Thiamine Deficiency - Differential Diagnosis Framework and Clinical Manifestations



Causes of Thiamine Deficiency:

 • Poor intake:

	- Diets high in polished rice/processed grains

	- Chronic alcoholism

	- TPN

	- Gastric bypass surgery

 • Poor absorption:

	- Malnutrition

	- Gastric bypass surgery

	- Malabsorption

 • Increased loss:

	- Diarrhea

	- Hyperemesis gravidarum

	- Diuretic use

	- Renal replacement therapy

 • Increased thiamine utilization:

	- Pregnancy

	- Lactation

	- Hyperthyroidism

	- Refeeding syndrome



Sources of Thiamine:

 • Found in: Yeast, Legumes, Pork, Brown rice, Cereals

 • Low in: White/polished rice, Milled white cereals, Milk products



Thiamine

 • Necessary For:

	- Oxidative phosphorylation

	- Myocardial energy production

 • Deficiency leads to increased pyruvate and lactate

 • Increased pyruvate & lactate decrease PVR and increase venous blood flow, increasing cardiac preload

 • Increased preload and myocardial dysfunction leads to congestive heart failure

 • Wet beri-beri triggers Right HF

 • Moderate pulmonary HTN is common

 • Hyperkinetic LVEF is also seen

 • Lactic acidosis may not demonstrate diminished pH due to compensatory hyperventilation



Wernicke-Korsakoff Syndrome:

 • Wernicke's Encephalopathy - Acute neurological condition:

	- Nystagmus

	- Ophthalmoplegia

	- Ataxia/confusion

	- WE + memory loss & psychosis with confabulation is consistent with WKS

 • Korsakoff Syndrome - Chronic neurological condition:

	- Impaired short-term memory

	- Confabulation



Beri Beri:

 • Dry Beri Beri:

	- Symmetrical peripheral neuropathy of the distal extremities

	- Sensory and motor impairments

	- Impaired reflexes

	- Burning pain in extremities

	- Muscle weakness

	- Falls due to peripheral neuropathy

 • Wet Beri Beri:

	- High output heart failure

	- Dilated cardiomyopathy

	- Tachycardia

	- High output congestive HF

	- Peripheral edema



Additional Findings:

 • Acute renal failure:

	- Increased Lactate/Pyruvate

	- AV shunt, renal vascular contraction, blood flow reduction

	- Decreased GFR

 • Acute liver failure: Hepatic congestion due to RHF



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