Page 108 - Problem-Based Feline Medicine

100 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

● PaO may be misleading in CO toxicity due to Prevention
2
extreme carboxyhemoglobinemia and very low O -
2
carrying capacity. Ensure proper ventilation for heaters and wood stoves,
avoid exposure to aerosol chemicals, and reduce exposure
● A profound mixed acidosis may be present.
to cigarette smoke (quit smoking or smoke outdoors).
Measuring carboxyhemoglobin levels are needed to
diagnose carbon monoxide toxicity. Routine STAT
AIRWAY/PULMONARY NEOPLASIA
assays are available in human hospitals.
Treatment Classical signs
● Dyspnea, other inspiratory and expiratory
Emergency treatment focuses on assessing three critical
● Coughing, ranging from harsh and dry to
areas – ABC – airway, breathing, circulation.
soft and productive.
A – airway
● If the upper airway is burned or edematous, establish-
Pathogenesis
ing a patent airway may require laryngeal suctioning,
tracheal intubation, or transtracheal catheterization, Upper respiratory tract masses may produce a cough
or tracheostomy. from post-nasal drip.
B – breathing Pulmonary or airway masses cause coughing by stimu-
● Oxygen is the single most important drug to use. lation of cough receptors within the airway lumina, or
Carbon monoxide is displaced from the carboxyhe- from extraluminal compression and distortion of the
moglobin complex 8–10 times faster on 100% O than airway.
2
on room air. Continue 100% O until carboxyhemo-
2
globin < 10% on follow-up samples. Upper airway neoplasms include:
● Nasopharyngeal polyps, oropharyngeal squamous
● Bronchodilators – terbutaline (0.01 mg/kg SQ) can
cell carcinoma, tracheal adenocarcinoma (Siamese),
be repeated every 4 hours.
nasal adenocarcinoma.
C – circulation
Pulmonary neoplasms include:
● Crystalloid administration supports the blood pres-
● Primary pulmonary neoplasia.
sure and cardiovascular status, promotes diuresis of
– Bronchogenic carcinoma, pulmonary adeno-
absorbed toxins, but must be used judiciously and
carcinoma, and squamous cell carcinomas.
monitored carefully for iatrogenic pulmonary
● Secondary metastases from distant neoplasms,
edema. Colloids (fresh frozen plasma, synthetic
including a variety of carcinomas (i.e., mammary
starch products, synthetic blood substitutes) may be
adenocarcinomas) and sarcomas (i.e., osteosar-
beneficial.
coma), as well as local metastases from primary
The prophylactic use of antibiotics is controversial. lung tumors.
Antibiotics reduce the normal flora, and may predis-
Pleural malignancy may cause coughing.
pose to a more serious nosocomial infection. If infec-
tion is suspected, antibiotic selection should be based
on culture results of lung wash fluid. Clinical signs
Tracheal tumors create fixed obstruction, leading to
Prognosis inspiratory and expiratory dyspnea, and a harsh, dry
cough. Hemoptysis may be present.
The prognosis is directly related to the extent of the
Bronchial tumors may be associated with a softer, pro-
injuries, both to the airways and non-respiratory dam-
ductive cough, fetid halitosis and hemoptysis.
age (i.e., skin burns, other organ damage, etc.). Signs
may progressively worsen over the initial 24–48 Very rarely, lameness from hypertrophic osteopathy
hours. occurs.