Page 457 - Clinical Small Animal Internal Medicine

43 Septic Shock 425

have polyuria, polydipsia, and vulvar discharge as Abnormalities in the minimum database generally reflect
VetBooks.ir part of their history. Many dogs with septic peritonitis the underlying disease although specific sepsis‐related
changes could be present.
secondary to gastrointestinal perforation will have a
An inflammatory response is expected on the hemo-
history of NSAID or corticosteroid administration.
Some of the etiologies of sepsis are subacute to chronic gram, although individual patients may demonstrate
in nature and subsequently the historical complaints high, normal, or low leukocyte counts with or without
may be somewhat vague. Regardless of the underlying toxic change or presence of band neutrophils. Patients
cause of sepsis, it is common for owners to report may have a regenerative or nonregenerative anemia and
decreased activity levels and loss of appetite for varying may be thrombocytopenic.
amounts of time prior to presentation. Travel history, The biochemistry profile can often be quite abnormal.
exposure to any and all medications (including com- Septic patients have a significant inflammatory compo-
mon over‐the‐counter drugs), housing (indoor vs out- nent to their disease that can affect blood protein levels
door), and exposure to other animals are all important dramatically. Hypoalbuminemia is found frequently in
historical facts to elucidate. septic patients as albumin loss into exudates occurs con-
Just as sepsis/SIRS occurs on a spectrum, the clinical currently with downregulation of albumin production
signs associated with sepsis/SIRS vary depending on the during the acute phase response. Other abnormalities
severity of the condition. By definition, all animals with identified on the biochemistry profile may include hypo-
sepsis have clinical signs consistent with SIRS. Additional glycemia, hyperbilirubinemia, hypocalcemia, and ele-
clinical signs that may be present include lethargy, recum- vated creatinine and blood urea nitrogen. Of these,
bency, vocalization, or seizures, with some patients even hypoglycemia is of particular concern since it contrib-
presenting moribund. utes to morbidity or mortality if not identified and cor-
Once septic shock develops, clinical signs vary but are rected rapidly.
generally related to deficits in oxygen delivery. Patients Imaging studies are often key to the identification of
with septic shock can have two different presentations: the source of sepsis. Plain radiographs of the chest and
they can be in hyperdynamic (compensated) or hypody- abdomen are useful for identifying possible sources of
namic (decompensated) shock. Hyperdynamic shock sepsis and the finding of unstructured interstitial to alve-
implies that there is greater than normal cardiac output olar pulmonary infiltrates, pleural effusion, obstructive
with vasodilation and these patients will be tachycardic, intestinal pattern, free abdominal air, or loss of abdomi-
have red mucous membranes, bounding femoral pulses, nal detail indicating free fluid should be considered sig-
and warm extremities. Patients in the hypodynamic nificant and additional confirmatory diagnostic tests
phase of shock can be tachycardic or bradycardic, have should be pursued.
weak pulses, pale to gray mucous membranes, and cold Collection of free abdominal fluid, if present, is often
extremities. the first step in diagnosing septic peritonitis and can be
accomplished via blind four‐quadrant paracentesis or
ultrasound‐guided needle aspiration. Ultrasound allows
Diagnosis the clinician to bring imaging to the bedside and perform
a rapid evaluation of the thoracic and abdominal cavities.
The diagnosis of septic shock is made by fulfilling the This can help with the initial identification of disease,
SIRS criteria and key hemodynamic parameters in con- and can provide a method to monitor progression.
junction with identification of an underlying infection. Ultrasound is particularly useful for identifying pockets
Patients in septic shock will show similar physical exam of fluid within the chest and abdominal cavities that can
findings to patients in shock for other reasons, but there then be sampled. In clinical practice, ultrasound is more
will generally be additional abnormalities related to the effective at identifying free fluid than is blind four‐quad-
underlying cause of sepsis. For instance, a patient with rant paracentesis, making it an objective and effective
septic peritonitis will have traditional signs of shock tool in the ER and ICU.
(tachycardia, weak pulses, and pale mucous membranes) Once fluid is obtained, cytologic evaluation can
but will also often have abdominal pain and peritoneal confirm the diagnosis of septic peritonitis or prompt
effusion as evidenced by abdominal distension with the the clinician to investigate further. Identification of
possibility of a palpable fluid wave. intracellular bacteria signifies that bacteria present in
When presented a patient with suspected sepsis or the peritoneal cavity are being phagocytized by inflam-
septic shock, it is important to first gather as much data matory cells and indicates infection rather than sample
as you can. The minimum database consists of a com- contamination. The finding of even one intracellular
plete blood count, biochemistry profile, and urinalysis. bacterium is significant and is an indication for immediate