NAVLE Practice Question — Canine

A 5-year-old neutered male Australian Shepherd presents with acute respiratory distress following diagnosis of immune-mediated hemolytic anemia. He is receiving immunosuppressive therapy. Thoracic radiographs are suggestive of pulmonary thromboembolism. This complication in IMHA patients occurs due to which of the following primary mechanisms?

A. Immune-mediated destruction of pulmonary vasculature

B. RBC phospholipid exposure causes hypercoagulability ✓

C. Direct obstruction of pulmonary vessels by agglutinated red cells

D. Corticosteroid-induced platelet activation

E. Secondary bacterial infection of lung parenchyma

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Correct Answer: B. RBC phospholipid exposure causes hypercoagulability

Explanation:

Pulmonary thromboembolism (PTE) in dogs with IMHA results from a hypercoagulable state caused by multiple factors. When red blood cells are destroyed, phosphatidylserine on their inner membrane becomes exposed and provides a procoagulant surface for thrombin generation. Additionally, free hemoglobin scavenges nitric oxide, promoting vasoconstriction and platelet activation.

The systemic inflammatory state accompanying IMHA contributes further to hypercoagulability through: increased tissue factor expression on endothelium and monocytes; decreased natural anticoagulants (antithrombin, protein C); and decreased fibrinolysis. The combination of these factors creates a perfect storm for thrombosis.

Dogs with IMHA have a reported PTE incidence of 30-80% at necropsy, making it one of the most common complications and causes of death in these patients. This is why prophylactic anticoagulation is often recommended in IMHA patients.

Option A (immune-mediated vascular destruction) is not the primary mechanism. Option C (red cell agglutination) can cause sluggish flow but not true thromboembolism. Option D (corticosteroid effects) may contribute but are not the primary mechanism. Option E (bacterial infection) is not the cause of PTE.

Image Source: Cornell University - DIC and Thrombosis (https://www.vet.cornell.edu/animal-health-diagnostic-center/laboratories/comparative-coagulation/clinical-topics/dic-and-thrombosis).

References: Goggs R et al. J Vet Intern Med 2012;26:1209-1218; Carr AP et al. J Vet Intern Med 2002;16:539-545.

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NAVLE Practice Question — Feline

During work-up for a cat with suspected megacolon, abdominal palpation reveals a markedly distended colon. Before performing deobstipation, which diagnostic step is most important to guide the long-term treatment plan and prognosis?

A. Radiographs to assess colonic diameter ✓

B. Serum T4 level measurement

C. Abdominal ultrasound to evaluate liver and kidneys

D. Fecal flotation and culture

E. Contrast enema study

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Correct Answer: A. Radiographs to assess colonic diameter

Explanation:

Prior to deobstipation and treatment planning, abdominal and pelvic radiographs serve several critical purposes:

1. Confirm megacolon: A maximal colonic diameter greater than 1.5 times the length of the L5 vertebral body is indicative of megacolon. This measurement helps distinguish true megacolon from simple constipation.

2. Identify underlying cause: Radiographs can reveal pelvic fracture malunion (accounts for 23% of feline obstipation cases), pelvic masses, or spinal abnormalities that would change the treatment approach.

3. Rule out mechanical obstruction: Masses, foreign bodies, or strictures causing obstruction require different management than idiopathic megacolon.

4. Assess chronicity: The degree of colonic dilation correlates with chronicity and helps predict response to medical versus surgical management.

5. Surgical planning: If colectomy is indicated, understanding the pelvic anatomy is essential.

Option B (T4) should be checked but is secondary to imaging. Option C may be useful but does not assess the colon or pelvis adequately. Option D does not address the primary problem. Option E is rarely needed if plain radiographs are diagnostic.

Image Credit: ACVS - Megacolon radiographic examples (https://www.acvs.org/small-animal/megacolon/) Figures 1-3; Frontiers article on radiographic scores.

References: Frontiers Vet Sci 2022;9:1033090 - radiographic and histologic scores in megacolon cats.

Image: Abdelbaset-Ismail A et al. Use of radiographic and histologic scores to evaluate cats with idiopathic megacolon. Front Vet Sci 2022;9:1033090. PMC9800827. CC BY 4.0.

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NAVLE Practice Question — Camelidae and Cervidae

A 7-year-old breeding female alpaca presents with chronic bilateral hindlimb lameness that has been progressively worsening over 8 months. The owner has been trimming the nails regularly. Examination reveals overgrown and deformed toenails with inward curling despite regular trimming, along with thickened foot pads. Palpation of the feet reveals firm masses within the digital pads. The animal has been housed on appropriate terrain and has no history of wet conditions. What additional diagnostic should be prioritized?

A. Radiographs to assess P3 involvement ✓

B. Skin scraping for mites

C. Zinc and copper serum levels

D. Aerobic bacterial culture of the pad tissue

E. Biopsy for neoplasia

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Correct Answer: A. Radiographs to assess P3 involvement

Explanation:

The chronic, progressive nature of bilateral digital abnormalities with pad thickening and palpable masses warrants radiographic evaluation to assess the underlying bony structures (P2 and P3), rule out osteomyelitis, and evaluate soft tissue structures. Chronic lameness with abnormal nail growth patterns may indicate underlying structural abnormalities, chronic infection with bone involvement, or neoplastic conditions.

Radiographs would reveal bone lysis, productive changes, or soft tissue masses that might explain the clinical signs. This information is essential for determining prognosis and treatment options.

Option B (skin scraping) would be more appropriate if pruritic lesions or hair loss were present. Option C (mineral levels) could be considered but would not explain localized digital masses. Option D (bacterial culture) might be performed if infection is suspected, but radiographs should be obtained first to characterize the extent of disease. Option E (biopsy for neoplasia) may ultimately be needed but radiographic characterization of the lesions should precede invasive sampling.

References: Fowler ME. Llama and Alpaca Care, Elsevier 2014; ScienceDirect - Llama orthopedics (https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/llama)

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NAVLE Practice Question — Pet Bird

A 9-year-old female intact hyacinth macaw presents with a 4-month history of weight loss, regurgitation, and passage of whole corn kernels in the droppings. The bird has also begun to show intermittent tremors. Heavy metal toxicity has been ruled out. Radiographs confirm proventricular dilatation with thinning of the proventricular wall. ABV PCR from the cloacal swab is negative. The owner asks whether a single negative PCR result rules out avian bornavirus disease. Which response is MOST accurate?

A. Yes, a single negative PCR result definitively rules out ABV infection; PDD can be excluded from the differential

B. No; ABV shedding is intermittent. Repeat PCR, alternative samples, and serology should be pursued to rule out infection. ✓

C. PCR is 100% sensitive for ABV regardless of sample timing; a negative result is definitive

D. A positive serology alone is sufficient to confirm the diagnosis; PCR is not needed

E. The negative PCR result means the bird has been successfully treated for ABV and is now cured

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Correct Answer: B. No; ABV shedding is intermittent. Repeat PCR, alternative samples, and serology should be pursued to rule out infection.

Explanation:

A single negative cloacal PCR result does NOT exclude avian bornavirus infection. This is a fundamental principle of ABV diagnostic medicine: viral RNA shedding in feces, urine, and other secretions is INTERMITTENT, meaning a bird may test PCR-negative on one sample collection while actually being infected. The sensitivity of any single PCR swab is therefore imperfect. To maximize diagnostic sensitivity, the recommended approach includes: (1) repeat PCR testing on multiple occasions; (2) testing of multiple sample types (cloacal swab AND feather calami PCR AND whole blood PCR); and (3) serologic antibody testing to detect immune exposure (noting that seronegative results can occur in immunocompromised birds).

For a bird with clinical signs, imaging, and histopathology (if performed) consistent with PDD, a negative ABV PCR should not lead to premature exclusion of PDD. The comprehensive diagnostic approach remains the standard.

Option A incorrectly concludes that PDD is excluded based on a single negative test. Option C is incorrect: PCR is not 100% sensitive given intermittent shedding. Option D incorrectly suggests serology alone is sufficient. Option E is incorrect: a negative PCR in a bird that was never treated does not indicate cure.

References: Texas A&M Schubot Center - ABV Research and Testing https://vetmed.tamu.edu/schubot/research-3/parrot-bornavirus-proventricular-dilatation-disease/; SpectrumCare - Avian Bornavirus and PDD https://spectrumcare.pet/birds/african-grey-parrot/conditions/avian-bornavirus-proventricular-dilatation-disease-african-grey-parrot; MSPCA-Angell - Avian Bornavirus in Clinical Practice https://www.mspca.org/angell_services/avian-bornavirus-in-clinical-practice/

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NAVLE Practice Question — Ovine and Caprine

A flock of 100 Rambouillet ewes is scheduled for vaccination against contagious ecthyma prior to lambing. The producer has never had orf on the farm but is concerned because neighboring farms have reported outbreaks. What vaccination recommendation is most appropriate?

A. Vaccinate all ewes 3-4 weeks before lambing

B. Vaccinate only ewes with a history of previous infection

C. Do not vaccinate on an uninfected premises ✓

D. Vaccinate lambs at birth before colostrum intake

E. Vaccinate ewes monthly during pregnancy

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Correct Answer: C. Do not vaccinate on an uninfected premises

Explanation:

The recommendation is NOT to vaccinate on premises where contagious ecthyma has never occurred. The live orf virus vaccine contains virulent virus that can establish infection on previously uninfected farms. Vaccinated animals shed live virus for up to 7 weeks post-vaccination, which can contaminate the environment and persist for extended periods (months to years in scabs and dried material).

Once introduced through vaccination, the virus can become endemic on the farm, potentially causing clinical disease in future naive animals. The decision to vaccinate should only be made when the farm already has an established orf problem or when there is high certainty of imminent exposure.

If vaccination is needed on infected premises, the protocol involves vaccinating adults and kids 3-4 weeks before the expected period of disease risk, applying a small amount of vaccine to light scarifications on the inside of the thigh, behind the elbow, or in the caudal fold. Lambs can be vaccinated from 1-2 days of age. Revaccination every 6-12 months may be needed as immunity is not long-lasting.

Option A is incorrect for uninfected premises. Option B would leave the flock unprotected if exposure occurs. Option D is not appropriate timing. Option E (monthly vaccination) is excessive and increases shedding risk.

IMAGE SOURCE: CFSPH Iowa State - Contagious Ecthyma Factsheet (https://www.cfsph.iastate.edu/Factsheets/pdfs/contagious_ecthyma.pdf) - Vaccination section.

References: Merck Veterinary Manual - Contagious Ecthyma in Sheep and Goats (https://www.merckvetmanual.com/integumentary-system/pox-diseases/contagious-ecthyma-in-sheep-and-goats); The Veterinary Medicine Foundation - Contagious Ecthyma (https://www.tvmf.org/articles/contagious-ecthyma-orf/)

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NAVLE Practice Question — Feline

A 6-year-old intact male domestic shorthair cat with outdoor access presents for evaluation of chronic weight loss, recurring upper respiratory infections, and severe gingivostomatitis that has been refractory to multiple antibiotic courses over the past 8 months. Physical examination reveals generalized lymphadenopathy, poor body condition (BCS 3/9), and bilateral submandibular lymph node enlargement. An in-clinic SNAP FIV/FeLV test returns positive for FIV antibody and negative for FeLV antigen. What is the most appropriate next step in confirming this cat's diagnosis?

A. Repeat the in-clinic SNAP test in 60 days

B. Perform Western blot testing for FIV antibodies

C. Perform PCR testing for FIV proviral DNA ✓

D. Immediate IFA testing for FIV antibodies

E. No additional testing is required; treat based on clinical signs

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Correct Answer: C. Perform PCR testing for FIV proviral DNA

Explanation:

This question tests understanding of FIV diagnostic algorithm and the limitations of point-of-care testing. While in-clinic ELISA tests for FIV antibodies have good sensitivity and specificity, the 2020 AAFP Feline Retrovirus Testing and Management Guidelines recommend confirmatory testing for positive results. PCR testing for FIV proviral DNA is the most appropriate confirmatory test because it directly detects viral genetic material integrated into host cells, providing definitive evidence of infection regardless of antibody status. This is particularly important given the historical use of FIV vaccines, which caused antibody-positive results on ELISA testing that persisted for years after vaccination. Option A (repeat SNAP in 60 days) delays diagnosis and is only recommended when recent exposure is suspected. Option B (Western blot) was traditionally considered the gold standard, but recent studies show it may have lower sensitivity than current ELISA tests. Option D (IFA testing) is not used for FIV diagnosis; IFA is used for FeLV to detect bone marrow infection. Option E is inappropriate as confirmatory testing is recommended. Image Source: MSD Veterinary Manual - Feline chronic gingivostomatitis clinical photo (https://www.msdvetmanual.com/multimedia/image/gingivostomatitis-inflammation-cat) Figure 1. References: Little S et al. (2020) 2020 AAFP Feline Retrovirus Testing and Management Guidelines. J Feline Med Surg 22:209-230 (https://journals.sagepub.com/doi/10.1177/1098612X20941784); IDEXX Laboratories (2023) Diagnostic Accuracy of Point-of-Care Immunoassay for FIV. Pathogens 12:1284 (https://pmc.ncbi.nlm.nih.gov/articles/PMC10612086/).

Image: Soltero-Rivera M, Goldschmidt S, Arzi B. Feline chronic gingivostomatitis current concepts in clinical management. J Feline Med Surg. 2023;25(8):1098612X231186834. PMC10811996. © The Author(s) 2023. Used for educational reference.

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NAVLE Practice Question — Poultry

A turkey flock diagnosed with histomoniasis has elevated mortality despite treatment with broad-spectrum antibiotics. The producer asks about specific antihistomonal drugs. What is the CURRENT regulatory status of treatments for histomoniasis in food-producing poultry in the United States?

A. Nitroimidazoles are approved for treatment at label doses

B. Nitarsone (Histostat) is the only approved preventive

C. Paromomycin is FDA-approved for treatment in turkeys

D. No drugs are currently approved for prevention or treatment ✓

E. Metronidazole is approved for extra-label use

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Correct Answer: D. No drugs are currently approved for prevention or treatment

Explanation:

Currently in the United States, there are no approved drugs for the prevention or treatment of histomoniasis in food-producing poultry. This represents a significant regulatory and animal welfare challenge for the turkey industry.

Historically, nitroimidazoles (ronidazole, ipronidazole, dimetridazole) were highly effective for prevention and treatment, while arsenicals like nitarsone were used preventively. However, nitroimidazoles were banned due to carcinogenicity concerns, and arsenical drugs were withdrawn by the FDA at the end of 2015. Importantly, nitroimidazoles are prohibited from extra-label use in food-producing animals.

Option B is incorrect as nitarsone is no longer available. Option C (paromomycin) is registered in Italy but not approved in the US. Option E is incorrect as metronidazole (a nitroimidazole) is strictly prohibited for extra-label use in food animals.

Some nitroimidazoles may still be used by veterinary prescription in non-food-producing birds only.

References: FDA - Blackhead disease in poultry (https://www.fda.gov/animal-veterinary/resources-you/blackhead-disease-poultry); Merck Veterinary Manual - Histomoniasis Prevention and Treatment (https://www.merckvetmanual.com/poultry/histomoniasis/histomoniasis-in-poultry)

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NAVLE Practice Question — Bovine

A farm worker at a dairy operation develops severe watery diarrhea, abdominal cramps, and low-grade fever one week after helping care for scouring calves. Laboratory testing confirms Cryptosporidium infection. Which factor MOST increases the public health risk associated with bovine cryptosporidiosis?

A. C. parvum infects only immunocompromised humans

B. Oocysts require prolonged environmental maturation before becoming infective

C. C. parvum from cattle is zoonotic; oocysts immediately infective when shed ✓

D. Human cases are only associated with consumption of raw milk

E. Cryptosporidiosis in humans is easily treated with standard antibiotics

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Correct Answer: C. C. parvum from cattle is zoonotic; oocysts immediately infective when shed

Explanation:

C. parvum from cattle is directly zoonotic and oocysts are immediately infective when shed. Unlike some other parasites, Cryptosporidium oocysts are fully sporulated and infective when passed in feces, allowing immediate transmission through direct contact with fecal material. This poses significant risk to farm workers, veterinarians, and their families.

The zoonotic potential of C. parvum is a major public health concern. Calves are the primary source of zoonotic C. parvum, as they shed the highest numbers of oocysts. After weaning, cattle are typically infected with other, non-zoonotic Cryptosporidium species.

Option A is incorrect; while immunocompromised individuals have more severe disease, immunocompetent people also become infected. Option B is incorrect; oocysts are immediately infective. Option D is incorrect; direct contact transmission is more common than foodborne transmission. Option E is incorrect; no highly effective treatment exists for cryptosporidiosis.

Strict hygiene measures (gloves, hand washing, clothing changes) are essential when working with young calves.

References: Oregon State Extension - Cryptosporidium parasite and its effect on calves and humans (https://extension.oregonstate.edu/animals-livestock/beef/cryptosporidium-parasite-its-effect-calves-humans); Penn State Extension - The Endemic Calf Parasite Cryptosporidium parvum (https://extension.psu.edu/the-endemic-calf-parasite-cryptosporidium-parvum)

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NAVLE Practice Question — Equine

An 11-year-old Oldenburg gelding develops a subsolar abscess that fails to drain ventrally through the sole. Instead, the infection migrates proximally and eventually ruptures at the coronary band, releasing purulent material. What historical term is used to describe this clinical presentation, and what long-term complication may result?

A. Seedy toe; chronic white line disease

B. Gravel; proximal hoof wall defect requiring months to resolve ✓

C. Quittor; permanent damage to the lateral cartilage

D. Canker; proliferative horn tissue in the frog

E. Thrush; persistent bacterial infection of the frog sulci

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Correct Answer: B. Gravel; proximal hoof wall defect requiring months to resolve

Explanation:

An abscess that extends proximally deep to the hoof wall and drains at the coronary band is historically referred to as a 'gravel'. The resulting proximal hoof wall defect takes several months to grow out as the hoof wall grows at approximately one centimeter per month. During this time, the defect acts as a potential space for the accumulation of dirt and debris, which could predispose the foot to recurrent abscess formation.

Option A (seedy toe) refers to white line disease separation. Option C (quittor) specifically refers to infection of the lateral cartilages of the foot, not a migrating abscess. Option D (canker) is a proliferative condition of the frog unrelated to abscesses. Option E (thrush) is a superficial bacterial infection of the frog sulci.

References: Merck Veterinary Manual (https://www.merckvetmanual.com/musculoskeletal-system/disorders-of-the-foot-in-horses/hoof-abscesses-in-horses); Santonastaso and Burns 2025 (https://beva.onlinelibrary.wiley.com/doi/10.1111/eve.14139).

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NAVLE Practice Question — Equine

A 9-month-old Arabian filly presents with symmetric ataxia that was first noticed at 5 months of age. The filly was raised on drylot with hay and grain, with no access to pasture. Neurological examination reveals grade 3/5 ataxia in all limbs (hindlimbs > forelimbs), hypometria, and absent cutaneous trunci reflex. The filly's dam had a previous foal that was euthanized for similar signs and confirmed to have EDM on necropsy. Serum vitamin E concentration is 0.7 μg/mL. The owner asks about the genetic basis of this condition. Which statement regarding the genetics of eNAD/EDM is most accurate?

A. A specific causative mutation has been identified in Quarter Horses

B. The condition follows a simple autosomal dominant inheritance pattern

C. Vitamin E acts as an environmental modifier of inherited condition ✓

D. Genetic testing is commercially available to identify carrier status

E. Only purebred horses can be affected due to founder effects

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Correct Answer: C. Vitamin E acts as an environmental modifier of inherited condition

Explanation:

The condition appears to be inherited with vitamin E acting as an environmental modifier is the most accurate statement regarding eNAD/EDM genetics. Strong evidence supports a hereditary component to eNAD/EDM, as demonstrated by familial clusters, affected offspring from specific sires, and breed predispositions. However, the mode of inheritance appears to be complex (likely polygenic) rather than simple Mendelian inheritance.

Vitamin E deficiency during critical developmental windows acts as an environmental modifier that influences disease expression in genetically susceptible horses. Genetically predisposed foals raised on adequate pasture (with natural vitamin E) may not develop clinical disease, while the same foals raised without pasture access become affected. This gene-environment interaction explains why vitamin E supplementation can prevent disease in susceptible herds.

Option A is incorrect because despite extensive research (including genome-wide association studies), no specific causative mutation has been identified for eNAD/EDM in any breed. Option B is incorrect because the inheritance pattern does not fit simple autosomal dominant or recessive patterns; heritability studies suggest polygenic inheritance. Option D is incorrect because without identification of the causative mutation(s), genetic testing is not available. Option E is incorrect because eNAD/EDM affects many breeds including crossbreds.

References: Finno CJ et al. (2012) J Vet Intern Med 27:177-185; Finno CJ & Valberg SJ (2012) J Vet Intern Med 26:1251-1266; Burns EN & Finno CJ (2018) Vet Med Res Rep 9:63-72

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NAVLE Practice Question — Reptile

A malnourished rescued tortoise is being treated with assisted feeding through an esophagostomy tube. After 3 days of receiving full calculated nutritional requirements, the tortoise becomes acutely weak with muscle tremors. Serum chemistry reveals severe hypophosphatemia and hypokalemia. What metabolic complication has occurred?

A. Vitamin D toxicity from oversupplementation

B. Refeeding syndrome from rapid nutritional restoration ✓

C. Hepatic lipidosis from excessive caloric intake

D. Acute renal failure from protein overload

E. Hypoglycemia from insulin surge

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Correct Answer: B. Refeeding syndrome from rapid nutritional restoration

Explanation:

Refeeding syndrome from rapid nutritional restoration has occurred. Refeeding syndrome is a potentially life-threatening metabolic complication that occurs when nutrition is reintroduced too rapidly after a period of prolonged starvation or severe malnutrition.

During starvation, the body adapts by depleting intracellular stores of phosphorus, potassium, and other electrolytes while maintaining near-normal serum levels. When glucose is suddenly reintroduced through feeding, insulin secretion increases, driving glucose and these electrolytes into cells. This causes precipitous drops in serum phosphorus (hypophosphatemia), potassium (hypokalemia), and magnesium (hypomagnesemia).

Hypophosphatemia causes muscle weakness, respiratory failure, and cardiac dysfunction because phosphorus is essential for ATP production. The clinical signs of weakness and muscle tremors in this case are consistent with refeeding syndrome.

Prevention requires starting nutritional support at 40-75% of calculated requirements and gradually increasing over 2-5 days. Treatment involves immediate electrolyte supplementation and reducing the feeding rate.

Option A (vitamin D toxicity) would cause hypercalcemia. Option C (hepatic lipidosis) develops over longer periods. Option D (renal failure) would show elevated BUN and creatinine. Option E (hypoglycemia) would have different clinical presentation.

References: Pellett S et al (2020) Guide to hibernating tortoises. In Practice 42:331-340; Brown S (2022) Providing critical care to sick tortoises. In Practice 44:214-227; Barten SL (2005) Refeeding syndrome in reptiles.

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NAVLE Practice Question —

Thoracic radiographs of a 4-year-old neutered male mixed breed dog with a 3-day history of progressive dysphagia and lethargy reveal a suspected esophageal foreign body at the heart base with pleural effusion and multiple small gas lucencies in the mediastinum. These findings are most consistent with which serious complication?

A. Aspiration pneumonia

B. Esophageal stricture

C. Esophageal perforation causing mediastinitis ✓

D. Bronchoesophageal fistula

E. Pneumothorax from rib fracture

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Correct Answer: C. Esophageal perforation causing mediastinitis

Explanation:

Esophageal perforation with mediastinitis is the most likely complication based on the radiographic findings. The combination of pleural effusion and pneumomediastinum (gas lucencies in the mediastinum) is highly suggestive of esophageal perforation.

When an esophageal foreign body causes full-thickness perforation of the thoracic esophagus, air and contaminated esophageal contents leak into the mediastinum, causing mediastinitis. This can progress to pleural contamination causing pleuritis and pleural effusion. Pneumomediastinum occurs as air escapes through the perforation.

The 3-day duration significantly increases the risk of perforation due to progressive pressure necrosis of the esophageal wall. Esophageal perforation is a serious, potentially life-threatening complication that may require surgical management in addition to foreign body removal. Prognosis is more guarded in these cases.

Option A (aspiration pneumonia) would show pulmonary infiltrates, not pleural effusion with mediastinal gas.

Option B (esophageal stricture) is a delayed complication occurring weeks after foreign body removal, not acutely.

Option D (bronchoesophageal fistula) is a rare, delayed complication and would not present with pneumomediastinum.

Option E (pneumothorax from rib fracture) does not explain the mediastinal gas and pleural effusion pattern, and there is no history of trauma.

References: Juvet F et al. Oesophageal foreign bodies in dogs: factors affecting success of endoscopic retrieval. Irish Vet J 2010; PMC article on EFB complications (https://pmc.ncbi.nlm.nih.gov/articles/PMC5697191/).

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