Anorexia Nervosa - Anomalies (Physical/Medical Complications)

1. Cardiovascular Anomalies

• Sinus bradycardia - most characteristic finding; results from hypometabolic state and vagal predominance
• Hypotension and orthostasis - due to reduced cardiac output and volume depletion
• Prolonged QTc interval on ECG - predisposes to fatal arrhythmias
• Cardiac arrhythmias - sudden cardiac death may result
• Left ventricular atrophy and cardiac fibrosis - structural changes due to prolonged starvation and muscle wasting (including cardiac muscle)
• Peripheral edema - due to hypoalbuminemia

2. Endocrine and Reproductive Anomalies

• Amenorrhea - nearly universal in females due to hypogonadism; caused by suppression of LH and FSH
• Low LH and FSH levels
• Low estrogen/testosterone
• Growth hormone resistance - GH levels may be elevated but IGF-1 is low
• Hypercortisolemia - elevated cortisol due to chronic stress of starvation
• Low thyroid hormones (low T4, low TSH) with elevated reverse T3 - "sick euthyroid" pattern
• Hypercholesterolemia - paradoxically seen due to reduced estrogen-mediated clearance

3. Metabolic and Electrolyte Anomalies

• Hypokalemia (low potassium) - especially with purging; major cause of arrhythmias
• Hyponatremia (low sodium)
• Hypochloremia (low chloride)
• Metabolic alkalosis - from vomiting (loss of HCl)
• Elevated blood urea nitrogen (BUN) - from dehydration and protein catabolism
• Hypoglycemia - from depleted glycogen stores
• Elevated liver aminotransferases - mild, from starvation hepatitis
• Serum phosphate must be monitored - risk of refeeding syndrome on nutritional rehabilitation

4. Hematologic and Musculoskeletal Anomalies

• Leukopenia with relative lymphocytosis - due to deficiencies in iron and vitamins plus gelatinous transformation of bone marrow
• Normochromic, normocytic anemia - from iron/vitamin deficiency and marrow suppression
• Gelatinous transformation of bone marrow - fat replaced by gelatinous material in severe starvation
• Decreased bone mineral density - leads to premature osteopenia and osteoporosis; due to low estrogen, low calcium intake, elevated cortisol, and low IGF-1
• Muscle wasting (cachexia) - including cardiac and skeletal muscle

5. Dermatological, Neurological, and Gastrointestinal Anomalies

• Lanugo hair - fine downy hair on trunk and limbs; thermoregulatory response to loss of body fat
• Carotenemia/Hypercarotenemia - yellowing of skin (not jaundice) from high beta-carotene intake + reduced conversion
• Hair loss and thinning (telogen effluvium)
• Petechiae and skin dryness

• Markedly delayed gastric emptying - causes early satiety, nausea, bloating, abdominal pain
• Superior mesenteric artery (SMA) syndrome - loss of fatty tissue at the SMA-aorta angle causes extrinsic duodenal compression
• Constipation - due to reduced gut motility and inadequate intake

• Alterations in reward circuitry (frontal cortex, anterior insula) affecting interoceptive awareness of hunger and satiety
• Hypothermia - hypometabolic adaptation to starvation

Key Summary Table

Anorectal Anomalies (Anorectal Malformations / Imperforate Anus)

1. Definition, Incidence, and Embryology

• Incidence: 1 in 2,500-5,000 live births, with a slight male predominance (~58%)
• Embryology: By week 5 of gestation, the urorectal septum migrates caudally to divide the cloaca into:
  • Anterior urogenital sinus
  • Posterior anorectal canal
• The anal membrane normally ruptures by week 8, completing patency of the distal rectum
• Mechanisms of malformation:
  • Failure of the urorectal septum to descend → fistula between bowel and urinary tract (males) or introitus (females)
  • Complete/partial failure of anal membrane to resorb → anal membrane or anal stenosis
  • Breakdown of cloacal membrane along its course → anal opening anterior to external sphincter (rectoperineal fistula)
  • Fusion failure of cloacal folds → absent perineal body

2. Classification

Low Lesions (rectum passes through or reaches the levator ani)

Intermediate Lesions

High Lesions (rectal pouch ends above pubococcygeal line)

• Cloaca (females only): rectum, vagina, and urethra fuse into a single common channel; severity determined by common channel length (< 3 cm = short; ≥ 3 cm = long)
• Rectal atresia: lumen of the rectum completely or partially interrupted; commonly associated with trisomy 21

3. Associated Anomalies - VACTERL

• Perineal (low) fistula → ~10% GU anomalies
• Rectovesical fistula/persistent cloaca → ~90% GU anomalies

4. Clinical Presentation and Diagnosis

• Diagnosis is made on careful examination of the neonatal perineum at birth
• Low lesions: meconium passed through a perineal/vestibular fistula within first 24 hours; "bucket-handle" skin tag at anal dimple is pathognomonic of a low lesion
• High lesions (males): no anal skin dimpling, flat gluteal contour, absent sphincter contraction on cutaneous stimulation; meconium/gas may be passed through the urethra
• If unrecognized: abdominal distention, feeding intolerance, bilious vomiting (intestinal obstruction)

• Physical exam determines high vs. low in most cases
• Wangensteen-Rice invertogram (lateral pelvic X-ray with infant inverted for 12-24 h): historical; allows gas in rectal pouch to mark level relative to skin marker - largely replaced
• Real-time perineal ultrasound: currently the preferred initial imaging to determine distal rectal pouch level
• CT/MRI: useful for evaluating pelvic striated muscle complex in complex/cloacal anomalies; MRI for spinal cord assessment
• Distal loop colostogram: gold standard for delineating fistula anatomy before definitive repair
• Renal ultrasound + voiding cystourethrogram (VCUG): mandatory to screen for GU anomalies
• Echocardiography: if cardiac defect suspected
• Orogastric tube: to rule out esophageal atresia

5. Surgical Management and Prognosis

Low Malformations (single-stage newborn repair, no colostomy needed):

• Anal stenosis: serial dilatations alone (gradual size increase over time)
• Anterior perineal/vestibular fistula: cutback anoplasty - posterior division of the fistula to the external sphincter; or transposition anoplasty (places neoanus at center of sphincter)
• Covered anus: simple unroofing procedure

Intermediate/High Malformations (three-stage repair):

1. Stage 1 (Newborn): Divided loop sigmoid colostomy with mucous fistula - provides complete fecal diversion and allows distal colostogram to define fistula
2. Stage 2 (3-12 months): Definitive Posterior Sagittal Anorectoplasty (PSARP) - the procedure of choice (described by de Vries and Peña):
   • Infant prone; midline posterior sagittal incision from coccyx to perineum
   • Muscle stimulator maps striated muscle complex for symmetric midline dissection
   • Rectal pouch mobilized, rectourinary fistula identified and divided
   • Rectum placed centrally within striated muscle complex (reconstructed circumferentially)
   • Neoanus centered within external sphincter
3. Stage 3: Colostomy closure (6-8 weeks after PSARP, after progressive anal dilatations)

Prognosis:

• Low lesions: favorable prognosis for fecal continence (rectum well within striated muscle complex)
• High lesions: less muscle surrounding the rectum → poorer continence outcomes
• Sacral agenesis/≥2 missing vertebrae: poor prognosis for both bowel and bladder continence
• Cloaca (long common channel): most complex; requires combined posterior sagittal and abdominal approach with urogenital reconstruction

Quick Summary Diagram

ANORECTAL MALFORMATIONS
         |
    ─────────────────
    |               |
   LOW             HIGH
(Below levator)  (Above levator)
    |               |
No colostomy    Colostomy first
Anoplasty        then PSARP
    |               |
Good continence  Variable continence
                 (depends on sacrum + muscle)

Always check VACTERL:
V - Vertebral (sacral agenesis)
A - Anorectal (the defect itself)
C - Cardiac (echocardiogram)
TE - Tracheoesophageal
R - Renal (ultrasound + VCUG)
L - Limb (radial)