Checking the gums is part of a basic physical examination (PE) protocol that plays a major part in the initial assessment of a pet’s health because gums are major indicators of the status of a pet’s over-all mucous membrane (MM).
To assess the MM in relation with the health of a patient, it all begins with the color:
- Pink MM
- Pale or White MM
- Bright Red or Injected MM
- Grey or Muddy MM
- Brown MM
- Blue or Purple MM
- Petechial or Ecchymotic MM
- Yellow MM
- Dry or Tacky MM
PINK MM
The normal color of the gums is pink. When pressed to check for the capillary refill time (CRF), it should return to its normal color within 2 seconds.
PALE or WHITE MM
White or pale mucous membranes typically indicate vasoconstriction or anemia. Both of these conditions may lead to decreased oxygen delivery to the tissues.
(1) Vasoconstriction. Vasoconstriction is usually a result of hypovolemic or cardiogenic shock. Vasoconstriction is technically caused by release of norepinephrine and subsequent stimulation of the peripheral alpha receptors, leading to vasoconstriction.
(2) Anemia. Animals that have pale or white mucous membranes secondary to anemia can present differently depending on if it is acute or chronic anemia. Acute anemia (i.e. hemorrhage) will typically cause hypovolemic shock (tachycardia, tachypnea, hypotension, dull mentation, etc.). Chronic anemia patients (e.g. cats with FeLV) usually tolerate their anemia very well. They may be slightly tachycardic, tachypneic, or weak, but won’t usually be hypotensive or in shock.
BRIGHT RED or INJECTED MM
Bright red mucous membranes may indicate decreased cellular utilization of oxygen (seen with cyanide poisoning or sepsis), decreased oxygen-hemoglobin binding (seen with carbon monoxide poisoning), or vasodilation (frequently seen with sepsis or heat-stroke).
(1) decreased cellular utilization of oxygen (cyanide poisoning or sepsis)
(2) decreased oxygen-hemoglobin binding (carbon monoxide poisoning)
(3) vasodilation (sepsis or heat stroke)
(4) high blood pressure
GREY or MUDDY MM
Grey or muddy mucous membranes usually indicate poor tissue perfusion and tissue hypoxia. Shock or hypoxemia should come to mind in patients with grey or muddy mucous membranes.
(1) Shock. It is a medical emergency in which the organs and tissues of the body are not receiving an adequate flow of blood. This deprives the organs and tissues of oxygen (carried in the blood) and allows the buildup of waste products. Shock can result in serious damage or even death. Shock is caused by three major categories of problems: cardiogenic (meaning problems associated with the heart’s functioning); hypovolemic (meaning that the total volume of blood available to circulate is low); and septic shock (caused by overwhelming infection, usually by bacteria).
(2) Hypoxemia. This is deficient oxygenation of the blood. The most reliable method for measuring the degree of hypoxemia is blood gas analysis to determine the partial pressure of oxygen in the arterial blood. Insufficient oxygenation of the blood may lead to hypoxia.
BROWN MM
Brown mucous membranes may indicate methemoglobinemia (metHb), which decreases the oxygen carrying capacity of hemoglobin, leading to decreased O2 delivery. Methemoglobinemia happens when excessive hemoglobin in the blood is converted to another chemical, methemoglobin, that cannot deliver oxygen to tissues.
Methemoglobinemia has been documented in small animals in association with acetaminophen ingestion, topical benzocaine products, phenazopyridine (a urinary tract analgesic) products, nitrites, nitrates, skunk musk, and metHb reductase deficiency. Agents that have resulted in metHb in humans and may be used in veterinary medicine include dapsone, nitroglycerin, and nitroprusside. Regardless of the toxic agent, metHb is often formed within minutes to hours of exposure. Substances that cause metHb production are likely to cause Heinz bodies (HzB) production and potentially hemolytic anemia in the days following the exposure. Numerous substances that cause an increase in HzBs are thought to cause some degree of methemoglobinemia, but associated clinical signs are typically attributable to a hemolytic anemia secondary to the HzBs rather than the metHb. These substances include Allium plants (onions and garlic), propylene glycol, zinc, methylene blue, crude oils, naphthalene (ingredient in moth balls), repeated use of propofol in cats, phenothiazine, phenylhydrazine, methionine (a urinary acidifier) in cats, menadione (vitamin K3) in dogs, and copper (particularly in animals with copper storage diseases). Depending on the individual patients’ metabolism, the dose, and the period over which it was ingested, these substances will cause varying degrees of HzB formation, and anemia does not usually occur until HzB formation is moderate to severe.
BLUE or PURPLE MM
Cyanosis indicates severe hypoxemia. By definition, cyanosis means greater than 5 g/dL of hemoglobin is desaturated, which correlates to an oxygen saturation (SaO2) of about 75% and a partial pressure of oxygen (PaO2) of approximately 40 mmHg. Hypoxemia to this degree is life-threatening. Therefore, if cyanosis is present, it indicates severe hypoxemia and oxygen therapy needs to be instituted immediately!
The term hypoxia and hypoxemia are not synonymous. Hypoxemia is defined as a decrease in the partial pressure of oxygen in the blood whereas hypoxia is defined by reduced level of tissue oxygenation. It can be due to either defective delivery or defective utilization of oxygen by the tissues. Hypoxemia and hypoxia do not always coexist. Patients can develop hypoxemia without hypoxia if there is a compensatory increase in hemoglobin level and cardiac output (CO). Similarly, there can be hypoxia without hypoxemia. In cyanide poisoning, cells are unable to utilize oxygen despite having normal blood and tissue oxygen level.
PETECHIAL or ECCHYMOTIC MM
May indicate a coagulation abnormality, or coagulopathy, manifested by either a petechiae or ecchymosies of the gums.
What is Coagulopathy? A condition in which the blood’s ability to clot is impaired, leading to hemorrhage or thrombosis. Causes of coagulopathy are:
a) Failure of primary hemostasis, or formation of the initial platelet plug. Decreased platelet numbers or function or reduced von Willebrand factor (vWF) can lead to mucosal bleeding and bruising.
b) Failure of secondary hemostasis, or formation of a stable fibrin clot via a cascade of enzymes that ultimately convert fibrinogen to fibrin. Defects can lead to severe bleeding diatheses.
(c) Excessive fibrinolysis, or plasmin breakdown of a fibrin clot. Excessive clot breakdown can result in prolonged bleeding or delayed rebleeding.
(1) Petechia. A small purplish spot on a body surface, such as the skin or a mucous membrane, caused by a minute hemorrhage.
(2) Ecchymosis. A hemorrhagic spot, larger than a petechia, in the skin or mucous membrane, forming a flat, rounded or irregular, blue or purplish patch.
JAUNDICE
It is the yellowness of skin, sclerae, mucous membranes, and excretions due to hyperbilirubinemia and deposition of bile pigments. It is usually first noticeable in the eyes or on the gums. It is also called icterus.
The pigment causing jaundice is called bilirubin. It is derived from hemoglobin that is released when erythrocytes are hemolyzed and therefore is constantly being formed and introduced into the blood as worn-out or defective erythrocytes are destroyed by the body. Normally the liver cells absorb the bilirubin and secrete it along with other bile constituents. If the liver is diseased, or if the flow of bile is obstructed, or if destruction of erythrocytes is excessive, the bilirubin accumulates in the blood and eventually will produce jaundice.
In veterinary medicine, these are the common types of jaundice:
(1) Cholestatic jaundice – Jaundice produced by failure of bile to flow to the duodenum. It may be caused by intrahepatic bile duct obstruction (as in certain drug reactions), liver cell damage (as in viral hepatitis), or extrahepatic obstruction to the flow of bile (as in cholecystitis).
(2) Hemolytic jaundice – Jaundice caused by the fragmentation of red blood cells and the release of unconjugated bilirubin in the bloodstream. This finding is associated with hemolytic anemia (HA). Because the bilirubin is not conjugated by the liver, it is not soluble in water and does not discolor the urine.
(3) Hepatocellular jaundice – Jaundice resulting from disease of liver cells, e.g., in acute hepatitis. Synonym: parenchymatous jaundice
(4) Leptospiral jaundice – Jaundice caused by leptospirosis. Synonym: hemorrhagic jaundice
DRY or TACKY MM
This is not a color classification but a check on the moisture of the gum as dryness accompanies other colors. Dryness of gums is just one sign that the pet is dehydrated.