Hyperproteinemia

Hyperproteinemia can result from an increase in both albumin and globulins (panhyperproteinemia) or an increase in only globulins (hyperglobulinemia) (Boxes 26.1 and 26.2).

Panhyperproteinemia

An increase in the concentration of all blood proteins results from hemoconcentration.

■ BOX 26.1

Causes of Hyperproteinemia in Horses Panhyperproteinemia-Dehydration

Common Causes

Acute toxic colitis of unknown cause

Acute salmonellosis

Potomac horse fever

Intestinal clostridiosis

Intestinal strangulating obstruction

Proximal enteritis

Gram-negative sepsis, endotoxemia Botulism

Choking (esophageal obstruction)

Less Common Causes

Chronic renal failure

Chronic hepatic disease

Guttural pouch mycosis with dysphagia

Equine protozoal myelitis

Salt toxicity

Toxins, poisonous plants

Lead toxicity

Yellow star thistle poisoning (dysphagia) Dysphagia of unknown cause

Hyperglobulinemia

Common Causes

Abdominal (mesenteric) abscess (including “bastard” strangles) Pulmonary abscess

Chronic pleuritis

Purpura haemorrhagica

Equine infectious anemia

Less Common Causes

Chronic hepatic disease

Strongylosis Lymphoma (lymphosarcoma) Immune-mediated cytopenia

■ TABLE 26.1

Normal Serum Protein Values for Horses, Cows, Sheep, and Goats

From Kaneko JJ, Harvey JW, Bruss ML, eds: Clinical biochemistry of domestic animals, ed 5, San Diego, 1997, Academic Press (Appendix VlH, Blood analyte reference values in large animals).

FIG. 26.2 Immunoglobulin in foal serum during the first 15 weeks of life.

■ BOX 26.2

Causes of Hyperproteinemia in Ruminants

Panhyperproteinemia-Dehydration

Common Causes

Ruminal acidosis (grain overload)

Abomasal torsion

Acute salmonellosis

Peritonitis

Sepsis, toxemia (mastitis, metritis) Intussusception

Vagal indigestion

Oral or pharyngeal foreign body with dysphagia

Coccidiosis

Diarrhea, undifferentiated

Salt toxicity

Toxins, poisonous plants

Less Common Causes

Renal amyloidosis

Lymphoma

Pregnancy toxemia

Rabies

Hyperglobulinemia

Common Causes

Abdominal abscess (traumatic reticuloperitonitis, uterine tear, other)

Chronic pneumonia

Umbilical abscess

Lymphoma

Caseous lymphadenitis (sheep and goats)

Other abscess

Less Common Causes

Parasitism

Pregnancy

with an associated increase in packed cell volume (PCV). This is due to a relative increase in protein and red blood cell (RBC) concentrations in blood. True hyperalbuminemia (i.e., increased albumin synthesis) does not occur. Hyperalbu- minemia is an insensitive indicator of dehydration. If the true albumin level is decreased, a dehydrated patient may have a normal albumin result that masks both hemoconcentration and hypoalbuminemia. Similarly a dehydrated, anemic animal may have hyperproteinemia with a normal or decreased PCV. In an animal with a plasma protein concentration of 7.0 g/dL in health, a 10% decrease in plasma volume (severe dehydration) will result in a plasma protein concentration of 7.8 g/dL.³ As with albumin measurement, the total plasma protein measure­ment will underestimate degree of dehydration if the patient is losing protein along with fluid. This is relatively common in renal disease, in protein-losing enteropathy with diarrhea, and in third-space loss when fluid and protein accumulate in the thoracic and/or abdominal cavity. Dehydration alone can result from gastrointestinal (GI) fluid sequestration, including intestinal obstruction, vagal indigestion with internal vomiting, and grain engorgement. Less common causes of dehydration include polyuria with renal failure, exudation from extensive skin wounds, and excessive sweating. Physiologic responses to dehydration include increased urine concentration and decreased urine output, increased fluid absorption from the GI tract, and increased thirst.