Case of the month is our diagnostic challenge. We present cases seen by Cornell University’s Clinical Pathology Laboratory. These cover the gamut of venous blood smears, cytologic specimens and result (CBC, chemistry) interpretation, including those pesky erroneous results (usually due to preanalytical errors). A new case will be presented every month. Test yourself with the questions and photomicrographs and make your own diagnosis! The answer along with explanations and discussion is provided on the following page to see how close you came to the diagnosis.
We also have an index of our previous cases (with answers) if you wish to see a list of all the cases. Please note, that the search tool does not search case of the month (yet!).
An 8 year old Morgan gelding presented to the Cornell University Hospital for Animals with a 3 week history of serohemorrhagic skin lesions and a 1 week history of a progressively worsening cough. The horse had also recently lost 100 lb. On physical examination, multifocal oozing lesions were present on the left hip, lower aspects of three limbs and neck. No abnormal lung sounds were detected on auscultation with or without a rebreathing bag. Thoracic ultrasonographic and radiographic examination revealed diffuse lung consolidation and pleuritis, with a mixed pulmonary pattern and coalescing nodules, respectively. Blood samples were taken for a hemogram plus fibrinogen by heat precipitation and chemistry profile.
Hemogram abnormalities included a mild neutrophilia of 7.3 thou/uL (reference interval: 2.7–6.6 thou/uL) and a mild hyperfibrinogenemia of 400 mg/dL (reference interval, 0-200 mg/dL). There was a mild hypoalbuminemia (2.5 g/dL, reference interval: 3.0–3.7 g/dL) and hyperglycemia (141 mg/dL, 71-113 mg/dL) on the biochemical panel.
An endoscopic tracheal wash and blind bronchoalveolar lavage were performed and submitted for cytologic evaluation.
Evaluate the representative photomicrographs of the direct smear of the tracheal wash and answer the questions posed below:
What cell types are present in the smears (how would you characterize the results)?
What are your differential diagnoses for the findings?
Figure 1: Tracheal wash from a horse (10x objective)
Figure 2: Tracheal wash from a horse (50x objective)
An approximately 18 month old, male Hermann’s tortoise presented for raspy breathing, exuberant, pink tissue over the eyes and being less active than normal. On physical examination the tortoise was small for his age, had increased respiratory rate and effort, was 5% dehydrated and would not open his eyes. While the tortoise was fully ambulatory, his left rear leg was swollen in the tarsal region. Whole body radiographs were taken to better assess the animal’s overall health. No abnormalities were seen in the lungs, but extensive bone loss and soft tissue swelling was noted in the region of the left tarsus. The left tarsal joint was aspirated and thick, gritty material was obtained. A portion of this sample was submitted for culture, while the remainder of the sample was assessed cytologically. Evaluate the photomicrographs of the submitted joint material and consider the following questions:
What types of inflammatory cells are present?
What are the structures indicated by the arrows in Figure 3 (also pictured in Figure 1A)?
What is the final diagnosis based on the cytological findings?
Figure 1A. Left tarsus joint aspirate from a tortoise (Wright’s stain 500x)
Figure 2A. Left tarsus joint aspirate from a tortoise (Wright’s stain 500x)
Figure 3A. Left tarsus joint aspirate from a tortoise (Wright’s stain 1000x)
A 2 year-old male castrated Cane Corso presented to the Cornell University Hospital for Animals for a two-day history of vomiting, hypoglycemia, and bradycardia. Blood-work performed at the referring veterinarian revealed a hyponatremia and hyperkalemia. No abnormalities were found on abdominal radiographs. Prior to referring the dog to the Cornell Emergency service, the rDVM began treatment with a bolus of 50% dextrose and 0.9% NaCl. The dog had a previous history of hospitalization for sepsis, vomiting, and diarrhea that had occurred one week after vaccination for rabies and distemper. Consequently, all vaccine protocols were discontinued and were therefore not up-to-date.
On presentation, the dog was quiet but alert, and hypothermic at 97.3ºF. The remainder of the physical examination was within normal limits. The dog was started on intravenous fluids supplemented with glucose. Rapid in-house assessment tests, venous blood gas analysis, complete blood count, and a full serum chemistry panel were performed. Fluids, supplemented with dextrose, were continued overnight and a constant rate infusion of hydrocortisone was started. A free catch urine and stool sample were also submitted for evaluation.
Review the laboratory data provided, and answer the following interpretive questions. (Abnormal and pertinent laboratory data have been included. Test results not included were within reference intervals.)
Given the dog’s clinical history and presentation, what is an unexpected finding in the hemogram results?
What are the differential diagnoses for hypocholesterolemia and which is the most likely in this case?
Presuming the dog’s azotemia resolves with fluid therapy, how would you explain the reduced concentrating ability of the kidney?
A 6 year old male castrated domestic shorthair cat presented to the Cornell University Hospital for Animals (CUHA) emergency service for evaluation of worsening eye pain and inappetance. The cat was previously seen by the ophthalmology service at CUHA one week prior for evaluation of ocular discharge and conjunctival swelling of the left eye. In the latter examination, there was no evidence of penetrating trauma or foreign body. The cat was diagnosed with conjunctivitis and discharged with erythromycin ophthalmic ointment q 8 hours.
Upon presentation to the emergency service, the cat demonstrated blepharospasm in both eyes. No other physical examination abnormalities were noted. A CBC and serum chemistry panel were performed and were largely unremarkable. A swab of the conjunctiva was performed and applied to a slide for cytologic evaluation. Representative images from the Wright’s stained smears are provided.
Evaluate the provided images below and answer the following questions:
What type of inflammation is present?
Can you identify the cause of the inflammation?
What additional diagnostic could be performed to confirm the cytologic diagnosis?
A 3-week-old thoroughbred filly was presented to the Cornell University Hospital for Animals (CUHA) for acute left hind limb lameness and fever. Two days prior to presentation to CUHA, the filly was found acutely lame with a suspicion of trauma (stepped on by another horse).
On presentation, the filly weighed 88 lb and had a temperature of 102.9ºF. The foal was quiet, alert and responsive, but was non-weight bearing on the left pelvic limb and had a moderately sized warm swelling over the left hip with no signs of external trauma. The rest of the physical examination was within normal limits. Blood was drawn for a complete blood count (CBC), equine IgG and serum amyloid A (SAA) testing.
The CBC revealed a microcytic normochromic anemia (27% Hct, 34-46%) with a leukocytosis of 15.8 x 103/uL (reference interval, 5.2 – 10.1 x 103/uL) consisting of a mature neutrophilia of 13.1 x 103/uL (reference interval, 2.7 – 6.6 x 103/uL). The SAA concentration was higher than the upper detection limit of 2500 ug/mL and the fibrinogen concentration by heat precipitation was 700 mg/dL (reference interval, 100-200 mg/dL). The serum IgG was 671 mg/dL (reference interval in adults, 984 – 1685 mg/dL).
Radiographic examination of the left pelvic limb and an abdominal ultrasonographic examination revealed no abnormalities. An ultrasound-guided fine needle aspirate was performed on the swelling and submitted to Clinical Pathology for a joint fluid analysis. The fluid was medium red, opaque and had decreased viscosity. The nucleated cell count was 51.5 x 103/uL, the RBC count was 441.2 x 103/uL, and the total protein (refractometer) was 5.7 g/dL.
Examine the representative images of the joint fluid that are provided below and answer the following questions:
How would you classify this joint fluid?
Based on the cytological findings and the history of this foal, what are your differential diagnoses?
What other diagnostic test should be performed?
Figure 1: Joint fluid direct smear (Wright’s stain, 20x objective)
Figure 2: Joint fluid direct smear (Wright’s stain, 100x objective)
An 11-year-old male castrated domestic longhair cat presented to the Cornell University Hospital for Animals (CUHA) Emergency Service for a five day history of lethargy, anorexia, persistent hyperthermia, and increased liver enzymes. The cat was first brought to the primary care veterinarian for a two day history of lethargy and inappetance. At that time, bloodwork revealed hypoproteinemia, hypoalbuminemia, and hypocholesterolemia. Radiographs of the chest and abdomen showed mild hepatomegaly. The cat was treated with subcutaneous fluids, antibiotics, and prednisone. After one week of treatment, no improvement was noted and the cat was brought to CUHA for further evaluation.
On presentation, the cat was bright, alert, and responsive, but was hyperthermic (104.8°F), tachycardic (210 bpm), and mildly dehydrated (5-7%). Physical examination also revealed mild icterus in both sclera and discomfort on cranial abdominal palpation. Blood was drawn for a CBC and chemistry panel. The CBC showed a mild normocytic normochromic nonregenerative anemia (hematocrit: 29%, reference interval [RI]: 31-48%). Results also showed a normal total leukocyte and neutrophil count with a mild left shift (0.2 thou/uL, RI: 0.0-0.1 thou/uL) and mild toxic change. Abnormal liver biochemical results are shown below:
An abdominal ultrasound examination revealed mild hepatomegaly, with rounding of the edges of the liver, and enlarged jejunal lymph nodes. Ultrasound-guided needle aspirates were taken from each site and samples were submitted for cytologic evaluation.
Examine the representative images of the liver aspirate that are provided below and answer the following questions:
How would you interpret the biochemical results reported above?
Based on the cytologic findings, what are your differential diagnoses for the underlying cause?
What other diagnostic tests could be done in this case?
A 3-month-old neutered male Siberian Husky puppy presented to the referring veterinarian with a 5 week history of respiratory symptoms and rhythmic jaw movements. An in-clinic hemogram revealed the following:
Table 1: Abbreviated hemogram results
Results for an in-house biochemistry panel were within provided reference intervals.
The veterinarian treated the puppy for a presumptive pneumonia with antibiotics, but there was little improvement. The dog was subsequently admitted to an emergency clinic for anorexia and dyspnea. When examined at the emergency clinic, the puppy was dyspneic (this was oxygen dependent), with a marginal increase in temperature (102.6ºF), and had a bilateral serous nasal discharge and chemosis. A swab of the dog’s conjunctival mucosa was taken and rolled onto a microscope slide, followed by rapid staining (Diff-quik®).
Evaluate the representative photomicrograph of the conjunctival swab and answer the questions posed below:
Are any abnormalities evident in the conjunctival swab?
Do the observed findings explain the hemogram results?
What are potential explanations for the dog’s microcytosis?
A 5 year old, male castrated, Australian shepherd dog was referred for thrombocytopenia, hypercalcemia and peripheral lymphadenopathy. The dog also demonstrated a decreased appetite and energy level. Mild, intermittent diarrhea, as well as polyuria and polydipsia, were noted. Prior to the onset of these symptoms, the dog was considered healthy and active.
Upon presentation, the dog was bright, alert and responsive and vital parameters were within normal limits. The left superficial, cervical and submandibular lymph nodes were notably enlarged, with other peripheral lymph nodes being mildly increased in size. The remainder of the physical examination was within normal limits. Significant laboratory abnormalities included a moderate increase in total calcium [13.5 mg/dL, reference interval (RI) 9.3-11.4 mg/dL], with a concurrent marked increase in ionized calcium (1.65 mmol/L, RI: 1.18-1.37 mmol/L) and a marked thrombocytopenia (25,000/uL, RI: 186,000-545,000/uL) with no platelet clumping noted on review of the blood film. Low numbers of suspected circulating neoplastic cells, with morphologic features most suggestive of lymphoid origin, were also seen on blood film review. In addition, some atypical morphological features of neutrophils were noted. Thoracic radiographs revealed a possible sternal and tracheobronchial lymphadenopathy. Fine needle aspiration of peripheral lymph nodes was performed (the cytologic results will be discussed in the Explanation section). Bone marrow aspiration was also performed.
Evaluate the representative images of the bone marrow below and answer the following questions:
What is the major process occurring in the bone marrow?
Why is the dog thrombocytopenic?
What additional diagnostic test could you perform to refine your diagnosis of the underlying process in this case?
What morphological abnormalities do you detect in the neutrophils within the marrow sample? What is the significance of this finding?
Figure 1. Low power image of bone marrow. Wright’s stain, 20x
Figure 2. Higher magnification image of the bone marrow. Wright’s stain, 50x
Figure 3. Higher magnification of the bone marrow. Wright’s stain 100x
A 2.5 year old castrated male alpaca presented febrile and obtunded with a history of diarrhea. Upon presentation, significant peritoneal effusion was noted. Blood was drawn for a CBC and chemistry profile and abdominocentesis was performed to collect peritoneal fluid. Significant CBC findings included a marked neutropenia (400 cells/ul; reference interval 3.5 – 11.7 x 103/uL) with a degenerative left shift extending to metamyleocytes (band neutrophil count of 4,200 cells/ul; reference interval 0 x 103/uL) with moderate toxic change in neutrophils. The chemistry profile revealed mild electrolyte depletion, moderate azotemia, a mild hyperglobulinemia, and a high anion gap titrational metabolic acidosis.
View the representative photomicrographs to aid in your consideration of the following questions:
What is the most likely causative agent based on morphological features evident in the photomicrographs?
What is the likely source of the infection (in terms of route of entry into the host as well as the suspected carrier)?
Are the cytological features of the neutrophils concordant with the pathological process that is occurring?
An 8 year old male castrated Chihuahua was presented to the Cornell University Hospital for Animals (CUHA) Emergency Service for evaluation of increased respiratory rate and effort. The owners reported that the day prior to presentation, the dog was lethargic and had vomited. The owners brought the dog to their primary veterinarian who noted a two pound weight loss since the last wellness exam (7 months prior), and performed routine bloodwork and two-view abdominal radiographs. The liver enzymes were reportedly markedly increased and the abdominal radiographs were unremarkable. The dog was discharged with metronidazole, Denamarin, and Fortiflora. The lethargy worsened and the dog developed hematochezia and respiratory difficulties, which prompted the owners to bring the animal to CUHA for further evaluation.
On presentation, the dog was bright, alert, and responsive, but was mildly febrile (103.2 F), tachycardic (170 bpm), and tachypneic. Other physical examination abnormalities included cranial organomegaly, a tense abdomen on palpation, and mucoid feces. A targeted ultrasound detected a small amount of free fluid in the peritoneal cavity. An abdominocentesis was performed and a sample was submitted for cytologic evaluation the next morning, along with a CBC, chemistry panel, and urinalysis. The CBC revealed a moderate leukocytosis (29,500/μL, reference interval [RI]: 5,700-14,200/μL) characterized by a mature neutrophilia (26,300/μL, RI: 2,700-9,400/μL) and monocytosis (2,400/μL, RI: 100-1,300/μL) with a mild lymphopenia (600/μL, RI: 900-4,700/μL). Abnormal chemistry results were as follows:
The submitted peritoneal fluid was dark red and opaque with a total protein by refractometer of 6.2 g/dL, nucleated cell count of 89.0 thou/μL, and RBC count of 651.0 thou/μL. Direct smears were prepared from the submitted fluid. Evaluate the chemistry results and representative images of the peritoneal fluid below, and consider the following questions:
Based on the CBC and chemistry panel, what pathologic processes are present?
How would you classify the effusion?
What are your differential diagnoses for the underlying cause of the effusion?
What additional diagnostic tests are indicated in this case?