Weight Management with Congenital Adrenal Hyperplasia (CAH) in South Africa
Congenital Adrenal Hyperplasia (CAH) is a family of autosomal recessive disorders of adrenal steroid synthesis, with 21-hydroxylase deficiency (CYP21A2 mutations) accounting for over 90% of cases. The adrenal glands cannot adequately produce cortisol and, in the classic salt-wasting form, aldosterone — so the pituitary gland releases excess ACTH to drive the adrenals harder, causing them to enlarge (hyperplasia) and overproduce the androgens that do not require 21-hydroxylase to manufacture. The result is a triple hormonal imbalance: cortisol deficiency, aldosterone deficiency (in salt-wasting), and androgen excess. In South Africa, CAH occurs across all population groups and is one of the more common single-gene endocrine disorders managed at paediatric and adult endocrinology services. Classic CAH is identified at birth or in early infancy (often through a neonatal adrenal crisis in salt-wasters, or ambiguous genitalia in 46,XX females). Non-classic CAH (NCAH) is much milder and may present in adolescence or adulthood with hirsutism, menstrual irregularity, acne, and fertility difficulties — closely mimicking PCOS. Weight management in CAH is complicated by the lifelong glucocorticoid replacement therapy that is both necessary for life and inherently weight-promoting, alongside the metabolic consequences of androgen excess.
Virilisation; early puberty; rapid growth then short stature
Glucocorticoid side effects; androgen-driven central adiposity; accelerated bone age leading to short stature
Non-Classic CAH (NCAH)
Cortisol sufficient; mild androgen excess
Hirsutism, acne, PCOS-like picture, infertility in women
Androgen excess drives insulin resistance; may not require glucocorticoids; PCOS-like weight gain
How CAH Treatment Causes Weight Gain
Glucocorticoid Replacement: Necessary but Weight-Promoting
All classic CAH patients require lifelong glucocorticoid replacement (typically hydrocortisone in children; prednisolone or dexamethasone in adults). This is not optional — cortisol deficiency is life-threatening, and adrenal crises (acute cortisol deficiency triggered by illness, surgery, or stress) can be fatal within hours. However, glucocorticoid therapy has well-known metabolic effects:
Central adiposity — glucocorticoids preferentially drive fat deposition to the trunk, abdomen, and viscera
Increased appetite — glucocorticoids stimulate appetite, particularly for calorie-dense foods
Muscle catabolism — high or supraphysiological doses break down muscle protein, reducing metabolic rate
Fluid retention — particularly with older formulations like prednisolone at higher doses
Bone density loss — long-term glucocorticoids reduce bone density; weight-bearing exercise is important
Critical Safety Note — Sick Day Rules: CAH patients must NEVER reduce their glucocorticoid doses during illness, surgery, or significant physical stress. Dose must be doubled or tripled. Weight management strategies that reduce glucocorticoid doses must ONLY be attempted under specialist endocrinologist supervision. Unsupervised dose reduction can trigger an adrenal crisis.
Androgen Excess and Body Composition
Excess adrenal androgens (primarily DHEA-S, androstenedione, and testosterone from adrenal androgen pathway) in inadequately controlled CAH cause:
Increased muscle mass initially — but also accelerated bone maturation causing early epiphyseal fusion and short adult stature
Visceral adiposity — paradoxically, androgen excess in females (46,XX) drives abdominal fat accumulation via insulin resistance mechanisms similar to PCOS
Insulin resistance and compensatory hyperinsulinaemia — driving further fat deposition
Polycystic-appearing ovaries and menstrual irregularity — with PCOS-like metabolic syndrome risk in 46,XX patients
Optimising Glucocorticoid Dosing to Minimise Weight Gain
The most important weight management intervention in CAH is optimal glucocorticoid dose calibration — neither over- nor under-dosing. Both extremes cause problems:
Scenario
Effect
Monitoring Marker
Over-treatment (too much glucocorticoid)
Cushing's-like weight gain, metabolic syndrome, insulin resistance, reduced growth in children
High ACTH, androgen excess, virilisation, central adiposity via different mechanism, adrenal crisis risk
17-OHP, androstenedione, DHEA-S; clinical signs of virilisation
Well-controlled
Normal cortisol rhythm, suppressed ACTH, controlled androgens, healthy body composition achievable
17-OHP in upper normal range; normal androstenedione; normal growth velocity
Glucocorticoid Choice and Timing
In adults, the choice of glucocorticoid and dosing schedule matters for weight:
Hydrocortisone (cortisol) — shortest-acting, most physiological; multiple daily doses (3x/day) mimic the natural cortisol rhythm better; generally preferred in adults despite tablet number burden
Modified-release hydrocortisone (Plenadren) — once-daily formulation designed to replicate the diurnal cortisol profile; may cause less weight gain. Not widely available in SA currently.
Prednisolone — longer-acting, more potent; convenient once or twice daily but greater risk of Cushingoid features and weight gain at equivalent doses
Dexamethasone — very long-acting, very potent; useful for suppressing androgens in NCAH but highest Cushingoid risk; avoid high doses and avoid taking at night
SA Context: Hydrocortisone tablets (10 mg and 20 mg) are available in South Africa through most hospital pharmacies and private pharmacies (Clicks, Dis-Chem) on prescription. Standard adult replacement doses typically range from 15–25 mg/day in divided doses. Fludrocortisone (for mineralocorticoid replacement in SW-CAH) is separately available on prescription.
Diet Strategies for Weight Management in CAH
Anti-Inflammatory, Low-Glycaemic Approach
Given the glucocorticoid-driven insulin resistance and androgen-mediated metabolic syndrome risk, the dietary pattern that best supports weight management in CAH is similar to that recommended for PCOS:
Low glycaemic index carbohydrates — brown rice, sweet potato, legumes, oats over white bread, white rice, pap, and sweets; reduces postprandial glucose and insulin spikes
Adequate dietary fibre — 25–35 g/day from vegetables, fruits, legumes; improves insulin sensitivity and supports satiety
High-quality lean protein at each meal — chicken, fish, eggs, legumes, amasi (fermented milk); supports muscle mass maintenance
Limit ultra-processed foods — high-sugar, high-sodium processed items worsen fluid retention, which is particularly relevant in SW-CAH patients on fludrocortisone
Salt and Sodium in Salt-Wasting CAH
Patients with salt-wasting CAH on fludrocortisone have specific sodium management needs. While the general population is advised to limit sodium, SW-CAH patients — especially infants and in hot weather — may need adequate salt intake. However, excessive sodium from ultra-processed foods contributes to hypertension and fluid retention. Work with your endocrinologist to establish appropriate sodium targets for your individual situation.
Exercise in CAH
Benefits of Exercise
Exercise is one of the most effective interventions for counteracting the metabolic effects of glucocorticoid therapy:
Resistance training (weights, bodyweight exercises) — preserves and builds muscle mass, counteracting glucocorticoid-induced muscle catabolism; significantly improves insulin sensitivity
Weight-bearing exercise — running, walking, strength training — essential for counteracting glucocorticoid-induced bone density loss
Target minimum 150 minutes moderate aerobic activity plus 2–3 resistance sessions per week
Exercise Safety in CAH
Stress Dosing with Intense Exercise: Very high-intensity exercise (marathon running, intense HIIT sessions) represents a physical stressor. Some CAH patients benefit from a small stress dose of hydrocortisone (5–10 mg) before prolonged strenuous exercise to prevent relative cortisol deficiency and fatigue. Discuss this with your endocrinologist — it is not needed for moderate exercise such as walking or gym sessions.
Always carry a medical alert bracelet or card identifying CAH and the need for emergency hydrocortisone
Carry an emergency hydrocortisone injection kit (IM hydrocortisone 100 mg) for crisis management — available on prescription in SA
Moderate-intensity exercise requires no dose adjustment in most patients
Build exercise intensity gradually — especially if deconditioned from previous poor hormonal control
CAH in Females (46,XX): The PCOS Overlap
Adult females with CAH — both classic and non-classic — frequently present with features indistinguishable from PCOS:
Polycystic-appearing ovaries on ultrasound
Oligomenorrhoea or amenorrhoea
Hirsutism, acne
Central obesity and insulin resistance
Reduced fertility
The key distinguishing test is an early morning (8 am) or ACTH-stimulated 17-OHP level. Women with NCAH are frequently misdiagnosed with PCOS for years. Correct diagnosis matters for treatment: NCAH responds to low-dose glucocorticoid supplementation (often dexamethasone 0.25 mg at night to suppress nocturnal ACTH), which is different from standard PCOS treatment. Weight loss responds better once the underlying androgen excess is adequately treated.
CAH in Males (46,XY)
CAH males face specific issues affecting weight and body composition:
Testicular adrenal rest tumours (TARTs) — ectopic adrenal tissue in the testes, common in poorly controlled CAH males; can cause subfertility and testicular discomfort; improving CAH control reduces TARTs
Short stature — excess androgens in childhood accelerate bone maturation; adult height often below genetic potential
Increased central adiposity — particularly with over-treatment (Cushingoid pattern)
Reduced bone density — from both the disease and glucocorticoid treatment
Monitoring in CAH
Measurement
Frequency
Target
Why It Matters
17-OHP (17-hydroxyprogesterone)
Every 3–6 months
Upper normal range (not fully suppressed)
Marker of androgen precursor excess; guides glucocorticoid dosing
Androstenedione, DHEA-S, testosterone
Every 6 months
Within normal range for sex/age
Androgen excess drives weight gain and PCOS-like features
Several newer therapies are changing CAH management and have important weight implications:
Crinecerfont (Neurocrine Biosciences) — a CRF1 receptor antagonist that suppresses ACTH directly at the pituitary, allowing glucocorticoid doses to be meaningfully reduced while maintaining androgen control. Clinical trial data shows significant weight reduction as glucocorticoid doses decrease. Not yet available in SA but likely to transform practice globally within the next few years.
Tildacerfont — similar CRF1 receptor antagonist mechanism; in late-stage clinical trials
Continuous subcutaneous hydrocortisone infusion — mimics the natural cortisol diurnal rhythm more precisely than oral tablets; may reduce glucocorticoid burden and improve metabolic outcomes; available at very limited specialist centres internationally
CAH Support in South Africa
Steve Biko Academic Hospital, Pretoria — adult and paediatric endocrinology; major public sector CAH management centre
Red Cross War Memorial Children's Hospital, Cape Town — leading paediatric endocrinology unit in SA
Inkosi Albert Luthuli Central Hospital, Durban — paediatric and adult endocrinology
Rare Diseases South Africa (RDSA): rarediseases.co.za
CARES Foundation (international): caresfoundation.org — excellent CAH-specific resources including diet guides and patient community
Endocrine Society of South Africa (ESSA): endocrine.org.za
Managing weight with an adrenal or hormonal condition in South Africa?
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Key Takeaways
CAH causes cortisol deficiency, and often aldosterone deficiency, with androgen excess — all three hormonal imbalances affect body composition
Lifelong glucocorticoid replacement is non-negotiable and life-saving, but promotes central adiposity and insulin resistance as side effects
Optimal dose calibration — neither over- nor under-treating — is the single most important weight management intervention in CAH
A low-glycaemic, high-fibre diet with adequate lean protein counteracts glucocorticoid-driven insulin resistance
Resistance and aerobic exercise both counteract glucocorticoid-induced muscle loss and fat deposition — strongly recommended
Never reduce glucocorticoid doses without specialist supervision — adrenal crisis is life-threatening
Non-classic CAH (NCAH) frequently masquerades as PCOS — if standard PCOS treatment is not working, ask about 17-OHP testing