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YR3 Gastro > Vitamin deficiencies > Flashcards

Vitamin deficiencies Flashcards

1
Q

What is the primary disease caused by vitamin A deficiency?

A

Xerophthalmia

Describes a spectrum of ocular manifestations that occur secondarily to systemic vitamin A (retinol) deficiency

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2
Q

Describe the aetiology of xerophthalmia

A

Vitamin A (retinol) is required for formation of rhodopsin, photoreceptor pigment in the retina.

Keratinisation of the eyes → dryness of the conjunctiva and cornea

  • Conjunctivae develop oval/triangular spots (Bitots spots)
  • Cornea becomes cloudy and soft.
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3
Q

State some causes of vitmain A deficiency

A
  1. Conditions that affect pancreatic function, such as:
    • cystic fibrosis
    • chronic pancreatitis
  2. Conditions that lead to reduced absorption of vitamin A, such as:
    • previous gastric surgery
    • Crohn’s disease
  3. Liver conditions:
    • Liver stores vitamin A
  4. Inadequate intake:
    • Common in southern and eastern Asia where rice is the staple food
    • rice is devoid of beta carotene (precursor to vit A)
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4
Q

What are the presenting symptoms of vitamin A deficiency?

A
  • First symptom = night blindness
    • multiple erosions develop = eventual blindness
  • Drying, scaling and follicular thickening of the skin due to keratinisation
  • Respiratory infections due to keratinisation of mucous membranes in respiratory tract.
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5
Q

Recognise the signs of vitamin A deficiency

A

Visual ability

  • decreased visual acuity in dim light
    • measure using Snellen chart
  • visual field loss

On Fundoscopy:

  • Retinal vascular attenuation
    • narrowing of the retinal arterioles.
  • Bitots spots on conjunctiva
  • peripheral chorioretinal degeneration

On observation

  • corneal xerosis – cornea appears dry and dull​
  • corneal ulcerations
  • Conjunctival xerosis – dry, dull and thick
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6
Q

What is the final stage of xerophthalmia before blindness?

A

Keratomalacia

softening of cornea, followed by perforation of eyeball and blindness

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7
Q

State appropriate investigations for Vit A deficiency

A

Check sight in darkness

Bloods:

  • Serum vitamin A level
  • Serum retinol binding protein
  • Zinc levels – zinc deficiency can interfere with production of retinol-binding protein
  • Iron studies – can affect metabolism of vitamin A
  • FBC: for anaemia or infection
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8
Q

Identify the possible complications of vitamin A deficiency

A
  • Blindness
  • Respiratory infections
  • Prognosis good if treated early, before blindness progresses
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9
Q

Vitamin B1 (thiamine)deficiency precipitates which disease?

A

Beri Beri

Can progress to Wernicke’s encephalopathy

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10
Q

Explain the risk factors for vitamin B1 deficiency

A

Developed world:

  • Chronic alcohol abuse- commonest
  • Refeeding and TPN​
    • ​B1 = co-factor in the metabolism of carbohydrates
  • GI surgery, including bariatric surgery, can lead to a reduced area of intestinal and gastric mucosa for absorbing thiamine
  • Cancer and chemotherapy
    • N+V, anorexia, malabsorption

Developing world:

  • High levels of milled (polished) rice
    • polished rice is deficient in thiamine.
    • wholegrains are rich however
  • High consumption of tea, coffee, fermented fish and betel nuts
    • ​Contain thiaminases- break down thiamine in food
  • Malnutrition
    • magnesium deifciency (cofactor)
    • B1 deficiency
  • Prolonged vomiting/ AWD
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11
Q

How does alcohol abuse cause thiamine deficiency?

A

Alcohol blocks the active-transport mechanism for the absorption of thiamine in the GI tract

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12
Q

What are the 2 types fo Beri-beri? Give examples of syndromes.

A

Dry beri beri

  • nervous system involvment- peripheral neuropathy
  • poor caloric intake and physical inactivity
  • Wernicke’s encephalopathy and Korsakoff syndrome

Wet beri beri

  • cardiovascular involvement
  • Leads to high-output cardiac failure with peripheral vasodilation, peripheral oedema, and orthopnoea
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13
Q

Summarise the epidemiology of vitamin B deficiency

A

Developed world-

  • prevalence of Wernicke’s encephalopathy = 0.1-1%
  • due to chronic alcohol abuse, in the context of poor nutritional intake

Developing-

  • prevalence of B1 deficiency = 58-66% in East Asian countries
  • Due to the large-scale consumption of thiamine-depleted polished rice.
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14
Q

What are the presenting symtoms of wet beriberi?

A

Symptom of cardiac failure in wet beriberi due to acute or chronic deficiency:

  • dyspnoea
  • orthopnoea
  • tachycardia, palpitations
  • peripheral cyanosis
  • peripheral oedema
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15
Q

What are the presenting signs/symptoms of dry beriberi?

A
  • Decreased sensation - distal peripheral polyneuropathy (particularly of the legs)
  • Parasthesia
  • Reduced knee jerks and other tendon reflexes
  • Progressive severe muscle weakness with muscle wasting
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16
Q

What is the triad of mental states in Wernicke’s encephalopathy?

A
  • Acute confusion
  • Ataxia
  • Ocular abnormalities (e.g., nystagmus and strabismus).

NOTE: common, non-specific sign in patients presenting to hospital.

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17
Q
A
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18
Q

State some early signs of B1 deficiency

A

Fatigue

Muscle aches

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19
Q

Generate a management plan for vitamin B deficiency

A

Thiamine replacement therapy-

  • IV for acute, oral for alcohol withdrawal and F/U
  • Pabrinex
  • Magnesium, potassium, and phosphate adjunct
  • If there is coexisting hypoglycaemia, ensure thiamine given before glucose
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20
Q

Identify appropriate investigations for vitamin B deficiency

A

Diagnosis mainly clinical

Bloods:

  • erythrocyte thiamine pyrophosphate
    • indicates thimaine stores
    • takes time- used retrospectively to confirm diagnosis (Tx immediately)
  • ABG + lactate- B1 deficiency is associated with lactic acidosis
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21
Q

Summarise the prognosis for patients with vitamin B deficiency

A

Good if treated early, but Korsakoff is minimally reversible

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22
Q

What is the outcome of severe vitamin C deficiency?

A

Scurvy

Most key clinical manifestations are related to impaired collagen synthesis.

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23
Q

What are the consequences of vitamin C deficiency?

A

wound healing

immune function

iron absorption

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24
Q

What are the commonest forms of Vit C deficiency?

A
  • famine and refugee populations
  • feeding infants on cow’s milk
  • psychiatric disorders, alcohol abuse
  • haemodialysis- dialyses vitamin C
  • 3Ss- sepsis, smoking, surgery
  • critical illness and acute hospitalisation
  • pancreatitis
25
Q

Recognise the presenting symptoms of vitamin C deficiency

A

Other

  • Gingivitis, loose teeth, foul breath
  • In children, bone growth may be impaired

Constitutional symptoms:

  • arthralgia
  • myalgia
  • weakness, lethargy
  • nausea, emesis
  • weight loss
  • dry skin
  • depression
  • dypsnoea

Endothelial dysfunction and haemorrhage:

  • Easy bruising, poor wound healing
  • Petechial and perifollicular haemorrhages
  • Oral mucosal petechiae
  • coiled hairs

Manifestation of cardiac failure:

  • pedal oedema
  • joint swelling
26
Q

Identify appropriate investigations for vitamin C deficiency

A

Clinical diagnosis

  • FBC
  • serum ascorbic acid
  • Xray- see corner fraction sign, a ground-glass appearance, trabecular atrophy, Pelkan’s sign, Frankel’s sign
27
Q

What disease is precipitated by vitamin D deficiency in adults?

A

Osteomalacia

Metabolic bone disease characterised by incomplete mineralisation of osteoid following growth plate closure in adults

28
Q

What disease is precipitated by vitamin D deficiency in children?

A

Rickets

Metabolic bone disease characterised by defective mineralisation of the epiphyseal growth plate cartilage in children

resulting in skeletal deformities and growth retardation.

29
Q

What is considered vitamin D deficient? What is considered insufficient?

A

Serum 25-hydroxyvitamin D

  • <50 nanomoles/L = deficiency
  • 52-72 nanomoles/L = insufficiency
30
Q

What are the risk factors for vitamin D deficiency?

A
  • Lack of exposure to sunlight
    • sunscreen use
    • season, latitude
    • older people confined home
  • Decreased Vit D GI absorption
    • Dietary deficiency
    • Malabsorption
  • Deacreased pre-vitamin D synthesis in skin
    • age
    • increased skin pigmentation
  • Decreased 25-hydroxylation of vitamin D
    • liver disease
    • anticonvulsants
  • Decrease 1a-hydroxylation of vitamin D
    • CKD
  • Enhanced metabolism of 25-hydroxy vit D:
    • primary hyperparathyroidism
    • granulomatous disorders- TB, sarcoidosis
    • obesity- BMI >30 = fat sequesters vitamin D
    • hyperthyroidism
  • Tumour- FGF23 - hypophosphataemia
31
Q

List some drugs that can cause vitamin D deficiency

A
  • glucocorticoids
  • antiepileptic medication
  • highly active ART
  • rifampicin
  • St John’s wort
32
Q

What is the name of the renal syndrome which can cause osteomalacia and what is its aetiology?

A

Fanconi syndrome (renal tubular acidosis)

Generalised dysfunction of the renal PCT that results in the urinary loss of:

  • bicarbonate
  • glucose
  • amino acids
  • phosphate
  • small proteins and peptides
  • organic acids and bases
33
Q

Summarise the epidemiology of vitamin D deficiency and osteomalacia

A

Most common nutritional deficiency- worldwide 40% of children and adults are vitamin D deficient

More common in females

34
Q

What are the presenting signs and symptoms of osteomalacia?

A
  • Fractures
    • occur with even mild trauma or movement
    • commonly long bones
  • Diffuse bone pain and tenderness
    • lower extremities, lower spine, ribs, and pelvis
  • Proximal muscle weakness
    • associated with wasting
    • Lead to a waddling gait and difficulty climbing stairs.
  • Mailaise
  • Signs of hypocalcaemia:
    • Trousseau’s sign,Chvostek’s sign
35
Q

What are the presenting signs and symptoms of rickets?

A
  • bone pain (fractures)
  • swelling of costochondral junctions (rickety rosary)
  • growth retardation (FTT)
  • bony deformities
    • Bow legs in early childhood
    • ‘Knock knees’ in later childhood
    • Bossing of frontal and parietal bones
  • muscle weakness and hypotonia- due to hypocalcaemia or hypophosphataemia
36
Q

Identify appropriate blood test investigations for vitamin D deficiency

A

Bloods

  • serum 25-hydroxyvitamin D
  • serum alkaline phosphatase (normal-high)
  • serum calcium (normal due to inc. PTH)
  • Check U&Es (look for renal failure)
  • Check ABGs (for renal tubular acidosis)
  • fasting serum phosphate (secondary hyperparathyroidism)
  • PTH (secondary hyperparathyroidism)
    • normal in mild vitamin D deficiency and insufficiency- not good diagnostic marker
37
Q

Identify the appropriate imaging investigations for osteomalacia/vitamin D deficiency and what you may see

A
  1. plain-film radiographs of knees and wrists
    • cupping, splaying, and fraying of the metaphysis
    • Looser’s zone (pseudofracture)- lucencies traversing partway at right angles
  2. DEXA
    • low BMD due to high serum PTH
  3. Iliac crest biopsy with double tetracycline labelling
    • ​​definitive diagnostic test for osteomalacia
    • you would see reduced distance between tetracycline bands = reduced mineralisation
38
Q

Generate a management plan for vitamin D deficiency and osteomalacia

A

Treat underlying cause

  1. Calcium + vitamin D
    • ergo/colecalciferol + calcium carbonate
  2. Vit D metabolite eg calcitriol + calcium carbonate if patient doesnt respond to primary treatment

Monitor:

  • Serum calcium
  • Phosphate
  • ALP
  • PTH
  • Vitamin D
39
Q

Identify possible complications of vitamin D deficiency and osteomalacia

A

Common:

  • Osteopenia/osteoporosis
    • secondary hyperparathyroidism → increase in bone resorption → decrease in BMD
  • Falls/fractures, deformities- permanent in children
  • Depression
  • Complications of hypocalcaemia

Increased risk of a number of chronic diseases:

  • cancer
  • autoimmune diseases eg MS
  • type 2 diabetes
  • heart disease and hypertension
  • neurocognitive dysfunction
  • infectious diseases (URTI, TB)
  • osteoarthritis
40
Q

What are the symptoms of hypocalcaemia?

A

CATS go NUMB:

  • Convulsions
  • Arrhythmias
  • Tetany
  • Numbness/parasthesia
41
Q

WHat are the risk factors of vitamin E deficiency?

A
  • cystic fibrosis
  • abetalipoproteinemia
  • chronic cholestatic hepatobiliary disease
  • short bowel syndrome

Impaired absorption of fat soluble vitamins

42
Q

What is the outcome of vitamin E deficiency?

A

Both central and peripheral nervous systems are affected

Can have UMN or LMN findigns including:

  • Peripheral neuropathy
  • Movement disorders- muscle contractions, dysarthria, and muscle weakness
  • Cerebellar dysfunction (e.g., ataxia, dysarthria, dysmetria),
  • Ocular disorders such as ophthalmoplegia and retinitis pigmentosa
43
Q

Epidemiology of vit E deficiency?

A

very rare

44
Q

Recognise the presenting symptoms of vitamin E deficiency

A
  • Weakness
  • Loss of vibration sense
  • Decline in visual field
45
Q

Recognise the signs of vitamin E deficiency

A
  • Hyporeflexia
  • Decreaed proprioception
  • Distal muscle weakness
  • Loss of vibration sense
  • Ataxia
  • Dysarthria
  • Retinopathy
  • Compromise immune system
46
Q

What are the risk factors for vitamin K deficiency?

A
  • Anticoagulants
  • Dietry deficiency
  • Antibiotics which interfere with vit K absorption
  • Fat malabsorption e.g. in coeliac disease, CF
  • Infants at risk of breast milk low in vit K
47
Q

Summarise the epidemiology of vitamin K deficiency

A

Rare in adults, more common in infants

48
Q

Recognise the presenting symptoms of vitamin K deficiency

A

Vitamin K is important for coagulopathy so main symptom is excessive bleeding

  • Ecchymoses at non-traumatic sites
  • Spontaneous bleeds
  • Dark black, tar like stool
  • Nose bleeds
49
Q

Identify appropriate investigations for vitamin K deficiency and interpret the results

A
  • History
  • Prothrombin time
50
Q

How to manage vit K deficiency?

A

dietry supplements

check for liver dysfunction

51
Q

State sme risk factors for B12 deficiency

A
  • >65 years
  • history of gastric surgery (gastrectomy, or bypass for obesity)
  • vegan and vegetarian diet- B12 found in animal protein
  • chronic GI illnesses (e.g., Crohn’s disease or coeliac disease)
  • Pernicious anaemia- lack of IF
  • medications -
    • PPIs
    • H2 receptor antagonists
    • metformin
    • anticonvulsants
52
Q

What is required for absorption of B12 and where does this occur?

A

Intrinsic factor- produced by gastric parietal cells

occurs in the terminal ileum

53
Q

What is haematological condition caused by lack of B12 and what is the commonest cause of this condition?

A

megaloblastic anaemia

80% of megaloblastic anaemia is caused by pernicious anaemia

Autoimmune condition involving gastritis, atrophy of all layers of the body and fundus of the stomach and loss of normal gastric glands, parietal and chief cells

No parietal cells = no IF = no B12 absorption

54
Q

Summarise the epidemiology of vitamin B12 deficiency

A
  • 39% of US adults at risk for vitamin B12 deficiency
  • dietry deficiency more common in vegans/developing countries
55
Q

Recognise the presenting symptoms of vitamin B12 deficiency

A

Typical anaemia symptoms

  • Fatigue
  • Lethargy
  • Dyspnoea
  • Faintness
  • Palpitations
  • Headache
  • Petichiae

Neurological Symptoms

  • Paraesthesia
  • Numbness, decreased vibration sense
  • Cognitive changes
  • Visual disturbances
  • Ataxia
56
Q

Recognise the signs of vitamin B12 deficiency on physical examination

A
  • Pallor
  • Heart failure (can occur with severe anaemia)
  • Glossitis
  • Angular stomatitis

Neuropsychiatric:

  • irritability
  • dementia
  • depression

Neurological

  • Subacute combined degeneration of the spinal cord= positive Romberg’s test
  • Peripheral neuropathy
57
Q

Identify appropriate investigations for vitamin B12 deficiency

A

NO gold standard for diagnosing vitamin B12 deficiency

Measurement of serum B12 is not very accurate or reliable

  • FBC and blood film
    • Hypersegmented neutrophils
    • Oval macrocytes
    • Circulating megaloblasts
    • elevated MCV, low haematocrit
  • Pernicious Anaemia Tests
    • Anti-intrinsic factor antibodies
    • Anti-parietal cell antibodies
    • Schilling test
  • Reticulocyte count
    • differentiate B12 deficiency from haemolytic anaemia.
    • low
58
Q
A

YR3 Gastro (12 decks)

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