Page 1305 - Clinical Small Animal Internal Medicine

135 Plasma Cell Disorders 1243

(range, 4–18). There is no breed or sex predilection in dogs. Table 135.1 Frequency of abnormal diagnostic test results
VetBooks.ir In cats, it is most common in domestic short‐hairs and a Test abnormality Dogs (%) Cats (%)
in dogs and cats with MM
slight male predisposition has been reported. EMPs usually
occur in middle‐aged to older dogs (median age 9–10
years). The cocker spaniel and West Highland white terrier
seem to be at increased risk. Solitary EMPs are less com­ Anemia (nonregenerative) 68 41–69
mon in cats and SOP is rarely reported in both species. Thrombocytopenia 33–45 50
Leukopenia 25 37
Circulating plasma cells 10 5–27
History and Clinical Signs Hypoalbuminemia 65 36

Hypocholesterolemia Not reported 68
Clinical signs of MM are variable, with a median duration
of one month prior to diagnosis. In dogs, the most com­ Renal azotemia 33 23–36
mon presenting sign is lethargy and weakness (62%). Hypercalcemia 17–50 9–25
Skeletal lytic lesions lead to lameness, pain and paresis or Proteinuria 35 77
paralysis with vertebral involvement (47%). Bleeding disor­ Bence Jones proteinuria 40 44–50
ders most commonly present as epistaxis or gingival bleed­ Hyperviscosity 32 35–44
ing (37%). Ocular and CNS abnormalities are caused by Bone lysis (radiographs) 50 8–56
HVS, systemic hypertension or both. Ocular signs include
retinal bleeding, enlarged tortuous retinal vessels, retinal
detachment (35%), and acute onset of blindness. Hyphema, tests such as anemia, hypoalbuminemia, renal dys­
episcleral injection, corneal edema, and aqueous flare may function, and hypercalcemia should prompt work‐up
also occur. CNS signs include dementia, personality for MM (Table 135.1).
changes, disorientation, and seizures (12%). Polyuria/poly­ Serum protein electrophoresis (SPE) separates pro­
dipsia (25%) may develop secondary to renal disease and teins based on their size and electrical charge. The
hypercalcemia. Cardiopulmonary signs (syncope, cyano­ immunoglobulins are contained in the beta and gamma
sis, congestive heart failure [CHF]) are less common. fractions and monoclonal gammopathies produce a nar­
Vomiting, anorexia, and weight loss have been seen in dogs row peak in one of these fractions (Figure 135.2). Rarely,
with hypercalcemia and/or renal disease. Some dogs may
present with secondary infections such as cystitis.
Physical examination findings may include pale mucous
membranes, dehydration, fundic changes, neurologic
deficits, fever, and cranial organomegaly.
In cats, lethargy, anorexia, and weight loss are the most
common clinical signs. Vomiting and diarrhea, as well as
cranial organomegaly and cutaneous or subcutaneous
masses are more common than in dogs.
Cutaneous and mucosal EMPs usually appear as pink
or red, raised, alopecic and sometimes ulcerated solid
nodules, about 1–2 cm in diameter (see Figure 135.1),
but they can range from 0.2 to 10 cm in diameter. The
majority of tumors are single, but some dogs may develop
more than one tumor simultaneously or sequentially.
Oral EMPs can cause bleeding and decreased appetite.
Colorectal EMPs can lead to hematochezia, rectal bleed­ Fractions % Ref. % g/L g/L
ing, tenesmus, and rectal prolapse. SOPs cause pain,
lameness, or neurologic symptoms. Albumin 12.9 55.8–66.5 16.4 43.0– 51.0
Alpha 1 2.3 2.9–4.0 2.9 1.0– 2.0
Alpha 2 5.3 7.1–14.5 6.7 5.0– 8.0
6.0– 9.0
9.8
12.4
Diagnosis Beta 69.7 8.6–14.8 88.5 6.0–11.0
9.2–18.2
Gamma
Suspicion of MM usually arises in an animal present­ Figure 135.2 Serum protein electrophoresis results in a dog with
ing with appropriate clinical signs and hyperglobuline­ MM. The albumin peak is on the far left and there is a tall, narrow
spike in the gamma region on the right consistent with monoclonal
mia. Initial evaluation includes CBC, full chemistry gammopathy. Total protein level was 12.7 g/dL. Source: Courtesy of
panel, and urinalysis. Additional findings on these Dr Roni Minke, American Medical Laboratories, Hertzeliah, Israel.