A Case of Macrophage Activation syndrome Heralding The Diagnosis of SLE

A Case of Macrophage Activation syndrome Heralding The Diagnosis of SLE

Background

Macrophage activation syndrome (MAS) is a form of hemophagocytic lymphohistiocytosis that occurs primarily in patients with juvenile idiopathic arthritis or other Rheumatologic diseases but rarely in SLE. It is characterized by an aggressive and life-threatening syndrome of excessive immune activation and presents as an acute or subacute febrile illness associated with multiple organ involvement and often diagnosed late due to its rarity. We present a case of MAS precipitated by Ehrlichia infection leading to the diagnosis of SLE in a young male.

Case Presentation

A 26-year-old male with a history of chronic ITP and nephrolithiasis who presented to the ER with complaints of fever, fatigue, generalized weakness, and presyncope. He reported unintentional weight loss of 30 pounds in three months and two months history of fatigue, malaise, night sweats, polyarthralgia, and episodic swelling in fingers and toes. He has a family history of SLE in his mother and maternal aunt.

His vital signs in the ER: Temperature 38.7oc, HR 111/min, BP 122/75mmhg and RR 20cpm, SPO2 98% on RA. He had tenderness in the small joints of the hands and bilateral axillary and inguinal lymphadenopathy on physical examination.

His initial laboratory work-up revealed pancytopenia, transaminitis, low fibrinogen, elevated D-dimer, troponin, and lipase. He had wall motion abnormality, low ejection fraction, and pericardial effusion on Transthoracic Echocardiogram. CT Chest/Abdomen/Pelvis showed hepatomegaly, inguinal and axillary lymphadenopathy, and findings suggestive of acute pancreatitis. The top differential diagnoses were autoimmune disease and malignancy. Immunologic work-up revealed positive Anti-nuclear antibody, anti-double-stranded DNA, anti-smith antibody, anticardiolipin, and B2-glycoprotein antibodies. He also had low complement levels, elevated ferritin, and ESR. An extensive infectious screen revealed a positive Erhilichia IgM antibody. Table 1. Flow cytometry and Axillary lymph node pathology were negative for malignancy. He met the diagnostic criteria for SLE (5 of 11 ACR criteria) and had an HScore of 228 points (96-98% probability of hemophagocytic syndrome). He was treated with high-dose steroid and hydroxychloroquine and completed ten days of doxycycline.

Conclusion

This case is a rare presentation of MAS in a young man with previously undiagnosed SLE. Prompt diagnosis and treatment are important to prevent an adverse outcome.

Table 1:

Laboratory tests(units)

Result

Normal Range

White cell count (X 10³/uL)

2.38

4.8 - 10.8

Platelet (X 10³/uL)

53

130 - 400

Hemoglobin(g/dL)

10

14.0 - 17.5

ESR (mm/hr)

40

0-15

CRP (mg/dl)

0.4

<1.00

Fibrinogen(mg/dL)

218

193 - 488

Blood protein electrophoresis

Polyclonal Hypergammaglobulinemia; increased alpha 1 globulin and hypoalbuminemia

Ferritin(ng/mL)

7500

24 - 336

Triglyceride(mg/dL)

408

<175

Creatinine(mg/dL)

0.64

0.60 - 1.30

Troponin(ng/mL)

0.1

<=0.06

D-dimer(ug/ml)

5

<0.50

LDH (units/L)

289

140- 280

Lipase (IU/L)

306

11 - 82

Haptoglobin(mg/dL)

213

20-200

Procalcitonin(ng/mL)

1.07

<0.50

Anti-double stranded DNA antibody

1:40

1:10

Anti-Smith

>8

<1

Cardiolipin

1:38

<=14

ANA

1:640(homogenous pattern)

<40

DRVVT (Dilute Russell's viper venom time)

Positive

Negative

DRVVT (Dilute Russell's viper venom time)

175

<=45

Cardiolipin Ab IgG

38

<=14

Cardiolipin Ab IgA

<11

<=11

Cardiolipin Ab IgM

32

<=12

Beta 2 glycoprotein 1 IgG(SGU)

23

<=20

Beta 2 glycoprotein 1 IgA(SAU)

45

<=20

Beta 2 glycoprotein 1 IgM (SMU)

60

<=20

PhosSerine IGG

46

<10

C3(mg/dL)

29

90-180

C4(mg/dL)

6

15-45

Mitochondrial antibodies

Negative

Negative

Smooth Muscle antibody

Negative

Negative

ANCA Screening

Negative

Negative

Anti-liver/kidney microsomal antibodies (Anti-LKM-1)

Negative

Negative

Ehrlichia chaffeensis IgM Ab

1:40

<1:20

Ehrlichia chaffeensis IgG Ab

<1:64

<1:64