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Autoimmune hepatitis


Diagnosis: piecemeal necrosis on liver biopsy, also correlate with serology

Treatment: steroids +/- azathioprine, cyclosporine, tacrolimus, MMF, liver transplant
Type 1 “classic” autoimmune hepatitis ANA, ASMA, AMA (rarely)

Type 2 –LKM-1, ASMA (occasional),

Type 3 – generally seronegative, ASMA (occasional), AMA (rarely)

Type 4 (PBC) – ANA, ASMA, AMA (rarely)



Primary biliary cirrhosis (PBC)

autoimmune destruction of small intrahepatic bile ducts / females 35-60 / cholestasis late /



Presentation: usu. begins with pruritis

Labs: high AMA (>1:40), elevated alkaline phosphatase (2-5x ↑)

Diagnosis: liver biopsy shows lymphocytic destruction of bile ducts

Associations: ⅔ have Sjogren’s / 20% have CREST / 17% with autoimmune thyroiditis / can get various lung disease (IPF, granulomatous, lymphocytic interstitial pneumonitis, pulmonary HTN, pulmonary hemorrhage)
Secondary biliary cirrhosis

obstruction / edema, inflammation / portal tract lesions, but hepatocytes intact



AMA (-), lower alkaline phosphatase
Sclerosing Cholangitis

Primary: 5% of ulcerative colitis

Secondary: many causes / in AIDS pts – CMV, cryptosporidium, PCP, MAI (some)
Primary Sclerosing Cholangitis (PSC) [NEJM]

men (70%), 75% of PSC and cholangiocarcinoma occur in IBD patients (UC >> Crohn’s) / 3 per 100,000 (1:100 as much as alcoholic cirrhosis) / 4th leading indications for liver transplant



Mechanisms (speculated): chronic portal bacteria, toxic bacterial metabolites of bile, ischemic damage, genetic/immunological

Location: mostly intra/extrahepatic ducts (15% with gall bladder/cystic duct too)

Presentation: asymptomatic until obstructive liver disease signs develop, episodes of acute bacterial cholangitis (fever, chills, lab abnormalities) / steatorrhea, vitamin A deficiency

Course: may evolve over many years / mean age at diagnosis 40 yrs, survival 12 yrs from diagnosis

Labs: hypergammaglobulinemia in 30% (elevated IgM 50%), pANCA (65%), ASMA (10%), ANA (20%), elevated obstructive liver enzymes, elevated urinary copper and serum ceruloplasmin

Ulcerative Colitis: more with early age onset of UC / may precede symptoms of UC by many years (diagnosed with ERCP) / some say some degree of UC exists in all PSC / PSC does not correlate with activity of UC

Other associations: thyroiditis, type I DM

Complications: liver failure, cholangiocarcinoma (20% of PSC patients, even 20 yrs after colectomy, smoking and presence of IBD increases risk), vitamin K deficiency (rare, but happens with chronic jaundice, cholestyramine use), vitamin D deficiency (osteoporosis)

Diagnosis: ERCP (fine ulcerations, dilatation, narrowing) with cholangiogram [pic] [pic] / transhepatic cholangiogram is the 2nd choice / percutaneous liver biopsy will probably miss lesions (concentric fibrosis around bile ducts) but can be used to follow disease

Ddx: stricture/obstruction from previous surgery, cholangitis, bile duct neoplasms, choledocholithiasis, congenital biliary tree abnormalities

Treatment: ursodiol is of debatable utility, steroids are not helpful (other immunosuppressives under investigation), ERCP may diagnose and treat complications, liver transplant only proven cure (cholangiocarcinoma is relative contraindication to transplant); may experience sclerosing cholangitis (recurrence vs. rejection vs. bacteria from roux-en-Y)

Pruritis: cholestyramine, colestipol binds bile acids / naloxone (elevated endogenous opiates implicated) / ursodiol, odansetron, m-testosterone, rifampin, phenobarbital, antihistamines, UV light, plasmapheresis
Recurrent cholangitis: optimal antibiotic choice and use of preventative abx under investigation
Alpha-1-antitrypsin (see lungs)

cholestatic liver disease in infancy, cirrhosis and/or portal hypertension / chronic liver disease / MM normal / ZZ abnormal


Hemochromatosis [NEJM]

Primary: inherited disorder / 5-10% frequency of gene in population [most common mutation can be tested, small minority have other mutations] / AR / most are homozygote for the C282Y mutation of the HFE gene increased iron absorption, progressive iron overload

Pathology: increased Fe uptake (normal 3 g, increased to 20-40 g) / women lose 20-30 mg at menses / hemosiderin deposition (causes direct damage to liver, pancreas)

Secondary: increased absorption (chronic liver disease, iron-loading anemias, porphyria cutanea tarda, dietary overload) or parenteral administration (multiple blood transfusions) of iron / secondary has much less total iron build-up (ferritin)

Presentation: often diagnosed early with fatigue, arthralgias (25-50%) or increased AST/ALT’s or  fatigue, arthralgias (frequent), skin pigmentation (90%, gray or bronze color), liver disease (RUQ pain, hepatomegaly, cirrhosis, HCC), and diabetes

Complications: micronodular cirrhosis, diabetes, skin pigmentation, restrictive cardiac failure, arthritis (may have CPPD, often 2nd and 3rd MCP (1st most-asked pimp question in history of mankind), impotence / 200 x risk of HCC (30% incidence)

Labs: ferritin increased (proportional to iron burden), transferrin increased (Fe %sat)

Diagnosis: liver biopsy can be useful to quantify iron overload and assess liver fibrosis (can also use genetic testing to risk stratify patients for development of fibrosis/cirrhosis (look for presence of the C282Y or H63D mutation)

Ddx: can have falsely high ferritin levels from other diseases

Treatment: phlebotomy, deferoxamine

Course: life expectancy goes to normal if treated before cirrhosis
Wilson’s disease

AR mutation in ATP7B gene / onset in 10s to 20s

Mechanism: abnormal copper transport causes increased GI absorption and decreased clearance

Liver: hepatitis, cirrhosis

CNS: extrapyramidal signs (hypertonia, rigidity, tremors, clumsiness), range of psychiatric disorders

Eyes: Kayser-Fleischer rings in cornea and sunflower cataracts

Renal: hematuria, tubular dysfunction

Hemolytic anemia: may be presenting finding (occurs in 10-50%), circulating Cu kills RBC’s, may have elevated HgA2

Presentation: hepatitis 1st (jaundice, malaise, anorexia) that usually resolves / may effect only liver or various organ combinations

Labs: serum ceruloplasmin < 20 ug/dl, urine Cu > 100 ug/24 hrs / elevation of serum copper can be a non-specific sign of cholestatic liver disease / low LAP score

Treatment: penicillamine (given with pyridoxine) / restrict dietary intake (shellfish, legumes) / maintenance therapy with oral Zinc (decreases absorption)
Liver Abscess
Pyogenic:

Organisms: E. coli, Klebsiella, Bacteroides, Enterococcus

Diagnosis: CT guided sampling

Treatment: antibiotics +/- drainage

Amebic:

2-5 months after travel to endemic area / occurs in 3-25% of intestinal amebiasis (especially with HIV) /most common presentation: RUQ abdominal pain



Diagnosis: positive antibodies in 98% of cases (indirect hemagglutinin test) / ultrasound 75-85% sensitivity

Treatment: metronidazole usually works +/- chloroquine, but drain if rupture is imminent

Parasitic:

echinococcus



Diagnosis: U/S or CT (90% sensitive and direct aspiration may seed peritoneum), eosinophilia, positive heme agglutination

Treatment: open resection (do not spill), instillation ethanol or 20% NaCl
Liver Neoplasia
5% of liver tumors are benign
Hemangioma

most common benign liver tumor / incidence of 7% of population / usually clinically unimportant but can cause consumptive coagulopathy



Presentation: pain (can rupture), jaundice (can obstruct)

Diagnosis: do NOT biopsy (risk of bleeding) / peripheral enhancement on CT, arteriography
Focal Nodular Hyperplasia

central stellate scar / unencapsulated, but well-defined / central blood supply, not likely to rupture / 2 cells thick / females 2:1 / not related to OCPs / any age / 20% symptomatic from

mass effects / not precursor to HCC
Hepatocellular Adenoma (not HCC precursor)

1 per million / risk factors: females, reproductive years, birth control pills (40 x risk)

Pathology: peripheral blood supply, may rupture (1/4 present with circulatory collapse) causing necrosis (increased ALT and CT findings) / portal tracts absent

Presentation: pain (may not be present; can rupture), jaundice (can obstruct) / more common in right lobe

Labs: LFT’s usually normal, a-FP negative

Treatment: remove hormones (stop OCPs, etc.) / tumor likely to regress spontaneously / however, may resect if symptomatic, > 10 cm or not regressing / patients should avoid pregnancy which increases likelihood of hemorrhage
Hepatocellular carcinoma (HCC)

very common worldwide / 3 per 100,000 in US (and rising) / males > female / 95% liver tumors are malignant



Risk Factors: HBV, HCV (major cause in US), alcoholic cirrhosis, hemochromatosis,

smoking?, vinyl chloride, OCPs



Pathology: large mass with satellite lesions / may be green with bile / 50% with mets to

regional nodes, lung



Presentation: weight loss, RUQ, shoulder pain, weakness

Physical Signs: hepatomegaly, portal hypertension, ascites, jaundice (50%)

Diagnosis: often positive AFP (elevated in germ cell tumors; >500 suggestive, >1000 almost diagnostic)

Ultrasound: cystic v. solid / radiography: benign v. malignant / CT or MRI: multiplicity and anatomical / hepatic arteriography to diagnose hemangioma

Treatment:

  • wedge resection (often difficult due to underlying liver disease) / entire lobectomy does not improve survival

  • transplant can be curative in selected patients (must have single lesion < 5 cm or 3 or fewer < 3 cm)

Prognosis: no treatment  3 month survival / with resection  3 yr survival / 5 yr survival rate is 10-50% / with successful transplant survival same as nonmalignant liver transplant patient
Liver metastases

most common malignant liver tumor / one source colon > stomach > pancreas > breast > lung / another source  lung > colon > pancreas > breast > stomach

Treatment: liver mets from colon cancer (up to 3 lesions) should be resected (some say 4-5)
Liver Transplant [NEJM]
Child-Pugh rating system: must have >= 7 to qualify for liver transplant / get points for INR, low albumin, ascites, hepatic encephalopathy

Must demonstrate (in rehab) no alcohol/drugs for 6 months


Malignancy develops in 2%-7% of transplant recipients (from immunosuppression) (100 fold > than normal) / transitional cell Ca of UG tract and renal cell Ca, skin and lips, lymphomas (esp. CNS), cervical, lung, head and neck, colon / onset time 1-158 months (avg. 40) / lymphomas develop faster

Hematology [onc] [transfusion medicine]


Anemia (work up) [Ddx] hemolytic anemia, HELLP, aplastic anemia

Hemoglobinopathy sickle cell, thalassemia

Thrombocytopenia [Ddx] HIT, TTP, ITP, APA
Coagulation

Bleeding disorders Hemophilia, Von Willebrand’s

Hypercoagulability APA, factor V, G20210

Thromboembolic DIC, HELLP, TTP, HUS, HSP
Leukemia

Lymphoblastic ALL, AML, CLL, Hairy Cell

Myeloproliferative CML, myelofibrosis, thrombocythemia, PRV, leukemoid reaction

Plasma cell dyscrasias MM, WM, heavy chain disease, benign monoclonal gammopathy

Histiocytoses
Lymphoma

Hodgkin’s

NHL B-cell small lymphocytic, cleaved cell, diffuse large cell, Burkitt’s

T-cell adult T-cell, lymphoblastic, Sezary
Basic Principles
Clotting Cascade [diagram][diagram]
[hematology lab slides]
Hb conc. in whole blood RBC count hematocrit

Male 14-18 g/dL male 4.7-6.1 e6/ul male .42 - .52

Female 12-16g/dL female 4.2-5.4 e6/ul female .37 - .47
Mean corpuscle volume (MCV)

hematocrit/RBC count (use fudge factor)

normal 80-94 fL (normocytic may include high degree of variation - anisocytosis)

false elevation with cold agglutinins


Mean corpuscular Hb

Hb/RBC count (fudge factor)


MCHC

Hb/hematocrit (normo, hyper or hypochromic)


Neutrophils

Dohle bodies (vague, blue cytoplasmic inclusions)

blacks may have lower low end (1160 vs. 1700)
Eosinophils
Eosinophilia: AEC > 500-750 / NAACP (Neoplasm, Allergy, Addison’s, Connective tissue diseases, Pancreatitis) / Other: atheroembolic vasculitis, IBD, sarcoidosis, TB, parasitic infection

Eosinophiluria: caused by eosinophilia and BPH/prostatitis, RPGN
Basophils no mitotic potential

Mast cells mitotic potential

Lymphocytes don’t confuse activated lymphocytes with leukemic blasts

Platelets number in one oil immersion field x 20K
Other

plasma cells, endothelial cells, histiocytes, nucleated RBC’s, myeloblasts


Anemia [causes of anemia]
Hb < 12 Hb < 15 in neonate
Hct < 37 Hct is 50 in neonate, then drops to 30 and gradually increases to puberty levels
Physiology

anemia in tissue produces more 2,3-DPG, shifts Hb curve to the right

redistribution of blood flow away from kidneys and skin

increased cardiac output (in severe anemia)

physiologic anemia in young infant – 2o shift in oxygen dissociation curve


  • clinical signs of acute anemia:

syncope, orthostatic hypotension, orthostatic tachycardia

very acute hemorrhage  normal Hct and Hb (corrects with fluid intake)




  • clinical signs of ongoing anemia:

tachycardia, pallor (conjunctiva, lips, oral mucosal, nail beds [pic], palmar creases), jaundice, petechiae, purpura (TTP), glossitis (pernicious anemia, iron deficiency), systolic ejection murmur, S3, splenomegaly (hemolysis, neoplasia, infiltration), LAD
Anemia Work-Up
Consider: age, sex, color, ethnic, neonatal, nutrition/diet, drugs, diarrhea, inflammation, infection, pica, prosthetic valves, guaiac status,
Initial workup:

  • reticulocyte count

  • iron studies (TIBC, ferritin, %sat)

  • haptoglobin, LDH, direct/indirect Bilirubin

  • serum or RBC folate, B12


More workup: peripheral smear, Coomb’s, Hgb electrophoresis, bone marrow
Classification of Anemia
Normochromic, Normocytic

Marrow hypoplasia (drugs, radiation)



Aplastic anemia

Marrow infiltration (myeloma, lymphoma, leukemia)

Myelofibrosis

Renal insufficiency



Hemolytic anemia

Acute hemorrhage

Anemia chronic disease
Hypochromic, Microcytic

Iron deficiency (most common)

Thalassemia

Porphyria?

Sideroblastic anemia (lead, INH, EtOH, congenital)

Anemia of chronic disease (?rarely)
Normochromic, Macrocytic

Folate, Vitamin B12

Drugs (AZT, TMP, pentamidine, phenytoin, primidone, phenobarbital [mild], chronic nitrous oxide)

Myelodysplasia

Liver disease
Note: elevated MCV (reticulocytes have increased diameter)
Reticulocyte count

reticulocytes live about 1-1.5 days then circulate 120 days

absolute reticulocyte count (normal 50-70,000/mm3)
reticulocyte production index (normal 1.0 to 2.0)

reticulocyte x [patient’s Hct / normal Hct] x [1/RBC maturation time]



<1 % is inadequate production, > 4% RBC destruction

corrected reticulocyte count accounts for any anemia


Peripheral Smear
Cell Types
Spherocytes

hereditary/secondary (autoimmune-mediated hemolysis)


Tear drop cells (extramedullary hematopoeisis)

myeloproliferative disease (e.g. myelofibrosis), pernicious anemia, thalassemia


Helmet cells – microangiopathic hemolysis, severe iron deficiency
Schistocytes – microangiopathic hemolysis [pic]
Sickle cell – HbSS
Findings

Hypochromic – lead, iron deficiency

Hyperchromic – B12, Folate, spherocytosis

Basophilic stippling – lead, hemolysis, thalassemia

Pappenheimer bodies – postsplenectomy, hemolytic, sideroblastic, megaloblastic

Rouleaux formation – multiple myeloma, Waldenstrom’s, other conditions

Parasites – Malaria, Babesiosis

Nucleated RBC’s – extramedullary hematopoeisis, hypoxia, hemolysis

Target cells – hemoglobinopathies, iron deficiency, liver disease

Heinz bodies (denatured Hgb) (requires supravital stain)

unstable hemoglobinopathies, some hemolytic anemias

Howell-Jolly Bodies (nuclear fragments) - hemolytic, megaloblastic, asplenia

Cabot ring (nuclear remnants) – megaloblastic
Bone marrow exam

myeloid/erythroid or M:E ratio / hyporegenerative, aplastic anemia / diagnosis of leukemia


aspirate Wright smear / more painful

core biopsy stained biopsy (and aspirate clot) for neoplasm, granuloma Dx


Ineffective Hematopoeisis

Causes: metabolic deficiency, primary stem cell defect (e.g. MDS), abnormal bone marrow microenvironment (autoimmune, infections—HIV, Tb, histoplasmosis)

Pathology: hypercellular marrow with thrombocytopenia, anemia, low reticulocyte count
Iron metabolism

There is no excretory pathway for iron (only through skin and GI loss)

menstruating women may lose 7 mg/day (30 mg/month) vs. 1 mg/day other males/females

Fe2+ absorbed in duodenum (1-2 mg of 15 mg total intake), transferrin takes Fe3+ in cell and blood, stored as ferritin (Fe3+/apoprotein) in equilibrium between blood and marrow histiocytes hemosiderin in histiocytes in erythron (iron > apoprotein)


Iron deficiency anemia (IDA) [NEJM]

Epidemiology: black females have slightly decreased Hgb in general / women > 50 (2%), < 50 (5%), men (~1%)

Causes:

Blood loss (GI bleeds): ulcer, cancer, angiodysplasia, IBD, hookworm

Uterine blood loss: menstruation, fibroids

Malabsorption: gastrectomy, celiac disease, IBD

Intake problem: bovine milk-fed infants (not enough Fe), pregnancy, vegetarian diet

Clinical: fatigue, shortness of breath, may have cravings for dirt or paint (pica) or ice (pagophagia), glossitis, cheilosis, koilonychias / rare/advanced cases: postcricoid esophageal web (Plummer-Vinson syndrome)

Labs: TIBC and FEP increase, decreased Fe saturation (<10%) decreases may precede other findings / low RPI, increased TIBC (transferrin), decreased ferritin, absent iron stores in marrow, increased protoporphyrin and zinc-protoporphyrin / may have elevated RPI and thrombocytosis due to bleeding (caused by iron deficiency)

Peripheral smear: hypochromic, microcytic [pic] / anisocytosis, poikilocytosis when severe

Note: peripheral smear may distinguish from thalassemia minor / RDW > 15 supports Fe deficiency (because marrow is producing a lot of erythrocytes; lower RDW suggests stable thalassemia)

2-3 months minimum age of onset

Treatment: oral ferrous sulfate / parenteral iron (use cautiously because of increased risk of anaphylaxis) / transfusion (see other)
Anemia of chronic disease (new term is anemia of chronic inflammation)

inflammatory cytokines (hepatic synthesis of hepcidin)  decreased RBC lifespan, impaired iron metabolism (including absorption), refractoriness to erythropoietin / slightly decreased MCHC / normo/macrocytic

Labs: decreased TIBC and Fe saturation (10-20%) but increased ferritin (usually) and Fe in macrophages [note: ACD may co-exist with IDA and make these labs difficult to interpret]

Treatment: can you use Epogen? Sure! Patients with ACD can have a so-called relative deficiency in erythropoietin levels (elevated but not enough for degree of anemia, in spite of normal kidneys)
Sideroblastic Anemia (microcytic)

Lead (Pb), alcohol, INH toxicity / congenital form (sex-linked)

Labs: increased Fe, increased Fe saturation, increased ferritin

Smear: dimorphic population of microcytic and normocytic cells [pic] / may have basophilic stippling / ringed sideroblasts (developing RBCs with engorged mitochondria due to faulty heme synthesis) in bone marrow
Aplastic Anemia or Pure Red Cell Aplasia (normocytic)

Infections: HBV, EBV, B19, HTLV, HIV

Drugs: Ara C, chloramphenicol, phenylbutazone, TMP-SMX, Dilantin)

Other: precursor to leukemia, autoimmune (SLE, RA), thymoma, lymphoma, hereditary, pregnancy

Labs: giant pronormoblasts on peripheral smear, ↑ erythropoietin

Treatment: if cause can be determined, sometimes immunologically active meds (prednisone, cyclosporin, IVIG) can be helpful
Anemia of Renal Failure

Mechanism: decreased RBC lifespan with inadequate erythropoietin response (this may actually be more complicated than just this, studies suggest increased CHF if over-normalized by Epogen 11/06)

Labs: BUN > 36, Cr 3-5, Hg may be < 7 / Fe labs are normal (may become Fe deficient following hemodialysis losses)

Exceptions: HUS (increased erythropoiesis), polycystic (normal erythropoiesis), diabetes mellitus (decreased erythropoiesis relative to state of renal failure)
Anemia of liver disease

Chronic: impaired LCAT leads to burr cells and stomatocytes

Alcoholic: bone marrow suppression, folate deficiency, dietary inadequacy, blood losses
Megaloblastic anemia (leukopenia, thrombocytopenia)

problems making DNA, so precursors get held up in marrow, macrocytic


Folate

made into THF by DHF reductase / FIGlu (histidine metabolite) is a marker for folate deficiency / malnourished, milk-fed, pregnant, drugs (phenytoin, isoniazid, phenobarbital, primidone, cycloserine)


B12

Molecular: important in reversing the “folate trap” / methylmalonic acid is a urine marker for folate deficiency (folate helps metabolize odd-chain fatty acids)

Diagnosis: > 2 hypersegmented PMNs/HPF [pic], macrocytic anemia, decreased WBC, decreased platelets / direct B12 / Schilling test (not needed now) / consider doing one EGD to r/o adenocarcinoma

Presentation: you can have CNS Sx without hematological findings

Causes:

pernicious anemia (see below)

dietary deficiency - only in vegans because body stores last several years

malabsorption – IF not produced by parietal cells (gastrectomy)

terminal ileum lesions - Crohn’s, celiac disease, etc.

bacterial overgrowth or D. latum (fish tapeworm)


Pernicious anemia [NEJM]

B12 deficiency / Ab to IF or gastric mucosa (anti-parietal Ab positive in 90%) / young blacks, old whites / 20-30% with family history



disease

Presentation: jaundice (hemolysis), cheilitis, glossitis (burning tongue, atrophy of papillae, deep/red mucosa, cobblestone appearance)

  • Neuropathy – paresthesias, weakness (demyelination in posterior columns)

  • CNS: “megaloblastic madness” - constellation of symptoms

Associations (autoimmune): vitiligo, thyroid

Treatment: 1 mg SC x 3 d and check reticulocyte count
Pediatric Anemias
birth – 12 months Blackfan-Diamond Syndrome

12 mo – 5 yrs transient erythroblastopenia of childhood (TEC)

follows viral infection, like childhood ITP, usually self-limited

any age transient erythroid aplasia in hemolytic disease

follows viral infection, exacerbates underlying hemolytic disease

late childhood – on pure red cell aplasia



Blackfan-Diamond Syndrome

congenital macrocytic anemia due to (lack erythropoietin receptors?) / presents within months of birth / associated with Turner’s and thumb abnormalities / may see urinary, cardiac, skeletal anomalies / Treatment: corticosteroids may help


Transient Erythroblastopenia of Childhood (TEC)

normocytic / 6 months – 4 yrs / usually only one episode per life / may require transfusion


Hemolytic anemia
Dx RPI to establish bone marrow response / look for erythrocyte detritus / increased unconjugated bilirubin, increased urobilinogen in urine (dark urine), free serum decreased haptoglobin / can measure haptoglobin, free serum Hb, urine Hb, hemopexin, methemalbumin / Note: haptoglobin, serum and urine Hb not as altered with extravascular hemolysis
Mechanical
Intravascular

artificial heart valves, DIC, TTP, malignant HTN (microangiopathic)

produces hemosiderin in urine, Hb in serum/urine, and schistocytes (broken cells)
Extravascular

RES enlargement produces spherocytes/chopped cells (could be considered immune-mediated by macrophages eating RBCs)


Autoimmune mechanisms
Warm agglutinins (occurs at any temperature)

IgG against certain universal Rh component (more extravascular, i.e. RES plucks RBC’s out of circulation, gives spherocytes, not schistocytes) [pic]

may be drug-induced (methyldopa), autoimmune (SLE et al) or alloimmune (erythroblastosis fetalis, transfusion reaction)

Treatment: remove offending agent and/or steroids / also consider cyclophosphamide, azathioprine, danazol, IVIG, rituximab) / splenectomy in refractory cases


Cold agglutinins

IgM against I antigen on RBC / paroxysmal cold hemoglobinuria - anti-P antigen



Causes: Mycoplasma pneumoniae and (rarely) EBV

Labs: same as other hemolytic anemias (↓ haptoglobin, ↑ MCV, erythroid hyperplasia)

Treatment: steroids, splenectomy, replacement, other?
Infectious

C. perfringens sepsis (and other GP/GN sepsis), malaria (and other protozoa), Bartonella, Tb (local and disseminated), Borrelia, Leptospirosis, malaria, mumps
Chemical Agents, Drugs, and Venoms

Oxidant Drugs and Chemicals

Oxygen (high pressure) / Vitamin E deficiency in infants

Nitrates, cisplatin, naphthalene (mothballs), nitrofurantoin, sulfonamides, ASA, sodium sulfoxone

Dapsone and phenazopyridine (Pyridium) also are associated with Heinz body hemolysis



triamterene, methyldopa, rifampin

Nonoxidant Mechanisms

PTU

arsine (metal industry, transistor, gold refining) – give exchange transfusions



Trimellitic Anhydride (plastic industry)

lead


copper (see Wilson’s disease)

Water (drowning with entry of > 0.6 L)

Hemodialysis (contaminants)

Other Agents

Venoms

spiders (brown recluse, hobo spider), snakes (cobras, Australian king-brown, saw-scaled carpet viper), Bee Stings (very rarely), scorpions

Physical Agents

Thermal Injury, ionizing irradiation (debatable)
Hypophosphatemia (see lytes)
Paroxysmal Nocturnal Hemoglobinuria (PNH)

massive intravascular hemolysis / 4 to 6 per million

Mechanism: acquired somatic mutation (H or I) in PIG-A gene on X chromosome (decay accelerating factor) / causes non-specific activation of complement  hemolysis  cell-free hemoglobin acts as NO scavenger  decreased NO may cause most of symptoms

Presentation: abdominal pain, esophageal spasms, erectile dysfunction, venous thrombosis (esp. European descent)

Findings: bone marrow hypoplasia with up to 13% aplastic anemia; thus may have anemia and/or thrombocytopenia without positive urine Hb), tea or cola-colored urine (or bright red in up to ⅓)

Labs: Prussian blue will stain urine for hemosiderin / low LAP score

Treatment: oral iron supplementation if iron-deficient, BMT may be used as last resort for aplastic anemia, eculizumab (antibody against C5 complement factor) is under investigation 9/06

Glucose-6-phosphate dehydrogenase deficiency (G6PD)

XLR / most common metabolic disorder (⅛ of world’s population) / 100 different variants / variable predominance and expressivity across ethnic groups (ranges from mild to life-threatening) / A-type occurs in 15% of black males / Mediterranean variant is more severe

Mechanism: glutathione peroxidase reduced peroxides to water / relies on reduced GSH, requires

NADPH from hexose monophosphate shunt (first step is G-6-PD)



  • neonatal hemolysis and jaundice only in premature infants / also less severe in blacks because young RBC’s have more enzyme function and are not susceptible to drug-induced attacks, so the hematocrit does not fall as much

Causes (of acute attacks):

  • Drugs: many antibiotics (sulfamethoxazole, nitrofurantoin), anti-malarials, phenacetin, vitamin K, seizure meds, chemotherapy agents, HIV meds

  • infection

  • favism (severe Mediterranean variant) due to fava beans

Labs: Heinz bodies / can have false negative G6PD levels during crisis (because decreased levels occur in older RBCs, not new ones being produced)

Diagnosis: measure decreased levels of GPI anchors or GPI-linked surface proteins CD55 or CD59

Treatment: usually self-limited once offending agent removed
Pyruvate kinase deficiency

autosomal recessive / RBCs have impaired glycolysis, reduced ATP, and lyse




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