Hemophagocytic Lymphohistiocytosis (HLH)
Pathophysiology: Triggering factor (infection,...)→Activation of CD8 T cells (IFN-y) → Excessive activation of macrophages that disrupts immune homeostasis → Phagocytosis of blood cells + production of pro-inflammatory cytokines (TNFa,lL1, IL6, IL12, IL18) → Auto-amplification loop
Diagnosis: accumulation of clinical and biological evidences, Biological + Bone Marrow + Etiological Assessment
• Clinical: fever +++, hepatosplenomegaly, adenopathies, confusion
• Biological: Cytopenia +++ (Plt, Hb), Hepatic dysfunction, ↑ Ferritin >1000 ng/ml, ↑ Triglycerides, ↓ Fibrinogen level, ↑ sIL-2R >2400 Ul/ml, ↑ LDH
• Bone marrow: Medullary hemophagocytosis = additional diagnostic argument, Interest for etiological assessment+++
Primary HLH:
• Familial HLH, Chediak-Higashi, Griscelli, Purtilo (XLP)
Acquired HLH:
• Infections+++: Virus (EBV, CMV, HHV8,...), Bacteria (Mycobacteria, salmonella, ...), Parasites (Leishmaniosis, malaria, toxoplasmosis,...), Mycosis (Histoplasmosis, candidiasis,...)
• Hemopathies+++: Hodgkin, T-cell lymphoma, B-cell lymphoma (DLBCL, intravascular B-LNH), solid cancers
• Autoimmune diseases: SLE+++, Adult-onset Still disease, Infection under immunosuppressants or biologics (CMV +++, EBV)
• Others: Cellular immune deficiency, Drugs, Unknown cause
Treatment:
• Etiological+++: Anti-infectious, chemotherapy, anti-CD20 (PTLD), allogeneic HSCT
• Symptomatic: Glucocorticoids +++, Etoposide/VP16 (100 mg/m2) : in case of emergency, ICU in case of life-threatening manifestations, Anti-IFN-y and JAK inhibitors under evaluation
By Dr. Nicolas Taar
#HLH #Hemophagocytic #Lymphohistiocytosis #diagnosis #management #treatment #summary #rheumatology
Management of SIADH
Treat underlying cause:
• Causes can include pain, primary lung pathology, post-operative phenomenon, medications, etc.
Free water restriction:
• Restrict 1 to 1.5L per day
• Can be difficult for patients to maintain long-term
Salt tablets:
• Start with 1g NaCl PO TID
• With lower Na, increase the number and frequency of salt tablets administered
• Can cause volume overload
Urea powder:
• 15-30g PO daily
• Induces osmotic water elimination by promoting passive sodium reabsorption in the ascending limb of the loop of Henle
• Contraindicated in cirrhosis given the potential for it to be metabolized into ammonium by urease-producing bacteria in the colon
0.9% Normal Saline:
• If Urine osmolality < 538 AND UNa + UK < 154, can try giving a 250cc bolus of 0.9% NS
Vasopressor receptor antagonists:
• Blocks ADH receptor
• Has many side effects
Satya Patel, MD @SatyaPatelMD
#SIADH #Management #hyponatremia #nephrology #treatment
