Respiratory system random quiz — Veterinaria Madrid

Question 1/10

6-year-old German Shepherd from Andalusia, frequently infested with ticks, presenting with bilateral epistaxis, petechiae on the oral mucosa and lethargy. Platelets 35,000/µL, hyperglobulinaemia and negative Leishmania serology; Ehrlichia canis serology positive.

What is the treatment of choice?

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A. Immunosuppressive glucocorticoids alone for immune-mediated thrombocytopenia

Platelet destruction has an immune-mediated component, but without treating the infection the disease is not controlled; glucocorticoids alone may make it worse.

B. Rhinoscopy with biopsy to rule out a nasal tumour

With 35,000 platelets/µL, nasal biopsy carries a high risk of severe bleeding, and the systemic cause has already been identified.

C. Oral doxycycline for about 4 weeks, monitoring the platelet count

Correct. Doxycycline is the treatment of choice for canine monocytic ehrlichiosis. In the acute phase, platelets usually recover within a few days, which supports the diagnosis.

D. Meglumine antimoniate and allopurinol

This is the treatment for leishmaniosis, which is seronegative in this dog; it has no effect on Ehrlichia.

lightbulb Key takeaway

In Spain, with epistaxis and thrombocytopenia, think of ehrlichiosis and leishmaniosis, which may coexist. Positive serology may reflect past exposure: interpret the titre together with the clinical picture and the response to doxycycline, and reinforce tick prevention.

Question 2/10

8-year-old crossbreed dog with a one-week history of cough and tachypnoea. It has both inspiratory and expiratory effort, no heart murmur, and inspiratory crackles are heard over both hemithoraces.

What do these crackles most likely indicate?

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A. An upper airway obstruction

The upper airway produces stertor or stridor audible at a distance, mainly inspiratory; crackles are adventitious sounds of intrathoracic origin.

B. Disease of the pulmonary parenchyma or small airways (pneumonia, oedema, fibrosis, haemorrhage)

Correct. Crackles are caused by the sudden opening of collapsed small airways or by fluid within them, and they localise disease to the parenchyma; they do not indicate its cause.

C. Pleural effusion

Pleural effusion muffles lung and heart sounds in the dependent area; it does not generate crackles.

D. Cardiogenic pulmonary oedema, so furosemide should be given

Crackles are not specific to oedema; without a murmur or cardiomegaly, pneumonia or another parenchymal disease is more likely, and a blind diuretic can do harm.

lightbulb Key takeaway

Crackles localise but do not diagnose: confirm with thoracic radiographs and, where indicated, bronchoalveolar lavage. Dry, velcro-like crackles in an older West Highland White Terrier suggest idiopathic pulmonary fibrosis.

Question 3/10

10-year-old domestic shorthair, FeLV and FIV negative, with unilateral nasal discharge that became bilateral over 2 months, stertor and mild deformity over the bridge of the nose. CT shows a nasal mass and biopsy confirms large cell lymphoma.

Which statement is correct?

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A. It is the most common nasal tumour in cats; after staging, if it is localised, radiotherapy often achieves good responses and prolonged survival

Correct. Nasal lymphoma is highly radiosensitive. Staging (bloodwork, lymph nodes, thorax and abdomen, and sometimes bone marrow) determines whether local treatment is enough or systemic chemotherapy should be added.

B. The most common nasal tumour in cats is adenocarcinoma, and nasal lymphoma is usually a form of multicentric lymphoma

In cats, lymphoma is the most common nasal tumour and is often localised to the nose at diagnosis.

C. Surgery with wide margins is the treatment of choice

The nasal cavity does not allow surgical margins, and lymphoma responds well to radiotherapy and chemotherapy, so surgery has no therapeutic role.

D. Without a positive FeLV test, the lymphoma diagnosis is unreliable and the biopsy should be repeated

Most feline nasal lymphomas today occur in FeLV-negative cats; histology is what confirms the diagnosis.

lightbulb Key takeaway

In older cats with chronic nasal discharge, stertor or facial deformity, think of nasal lymphoma. It can spread to the central nervous system or other organs, so follow-up after radiotherapy is important.

Question 4/10

12-year-old Labrador Retriever with inspiratory stridor that worsens in hot weather, a hoarse bark for months and scuffing of the hind nails. The owners say it sometimes coughs when drinking.

Which statement about its disease is correct?

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A. It is an isolated idiopathic laryngeal paralysis; the hind-limb weakness is due to osteoarthritis

Most 'idiopathic' laryngeal paralyses in older dogs are the first manifestation of a generalised polyneuropathy; attributing the weakness to osteoarthritis overlooks its progression.

B. It is usually due to hypothyroidism, and levothyroxine supplementation resolves the paralysis

Hypothyroidism should be ruled out, but a causal link has not been shown and supplementation rarely reverses laryngeal paralysis.

C. It is acquired myasthenia gravis and should be treated with pyridostigmine

Myasthenia can cause laryngeal dysfunction and megaoesophagus, but presents with exercise-induced weakness and is confirmed by acetylcholine receptor antibodies. Here the slow, progressive picture suggests polyneuropathy.

D. It is part of a progressive geriatric polyneuropathy (GOLPP) that also affects the oesophagus and limbs, increasing the risk of aspiration

Correct. In GOLPP (geriatric onset laryngeal paralysis polyneuropathy) laryngeal paralysis is the first sign, followed by hind-limb weakness and oesophageal dysmotility. Dysphagia and coughing when drinking warn of a higher risk of aspiration pneumonia after lateralisation.

lightbulb Key takeaway

Before operating on laryngeal paralysis, look for signs of polyneuropathy and oesophageal dysfunction (neurological exam, history of regurgitation, thoracic radiographs). They do not contraindicate surgery, but they worsen the long-term prognosis and must be explained to owners.

Question 5/10

3-year-old Brittany Spaniel that, after a walk through a cereal field in May, starts violent paroxysmal sneezing, paws at its muzzle and has a drop of blood at the right nostril.

What is the most appropriate course of action?

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A. Antibiotic and antihistamine for a week and reassess

They do not remove the awn and delay diagnosis; acute signs may subside and leave a chronic unilateral rhinitis that is difficult to resolve.

B. Skull radiographs to confirm the awn before anaesthesia

Grass awns are plant material and not radiopaque; normal radiographs do not rule them out and only delay rhinoscopy.

C. Vigorous nasal flushing in the conscious dog to expel it

It is poorly tolerated, ineffective against a barbed awn anchored in the mucosa, and may push it further caudally.

D. Rhinoscopy under general anaesthesia as soon as possible to locate and remove the foreign body

Correct. Sudden-onset paroxysmal sneezing with pawing at the muzzle after a walk among grasses is highly suggestive of a grass awn. The sooner it is sought, the easier it is to find before it migrates towards the nasopharynx or becomes surrounded by discharge.

lightbulb Key takeaway

If it is not found rostrally, also examine the nasopharynx with a flexible endoscope in retroflexion. After removal, check the other nasal cavity and warn the owner that there may be more than one awn.

Question 6/10

3-year-old intact male cat with outdoor access, presenting with dyspnoea, fever and anorexia. Thoracocentesis yields a turbid, foul-smelling fluid with abundant degenerate neutrophils and mixed intra- and extracellular bacteria.

What is the most appropriate initial treatment?

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A. Oral amoxicillin-clavulanate for 2 weeks and recheck, without drainage

Pus in the pleural cavity is a closed abscess: without evacuating it, the antibiotic penetrates poorly and the cat remains dyspnoeic and septic.

B. Immediate exploratory thoracotomy in every cat with pyothorax

In cats most respond to medical treatment with drainage; surgery is reserved for identifiable foci (lung abscess, foreign body), loculated effusion or lack of response.

C. Corticosteroids to reduce pleural inflammation and thoracocentesis if it worsens

Corticosteroids are contraindicated in an active bacterial infection and do not replace draining the pus.

D. Chest drains (often bilateral), pleural lavage with warm saline and intravenous antibiotics covering anaerobes and Pasteurella

Correct. In cats pyothorax is usually due to bite wounds, with mixed oral flora: Pasteurella and obligate anaerobes. Draining and lavaging removes pus and fibrin; an intravenous beta-lactam with a beta-lactamase inhibitor is a good basis, widening gram-negative cover if culture or severity requires it.

lightbulb Key takeaway

Always send fluid for aerobic and anaerobic culture before starting antibiotics, and adjust afterwards. Total antibiotic treatment usually lasts several weeks. Watch for sepsis: hypoglycaemia, hypothermia, bradycardia and effusion in other cavities worsen the prognosis.

References: ISCAID: guías de uso de antimicrobianos en enfermedad respiratoria del perro y el gato (2017)

Question 7/10

10-year-old Labrador with recurrent pleural effusion. Thoracoscopy with biopsy confirms a diffuse, non-resectable mesothelioma. It needs thoracocentesis every 5–7 days and the owners want palliation.

Which palliative option is most appropriate?

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A. Indwelling pleural catheter with a subcutaneous port for drainage at home or in the clinic, considering intracavitary chemotherapy

Correct. A pleural port allows drainage with little handling and without repeated sedation, and can be used to give intracavitary chemotherapy (for example, carboplatin), which may slow effusion in mesothelioma and carcinomatosis.

B. Talc pleurodesis, which achieves pleural symphysis in most dogs

In dogs and cats pleurodesis gives inconsistent results: their pleura seems to fuse less readily than human pleura. It can be tried, but it is not the most reliable option.

C. High-dose furosemide to reduce pleural fluid production

Neoplastic effusion results from increased permeability and lymphatic obstruction, not volume overload; the diuretic dehydrates without controlling it.

D. A conventional chest drain kept indefinitely in hospital

A long-term external drain carries a high risk of infection, disconnection and protein loss, and requires hospitalisation; implanted devices are better for long-term management.

lightbulb Key takeaway

Fluid cytology rarely distinguishes mesothelioma from reactive mesothelial hyperplasia: biopsy by thoracoscopy or thoracotomy is usually needed. In carcinomatosis look for a primary (lung, mammary). Avoid intracavitary cisplatin in cats because of its pulmonary toxicity.

Question 8/10

10-year-old cat with a haematocrit of 13% and pleural effusion. It is dyspnoeic, with pale but not cyanotic mucous membranes. PaO2 on room air is 52 mmHg.

Why does this cat not show cyanosis despite severe hypoxaemia?

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A. Because anaemia increases 2,3-DPG, which makes cyanosis appear earlier, not later

Increased 2,3-DPG favours oxygen unloading to tissues but does not bring cyanosis forward; its visibility depends on the absolute amount of deoxygenated haemoglobin.

B. Because the absence of cyanosis indicates adequate tissue oxygenation

Absence of cyanosis does not rule out hypoxaemia or tissue hypoxia; this cat has a PaO2 of 52 mmHg and a very low oxygen content due to anaemia.

C. Because cyanosis appears as soon as SpO2 falls below 95%

Cyanosis is a late sign: it usually requires severe hypoxaemia (PaO2 around 50 mmHg or less, SpO2 roughly 80–85%) even with a normal haematocrit.

D. Because cyanosis requires about 5 g/dL of deoxygenated haemoglobin in the capillaries, an amount hard to reach with severe anaemia

Correct. With so little total haemoglobin, even severe hypoxaemia does not produce enough deoxygenated haemoglobin to show a bluish colour. Polycythaemia, by contrast, makes cyanosis easier to see.

lightbulb Key takeaway

Cyanosis is a late and serious sign: if you see it, give oxygen immediately. Chocolate-brown mucous membranes in a cat suggest methaemoglobinaemia (for example, paracetamol poisoning), which oxygen alone does not correct.

Question 9/10

Which description of the thoracocentesis technique is correct?

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A. 7th–8th intercostal space, next to the cranial border of the rib, with a butterfly needle or catheter connected to an extension set and three-way tap, and on both sides if needed

Correct. The intercostal vessels and nerves run along the caudal border of each rib, so you enter along the cranial border. The three-way tap lets you empty the syringe without losing suction or letting air in, and the mediastinum may not connect both sides, especially if inflamed.

B. 7th–8th intercostal space, next to the caudal border of the rib, to avoid damaging the visceral pleura

The caudal border of the rib is exactly where the intercostal artery, vein and nerve lie: puncturing there increases the risk of haemorrhage and pain.

C. 4th–5th intercostal space, to reach the area of greatest fluid accumulation

The cranial spaces are close to the heart and great vessels, and fluid is distributed throughout the thorax; the 7th–8th space is the safest and most productive.

D. One hemithorax is enough, because the mediastinum of dogs and cats always connects both sides

The mediastinum is fenestrated but often incomplete or sealed (pyothorax, chylothorax, chronic effusions). If you do not drain both sides you may leave a large amount of fluid or air.

lightbulb Key takeaway

For fluid, puncture the ventral third; for air, the dorsal third (sternal recumbency is usually safest). Use ultrasound to choose the site, and once in the pleural space angle the needle parallel to the thoracic wall. Keep samples in EDTA, plain and culture tubes.

Question 10/10

4-year-old Golden Retriever with right-sided mucopurulent and haemorrhagic nasal discharge for 6 weeks, sneezing and pain on facial palpation. The rim of the right nostril is depigmented and ulcerated.

What is the most likely diagnosis?

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A. Discoid lupus erythematosus

It depigments the nasal planum but does not cause unilateral mucopurulent nasal discharge or facial pain.

B. Sinonasal aspergillosis

Correct. This is the typical presentation: a young or middle-aged dolichocephalic or mesocephalic dog, unilateral discharge, nasal pain and depigmentation or ulceration of the nostril caused by fungal toxins. It causes destructive rhinitis with turbinate lysis and fungal plaques.

C. Lymphoplasmacytic rhinitis

It is usually bilateral, does not cause marked turbinate destruction and does not produce severe pain or nostril depigmentation.

D. Nasal adenocarcinoma

It is an important differential, but it occurs mostly in older dogs, and nostril depigmentation with pain points more towards aspergillosis.

lightbulb Key takeaway

Diagnosis combines CT (turbinate lysis, cavitation, bone thickening, frontal sinus involvement) with visualisation of fungal plaques at rhinoscopy, plus cytology, histology or culture. Serology or culture alone is not enough, because Aspergillus can be found in healthy noses.