A Case A Week for Veterinarians: August 2025

Solution for Case 29

Diagnosis: The tentative diagnosis is Acute Congestive Glaucoma. The combination of a painful, red, cloudy eye with a fixed, dilated pupil and acute vision loss is highly suggestive of a rapid and severe increase in intraocular pressure. More information on this condition can be found at the Merck Veterinary Manual.

DDx: The main differential diagnoses for a painful red eye are severe anterior uveitis and a deep corneal abscess or melting ulcer. However, uveitis typically presents with a constricted (miotic) pupil, and an ulcer would be visible with a fluorescein stain.

Diagnostic tests: This is a true ophthalmic emergency, and diagnosis must be confirmed immediately.

Intraocular Pressure (IOP) measurement (Tonometry): This is the definitive diagnostic test. The pressure in both eyes was measured with a rebound tonometer (TonoVet/Tono-Pen).
- Result OD (affected eye): 68 mmHg [Ref: 15-25 mmHg]
- Result OS (normal eye): 22 mmHg
- The extremely high IOP in the right eye confirms acute glaucoma.
Fluorescein stain: A stain was applied to the right eye to rule out a concurrent corneal ulcer before starting aggressive topical therapy. The test was negative.

Definitive diagnosis: Primary Acute Congestive Glaucoma. Given the breed (Cocker Spaniel) and the normal appearance of the other eye, a primary (inherited) cause is most likely.

Treatment: The goal is to rapidly reduce the IOP to save the optic nerve and preserve vision. Treatment must be aggressive and immediate. 🚑

Emergency Medical Treatment:
- An IV catheter was placed and a slow IV infusion of Mannitol (an osmotic diuretic) was started to rapidly draw fluid out of the eye.
- A combination of topical medications was started in the right eye:
  - Latanoprost: A prostaglandin analog to increase uveoscleral outflow. One drop was given immediately. (Note: This is contraindicated if glaucoma is secondary to uveitis).
  - Dorzolamide-Timolol combination: A carbonic anhydrase inhibitor and a beta-blocker to decrease aqueous humor production. One drop was given, to be continued every 8 hours.
- The IOP was rechecked every 30-60 minutes.
Long-term and Prophylactic Treatment:
- Once the IOP in the right eye was reduced to < 25 mmHg, the dog was started on a long-term topical medication plan (e.g., Dorzolamide-Timolol) to maintain normal pressure.
- Prophylactic therapy (e.g., a single daily drop of a beta-blocker like Timolol) was started in the left ("good") eye, as primary glaucoma almost always becomes bilateral.
- The owner was informed that medical therapy often fails over time and that the gold standard for long-term control is referral to a veterinary ophthalmologist for surgical options (e.g., laser cyclophotocoagulation or a gonioimplant).

Case 29

A 6-year-old female spayed Cocker Spaniel is brought in for an emergency visit. The owner reports that the dog woke up this morning with a very red, cloudy right eye (OD). The dog is keeping the eye shut, is refusing to eat, and seems lethargic and painful. The owner does not know of any trauma. The left eye (OS) appears normal.

Physical Exam:

T: 102.6°F
P: 130 bpm
R: Panting
MM: pink/moist
CRT <2 sec

The dog is visibly depressed and in pain, resenting any handling of her head. The ophthalmic exam of the right eye (OD) reveals severe blepharospasm. When the eyelids are opened, there is marked episcleral injection (intense redness of the "white" of the eye) and diffuse, steamy-looking corneal edema. The pupil is mydriatic (dilated) and unresponsive to a bright light source. A menace response is absent in the right eye. The left eye (OS) appears normal on gross examination.

CBC and Biochemistry:

All values are within the reference range.

Urinalysis:

Not performed at presentation.

What will be your tentative and differential diagnosis? What further diagnostic test(s) you will perform to confirm your diagnosis? What will be your treatment plan(s)?

Solution to Case 29 will be posted on Aug 29

Solution for Case 28

(Click here to See Case 28)

Diagnosis: Tentative diagnosis is unilateral anterior uveitis based on the classic ophthalmic exam findings of a painful, red, cloudy eye with miosis and aqueous flare. The systemic signs (fever, lethargy) and lab abnormalities (thrombocytopenia, hyperglobulinemia) strongly suggest an underlying systemic, likely infectious, cause.

DDx:

For the red eye: The primary differentials include glaucoma and a deep corneal ulcer with reflex uveitis.
For the underlying cause of uveitis: Given the signalment and history (hunting dog, rural area) and the finding of thrombocytopenia, tick-borne infectious diseases (e.g., Ehrlichia canis, Rocky Mountain Spotted Fever) are high on the list. Other considerations include systemic fungal infections (e.g., Blastomycosis), protozoal infections, neoplasia (e.g., lymphoma), and immune-mediated disease.

Diagnostic tests:

Ophthalmic diagnostics:
- Intraocular Pressure (IOP) measurement (Tonometry): To differentiate from glaucoma. Uveitis typically causes a low IOP. Result in this case: OS = 8 mmHg, OD = 17 mmHg [Ref: 15-25 mmHg]. This low pressure in the affected eye supports the diagnosis of uveitis.
- Fluorescein stain: To rule out a corneal ulcer before starting topical steroids. The stain was negative in this case.
Systemic diagnostics:
- Infectious Disease Panel: A blood sample was submitted for a 4Dx Plus SNAP test and tick-borne disease PCR panel. The 4Dx test was positive for Ehrlichia canis antigen.
- Thoracic Radiographs: Three-view chest x-rays were performed to screen for fungal disease or metastatic neoplasia, which were unremarkable.

Definitive diagnosis: Anterior uveitis secondary to systemic Ehrlichia canis infection.

Treatment: The treatment plan is twofold: control the ocular inflammation to preserve vision and treat the underlying systemic infection.

Ocular Treatment:
- Topical anti-inflammatory: Prednisolone acetate 1% ophthalmic suspension, 1 drop in the left eye every 6 hours to control the inflammation.
- Topical mydriatic/cycloplegic: Atropine 1% ophthalmic ointment, a small strip applied to the left eye every 12 hours. This dilates the pupil to relieve the pain from ciliary muscle spasms and to prevent the iris from scarring down to the lens (posterior synechiae).
Systemic Treatment:
- Antibiotic: The dog was started on Doxycycline at 10 mg/kg orally once daily for 28 days to treat the Ehrlichia infection.
- Systemic anti-inflammatory: A short, anti-inflammatory course of a systemic NSAID (e.g., Carprofen) was considered for the fever and discomfort but held in reserve to monitor initial response.

Monitoring: The patient will be re-evaluated in 3-5 days to check the intraocular pressure and assess the response of the uveitis to topical therapy. The atropine frequency will be reduced as the pupil remains dilated, and the prednisolone will be tapered slowly over several weeks based on clinical response. The dog's platelet count and clinical signs will be monitored for response to the doxycycline.

Case 28

A 5-year-old intact male German Shorthaired Pointer is presented with a 3-day history of squinting his left eye (OS). The owner reports the eye appears red and hazy, and the dog is less active than usual with a decreased appetite. He is an active hunting dog, is up to date on vaccinations, and spends a lot of time in a wooded, rural area. The owner has not noticed any trauma to the eye.

Physical Exam:

T: 103.4°F
P: 90 bpm
R: 24 bpm
MM: pink/moist
CRT <2 sec

The general physical exam reveals mild lethargy and a low-grade fever. On ophthalmic exam, the left eye (OS) shows marked blepharospasm, moderate conjunctival and episcleral hyperemia (a "red eye"), and diffuse corneal edema (a "hazy" or "cloudy" appearance). The pupil is constricted (miosis) and responds poorly to light. Using a transilluminator in a dark room, a faint "flare" is visible in the anterior chamber, indicating increased protein. The right eye (OD) appears normal.

CBC and Biochemistry:

CBC: Mild thrombocytopenia (Platelets: 120 K/uL [Ref: 175-500 K/uL])
Biochemistry: Mild hyperglobulinemia (Globulins: 4.5 g/dL [Ref: 2.5-4.5 g/dL]). All other values are within reference range.

Urinalysis:

All values within reference range.

What will be your tentative and differential diagnosis? What further diagnostic test(s) you will perform to confirm your diagnosis? What will be your treatment plan(s)?

Solution for Case 28 will be posted on Aug 22

Solution for Case 27

(Click here to see Case 27)

Diagnosis: Tentative diagnosis is Diabetes Mellitus based on the hallmark clinical signs of polyuria, polydipsia, polyphagia, and weight loss, in conjunction with significant hyperglycemia and glucosuria.

DDx: The primary differential diagnoses for significant PU/PD in a dog include Hyperadrenocorticism (Cushing's Disease) and Chronic Kidney Disease (CKD). However, the profound hyperglycemia and glucosuria make Diabetes Mellitus the leading diagnosis.

Diagnostic tests:

The combination of persistent fasting hyperglycemia (blood glucose > 250 mg/dL) and glucosuria is diagnostic for Diabetes Mellitus in dogs. Stress hyperglycemia in dogs rarely exceeds 200 mg/dL, so the value of 485 mg/dL is definitive.
A fructosamine level could be measured to confirm sustained hyperglycemia over the previous 2-3 weeks, but it is not strictly necessary for diagnosis in this case given the classic signs and degree of hyperglycemia.
The presence of trace to small ketones in the urine indicates the body is breaking down fat for energy and warns of the potential to progress to Diabetic Ketoacidosis (DKA), a medical emergency. Since this patient is still eating and appears bright, she is classified as having uncomplicated diabetes.

Definitive diagnosis: Diabetes Mellitus with secondary diabetic cataracts.

Treatment: The goals of treatment are to eliminate the clinical signs, prevent complications like DKA and hypoglycemia, and provide a good quality of life.

Insulin Therapy: This patient was started on an intermediate-acting insulin. A common starting choice is a porcine lente insulin (Vetsulin®) or NPH insulin (Humulin-N®, Novolin-N®) at a dose of 0.25 - 0.5 Units/kg every 12 hours. The injections are given subcutaneously immediately following a meal.
Dietary Management: The dog will be transitioned to a prescription therapeutic diet formulated for diabetic dogs, which is typically high in fiber and complex carbohydrates. The owner was instructed to feed two equal-sized meals every 12 hours, just prior to each insulin injection. No other treats or food should be given to ensure consistent glucose absorption.
Client Education & Monitoring: This is a critical component of management. The owner was taught how to handle and administer insulin and educated on the signs of hypoglycemia (weakness, lethargy, stumbling, seizures). The plan is to have the dog return in 7-10 days to perform a blood glucose curve, where blood glucose is measured every 2 hours for 12 hours to assess the insulin's effectiveness and duration. The dose will be adjusted based on the curve results and the resolution of clinical signs.
Cataracts: The owner was informed that the cataracts are a direct and common result of diabetes in dogs and are unlikely to resolve. Once the dog's diabetes is well-regulated, she can be referred to a veterinary ophthalmologist to discuss surgical cataract removal to restore vision.

Case 27

A 7-year-old female spayed Beagle mix is presented for a 3-week history of drinking and urinating excessively (polyuria/polydipsia). The owner reports the dog has an excellent appetite but has lost a noticeable amount of weight. Over the last few days, the owner thinks the dog’s eyes have developed a "cloudy" appearance and she has been bumping into furniture. The dog is up to date on vaccinations and preventatives.

Physical Exam:

T: 101.9°F
P: 110 bpm
R: 28 bpm
MM: pink/moist
CRT <2 sec

The dog is bright and alert but has a slightly thin body condition (BCS 4/9). The remainder of the physical exam is unremarkable except for the ocular exam, which reveals bilateral, symmetrical, dense opacities within the lenses consistent with mature cataracts.

CBC and Biochemistry:

CBC: All values within reference range.
Biochemistry:
- Glucose: 485 mg/dL [Ref: 75-125 mg/dL]
- Alanine Aminotransferase (ALT): 180 U/L [Ref: 10-125 U/L]
- Alkaline Phosphatase (ALP): 350 U/L [Ref: 23-212 U/L]
- All other values are within reference range.

Urinalysis: (performed on a free-catch sample)

Color: Clear
pH: 6.0
SG (refractometer): 1.012 [Ref: >1.025]
Protein (dipstick): Trace
Glucose (dipstick): 4+ (>1000 mg/dL) [Ref: Negative]
Ketones (dipstick): 1+ (Small) [Ref: Negative]
Sediment exam: Unremarkable

What will be your tentative and differential diagnosis? What further diagnostic test(s) you will perform to confirm your diagnosis? What will be your treatment plan(s)?

Solution for Case 27

Solution for Case 26

(Click here to see Case 26)

Diagnosis: Tentative diagnosis is feline hyperthyroidism based on the classic signalment (older cat) and clinical signs (weight loss, polyphagia, PU/PD, tachycardia, palpable thyroid nodule).

DDx: The main differential diagnoses for a cat with weight loss and PU/PD include Chronic Kidney Disease (CKD) and Diabetes Mellitus. Gastrointestinal disease (e.g., Inflammatory Bowel Disease, GI lymphoma) could also cause weight loss, but less commonly causes significant PU/PD.

Diagnostic tests:

Total Thyroxine (T4) Concentration: A single blood sample was submitted for a total T4 measurement.
- Result: 9.8 µg/dL [Reference Range: 0.8–4.0 µg/dL]
This significantly elevated T4 level is diagnostic for hyperthyroidism.
Blood Pressure Measurement: Given the tachycardia and heart murmur, blood pressure was measured using a Doppler.
- Result: 175 mmHg systolic [Reference: <160 mmHg]
- This result confirms systemic hypertension, a common complication of hyperthyroidism.

Definitive diagnosis: Feline Hyperthyroidism with secondary systemic hypertension.

Treatment: There are four main treatment options for feline hyperthyroidism: medical management, radioactive iodine therapy, therapeutic diet, and surgical thyroidectomy.

This patient was started on medical management to stabilize her condition. She was prescribed Methimazole 2.5 mg orally twice daily. Methimazole works by blocking the synthesis of thyroid hormones in the thyroid gland. The owner was warned to watch for potential side effects, including facial excoriations, vomiting, or lethargy.
For the systemic hypertension, the cat was also started on Amlodipine 0.625 mg orally once daily.
Monitoring Plan: The patient will be re-evaluated in 2 weeks. The recheck appointment will include a physical exam, blood pressure measurement, and a blood draw to check her Total T4, creatinine, and BUN. The creatinine and BUN are monitored closely because treating hyperthyroidism can "unmask" underlying kidney disease by decreasing the glomerular filtration rate ( $GFR$ ). Once a stable dose of methimazole is achieved (T4 in the low-normal range), she will be monitored every 3-6 months. The owner was also educated on the benefits of radioactive iodine (I-131) therapy as a potential cure once the cat is stable.

Case 26

An 11-year-old spayed female Domestic Shorthair cat was presented to the clinic with a 2-month history of progressive weight loss despite a ravenous appetite (polyphagia). The owner also reports increased thirst and urination (polyuria/polydipsia) and occasional vomiting for the past few weeks. The cat has become more vocal and restless, especially at night. She is an indoor-only cat and is current on all preventative care.

Physical Exam:

T: 102.9°F
P: 230 bpm
R: 40 bpm
MM: pink/moist
CRT <2 sec

The cat is thin with a body condition score of 3/9 and has palpable muscle wasting over the spine and hips. The hair coat is unkempt and mildly greasy. Cardiac auscultation reveals a tachycardia with a Grade II/VI systolic heart murmur. Careful palpation of the ventral neck reveals a small, firm, movable nodule on the right side, consistent with a "thyroid slip".

CBC and Biochemistry:

CBC: Mild erythrocytosis (PCV 48% [Ref: 29-45%])
Biochemistry: Alanine Aminotransferase (ALT): 155 U/L [Ref: 12-130 U/L]. All other values are within reference range.

Urinalysis:

Color: Pale yellow
pH: 7.0
SG (refractometer): 1.020 [Ref: >1.035]
Protein (dipstick): Trace
Blood (Dipstick): Negative
Sediment exam: Unremarkable

What will be your tentative and differential diagnosis? What further diagnostic test(s) you will perform to confirm your diagnosis? What will be your treatment plan(s)?