Tracheal Foreign Body and Pneumonia in a Cat: A Near Missed Diagnosis Sara Johns, DVM*, Rance Sellon, PhD, DVM, DACVIM (Small Animal Internal Medicine and Oncology), Erick Spencer, MS, DVM, DACVIM (Small Animal Internal Medicine)y, Melissa Tucker, DVMx**

ABSTRACT A 12 yr old mixed-breed Maine coon was referred with a 1 wk history of intermittent respiratory distress. Physical examination and thoracic radiograph abnormalities were consistent with bronchopneumonia and chronic feline asthma. Repeat thoracic radiographs and lung aspirate cytology supported those diagnoses. Response to treatment was incomplete. One wk later, due to a change in respiratory pattern, cervical radiographs were obtained. A soft-tissue density was apparent in the cat’s cervical trachea. Bronchoscopy was performed and a segment of a pine cone was removed from the cat’s trachea. Following removal of the foreign body, the cat’s respiratory signs resolved. Premature diagnostic closure may prevent a clinician from recognizing an underlying missed diagnosis when response to treatment does not occur as expected. (J Am Anim Hosp Assoc 2014; 50:273–277. DOI 10.5326/JAAHA-MS-6008)


Case Report

The phenomenon of diagnostic error has been gaining attention in human medicine.


A 12 yr old castrated male mixed-breed Maine coon weighing

Once a plausible diagnostic hypothesis is

4.36 kg was referred to the Emergency Service at the Washington

reached, the clinician is likely to accept it and might resist per-

State University Veterinary Teaching Hospital for evaluation of

forming further diagnostics even if response to treatment is poor

respiratory distress. The cat was originally seen by his primary

or subsequent diagnostics are inconsistent with that hypothesis.

care veterinarian 6 days earlier (day 1). At that time, physical

These are common errors of premature closure and anchor-

examination revealed that the cat had increased inspiratory and


There has been little discussion of the effect of diagnostic

expiratory effort. The nasal passage was clear and a laryngeal

error on patient care in the veterinary literature. The authors

exam performed while the cat was sedated was unremarkable. A

present a case of a feline patient who failed to respond to treat-

patchy interstitial pulmonary pattern was noted on lateral and

ment for its original diagnosis (pneumonia and feline asthma).

ventrodorsal full-body radiographs. The cat was administered

Repeat physical exam by multiple clinicians resulted in ques-

0.46 mg/kg dexamethasone and 2.3 mg/kg furosemide subcu-

tioning of the original diagnostic hypothesis, further diagnostics,

taneously for severe respiratory difficulty, and some improve-

and a more complete and accurate diagnosis (tracheal foreign

ment in effort was noted. The cat was discharged with 2.5 mg/kg


enrofloxacin per os (PO) q 12 hr. The following day (day 2), the

From the Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA.

IM, intramuscularly; PO, per os

Correspondence: [email protected] (S.J.)

erinary Medicine, Knoxville, TN.


*S. Johns’ present affiliation is the University of Tennessee College of Vet†

E. Spencer’s present affiliation is Friendship Hospital for Animals, Washington,

DC. x

M. Tucker’s updated credentials since article acceptance are DVM, MS,

DACVIM (Small Animal Internal Medicine). pp

ª 2014 by American Animal Hospital Association

M. Tucker’s present affiliation is Utah Veterinary Center, Midvale, UT.



cat was reexamined and had mildly increased respiratory noise on inspiration. Otherwise, he was bright, alert, and eupneic. One day later (day 3), the cat re-presented to the primary care veterinarian with severe respiratory distress. Dexamethasone and furosemide treatment was repeated and by the following day (day 4), the cat was eupneic. Three days later (day 7), respiratory distress returned, and the cat was referred to Washington State University for further evaluation and care. At the time of presentation, the cat was bright and alert, and had mild respiratory distress characterized by an end expiratory wheeze and occasional forced abdominal expiration. The cat’s temperature was 38.98C, heart rate was 144 beats/min, and respiratory rate was 40 breaths/min. Mucous membranes were pink with a capillary refill time of , 2 sec, and heart sounds were normal. The cat was hospitalized overnight in 40% O2 and administered 90 mg of albuterol via face maska. The following morning (day 8), thoracic radiographs were obtained. Manipulation of the cat produced profound respiratory distress; therefore, sedation with 0.2 mg/kg of butorphanol intramuscularly (IM) and O2 face mask were required for handling. A multifocal, interstitial to alveolar pattern was noted in the accessory, right middle, and left caudal lung lobes on radiographs (Figures 1A, B). Either bronchoalveolar lavage or fine-needle aspirates were recommended to assess for infectious agents, and ultrasound-guided fine-needle aspirates were obtained from the consolidated right middle lung lobe, which was the lung lobe that was most clearly visualized for sampling. Aspirates contained a mix of inflammatory cells, including mildly elevated proportions of eosinophils and mast cells. Differential diagnoses at that time included infectious bronchopneumonia, chronic feline asthma, parasitism, or an infiltrative processes. Further diagnostics were delayed due to the cat’s inability to tolerate handling. Empirical therapy for feline asthma, infection, and parasitism was initiated. Enrofloxacinb was administered at 5 mg/kg PO q 24 hr. Additional treatments at this time in-

FIGURE 1 Ventrodorsal (A) and lateral (B) radiographs of a

cluded 27.5 mg/kg trimethoprim-sulfadiazine PO q 12 hr,

12 yr old mixed-breed Maine coon with an 8-day history of inter-

5.8 mg/kg doxycyclined PO q 12 hr, 0.14 mg/kg terbutalinee PO

mittent and severe respiratory distress. A multifocal interstitial to

q 12 hr, 23 mg/kg fenbendazole PO q 12 hr, 110 mg fluticasone via

alveolar pattern is noted in the accessory, right middle, and left





metered dose inhaler q 12 hr, and 1.1 mg/kg prednisolone PO

caudal lung lobes. L, left; R, right.

q 24 hr. The cat was hospitalized in 40% O2 and administered 0.2 mg/kg butorphanoli IM, 1 mg/kg furosemide j IM, and 90 mg

were delivered at a rate of 12 mL/hr, and treatment with

of albuterol via face mask as needed for episodes of acute respi-

0.86 mg/kg mirtazapinel PO q 72 hr and 1 mg/kg maropitantm

ratory distress.

subcutaneously q 24 hr was initiated. Results of a serum bio-

On day 10, the cat became depressed and anorexic. After se-

chemical analysis were unremarkable. A complete blood cell

dating with 0.2 mg/kg butorphanol IM, an IV catheter was placed

count revealed a mild leukocytosis (20.9 3 109/L; reference range,

and blood samples were drawn. A brief echocardiogram was

4–14 3 109/L), characterized by a neutrophilia (17.765 3 109/L;

performed and the cat’s heart was structurally normal. IV fluids

reference range, 2–12 3 109/L) with left shift (band neutrophils



50:4 Jul/Aug 2014


Tracheal Foreign Body and Pneumonia in a Cat

were 0.209 3 109/L; reference range, 0–0.1 3 109/L), lymphopenia (1.254 3 109/L; reference range, 1.5–6 3 109/L), and monocytosis (1.672 3 109/L; reference range, 0–0.8 3 109/L). There was a mild normocytic, normochromic anemia (packed cell volume was 28%; reference range, 30–46%). A reticulocyte count to define the anemia as regenerative or nonregenerative was not performed. An ELISAn test for the feline leukemia and feline immunodeficiency viruses was negative. The following day (day 11), the cat’s attitude improved and his appetite returned. The cat remained eupneic in 40% O2 with minimal handling. On day 12, weaning of O2 supplementation began and O2 was discontinued the morning of day 13. The cat remained eupneic on room air and discharge was planned for day 15. Early in the morning of day 15, moderate respiratory distress returned and the cat was administered 90 mg of albuterol via metered dose inhaler and was returned to 30% O2 supplementation. The clinical signs resolved and the cat was returned to room air. On thoracic radiographs obtained on day 15, there was improvement of the interstitial pattern within the accessory, right middle, and left caudal lung lobes. Later in the afternoon of day 15, severe respiratory distress returned with inspiratory and expiratory effort and audible stridor. On auscultation, respiratory noise was loudest over the cervical trachea. On cervical radiographs, there was a focal increase in soft-tissue opacity overlying the tracheal lumen (Figure 2A). Bronchoscopy was performed the following day (day 16). A foreign body identified as a segment of pine cone (Figure 2B) was visualized within the trachea and removed. Bronchoalveolar lavage was performed, and the cat recovered uneventfully from anesthesia without any respiratory distress. Enterococcus spp. and Streptococcus spp. were cultured from lavage fluid, both susceptible to doxycycline. The cat was discharged the next day (day 17) with continued treatment of bronchopneumonia (5.8 mg/kg doxycycline PO q 12 hr) and feline asthma (110 mg fluticasone via metered dose inhaler q 12 hr). Immediate and complete resolution of respiratory signs was reported by the owner. The course


of doxycycline was completed, and treatment with fluticasone

breed Maine coon being treated for pneumonia with clinical signs

was discontinued without recurrence of respiratory distress.

indicative of an upper airway obstruction. A soft-tissue opacity is


moved from the cat’s trachea. L, left.

A: Lateral cervical radiograph of a 12 yr old mixed-

noted overlying the cervical trachea. B: Segment of pine cone reTracheal foreign bodies in cats have been intermittently reported.8–13 The manifestation of clinical signs may vary widely depending

located in the cervical trachea and was not apparent on thoracic

on chronicity, degree of airway obstruction, and severity of

radiographs. On bronchoscopy, the foreign body was observed

secondary infection or inflammation.


Nearly all large tracheal

to be highly mobile. The study authors speculate that because of

foreign bodies reported in cats have been located at the carina,

the mobility and shape of the foreign body, it intermittently

whereas smaller objects may move into distal airways. The cat

acted like a flap valve with changes in its position resulting in

described in this report was unusual in that the foreign body was

varying degrees of airway obstruction and transient clinical



signs. Evidence of pulmonary parenchymal disease identified

previous examinations. It is also possible that the clinical signs

on thoracic radiographs obtained by the referring veterinarian

were not correctly interpreted or, in fact, that some anchoring

and at the authors’ institution provided a suitable explanation

had already taken place and they were initially disregarded. As

for respiratory distress, and the cat’s respiratory pattern at the

the history, test results, and clinical context were interpreted as

time of referral was consistent with feline asthma. Respon-

consistent with bronchopneumonia and feline asthma, whether

siveness to O2 and improvement with empirical therapy were

the pattern of respiratory distress continued to fit those diagnoses

consistent with the radiologic and cytologic diagnoses of

may not have been adequately considered. Recognition that the

bronchopneumonia and chronic feline asthma, and those diag-

cat’s clinical signs were no longer consistent with the original

noses were initially accepted as complete. The fact that the tra-

diagnosis was facilitated by observations made by clinicians who

cheal foreign body was not identified sooner could thus be viewed

were not as familiar with the cat’s previous clinical features and

as a diagnostic error.

diagnostic test results and perhaps not as biased by the initial

In human medicine, a number of ways by which diagnostic errors occur have been described.


In most cases, diagnostic

error is multifactorial, and one error often leads to another.3 A

diagnostic hypothesis. At that time, questioning of the initial diagnostic hypothesis and further investigation revealed the tracheal foreign body that had previously been overlooked.

diagnostic hypothesis is generated early in the course of investi-

It has been demonstrated in human medicine that ques-

gating a presenting complaint and is based on the patient’s (or

tioning an original diagnostic hypothesis will not harm a correct

owner’s) description of the problem, the physical examination,

diagnosis but may be likely to correct an erroneous one.1 Al-


and any available test results. With clinical experience and ex-

though diagnostic error in veterinary medicine has been studied

pertise comes the ability to quickly and accurately determine

very little, it is likely to occur for similar reasons as those iden-

a diagnosis based on this limited information. History and clinical

tified in human medicine. Pitfalls in clinicians’ diagnostic rea-

context alone can suggest an initial diagnosis, and subsequent

soning may also be confounded by owners’ financial constraints,

interpretation of physical exam findings and test results may be

which frequently preclude recommended diagnostic testing. Vet-


biased by this suspected diagnosis. When a suitable diagnosis

erinarians therefore may have no choice but to end the search for

fits the available evidence, the clinician may accept it without

further diagnoses once a plausible one has been identified, aban-

consideration of whether other differentials could cause similar

doning consideration of alternatives.14 The inability to arrive at a

clinical features. Further diagnostic testing to exclude other plau-

definitive diagnosis, and the loss of opportunity to potentially

sible differential diagnoses may not be pursued, leading to one

recognize the diagnostic error, may predispose to repeating the

cause of diagnostic error, premature closure.6 Premature diag-

diagnostic error in the future.

nostic closure is the failure to consider other diagnostic possibilities once an initial diagnosis has been reached, and is the


most common cause of diagnostic error in human medical cases

Quick and logical diagnoses based on a clinician’s experience,

where the initial diagnosis is either incorrect or incomplete.1,2 In

the clinical context, and the likelihood of a common diagnosis

turn, acceptance of a diagnosis as complete may blind the cli-

being the correct one usually produce accurate results and rapid

nician to either new or previously overlooked information that

resolution.5 However, failing to question the diagnosis or ex-

is incompatible with that diagnosis (i.e., the secondary error of

cluding other plausible competing differential diagnoses with

anchoring).7 Anchoring is the decision to retain an initial di-

additional diagnostic investigation (when appropriate) leads to

agnosis and resist acknowledging evidence that conflicts with

the diagnostic error of premature closure.1 Follow-up is a ne-

that diagnosis.


cessity in such cases, as well as repeating the physical exami-

Research on diagnostic error in human medicine has dem-

nation on another day more removed from the original data and

onstrated that although knowledge of the clinical context in-

initial clinical impressions. Alternatively, having another clini-

creases diagnostic accuracy, it also predisposes to premature

cian less familiar with the working diagnostic hypothesis, and

On day 15, the reassessed physical examination findings

thus less susceptible to the additional diagnostic error of an-

of the cat described in this report were identified by multiple

choring, perform an examination and review the case would be

clinicians as consistent with an upper airway obstruction. It is

beneficial.5 Questioning every hypothesis is impractical and

possible that the dynamic nature of the obstruction may have

unnecessary; however, such questioning should be used when

delayed recognition of the obstructive breathing pattern. The

either a patient’s course of recovery or response to treatment is

signs may have been transient enough to have been missed on

not proceeding as expected.





50:4 Jul/Aug 2014

Tracheal Foreign Body and Pneumonia in a Cat

FOOTNOTES a Aerokat Feline Aerosol Chamber; Trudell Medical International, London, ON, Canada b Baytril; Bayer Healthcare LLC Animal Health Division, Shawnee Mission, KS c TMS; Qualitest Pharmaceuticals, Huntsville, AL d Doxycycline; West-Ward Pharmaceutical Corp., Eatontown, NJ e Terbutaline; IMPAX Laboratories, Hayward, CA f Panacur C; Intervet, Millsboro, DE g Flovent; GlaxoSmithKline, Research Triangle Park, NC h Prednisolone; Lloyd Inc., Shenandoah, IA i Butorphanol; Pfizer Animal Health, New York, NY j Furosemide; Vedco, Inc., St. Joseph, MO k Normosol-R; Hospira, Lake Forest, IL l Mirtazapine; Patheon Pharmaceuticals, Cincinnati, OH m Cerenia; Pfizer Animal Health, New York, NY n SNAP FIV/FeLV Combo test; IDEXX Laboratories, Westbrook, ME REFERENCES 1. Coderre S, Wright B, McLaughlin K. To think is good: querying an initial hypothesis reduces diagnostic error in medical students. Acad Med 2010;85(7):1125–9. 2. Eva KW, Link CL, Lutfey KE, et al. Swapping horses midstream: factors related to physicians’ changing their minds about a diagnosis. Acad Med 2010;85(7):1112–7. 3. Graber ML, Franklin NF, Gordon R. Diagnostic error in internal medicine. Arch Intern Med 2005;165(13):1493–9.

4. Leblanc VR, Brooks LR, Norman GR. Believing is seeing: the influence of a diagnostic hypothesis on the interpretation of clinical features. Acad Med 2002;77(10)(suppl):S67–9. 5. Redelmeier DA. Improving patient care. The cognitive psychology of missed diagnoses. Ann Intern Med 2005;142(2):115–20. 6. Sibbald M, Panisko D, Cavalcanti RB. Role of clinical context in residents’ physical examination diagnostic accuracy. Med Educ 2011; 45(4):415–21. 7. Sutherland DC. Improving medical diagnoses by understanding how they are made. Intern Med J 2002;32(5–6):277–80. 8. Dimski DS. Tracheal obstruction caused by tree needles in a cat. J Am Vet Med Assoc 1991;199(4):477–8. 9. Goodnight ME, Scansen BA, Kidder AC, et al. Use of a unique method for removal of a foreign body from the trachea of a cat. J Am Vet Med Assoc 2010;237(6):689–94. 10. Levitt L, Clark GR, Adams V. Tracheal foreign body in a cat. Can Vet J 1993;34(3):172–3. 11. Pratschke KM, Hughes JML, Guerin SR, et al. Foley catheter technique for removal of a tracheal foreign body in a cat. Vet Rec 1999; 144(7):181–2. 12. Tenwolde AC, Johnson LR, Hunt GB, et al. The role of bronchoscopy in foreign body removal in dogs and cats: 37 cases (2000– 2008). J Vet Intern Med 2010;24(5):1063–8. 13. Tivers MS, Moore AH. Tracheal foreign bodies in the cat and the use of fluoroscopy for removal: 12 cases. J Small Anim Pract 2006;47(3): 155–9. 14. Ely JW, Graber ML, Croskerry P. Checklists to reduce diagnostic errors. Acad Med 2011;86(3):307–13.



Tracheal foreign body and pneumonia in a cat: a near missed diagnosis.

A 12 yr old mixed-breed Maine coon was referred with a 1 wk history of intermittent respiratory distress. Physical examination and thoracic radiograph...
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