Paraproteinemia: blood hyperviscosity and clinical manifestations

Association of blood viscosity and device-free days among hospitalized patients with COVID-19

BACKGROUND

Increased estimated whole blood viscosity (eWBV) predicts higher mortality in patients hospitalized for coronavirus disease 2019 (COVID-19). This study assesses whether eWBV is an early predictor of non-fatal outcomes among patients hospitalized for acute COVID-19 infection.

METHODS

This retrospective cohort study included 9278 hospitalized COVID-19 patients diagnosed within 48 h of admission between February 27, 2020 to November 20, 2021 within the Mount Sinai Health System in New York City. Patients with missing values for major covariates, discharge information, and those who failed to meet the criteria for the non-Newtonian blood model were excluded. 5621 participants were included in the main analysis. Additional analyses were performed separately for 4352 participants who had measurements of white blood cell count, C-reactive protein and D-dimer. Participants were divided into quartiles based on estimated high-shear blood viscosity (eHSBV) and estimated low-shear blood viscosity (eLSBV). Blood viscosity was calculated using the Walburn-Schneck model. The primary outcome was evaluated as an ordinal scale indicating the number of days free of respiratory organ support through day 21, and those who died in-hospital were assigned a value of -1. Multivariate cumulative logistic regression was conducted to evaluate the association between quartiles of eWBV and events.

RESULTS

Among 5621 participants, 3459 (61.5%) were male with mean age of 63.2 (SD 17.1) years. The linear modeling yielded an adjusted odds ratio (aOR) of 0.68 (95% CI 0.59-0.79, p value < 0.001) per 1 centipoise increase in eHSBV.

CONCLUSIONS

Among hospitalized patients with COVID-19, elevated eHSBV and eLSBV at presentation were associated with an increased need for respiratory organ support at 21 days. These findings are highly relevant, as they demonstrate the utility of eWBV in identifying hospitalized patients with acute COVID-19 infection at increased risk for non-fatal outcomes in early stages of the disease.

Effects of sarpogrelate on blood viscosity

The objective of the present study was to evaluate the effects and safety of sarpogrelate hydrochloride (sarpogrelate) in patients with elevated blood viscosity (BV), after 12 and 24 weeks of twice (BID) or thrice (TID) daily administrations of sarpogrelate (100 mg). The participants received oral sarpogrelate administration for 24 weeks and visited the hospital every 12 ± 2 week for blood viscosity measurements at shear rates of 5 and 300 s^-1. The BV measured at shear rate of 5 s^-1 in male patients decreased significantly from 18.91 cP at the baseline to 16.3 cP after 24 weeks of sarpogrelate administration (13.6 % drop, p < 0.001). The BV measured at 5 s^-1 in female decreased more significantly from 17.5 cP at the baseline to 13.4 cP after 24 weeks of sarpogrelate administration (23.0 % drop, p < 0.001). In summary, sarpogrelate may be considered as a possible therapeutic option for improving BV in patients with elevated blood viscosity. In particular, the reduction of the low-shear BV with the help of a viscosity-reducing drug such as sarpogrelate may be considered as a potentially new pharmacological tool for microvascular disease.

Crystalglobulinemia in Multiple Myeloma: A Rare Case Report of Survival and Renal Recovery

Rationale:

Crystalglobulinemia is a rare complication of monoclonal gammopathy wherein crystallized immunoglobulins deposit in various organs causing occlusive vasculopathy, endothelial damage, and thrombosis. It should be differentiated from light chain cast nephropathy without crystalline nephropathy through timely diagnosis with a kidney biopsy.

Presenting concerns of the patient:

We report a case of a 74-year-old female with polyarthralgia, chest pain, petechial rash, and acute kidney injury.

Diagnoses:

Kidney biopsy revealed eosinophilic casts in the tubular lumen and similar occlusive crystalline deposits within the glomerular vasculature and interlobular arteries. Bone marrow biopsy and serum electrophoresis confirmed immunoglobulin G (IgG) κ multiple myeloma.

Interventions:

Dialysis was initiated for severe oligoanuric acute kidney injury. The patient was treated with 5 sessions of plasmapheresis and 11 cycles of clone reduction chemotherapy with CyBorD (cyclophosphamide, bortezomib, and dexamethasone).

Outcomes:

This patient achieved excellent kidney recovery and is no longer dialysis dependent.

Teaching points:

Crystalglobulinemia should be suspected in patients with rapidly progressive acute kidney injury and monoclonal gammopathy. Timely investigation with kidney biopsy to differentiate this condition from light chain cast nephropathy and initiation of appropriate treatment can lead to remission of disease and excellent recovery of kidney function.

Plasma viscosity: Evaluation of a new measuring method using microfluidic chip technology (microVisc™) for clinical use and determination of a new reference range

BACKGROUND

Plasma viscosity is an important biomarker both in diagnostics and treatment monitoring of plasma cell dyscrasias and other disorders with hyperviscosity syndrome as a clinical manifestation. Here, we investigate the performance of a new microfluidic-based viscometer for clinical use, establish a new reference range to be used with this instrument and determine the importance of sampling temperature.

METHODS

The microVisc™ viscometer was evaluated for within-run and between-run imprecision and bias using standardized reference material (Paragon controls) and Seronorm™ control material. The reference range was established for the adult population using EDTA-plasma from 120 healthy blood donors. Sampling temperature was investigated by drawing and transporting blood at room temperature and 37°C and comparing the viscosity between the two sampling methods.

RESULTS

The microfluidic-based viscometer performed well, and imprecision was comparable to ReoRox® G2 free oscillation rheometer. A new reference range for the adult Danish population was established as 1.2-1.5 mPa s at 37°C. Furthermore, sampling temperature at room temperature and 37°C was investigated, and there was no difference in results obtained.

CONCLUSIONS

MicroVisc™ is suitable for measuring plasma viscosity in a clinical setting and results can be evaluated using the established reference range. Blood sampling for viscosity analysis can be performed as a standard procedure at room temperature.

A threshold trajectory was revealed by isolating the effects of hemoglobin rate of rise in anemia of chronic kidney disease

BACKGROUND

To assess cardiovascular risk among various hemoglobin (Hb) rates of rise (RoR) in chronic kidney disease (CKD) patients with anemia who have initiated therapy with erythropoiesis stimulating agents (ESAs).

METHODS

Observational cohort of CKD patients initiating ESA therapy from the Centricity® database, 1990-2011. Proportional hazards models tested the hypothesis that a slower Hb RoR (0 < g/dl/month ⩽ 0.125) is associated with a lower cardiovascular (CV) incidence [composite of fatal/nonfatal myocardial infarction (MI) and stroke] compared with faster RoR (0.125 < g/dl/month ⩽ 2.0, and >2.0 g/dl/month).

RESULTS

A total of 9220 patients receiving ESAs were followed for an average of 3.1 years. Slow (group B) RoR versus medium (group C') and fast (group D') RoR in Hb, throughout all Hb milestones, was associated with lower risk of the composite endpoint [B (slow) versus D' (fast) [hazard ratio (HR) = 0.20 (0.11, 0.39), p < 0.0001]; B versus C' (medium) [HR = 0.34 (0.19, 0.62), p = 0.0004], and C' versus D' [HR = 0.60 (0.42, 0.85), p = 0.005]]. Within achieved Hb milestones, HRs were: B versus D' at milestone ⩾ 14.1 g/dl [HR = 0.17 (0.05, 0.56); p = 0.004] and at milestone 12.6-14.0 [HR = 0.18 (0.07, 0.46), p = 0.0004].

CONCLUSION

Rapid Hb rise is associated with adverse CV outcomes, with markedly lower risk for rates below a threshold trajectory of 0.125 g/dl/month, even with complete correction.

[Hyperviscosity syndrome]

Hyperviscosity syndrome is a life-threatening complication. Clinical manifestations include neurological impairment, visual disturbance and bleeding. Measurement of plasma or serum viscosity by a viscometer assesses the diagnosis. Funduscopic examination is a key exam because abnormalities are well-correlated with abnormal plasma viscosity. Etiologies are various but symptomatic hyperviscosity is more common in Waldenström's macroglobulinemia and multiple myeloma. Prompt treatment is needed: treatment of the underlying disease should be considered, but generally not sufficient. Symptomatic measures aim to not exacerbate blood viscosity while urgent plasmapheresis effectively reduces the paraprotein concentration and relieves symptoms.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Plasmapheresis and cold sensitivity of immunoglobulin molecules. I. A study of hyperviscosity, cryoglobulinemia, euglobulinemia and macroglobulinemia vera

There is a close connection between molecular changes of the Ig molecule with sinking temperature and the syndrome of hyperviscosity. The cryoglobulins are usually macroglobulins or complexes between IgM and other immunoglobulin classes. Many of these molecules can also be characterized as euglobulins. The connection between precipitation in the cold and in solutions with low electrolyte content is studied. Data on these connections are presented. The dependence of relative viscosity on the temperature has been investigated in a large number of sera from patients with different diseases. It is clear that most of these cold-sensitive globulins are macroglobulins (IgM). A number of viscosity curves at different temperatures in such sera are given. Also a few sera from patients with IgG myeloma have similar curves. The change in viscosity with lower temperatures implies that relative viscosity has to be determined at 37 degrees C in order to correspond to the condition in the living body. In practice, however, it is usually correct to state that IgM levels above 40 g/l are an indication that plasmapheresis should be considered. The best clinical sign is obtained by ophthalmoscopy. Difficulties with the counting of leukocytes and platelets in electronic counters may be caused by the presence of macroglobulins, usually but not always, cryoglobulins.

Synthesis and use of an in-solution ratiometric fluorescent viscosity sensor

A procedure for the synthesis of a ratiometric viscosity fluorescent sensor is described in this protocol. The essential requirement for the design of this sensor is the attachment of a primary fluorophore that has both a viscosity-independent fluorescence emission (coumarin dye shown in blue) and an emission from a fluorophore that exhibits viscosity-dependent fluorescent quantum yield (p-amino cinnamonitrile dye shown in red). The use of sensor 1 in viscosity measurements involves solubilization in a liquid of interest and excitation of the primary fluorophore at lambda(ex) = 360 nm. The secondary fluorophore is simultaneously excited via resonance energy transfer. The ratio of the fluorescent emission of the secondary over the primary fluorophore provides a fast and precise measurement of the viscosity of the solvent. The synthesis of compound 1 using commercially available materials can be completed within 5 d.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.

Molecular rotors—fluorescent biosensors for viscosity and flow

Viscosity is a measure of the resistance of a fluid against gradients in flow (shear rate). Both flow and viscosity play an important role in all biological systems from the microscopic (e.g., cellular) to the systemic level. Many methods to measure viscosity and flow have drawbacks, such as the tedious and time-consuming measurement process, expensive instrumentation, or the restriction to bulk sample sizes. Fluorescent environment-sensitive dyes are known to show high sensitivity and high spatial and temporal resolution. Molecular rotors are a group of fluorescent molecules that form twisted intramolecular charge transfer (TICT) states upon photoexcitation and therefore exhibit two competing deexcitation pathways: fluorescence emission and non-radiative deexcitation from the TICT state. Since TICT formation is viscosity-dependent, the emission intensity of molecular rotors depends on the solvent's viscosity. Furthermore, shear-stress dependency of the emission intensity was recently described. Although the photophysical processes are widely explored, the practical application of molecular rotors as sensors for viscosity and the fluid flow introduce additional challenges. Intensity-based measurements are influenced by fluid optical properties and dye concentration, and solvent-dye interaction requires calibration of the measurement system to a specific solvent. Ratiometric dyes and measurement systems help solve these challenges. In addition, the combination of molecular rotors with specific recognition groups allows them to target specific sites, for example the cell membrane or cytoplasm. Molecular rotors are therefore emerging as new biosensors for both bulk and local microviscosity, and for flow and fluid shear stress on a microscopic scale and with real-time response.

Effects of solvent polarity and solvent viscosity on the fluorescent properties of molecular rotors and related probes

Fluorescent molecular rotors belong to a group of twisted intramolecular charge transfer complexes (TICT) whose photophysical characteristics depend on their environment. In this study, the influence of solvent polarity and viscosity on several representative TICT compounds (three Coumarin derivatives, 4,4-dimethylaminobenzonitrile DMABN, 9-(dicyanovinyl)-julolidine DCVJ), was examined. While solvent polarity caused a bathochromic shift of peak emission in all compounds, this shift was lowest in the case of molecular rotors. Peak intensity was influenced strongly by solvent viscosity in DMABN and the molecular rotors, but polarity and viscosity influences cannot be separated with DMABN. Coumarins, on the other hand, did not show viscosity sensitivity. This study shows the unique suitability of molecular rotors as fluorescent viscosity sensors.

Precision Assessment of Biofluid Viscosity Measurements Using Molecular Rotors

Blood viscosity changes with many pathologic conditions, but its importance has not been fully investigated because the current methods of measurement are poorly suited for clinical applications. The use of viscosity-sensitive fluorescent molecular rotors to determine fluid viscosity in a nonmechanical manner has been investigated recently, but it is unknown how the precision of the fluorescence-based method compares to established mechanical viscometry. Human blood plasma viscosity was modulated with high-viscosity plasma expanders, dextran, pentastarch, and hetastarch. The samples were divided into a calibration and a test set. The relationship between fluorescence emission and viscosity was established using the calibration set. Viscosity of the test set was determined by fluorescence and by cone-and-plate viscometer, and the precision of both methods compared. Molecular rotor fluorescence intensity showed a power law relationship with solution viscosity. Mechanical measurements deviated from the theoretical viscosity value by less than 7.6%, while fluorescence-based measurements deviated by less than 6%. The average coefficient of variation was 6.9% (mechanical measurement) and 3.4% to 3.8% (fluorescence-based measurement, depending on the molecular rotor used). Fluorescence-based viscometry exhibits comparable precision to mechanical viscometry. Fluorescence viscometry does not apply shear and is therefore more practical for biofluids which have apparent non-Newtonian properties. In addition, fluorescence instrumentation makes very fast serial measurements possible, thus promising new areas of application in laboratory and clinical settings.

Hydrophilic molecular rotor derivatives—synthesis and characterization

Recent research shows high potential for some p-N,N-dialkylaminobenzylidenecyanoacetates, part of a group known as fluorescent molecular rotors, to serve as fluorescent, non-mechanical viscosity sensors. Of particular interest are molecules compatible with aqueous environments. In this study, we present the synthesis and physical characterization of derivatives from 9-(2-carboxy-2-cyanovinyl)-julolidine and related molecules. All compounds show a power-law relationship of fluorescence emission with the viscosity of the solvent, different mixtures of ethylene glycol and glycerol to modulate viscosity. Compounds with high water solubility exhibit the same behavior in aqueous solutions of dextran, where the dextran concentration was varied to modulate viscosity. In addition, some compounds have been found to have low sensitivity towards changes in the pH in the physiological range. The compounds presented show promise to be used in biofluids, such as blood plasma or lymphatic fluid, to rapidly and non-mechanically determine viscosity.

A novel approach to blood plasma viscosity measurement using fluorescent molecular rotors

Molecular rotors, a group of fluorescent molecules with viscosity-dependent quantum yield, were tested for their suitability to act as fluorescence-based plasma viscometers. The viscosity of samples of human plasma was modified by the addition of pentastarch (molecular mass 260 kDa, 10% solution in saline) and measured with a Brookfield viscometer. Plasma viscosity was 1.6 mPa x s, and the mixtures ranged up to 4.5 mPa x s (21 degrees C). The stimulated light emission of the molecular rotors mixed in the plasma samples yielded light intensity that was nonoverlapping and of significantly different intensity for viscosity steps down to 0.3 mPa x s (n = 5, P < 0.0001). The mathematical relationship between intensity (I) and viscosity (eta) was found to be eta = (kappaI)(nu). After calibration and scaling the fluorescence based measurement had an average deviation versus the conventional viscometric measurements that was <1.8%. These results show the suitability of molecular rotors for fast, low-volume biofluid viscosity measurements achieving accuracy and precision comparable to mechanical viscometers.

Indications for emergency apheresis procedures

Therapeutic apheresis has gained tremendous popularity worldwide in the last 2 decades. Emergency procedures can be life saving but should be undertaken for limited indications. Our emergency indications and experiences since the 1970s are critically described.

Lipoprotein alterations in liver cirrhosis: a possible contribution to changes in plasma oncotic pressure and viscosity

BACKGROUND/AIMS

To investigate whether physicochemical alterations in plasma lipoproteins are associated with changes in plasma oncotic pressure and viscosity in liver cirrhosis.

METHODS

The study included 66 patients with cirrhosis (confirmed by liver biopsy) and 58 healthy volunteers. The constituents measured were: the concentration, density and composition of plasma lipoproteins; plasma oncotic pressure and viscosity; and the concentrations of albumin, total protein, haptoglobin, transferrin, immunoglobulin M and alpha2-macroglobulin.

RESULTS

Step-wise multiple regression analysis indicated that, in the patients with cirrhosis, plasma oncotic pressure was significantly correlated with plasma albumin+viscosity (r=+0.85; p<0.001) and with plasma total protein+the density of low density lipoprotein (r=+0.74; p<0.001). The inclusion of viscosity and the density of low density lipoprotein in the regression equations significantly improved the observed correlation between albumin and plasma oncotic pressure (r=+0.70; p<0.001). Similarly, plasma viscosity was significantly correlated with the sum of plasma total protein and cholesterol (r=+0.68; p<0.001). The inclusion of cholesterol in the regression equation significantly increased the observed correlation between total protein and plasma viscosity (r=+0.59; p<0.001).

CONCLUSIONS

These results suggest that lipoprotein alterations associated with liver cirrhosis may play a role in determining plasma oncotic pressure and viscosity, and thus could influence the progression of the disease.

Blood rheology and ischaemia

Ischaemia is essentially the failure of tissue to obtain a sufficient oxygen supply for its function. In the context of rheology, which is the study of the deformation and flow of materials, this implies failure to deliver the blood, rather than failure to oxygenate the blood or extract oxygen from it. Resistance to the delivery of blood is generally considered to have vascular and rheological components. Vascular effects on resistance may often be dominant, and there is wide appreciation of the ischaemic consequences of vascular obstruction and narrowing, for example in atherosclerotic disease. However, rheological factors can vary widely between individuals and in disease, and such variations have the potential to influence oxygen supply. Here, the rheological factors which affect blood flow are reviewed and their role in the development of ischaemia is discussed, with particular reference to the eye where possible.

Relationship between blood-oxygen affinity and blood volume

The hypothesis was tested that total blood volume (TBV) is correlated with hemoglobin oxygen affinity. Intraspecifically Hb-O2 affinity was manipulated in rats using NaOCN. Interspecifically the hypothesis was evaluated using data gathered from the literature. Both intra- and interspecifically TBV increased with increasing hemoglobin oxygen affinity (delta TBV/delta P50 = -1.18). Intraspecifically decreases in P50 were associated with an increase in red blood cell mass and hematocrit. Interspecifically plasma volume had an inverse relationship with Hb-O2 affinity (delta TBV/delta P50 = -1.10) and hematocrit showed no changes. These data suggest that an increased blood volume may be part of the mechanism explaining the inverse correlation between P50 and hypoxic tolerance.

Waldenström's macroglobulinemia

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Drs Homer A. Boushey, Professor of Medicine, and David G. Warnock, Associate Professor of Medicine, under the direction of Dr Lloyd H. Smith, Jr, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143.

Rheology of paraproteinaemias and the plasma hyperviscosity syndrome

The proper understanding of the causes, pathophysiology, diagnosis and management of the plasma hyperviscosity syndrome is based on good knowledge of malignant paraproteinaemias, properties of immunoglobulins, rheology of blood in the microcirculation, and modern plasma separation techniques. This multifaceted syndrome complicates less than ten per cent of IgA and IgG myelomas, and up to one-third of Waldenström's macroglobulinaemias. A few cases of HVS have also been reported in association with polyclonal hypergammaglobulinaemias. Excessive paraproteinaemia may cause the plasma HVS, especially when paraproteins are extraordinarily large, asymmetrical or cryosensitive, or if they aggregate into hyperviscous macroaggregates. The resultant severe microcirculatory impairment is mainly due to the combined effects of plasma hyperviscosity, significant plasma volume expansion and intense red cell aggregation. The individually variable general symptoms, bleeding tendency, ocular, neurological, cardiovascular, and renal manifestations and laboratory parameters of the HVS are summarized briefly. The majority of patients present hyperviscosity manifestations when the plasma viscosity exceeds 5-6 mPa.s. Plasmapheresis or plasma exchange have established themselves as efficient and safe modes of therapy of hyperviscosity and hypervolaemia. The therapeutic guidelines for the plasma HVS are briefly discussed with regard to recent experience with developing plasma separation techniques. Diagnostic and therapeutic advances combined with increasing haemorheological knowledge have greatly improved the proper management of this potentially lethal complication of paraproteinaemias.

Multicenter trial of hemodilution in acute ischemic stroke. I. Results in the total patient population. Scandinavian Stroke Study Group

Hemodilution by the combination of venesection and dextran 40 administration has previously been reported to enhance neurologic recovery in the acute phase of ischemic stroke. To study this therapeutic principle in its "natural habitat," a stratified and randomized multicenter trial involving 15 large and small hospitals was performed. Patients with acute ischemic stroke of less than 48 hours' duration and with hematocrits of 38-50% on admission were randomized to a hemodilution (183 patients, mean age 72.0 years) or a control group (190 patients, mean age 71.6 years). The two groups did not differ in sex distribution or medical history. Hematocrit, blood pressure, and neurologic score were closely similar at entry. By graded venesection (250-1000 ml) during the first 2 days and dextran 40 infusions (500 ml daily) during 5 days, the mean hematocrit was reduced from 44.2 to 37.1%. Three-month survival expressed as life table product was 0.84 in hemodilution and 0.88 in control patients. In survivors, neurologic score and activities of daily living performance during 3 months of follow-up were not improved by hemodilution. Length of stay in an acute-care hospital and the need for long-term institutional care was not reduced among patients in the hemodilution group. Major cardiovascular events occurred somewhat more often and there was an apparent increase in mortality during the first few days of hemodilution therapy. However, the differences were not significant. We conclude that the present standardized treatment with moderate hemodilution has no overall beneficial effects in general patients with acute ischemic stroke.

[Predictor function of hemorheologic parameters with reference to the incidence of manifest circulatory disorders: Concept of the Aachen study]

The prevention of cardiovascular disease has up till now generally been limited to control of the classical risk factors. The primary problem of the risk factor model is, that although a statistically verified relationship exists between risk factors and vascular disease, an individual prognosis is presently impossible. Surveys that show a relation between risk factors and impaired blood fluidity support the conception that a change in blood fluidity could be considered an early detection screening of vascular diseases. Prospective studies have shown that the hematocrit is related to circulatory disturbances. The main aim of the present study was to determine the clinical relevance of rheological parameters (hematocrit, plasma viscosity, erythrocyte rigidity, thrombocyte aggregation, erythrocyte aggregation), and the importance of altered blood fluidity as a predictor of manifest cerebral, cardiac or peripheral vascular disturbance.

Hyperviscosity retinopathy secondary to polyclonal gammopathy in a patient with rheumatoid arthritis

A patient with rheumatoid arthritis developed retinal venous stasis as part of a hyperviscosity syndrome secondary to a polyclonal gammopathy. Ocular findings included bilateral retinal venous dilation, disc hyperemia, optociliary venous collaterals, and left macular edema. This clinical picture improved following systemic corticosteroid therapy. Although occasional cases of rheumatoid polyclonal gammopathy causing hyperviscosity have been described in the rheumatology literature, this case represents the first detailed ophthalmological documentation of this occurrence.

Myeloma, paraproteinemias, and the skin

This review focuses on those systemic diseases or syndromes associated with monoclonal plasma cell disorders that may present with important cutaneous manifestations. Amyloidosis, POEMS syndrome, cutaneous plasmacytoma, xanthomas, benign hypergammaglobulinemic purpura of Waldenström, and scleromyxedema are emphasized.

[Hemorrheological changes in 50 monoclonal dysglobulinemias treated by plasma exchange]

Rheological examinations were performed before and after plasma exchanges in 50 patients with monoclonal dysglobulinaemia. The parameters investigated were blood and plasma viscosity, erythrocyte filtrability, erythrocyte aggregation and kinetics of agglutination. The results showed reduction of blood and plasma viscosity and improvement in agglutination kinetics under plasma exchanges. Rheological examinations therefore seem to be useful to follow up blood disorders, notably the hyperviscosity syndrome. They can be performed prophylactically, leading to early plasma exchanges to prevent clinical deterioration.

Plasmapheresis in paraproteinemia

Indications, results, techniques, laboratory monitoring and complications of therapeutic plasmapheresis in patients with symptomatic paraproteinemia are reviewed. In paraproteinemia associated with severe complications plasma-pheresis has been used successfully as an emergency treatment, as a treatment that reduces temporarily the paraprotein level until reduction of resynthesis is reached by cytotoxic therapy, or as a longterm adjuvant therapy in cases of slowly proliferating plasmacytoma or lymphoma. Plasmapheresis has not been shown to influence the underlying malignant process. Paraprotein-related complications that can be reduced by plasmapheresis are hyperviscosity, hypervolemia, haemorrhagic diathesis, cryoglobulinemic symptoms, rapidly deteriorating renal insufficiency, visual impairment, and neurologic disturbances. Technically, large-pored plasma filters have some advantage as compared to centrifugation techniques. Paraprotein-specific complications of therapeutic plasmapheresis are rare. As an ancillary treatment, therapeutic plasmapheresis has expanded the therapeutic tools in the management of paraproteinemia.

IgA . K type myeloma with severe postextraction bleeding

A case of multiple myeloma detected by the first symptom of severe postextraction bleeding was presented. Although laboratory data showed severe anemia, rouleaux formation of erythrocytes, abnormal hemostatic parameters, elevated erythrocyte sedimentation rate and hyperglobulinemia, no involvement of bones such as the jaws, skull, ribs or sternum was demonstrated roentgenologically. Final diagnosis obtained by immunoelectrophoresis was Ig A . K type myeloma. During a therapeutic period with melphalan and predonine, bleeding from the extracted wound was repeated. 2 months after the onset of the first symptoms, the patient died of systemic bleeding. Autopsy findings revealed many hemorrhagic sites in the lungs, stomach, kidney and bladder and the existence of plasma cell-like tumor cells in the bone marrow of lumber vertebra and sternum.

Monoclonal Gammopathy (IgM-k) in a Patient with Burkitt's Type Lymphoblastic Lymphoma

We report a Burkitt's type lymphoblastic lymphoma (B-LL) case characterized by an abnormal IgMk immunoglobulin secretion and referred to us on February 12, 1982. The diagnosis has been histologically documented and the pathological stage of the disease (IV B) was determined according to the diagnostic criteria usually employed for the non-Hodgkin's lymphoma (NHL). Serum proteins were determined by electrophoresis and immunodiffusion. The review of the literature has allowed us to ascertain that the presence of a monoclonal IgM peak can be associated with NHL, particularly with those of B cell type and in adult subjects. Up to now, only six IgM B-LL secreting cases have been described. The biological and prognostic significance of this elevated Ig secretion is uncertain; therefore it may be important for the future to evaluate, in B-LL this immunological parameter.

Plasma viscosity, haematocrit and red-cell transport

An erythrocyte transport function (ETF) is proposed, as an index of the efficiency of the circulation of red cells. Under defined conditions, this ETF is shown to be proportional to the ratio of haematocrit to whole-blood viscosity (phi/eta), a ratio already used by Chien. The variations of phi/eta with phi, at selected driving pressures in a capillary viscometer, are presented, both for normal and for pathological blood samples. Maximal values of phi/eta appear generally to occur at haematocrits of about 42%, and are strongly dependent upon plasma viscosity. They are also influenced by shear. The concept of 'isograds' (curves of phi/eta against phi at constant velocity gradient) is introduced, and is analysed in technical appendices which also deal with rates of shear in capillary and rotational viscometers when Newtonian or shear-sensitive liquids are measured.