Clinical Findings

Table 88.1 Clinical symptoms of hyperviscosity

(1) General symptoms

- Tiredness/fatigue

- Loss of weight

- Anorexia

(2) Neurologic symptoms

- Headache

- Nausea

- Vertigo

- Dizziness that can rarely lead to coma

- Ataxia

- Paresthesia

- Decreased hearing

(3) Vascular disturbance

- Epistaxis

- Gingival and gastrointestinal hemorrhages or menorrhagia

- Congestive heart failure

- HV-related retinopathy

- HV-related kidney problems patients with HV due to WM have symptoms of visual disturbance, and up to 50% of these patients will demonstrate ocular changes.25-27 The percentage of retinal involvement in patients with HV due to other paraproteinemias is unknown, but such cases have been reported.28 29 In a recent study, Menke et al. examined 46 patients with WM by indirect ophthal-moscopy and the laser Doppler blood flow technique, which assessed retinal vessel diameter and blood flow.30 These studies showed a relationship between retinal vessel caliber, particularly retinal veins, and serum viscosity, with increases in the caliber of vessels accompanying increases in serum viscosity.2830 Fluorescein angiography has also been used to investigate retinal microcirculation, with finding of increased arteriovenous passage times and vessel diameters in WM patients with increased serum viscosities.2829

The clinical findings for HVS are summarized in Table 88.1. Symptoms due to HV can be categorized into (1) general symptoms, such as tiredness, fatigue, weight loss, and anorexia, (2) neurologic symptoms, such as headaches, nausea, vertigo, dizziness, ataxia, paresthesia, decreased hearing, and rarely coma, and (3) vascular disturbances, such as epistaxis, gingival and gastrointestinal hemorrhages or menorrhagia, congestive heart failure, retinopathy (including retinal hemorrhages), papilledema, dilated retinal veins and visual disturbances, and perfusion-related renal problems. The typical opthalmologic changes in a WM patient with HVS are depicted in Figure 88.1.

ASSOCIATED MANIFESTATIONS OF HVS Retinal findings

Circulatory disturbances due to HV can be best appreciated by ophthalmoscopy. Approximately 10% of

^ Venous "sausaging"

Optic disc edema , i Dilated veins kclina) hemorrhaRcs

Figure 88.1 Ocular exam of a patient with Waldenstrom's macroglobulinemia depicting typical findings of hyperviscosity

Among the first clinical signs of HV is the appearance of peripheral and mid-peripheral dot- and blot-like hemorrhages in the retina, which are best appreciated with indirect ophthalmoscopy and scleral depression.3031 In more severe cases of HVS, dot, blot, and flame-shaped hemorrhages can appear in the macular area, and may be accompanied by retinal edema and visual disturbance. Although visual acuity usually improves with plasmapheresis treatment, irreversible visual loss has been reported.32 Some patients with HVS show papilledema and markedly dilated and tortuous veins with focal constrictions, predominantly at the arterio-venous junctions (i.e., venous sausaging). Other clinical findings associated with HVS can include intraretinal exudates resulting from more severe leakage from retinal vessels and retinal detachments.33 Fluorescein angiography may be helpful in cases of intraretinal exudates in identifying areas of leakage.

Corneal and conjunctival findings

Slitlamp examination frequently reveals sludging of red blood cells in the conjunctival vessels. Keratoconjunctivitis associated with HV in patients with WM has also been reported. In some cases, corneal and conjunctival crystals consisting of immunoglobulin deposits can be found in patients with paraproteinemia.34

Neurologic findings

Common neurologic symptoms of HVS include headaches, nausea, vertigo, and dizziness, which rarely can progress to coma.114'35 36 Some patients with HVS can show sensorineural hearing loss.37 In most cases, neurologic symptoms usually appear at higher viscosity levels (i.e., >4 cp), though early appearance before retinal findings at lower serum viscosity levels (i.e., 2-3 cp) has also been reported.18

Several animal models have been used to investigate the neurologic consequences of HVS. The effects of blood hyperviscosity on functional integrity in the brain stem have been investigated using brain stem auditory evoked potentials.38 Animals with elevated blood hyper-viscosity showed either a total lack of any waveforms, or a prolongation of waves, indicating a severe disturbance in functional brain stem integrity, which could be improved partially with hemodilution therapy. In a study investigating the cerebral cortical blood flow and oxygen metabolism in newborn piglets with hypervis-cosity, cerebral cortical blood flow and oxygen delivery were found to be decreased.39 Moreover, in studies of the cerebral microcirculation in macroglobulinemic mice, decreased plasma velocities in the presence of increased serum viscosities were observed, whereas red blood cell velocities were within normal limits or even elevated. These findings suggest that alterations of viscosity can lead to disturbances in the microcirculation of the cerebral cortex, and are likely to account at least in part for the neurologic manifestations of HVS.40

Kidney findings

Renal failure is an uncommon manifestation of HVS, and may result from perturbations in renal perfusion, leading to ischemic injury of the kidney. In experimental animal models, the influence of blood rheol-ogy on glomerular hemodynamics has been investigated. Elevation of either serum or whole blood viscosity resulted in renal vasodilation and decreased renal blood flow.4142 Ischemic acute tubular necrosis as a result of HVS has also been reported in a patient with WM.43 In HVS-related renal dysfunction, decreased urine output, defects in concentrating and diluting urine, and increased serum creatinine may be observed.43 In such cases, a kidney biopsy can be considered. Increased mesangial matrix, cytoplasmatic vacuolation of the epithelial cells lining the proximal tubules, foci of atypical lymphoplasmacytoid infiltration in the interstitium, and mitosis in the tubules as a sign of regenerative activity may be observed in biopsy specimens from a patient with HVS-induced renal injury.

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