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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