Comprehensive FNP Clinical Review: Endocrine, Ophthalmology, Fluid & Electrolytes, and GI Disorders

A comprehensive vocabulary flashcard set covering clinical endocrine, ophthalmology, fluid and electrolyte lab parameters, and gastrointestinal clinical conditions based on lecture notes.

Atenolol

A beta-blocker administered at $25-100\,\text{mg}$ once daily, used primarily to treat hypertension, as well as akathisia, essential tremor, hypertrophic subaortic stenosis, pheochromocytoma, stable angina, tachydysrhythmias, thyrotoxicosis, congestive heart failure, congenital heart conditions, migraine headache prophylaxis, and variceal hemorrhage prophylaxis; contraindicated in decompensated heart failure, hypoglycemia, bradycardia, MAOIs, and tricyclic antidepressants.

Propranolol

A beta-blocker administered at $20-40\,\text{mg}$ every $6\,\text{hours}$, used primarily to treat hypertension and conditions such as thyrotoxicosis, essential tremor, and migraine prophylaxis; contraindicated in decompensated heart failure, hypoglycemia, bradycardia, MAOIs, and tricyclic antidepressants.

Cholestyramine

An adjunctive therapy given in a dose of $4\,\text{g}$ 2 to 4 times daily alongside methimazole that lowers serum $T_4$ and $T_3$ concentrations more rapidly than methimazole alone in patients requiring rapid hyperthyroid symptom amelioration.

Radioactive Iodine (RAI)

A colorless and tasteless liquid treatment that disrupts thyroid hormone synthesis, causing follicle breakdown and thyroid tissue fibrosis; contraindicated during pregnancy.

Propylthiouracil (PTU)

The antithyroid drug of choice during the first trimester of pregnancy and administered in large doses during thyroid storm emergencies.

Methimazole (MMI)

The preferred antithyroid drug of choice during the 2nd and 3rd trimesters of pregnancy and the first-line agent for pediatric hyperthyroidism.

Thyroid Storm

A life-threatening medical emergency characterized by decompensated thyrotoxicosis presenting with high fever, tachycardia, dehydration, delirium, diaphoresis, hyperthermia, restlessness, confusion, and coma; most commonly associated with Graves' disease.

Levothyroxine (Synthroid)

A synthetic $T_4$ replacement with a $7\,\text{day}$ half-life, taken separately from H2 blockers, PPIs, and iron supplements; standard maintenance dose is $125\,\text{mcg/day}$.

Liothyronine (T3)

A synthetic $T_3$ medication with a half-life of $1.5\,\text{days}$, requiring TID administration; carries a higher incidence of cardiac adverse reactions and higher cost compared to Levothyroxine.

Liotrix

A synthetic combination of $T_4$ and $T_3$ in a $4:1$ ratio that features high cost and a lack of therapeutic rationale.

Myxedema Coma

A life-threatening hypothyroid complication presenting with hypothermia, advanced hypothyroid symptoms, and altered sensorium ranging from delirium to coma; managed with IV Synthroid bolus ($300-500\,\text{mcg}$) and IV hydrocortisone ($100\,\text{mg}$ every $8\,\text{hours}$).

Thyroid-Stimulating Hormone (TSH)

The primary first-line test for suspected thyroid disorders with a normal reference range of $2.0-11.0\,\text{mIU/L}$.

Free T4

A thyroid function test measuring the $<1\%$ of unbound serum $T_4$ (normal range $1.1-4.3\,\text{ng/dL}$) that remains unaffected by changes in serum carrier proteins or binding sites.

Reverse T3

A hormonally inactive isomer of $T_3$ that is elevated in sick euthyroid syndrome, serving to differentiate sick euthyroid state from true hypothyroidism.

Thyroxine-Binding Globulin (TBG)

The primary glycoprotein carrier protein for $T_3$ and $T_4$; increased by high estrogen (pregnancy, OCPs), hepatitis, opioids, or genetics, and decreased by androgens, glucocorticoids, nephrotic syndrome, cirrhosis, acromegaly, and antiepileptics.

Antithyroid Peroxidase Antibodies (TPOAb)

Sensitive autoantibodies used to diagnose Hashimoto's thyroiditis, where serum concentrations are markedly elevated.

TSH Receptor Antibodies (TSHRAbs)

Sensitive antibodies used in diagnosing Graves' disease; classified into stimulating (TSI, causing Graves'), blocking (causing hypothyroidism), or neutral.

Thyrotropin Binding Inhibitory Immunoglobulin (TBII)

A classification of TSH receptor antibody that acts as a TSH antagonist.

Radioactive Iodine Uptake Scan

An endocrinology imaging modality used to differentiate causes of hyperthyroidism: shows homogenous uptake in Graves' disease, heterogenous uptake in multinodular goiter, and absent uptake in hypothyroidism or exogenous hormone ingestion.

Acute Angle Closure Glaucoma

An eye emergency caused by iris blockage of the trabecular meshwork, presenting with sudden severe eye pain, high intraocular pressure, cloudy eye that feels firm to touch, halo vision, headache, nausea, and vomiting.

Blepharitis

Eyelid inflammation divided into anterior (outer eyelid/lashes, Staph/seborrheic) and posterior (inner eyelid, meibomian glands); Staph aureus is the most common infectious cause.

Cataracts

Opacification of the crystalline lens caused by protein buildup, leading to progressive vision loss, cloudy vision, diplopia, impaired night driving, and a black or absent red light reflex.

Viral Conjunctivitis

Highly contagious conjunctival infection often following a recent URI, presenting with red eye, watery discharge, lymphadenopathy (50% preauricular node involvement), starting unilaterally and often spreading bilaterally.

Bacterial Conjunctivitis

Conjunctival infection caused by Hemophilus influenzae, Streptococcus, or M. catarrhalis, characterized by purulent discharge, sticky glued eyes worse in mornings, absence of lymphadenopathy, and unilateral onset progressing bilaterally within $48\,\text{hours}$.

Allergic Conjunctivitis

Bilateral ocular inflammation presenting with serous stringy rope-like drainage, intense itching, eyelid cobblestoning, fatigue, and cervical chain adenopathy; treated with mast cell stabilizers or oral antihistamines.

Corneal Abrasion

A scratch on the corneal surface presenting with pain, photophobia, foreign body sensation, and tearing; diagnosed via fluorescein stain under blue light and managed with irrigation and oral analgesics. Topical steroids are strictly contraindicated.

Presbyopia

Gradual loss of the eye's ability to focus on nearby objects ('farsightedness') seen in individuals $>40\,\text{years}$ old, causing patients to complain that their arms are too short; treated with progressive or bifocal lenses.

Cones

Retinal photoreceptor cells responsible for color perception, $20/20$ visual acuity, and sharp vision.

Rods

Retinal photoreceptor cells responsible for light/shadow detection and night vision.

Snellen Chart

A visual acuity test conducted at a distance of $20\,\text{feet}$ to assess cranial nerve 2 (optic nerve); a result of $20/200$ indicates legal blindness.

Ishihara Color Test

A diagnostic screening exam administered in childhood to test for color blindness.

Papilledema

Hypertensive fundoscopic finding characterized by bilateral swollen optic discs with blurred edges and elevated intraocular pressure, representing a medical emergency requiring ED referral.

AV Nicking

Fundoscopic finding in hypertension where crossing arterioles and veins create bulging; reversible with blood pressure control.

Copper Wire Arteries

Fundoscopic finding in hypertension where arterioles appear red and copper due to thickening; reversible with blood pressure control.

Flame Hemorrhages

Diffuse, brush-stroke hemorrhages located on the retinal nerve fiber layer seen in hypertensive retinopathy.

Cotton Wool Spots

Yellow-white fluffy patches on the retina reflecting underlying vascular insufficiency, commonly seen in diabetic retinopathy.

Arcus Senilis

Lipid deposits appearing as gray-colored rings or halos around the iris, associated with hypercholesterolemia.

Xanthelasma

Sharply demarcated yellow patches located on the bilateral inner canthus or eyelids associated with elevated lipid levels.

Strabismus

Horizontal or vertical misalignment of the eyes; normal in infants up to $4-6\,\text{months}$ of age and evaluated using cover/uncover tests.

Esotropia

A type of strabismus colloquially described as being cross-eyed.

Pterygium

A pink, triangular-shaped fibrovascular overgrowth of conjunctival tissue that extends onto and touches the cornea due to chronic UV exposure and irritation, impacting vision.

Pinguecula

A benign yellowish raised round mass on the conjunctiva caused by UV exposure and age that does NOT extend to the cornea and does NOT affect vision.

Open Angle Glaucoma

A chronic ocular condition caused by increased resistance of aqueous outflow through the trabecular meshwork, resulting in slow and progressive loss of peripheral vision leading to tunnel vision.

Hordeolum (Stye)

An acute, painful infection or abscess of an eyelash hair follicle or gland (external: Zois/Moll; internal: meibomian), most commonly caused by Staph aureus.

Chalazion

A non-infectious, mildly painful or painless eyelid lesion caused by a blocked meibomian gland duct and narrowing of the gland opening.

Hyphema

Pooling of blood in the anterior chamber between the cornea and iris caused by trauma, inflammation, or tumor; presents with pain, blood pooling, and decreased vision, requiring a protective plastic shield and emergent ophthalmology consult.

Iritis

Anterior uveitis involving inflammation of the iris, ciliary body, and choroid, presenting with eye redness/swelling without discharge, constricted pupils, photophobia, and risk for permanent blindness.

Macular Degeneration

The leading cause of blindness, characterized by slow or sudden painless loss of central vision; managed using large print materials.

Periorbital Cellulitis

An infectious eye disorder classified as pre-septal (anterior to orbital septum) or orbital cellulitis (posterior to septum), presenting with eyelid erythema, proptosis, restricted eye movements, warmth, and decreased visual acuity.

Retinal Detachment

An ocular condition presenting with a classic 'curtain pulled over eyes' sensation, sudden appearance of floaters, blurred vision, and flashes of light (photopsia).

Subconjunctival Hemorrhage

Painless blood collection trapped between the sclera and conjunctiva caused by trauma, Valsalva maneuvers, or straining; resolves spontaneously within $2\,\text{weeks}$ without discharge or photophobia.

Anion Gap

The calculated difference between circulating cations and anions: $\text{Anion Gap} = \text{Sodium} - (\text{Chloride} + \text{Bicarbonate})$; a value $>20$ defines high anion gap metabolic acidosis.

MUDPILES

Mnemonic for causes of high anion gap ($>20$) metabolic acidosis: Methanol, Uremia, DKA, Paraldehyde or Poisoning, INH, Lactic Acidosis, Ethanol, Salicylates and Starvation.

Serum Bicarbonate

Major buffer electrolyte with normal lab values of $20-29\,\text{mEq/L}$ in adults ($>2\,\text{years old}: 22-26\,\text{mEq/L}$; $<2\,\text{years old}: 17-24\,\text{mEq/L}$); levels $<20\,\text{mEq/L}$ indicate acidosis and $>29\,\text{mEq/L}$ indicate alkalosis.

Total Calcium

Total body calcium parameter (normal range $8.8-10.3\,\text{mg/dL}$), of which $99\%$ is stored in bone as hydroxyapatite and $1\%$ circulates in plasma and cells ($50\%$ protein-bound, $50\%$ ionized).

Calcitonin

Hormone secreted by thyroid C cells that lowers serum calcium by inhibiting osteoclast activity in bone.

Parathyroid Hormone (PTH)

Hormone secreted in response to low serum calcium that increases renal calcium reabsorption, promotes renal phosphate excretion, and stimulates osteoclast activity to release calcium and phosphate into plasma.

Hypocalcemia

Serum total calcium level $<8.8\,\text{mg/dL}$, presenting with perioral paresthesias, cramps, hyperreflexia, positive Trousseau and Chvostek signs, prolonged QT interval, and potential cardiac arrest.

Chvostek's Sign

Clinical sign of tetany in hypocalcemia or severe hyperphosphatemia characterized by facial muscle twitching elicited by tapping the facial nerve.

Trousseau's Sign

Clinical sign of latent tetany in hypocalcemia or severe hyperphosphatemia elicited by inflating a blood pressure cuff above systolic pressure, causing carpopedal spasm.

Hypercalcemia

Serum total calcium level $>10.3\,\text{mg/dL}$, presenting with BONES (osteopenia, fractures), STONES (nephrolithiasis), MOANS (abdominal pain, constipation, pancreatitis), GROANS (depression, confusion), and SEVER (AMS, coma, polyuria, short QT).

Chloride

Predominant extracellular anion (normal range $97-108\,\text{mEq/L}$) that maintains acid-base and fluid balance; helps differentiate hypercalcemia of primary hyperparathyroidism (increased Cl) from hypercalcemia of malignancy (decreased Cl).

Hyperchloremia

Serum chloride level $>108\,\text{mEq/L}$, caused by free water loss, hypotonic fluid loss, hyperchloremic metabolic acidosis, respiratory alkalosis, or drugs such as acetazolamide, aspirin, lithium, and thiazides.

Hypochloremia

Serum chloride level $<97\,\text{mEq/L}$, caused by total body depletion, dilutional states (hypertonic IV fluids, SIADH, HF, cirrhosis), or acid-base disturbances.

Magnesium

Intracellular cation (normal range $1.7-2.5\,\text{mEq/L}$) stored mostly in bone and muscle ($40-60\%$) and cells ($30\%$), essential for neuromuscular function, nucleic acid synthesis, and energy production.

Hypermagnesemia

Serum magnesium level $>2.5\,\text{mEq/L}$, caused by renal failure, excessive antacid/laxative intake, or preeclampsia therapy; presents with nausea, muscle weakness, hypotension, bradycardia, and respiratory depression, treated with IV Calcium Gluconate.

Hypomagnesemia

Serum magnesium level $<1.7\,\text{mEq/L}$, caused by malabsorption, alcoholism, PPIs, or diuretics; presents with weakness, muscle fasciculations, hyperreflexia, tetany, seizures, and arrhythmias.

Hyperphosphatemia

Serum phosphate level $>4.5\,\text{mg/dL}$, most commonly caused by acute or chronic kidney disease ($\text{eGFR} <30$); severe cases cause increased neuronal excitability, tetany (Chvostek/Trousseau signs), and joint calcifications.

Fanconi Syndrome

A genetic renal disorder in which nephrons lose the ability to reabsorb phosphate in the distal convoluted tubule, leading to increased renal phosphate excretion and hypophosphatemia.

Hypophosphatemia

Serum phosphate level $<2.5\,\text{mg/dL}$, caused by intracellular shifts (refeeding syndrome, DKA, respiratory alkalosis), GI malabsorption, or renal loss; leads to muscle weakness, rhabdomyolysis, red cell hemolysis, and AMS.

Potassium

Primary intracellular cation ($98\%$ intracellular, normal range $3.5-5.1\,\text{mEq/L}$), regulated at the distal nephron to maintain nerve conduction, muscle function, and heart contraction rate/force.

Hypokalemia

Serum potassium level $<3.5\,\text{mEq/L}$, presenting with muscle weakness, cramps, polyuria, U waves, prolonged QT interval, and ventricular ectopy.

Hyperkalemia

Serum potassium level $>5.1\,\text{mEq/L}$, presenting with peaked T waves, prolonged PR interval, widened QRS, loss of P waves, and risk of PEA/V-fib; treated with IV calcium, insulin with bicarbonate, beta-2 agonists, and Kayexalate.

Serum Sodium

Most abundant extracellular cation (normal range $135-145\,\text{mEq/L}$) that maintains osmotic pressure, acid-base balance, and nerve impulses; osmolality is estimated as $\text{Sodium} \times 2$.

Hypernatremia

Serum sodium level $>145\,\text{mEq/L}$, caused by dehydration, loss of hypotonic fluids, diabetes insipidus, or sodium overload; presents with thirst, fever, dry mucous membranes, hypotension, tachycardia, and pulmonary edema.

Hyponatremia

Serum sodium level $<135\,\text{mEq/L}$, the most common fluid and electrolyte imbalance; categorized into hypovolemic, hypervolemic, or euvolemic (SIADH), frequently appearing within 2 weeks of starting thiazide diuretics.

Ergocalciferol (Vitamin D2)

Plant-derived form of vitamin D used in dietary sources and oral supplementation.

Cholecalciferol (Vitamin D3)

The most potent and effective form of vitamin D, synthesized in skin upon UVB exposure or obtained from animal-based dietary sources.

Calcitriol (1,25-hydroxyvitamin D)

The active form of vitamin D produced by the kidneys from 25-hydroxyvitamin D; enhances intestinal absorption of calcium and phosphorus, suppresses PTH, and promotes bone remodeling.

Serum 25-hydroxyvitamin D

The gold standard laboratory diagnostic test for evaluating overall vitamin D status ($<12\,\text{ng/mL}$ = severe deficiency; $12-20\,\text{ng/mL}$ = moderate deficiency; $20-30\,\text{ng/mL}$ = insufficiency).

Rickets

Pediatric vitamin D deficiency disorder characterized by leg bowing, costochondral beading ('rachitic rosary'), delayed growth, delayed fontanelle closure, and dental enamel defects.

Somatic Abdominal Pain

Abdominal pain that is well-localized, sharp, squeezing, or stabbing in nature.

Visceral Abdominal Pain

Abdominal pain that is poorly localized, crampy, dull, or aching in nature.

Neuropathic Abdominal Pain

Abdominal pain characterized by shooting or burning sensations.

Anal Fissure

A linear tear in the lining of the anal canal distal to the dentate line, presenting with severe sharp rectal pain, tearing sensation during defecation, and bright red blood on toilet paper.

Appendicitis

Inflammation of the appendix presenting with epigastric/periumbilical pain migrating to the RLQ, rigid abdomen, McBurney's point guarding, positive Rovsing's, Psoas, and Obturator signs, and positive JUMP UP test.

Rovsing's Sign

Physical exam maneuver where deep palpation of the left lower quadrant elicits pain in the right lower quadrant, indicative of appendicitis.

Psoas Sign

Physical exam sign for appendicitis elicited when passive extension of the right hip causes right lower quadrant abdominal pain.

Obturator Sign

Physical exam sign for appendicitis elicited when passive internal rotation of the flexed right hip causes right lower quadrant abdominal pain.

McBurney's Point

An anatomical location in the right lower quadrant (one-third distance from anterior superior iliac spine to umbilicus) where tenderness and guarding signal acute appendicitis.