current Illness
Three days prior to admission she developed:
- fatigue
- dark urine
- worsening jaundice
Testing revealed influenza A infection.
Laboratory studies showed:
| Test | Result |
|---|---|
| Hemoglobin | 7.2 g/dL |
| LDH | 686 U/L |
| Haptoglobin | <10 mg/dL |
| Total bilirubin | markedly elevated |
She received pre-warmed packed red blood cells, with improvement in hemoglobin.
Which of the following is the most likely trigger for this patient’s acute hemolytic episode?
Explanation
In patients with cold agglutinin disease, hemolytic flares are frequently triggered by infections, particularly:
- viral respiratory infections
- Mycoplasma pneumoniae
- Epstein–Barr virus
Infections increase inflammation and complement activation, which can amplify hemolysis in patients with pre-existing CAD.
A Laboratory Clue
During this episode, the absolute reticulocyte count was lower than expected for the degree of anemia.
What is the most likely explanation for this finding?
Explanation
During acute infection, inflammatory cytokines such as IL-6 and TNF can suppress erythropoiesis and alter iron metabolism.
This produces a physiology similar to anemia of inflammation, in which marrow production is temporarily reduced.
As a result:
- reticulocyte production may be inappropriately low
- marrow compensation for hemolysis is impaired
In this patient, the reduced reticulocyte response likely contributed to the drop in hemoglobin and explains why transfusion support was required despite her usually compensated hemolysis.
The reticulocyte response typically recovers as the infection resolves.
Clinical Course
With treatment of influenza and supportive care, the patient’s hemolysis gradually improved.
Follow-up laboratory testing showed:
| Test | Result |
|---|---|
| Hemoglobin | 10.5 g/dL |
| LDH | 554 U/L |
| Total bilirubin | 5.3 mg/dL |
These values were consistent with her baseline compensated hemolysis.
Which of the following is the most appropriate management strategy for this patient?
Explanation
Treatment of cold agglutinin disease is generally reserved for patients with:
- severe symptomatic anemia
- transfusion dependence
- disabling cold-induced circulatory symptoms
This patient has a 12-year history of compensated hemolysis with infection-triggered flares and returned to her baseline hemoglobin after treatment of influenza and supportive transfusion.
In this context, supportive care and observation are appropriate.
Teaching Points
- Cold agglutinin disease often follows a chronic relapsing course with compensated hemolysis.
Many patients live for years with mild anemia and intermittent hemolytic flares. - Respiratory infections are common triggers for hemolytic flares.
Viral infections and pathogens such as Mycoplasma pneumoniae can increase complement activation and amplify hemolysis. - Inflammation can suppress erythropoiesis during acute infection.
This may produce a blunted reticulocyte response despite ongoing hemolysis. - Treatment decisions in CAD are guided by clinical burden.
Patients with compensated hemolysis and manageable symptoms are often treated with supportive care alone, reserving disease-directed therapy for severe or persistent anemia.
Why This Case Matters
Cold agglutinin disease is often portrayed as a rare and dramatic disorder.
In reality, many patients live for years with:
chronic compensated hemolysis
mild anemia
intermittent infection-triggered flares
Recognizing this natural history helps clinicians interpret acute decompensation appropriately, treat reversible triggers such as infection, and avoid unnecessary escalation of therapy.