Quiz 3

(Ref: Harrison 20th edition, p 2313; Harrison 19th p 96e-1t, 360)
Symptoms of vitamin B6 deficiency
1. Include epithelial changes, as seen frequently with other B vitamin deficiencies.
2. Peripheral neuropathy
3. Abnormal electroencephalograms
4. Personality changes, Depression and confusion.
5. Microcytic hypochromic anemia is due to diminished hemoglobin synthesis, since the first enzyme involved in heme biosynthesis (Amino-levulinate synthase) requires PLP as a cofactor
6. Increased risk of cardiovascular disease.

(Ref: Harrison 20th edition, p 2317; Nelson 18th ed. ch 670, Harrison 19th p 96e-9, 461)
 Autosomal recessive disorder caused by an inability to absorb sufficient zinc from the diet.
 The genetic defect is in the intestinal zinc specific transporter gene SLC39A4. Clinical findings include:
1. The cutaneous eruption consists of eczematous skin lesions symmetrically distributed in the perioral, acral, and perineal areas and on the cheeks, knees, and elbows.
2. Chronic diarrhea, stomatitis, glossitis, paronychia, nail dystrophy, growth retardation
3. Delayed wound healing,
4. Intercurrent bacterial infections and super-infection with Candida albicans.
5. Growth retardation and delayed development may be apparent.
6. Hair often has a peculiar reddish tint, and alopecia.
7. Ocular manifestations include photophobia, conjunctivitis, blepharitis, and corneal dystrophy detectable by slit-lamp examination.

(Ref: Harrison 20th edition, p 2313; Harrison 19th p 96e-5)
 Taking > 2 g of vitamin C in a single dose may result in abdominal pain, diarrhea, and nausea.
 Since vitamin C may be metabolized to oxalate, it could result in an increased prevalence of kidney stones.
 High doses of vitamin C could promote iron overload in patients taking supplemental iron.
 High doses of vitamin C can induce hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency.

(Ref: Harrison 20th edition, p 2316; Harrison 19th p 96e-1t, 96e-8)
 Vitamin E deficiency is associated with axonal degeneration of spino-cerebellar and dorsal column tracts.
 Hence most patients present with peripheral neuropathy with arreflexia and later with ataxic gait
 Opthalmoplegia, skeletal myopathy and pigmentary retinopathy are also seen

(Ref: Harrison 20th edition, p 2315; Harrison 19th p 256e-12, 96e-7)
When vitamin A is provided in excess to pregnant- women, congenital malformations have included spontaneous abortions, craniofacial abnormalities, and valvular heart disease. In pregnancy, the daily dose of vitamin A should not exceed 3 mg.

(Ref: Harrison 19th p 96e-10)
 Menke is XLR defect caused by ATP 7A gene
 It is characterized by mental retardation and kinky hair and copper deficiency anemia.
 Most children die within 5 years of diagnosis because of dissecting aneurysm or cardiac rupture.
 Diagnosis is based on low serum copper levels with low ceruloplasmin levels.
 Serum copper can be elevated in pregnancy or stress conditions since ceruloplasmin is an acute phase reactant.

(Ref: Harrison 20th edition, p 2309; Harrison 19th p 96e-1t, 2690)
Causes of thiamine deficiency:
1. Poor dietary intake.
2. In Western countries, the primary causes of thiamine deficiency are alcoholism and chronic illnesses such as cancer.
3. Hyperemesis gravidarum
4. Bariatric bypass surgery
5. Chronic diuretic therapy due to increased urinary thiamine losses.

(Ref: Harrison 20th edition, p 2330; Harrison 19th p 98e-6-8, 98e-7t)
 The most common problems related to PN are fluid overload and hyperglycemia.
 Hypertonic dextrose stimulates a much higher insulin level than meal feeding. Because insulin is a potent anti-natriuretic and antidiuretic hormone, hyper-insulinemia leads to sodium and fluid retention.
 In the absence of gastrointestinal losses or renal dysfunction, net fluid retention is likely when total fluid intake exceeds 2000 mL/d.
 Close monitoring of body mass, as well as fluid intake and output, is necessary to prevent this complication.