The correct answer is- Normal bruising from toddler activity. Bruises on the shins are common in active toddlers and are usually not indicative of abuse. Differential diagnoses include non-accidental injury, vitamin deficiency, coagulation disorder, allergic reaction, eczema, contact dermatitis, and insect bites.

Pityriasis rosea is the most likely diagnosis given the patient’s history of a herald patch and the appearance of the rash. Tinea corporis is a fungal infection that typically presents with a red, scaly rash with a clear center. Psoriasis is a chronic inflammatory skin condition that is characterized by red, scaly patches of skin. Eczema is a chronic inflammatory skin condition that is often associated with allergies and asthma. Drug eruption is a rash caused by an allergic reaction to a medication.

Lisa’s symptoms are suggestive of lichen sclerosus, which requires treatment with potent topical corticosteroids and regular follow-up due to the increased risk of squamous cell carcinoma. Differential diagnoses include: 1. Lichen sclerosus, 2. Atrophic vaginitis, 3. Vulvar intraepithelial neoplasia, 4. Chronic vulvovaginal candidiasis, 5. Psoriasis, 6. Lichen planus, 7. Intertrigo. The wrong answers either misdiagnose or inadequately manage the risk factors involved.

The most appropriate management is to discontinue the irritant and use topical corticosteroids . The appearance of the rash after starting a new detergent suggests allergic contact dermatitis. Dapsone is used for dermatitis herpetiformis, permethrin is for scabies, a gluten-free diet is for dermatitis herpetiformis, and oral antihistamines may help with itching but do not address the underlying cause. Differential diagnoses include eczema, psoriasis, and urticaria.

For a red-back spider bite with localized symptoms only, the most appropriate treatment is to apply ice to the bite area and provide analgesics for pain management. Antivenom and antibiotics are not typically required unless there are signs of severe envenomation or secondary infection. Differential diagnoses include: red-back spider bite, cellulitis, allergic reaction, local trauma, insect bite, abscess formation, and non-venomous spider bite.

The correct answer is- Explain that geographic tongue is benign and not cancerous. Reassuring the patient about the benign nature of geographic tongue can alleviate his concerns. Differential diagnoses include oral candidiasis, tongue cancer, iron deficiency anemia, herpes simplex infection, vitamin B12 deficiency, allergic reactions, and lichen planus.

Otitis externa is the most likely diagnosis given the patient’s history of surfing, ear canal debris, and pain with earlobe movement. The symptoms are consistent with inflammation and infection of the external ear canal.

Correct answer is – MRI of the brain and internal auditory canal. This investigation can help rule out acoustic neuroma and other central causes of sudden sensorineural hearing loss. Tympanometry and pure tone audiometry assess hearing loss but do not identify the underlying cause. A CT scan is less sensitive for soft tissue lesions like neuromas. Blood glucose level is irrelevant to the immediate investigation of hearing loss. Differential diagnoses include acoustic neuroma, labyrinthitis, sudden idiopathic sensorineural hearing loss, vascular events, and multiple sclerosis.

The correct answer is- Acute pancreatitis. The combination of epigastric pain radiating to the back and elevated lipase levels is indicative of acute pancreatitis, commonly associated with alcohol use. Differential diagnoses include peptic ulcer disease, gallstones, gastritis, hepatitis, myocardial infarction, esophageal spasm, and biliary colic.

The correct answer is- Refer urgently to a hematologist. The presence of anemia, lymphadenopathy, and weight loss warrants urgent referral for further investigation. Differential diagnoses include infectious mononucleosis, iron deficiency anemia, depression, substance abuse, chronic fatigue syndrome, tuberculosis, and non-Hodgkin’s lymphoma.

Correct answer: Susan’s presentation is highly suggestive of a possible ectopic pregnancy, and a serum beta-hCG test is crucial for diagnosis. Differential diagnoses include: 1) Ectopic pregnancy, 2) Acute appendicitis, 3) Ovarian torsion, 4) Ruptured ovarian cyst, 5) Pelvic inflammatory disease, 6) Endometriosis, 7) Urinary tract infection. B – An ultrasound is important but follows confirmation of pregnancy. C – Antibiotics are not indicated without confirmation of PID. D – Laparotomy is invasive and follows confirmation. E – NSAIDs do not address the potential ectopic pregnancy.

The Red Book promotes evidence-based medicine, ensuring that recommended interventions offer clear benefits for specific populations. Screening tests without proven benefit are not recommended to avoid potential risks.

Methotrexate, in combination with folic acid, is used to manage rheumatoid arthritis by modifying the disease course and preventing joint damage. Folic acid is given to reduce the side effects of methotrexate, such as gastrointestinal issues and mucositis. Differential diagnoses for consideration include rheumatoid arthritis, SLE, osteoarthritis, gout, psoriatic arthritis, viral arthritis, and spondyloarthritis. Methotrexate is effective in managing rheumatoid arthritis and modifying the disease course, while folic acid helps mitigate its side effects.

The correct answer is- Seronegative rheumatoid arthritis. A positive anti-CCP with a negative rheumatoid factor suggests seronegative rheumatoid arthritis, which can still be aggressive and requires treatment. Osteoarthritis, SLE, gout, and fibromyalgia have different diagnostic profiles. Differential diagnoses include seronegative rheumatoid arthritis, osteoarthritis, SLE, psoriatic arthritis, gout, viral arthritis, and spondyloarthritis.

Topical estrogen therapy is the most appropriate initial management for postmenopausal women experiencing dyspareunia due to vaginal atrophy. Referral to a pelvic pain specialist may be needed if symptoms persist. Cognitive-behavioral therapy is more appropriate for psychological factors. Vaginal dilators and pelvic floor physical therapy may be considered if topical estrogen therapy fails, but are not first-line treatments. Differential diagnoses include vaginal atrophy, vulvovaginal atrophy, lichen planus, endometriosis, pelvic inflammatory disease, vestibulodynia, and vulvodynia.

Polycystic ovary syndrome (PCOS) is the most likely cause given Maria’s irregular menstrual cycles and hirsutism. Tubal obstruction is less likely with normal semen analysis. Hyperprolactinemia usually presents with additional symptoms. Endometriosis often has different symptoms. Uterine fibroids would present with other symptoms. Differential diagnoses include PCOS, hypothyroidism, ovarian insufficiency, early menopause, chronic anovulation, adrenal hyperplasia, and stress-related infertility.

Correct answer: Order serological tests for tick-borne diseases
Given Mia’s symptoms and travel history, Lyme disease should be considered. Serological tests can confirm tick-borne diseases like Lyme disease, which may present with a rash, fever, and joint pain.

Incorrect answers:
❌ Start oral antihistamines – Antihistamines are not appropriate for suspected tick-borne diseases like Lyme disease.
❌ Administer intravenous antibiotics – Antibiotics should be considered only after confirming a diagnosis, not as the first step.
❌ Provide supportive care and monitor – While supportive care is important, it does not address the potential underlying infectious cause.
❌ Initiate corticosteroid therapy – Steroids may be necessary for certain conditions but should not be started without a confirmed diagnosis.

Learning Objective:
To recognize tick-borne diseases in travelers and understand the role of serological testing in diagnosis.. Differential diagnoses include: 1) Lyme disease, 2) Rocky Mountain spotted fever, 3) Viral exanthem, 4) Juvenile idiopathic arthritis, 5) Rheumatic fever, 6) Parvovirus infection, 7) Systemic lupus erythematosus. A – Antihistamines are not indicated for suspected tick-borne disease. B – Antibiotics may be needed but should follow confirmation of diagnosis. D – Supportive care is important but does not address the underlying cause. E – Steroids may be used in certain conditions but not as an initial step without diagnosis.

The most appropriate management is urgent laparoscopy due to the presence of circulatory collapse and severe pain, indicating a possible ruptured ectopic pregnancy. Differential diagnoses include: 1. Ectopic pregnancy, 2. Ovarian torsion, 3. Acute appendicitis, 4. PID, 5. Ovarian cyst rupture, 6. Endometriosis, 7. Gastrointestinal perforation.

The correct answer is- Sarcoidosis is compatible with a long and active life. Most patients with sarcoidosis have a good prognosis and can lead normal lives, although some may require intermittent treatment. Differential diagnoses include tuberculosis, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, granulomatosis with polyangiitis, systemic lupus erythematosus, thyroid cancer, and metastatic breast cancer.

The appropriate management step for retinal detachment is immediate referral for sealing of retinal tears. The symptoms suggest retinal detachment, which requires urgent surgical intervention. Differential diagnoses include vitreous haemorrhage, central retinal artery occlusion, and central retinal vein thrombosis.

The most appropriate initial treatment for a confirmed DVT is to start low molecular weight heparin (LMWH), such as enoxaparin, to prevent further clot formation and embolization. Differential diagnoses include cellulitis, Baker’s cyst, muscle strain, venous insufficiency, lymphedema, and superficial thrombophlebitis. Oral aspirin is not effective for treating DVT. Thrombolytic therapy is reserved for massive DVT with severe symptoms. Warfarin is typically started after LMWH, not immediately. Compression stockings are supportive but not a primary treatment.

The most appropriate management involves prescribing analgesics and encouraging deep breathing to prevent complications such as pneumonia. Differential diagnoses include: rib fracture, pneumothorax, lung contusion, splenic injury, hepatic injury, kidney trauma, and intercostal muscle strain. Elastic rib belts or surgical interventions are less supported by evidence or unnecessary for simple fractures.

The correct answer is- Abstain from sexual activity during outbreaks. Avoiding sexual contact during active outbreaks reduces the risk of transmission to partners. Differential diagnoses include syphilis, gonorrhea, chlamydia, balanitis, chancroid, fixed drug eruption, and Behçet’s disease.

Referral for adenotonsillectomy is the most appropriate management for a child with obstructive sleep apnea due to enlarged tonsils. Differential diagnoses include: 1) Allergic rhinitis 2) Asthma 3) Attention deficit hyperactivity disorder 4) Gastroesophageal reflux disease 5) Obesity 6) Craniofacial abnormalities 7) Neuromuscular disorders

The correct answer is- Chromosomal abnormalities. Early miscarriages are often due to isolated chromosomal abnormalities, which are usually not recurrent. Differential diagnoses include uterine abnormalities, hormonal imbalance, infection, immunological disorders, cervical incompetence, lifestyle factors, and thrombophilia.

Obesity is a major risk factor for a number of chronic diseases, including type 2 diabetes, heart disease, stroke, and sleep apnea. It is important to address obesity early to reduce the risk of these complications.

The correct answer is- Non-maleficence (do no harm). The GP must ensure that any action taken does not intentionally harm the patient, such as administering a medication with the intent to hasten death. Differential diagnoses include ethical dilemmas in palliative care, end-of-life care issues, anxiety in family members, misunderstanding of medical processes, potential elder abuse, depression in family members, and caregiver fatigue.

The correct answer is- Polymyalgia rheumatica (PMR). The age of the patient, sudden onset of stiffness, and prolonged morning stiffness are characteristic of PMR. Other conditions like rheumatoid arthritis and fibromyalgia have different clinical presentations. Differential diagnoses include rheumatoid arthritis, osteoarthritis, fibromyalgia, depression, multiple myeloma, temporal arteritis, and hypothyroidism.

Blood glucose level, urine analysis, and HbA1c are necessary to confirm the diagnosis of type 1 diabetes mellitus. Thyroid function tests can help to rule out hyperthyroidism as a possible cause of the patient’s symptoms.

The correct answer is- Corneal light reflex test. The corneal light reflex test helps assess eye alignment by observing the reflection of light on the corneas. Differential diagnoses include congenital esotropia, intermittent exotropia, pseudostrabismus, refractive error, retinoblastoma, cataract, and neurological disorder.

The likely diagnosis is dry macular degeneration . It presents with gradual loss of central vision and distortion of vision. Differential diagnoses include wet macular degeneration, retinal detachment, central retinal artery occlusion, and vitreous haemorrhage.

The correct answer is- Malabsorption due to Coeliac disease. Coeliac disease can cause malabsorption, leading to iron deficiency anemia and fatigue. Noncompliance with a gluten-free diet could contribute, but malabsorption is the direct cause. Differential diagnoses include iron deficiency anemia, vitamin B12 deficiency, folate deficiency, inflammatory bowel disease, small intestinal bacterial overgrowth, chronic gastrointestinal bleeding, and thyroid dysfunction.

The patient’s presentation, including persistent lymphadenopathy and elevated lymphocytes, with a blood film showing sparse cytoplasm, is indicative of Chronic Lymphocytic Leukaemia (CLL). This condition is common in older adults and often presents with lymphadenopathy and elevated lymphocytes. Acute lymphoblastic leukaemia and other conditions like infectious mononucleosis or myeloma have different clinical and laboratory features.

Correct answer is to refer to a hepatologist for further assessment and potential antiviral therapy. Differential diagnoses include autoimmune hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease, hemochromatosis, Wilson’s disease, alpha-1 antitrypsin deficiency, and drug-induced liver injury. Vaccination is inappropriate in an already infected patient; antivirals might be necessary but require specialist input; lifestyle modifications alone are insufficient; liver biopsy may be considered after hepatology consultation.

Endoscopy is useful for assessing oesophageal causes of chest pain, such as GERD. An exercise stress test and transthoracic echocardiography are more relevant for cardiac causes. Serum enzymes and chest X-ray do not directly assess oesophageal conditions. Endoscopy allows direct visualization of the esophagus and can identify inflammation or structural abnormalities.

Transoesophageal echocardiography (TOE) is the most sensitive investigation for aortic dissection. A chest X-ray and transthoracic echocardiography are useful but less sensitive. An exercise stress test and serum enzymes are not relevant for diagnosing aortic dissection. TOE provides detailed images of the aorta and can quickly confirm the presence of a dissection.

An exercise stress test is most appropriate to define the cardiac origin of chest pain during exercise. A chest X-ray and transthoracic echocardiography are useful but do not specifically assess exercise-induced ischemia. Blood glucose and haemoglobin tests are not directly related to diagnosing cardiac chest pain. The exercise stress test evaluates for myocardial ischemia by assessing ECG changes during physical exertion.

Retained tampons can cause persistent discharge and irritation. Removing the tampon and managing any resultant infection or irritation is crucial. Differential diagnoses include: 1. Retained foreign objects (e.g., tampons), 2. Bacterial vaginosis, 3. Candida albicans, 4. Atrophic vaginitis, 5. Contact dermatitis, 6. Diabetes-related infections, 7. Vulvar malignancies.

The most appropriate action for the GP in this situation is to repeat the blood test to confirm the results. The eGFR calculation may be inaccurate due to factors such as ethnicity and age. It is important to confirm the diagnosis of chronic kidney disease before initiating any treatment or referral. Explaining the results to the patient and monitoring kidney function are important, but they should be done after confirming the diagnosis. Starting treatment with antihypertensive medication is not necessary at this stage, as the patient’s blood pressure is already well controlled.

Patient education is crucial in the management of BPH. The patient should be informed about the importance of regular follow-up appointments, lifestyle modifications to improve symptoms, the potential complications of BPH, and the importance of seeking medical attention for worsening symptoms.

Rheumatic fever is associated with a history of untreated sore throats, fever, joint pain, and rash. Differential diagnoses include systemic lupus erythematosus, infective endocarditis, viral exanthema, reactive arthritis, rheumatoid arthritis, and Kawasaki disease. A is incorrect as systemic lupus erythematosus would have additional systemic involvement. B is incorrect as infective endocarditis would present with a history of intravenous drug use or prosthetic valves. C is incorrect as viral exanthema would not cause joint pain. E is incorrect as reactive arthritis follows gastrointestinal or genitourinary infections.

Diabetic Nephropathy (DN)

Diabetic nephropathy (DN) is exceedingly common in patients with both type 1 and type 2 diabetes mellitus and is characterized by persistent albuminuria (>30 mg/g) and/or decreased glomerular filtration rate (GFR) (e.g., elevated creatinine). DN is typically slowly progressive for years before clinical signs occur.

The diagnosis is usually made clinically, with renal biopsy reserved for patients with an unclear presentation. In the absence of signs suggesting another etiology (e.g., casts in the urine, rapid progression of renal dysfunction), the diagnosis can be presumed in patients who have persistent albuminuria and/or decreased GFR and either of the following:

• Prolonged history of diabetes:

  • Type 1 diabetes is typically clinically obvious at onset; therefore, DN may be assumed in those with a disease duration of ≥5 years.
  • In contrast, type 2 diabetes is often asymptomatic, so patients may have this disorder for years before diagnosis, making the duration of the disease difficult to calculate.

• Proliferative Diabetic Retinopathy (PDR):

  • Both PDR (i.e., retinal neovascularization) and DN are chronic microvascular complications of diabetes due to persistent hyperglycemia, so the presence of PDR correlates with diabetic kidney disease.
  • Therefore, patients may be diagnosed with DN if there is concomitant PDR, regardless of the length of time since diagnosis.

Differential Diagnoses

• (Choice A) Renal Size Discrepancy

  • Seen in patients with unilateral chronic kidney disease (e.g., renal artery stenosis, ureteral obstruction).
  • With prolonged DN, both kidneys would likely be shrunken and atrophic.

• (Choice B) Left Ventricular Hypertrophy (LVH)

  • Correlates with chronic, uncontrolled hypertension.
  • Although uncontrolled hypertension may be seen in patients with chronic kidney disease, it is not specific for DN.

• (Choice C) Microscopic Hematuria

  • Although microscopic hematuria may occur with DN, it is nonspecific and may be seen in a variety of diseases (e.g., malignancy, nephritic syndromes).

• (Choice D) Rapidly Progressive Renal Dysfunction

  • DN usually develops over a prolonged period (years).
  • Rapidly progressive renal dysfunction suggests an alternate diagnosis (e.g., lupus nephritis) and further workup.
  • Renal biopsy may be indicated.

Learning Objective

Diabetic nephropathy (DN) is characterized by persistent albuminuria (>30 mg/g) and/or decreased glomerular filtration rate. In the absence of signs suggestive of another etiology, the diagnosis can be presumed in patients with renal dysfunction and either:

• A prolonged history of diabetes (≥5 years for type 1 diabetes)
• Proliferative diabetic retinopathy, which correlates with the presence of DN

Type 2 Diabetes in Adolescents and Young Adults

This patient with a new diagnosis of diabetes mellitus (elevated hemoglobin A1c level, symptomatic hyperglycemia [e.g., polydipsia], vulvovaginal candidiasis) likely has type 2 diabetes. Although type 2 diabetes is more common in older individuals, the incidence in adolescents and young adults is increasing in association with a rise in childhood obesity (e.g., BMI ≥95th percentile for age).

Excess adiposity contributes to insulin resistance, which is further aggravated by rising growth hormone levels at puberty. A positive family history of diabetes increases the risk; the incidence is also higher in certain racial and ethnic groups (e.g., Black and Native American patients).

Associated Features of Insulin Resistance

• Central (visceral) obesity
• Elevated blood pressure
• Lipid abnormalities (e.g., hypertriglyceridemia, decreased HDL levels)
• Acanthosis nigricans: Velvety, hyperpigmented patches in intertriginous areas (e.g., neck, axillae)

Differential Diagnoses

• (Choice A) Growth Hormone-Secreting Pituitary Adenoma

  • Can cause diabetes mellitus
  • Bitemporal hemianopia may occur due to optic chiasm compression
  • However, patients typically display gigantism or acromegaly rather than obesity

• (Choice B) Chronic Pancreatitis

  • Can lead to exocrine pancreatic insufficiency → steatorrhea
  • Loss of beta cells can cause secondary diabetes
  • However, this is much more common at age >30 and is typically associated with:
    • Chronic abdominal pain
    • Nausea
    • Weight loss

• (Choice D) Glucokinase Gene Mutation (MODY – Maturity-Onset Diabetes of the Young)

  • Characterized by decreased insulin secretion at any glucose level
  • Patients are typically not obese
  • Hyperglycemia is usually mild (<140 mg/dL)

• (Choice E) Autoimmune Type 1 Diabetes

  • Pancreatic autoantibodies cause loss of islet cells
  • Leads to absolute insulin deficiency (vs. relative deficiency in type 2 diabetes)
  • Increased ketone production can lead to diabetic ketoacidosis (DKA)
  • Typical features include:
    • Rapid-onset hyperglycemia
    • Ketonuria (absent in this patient)
    • Hyperventilation
    • Abdominal pain

Learning Objective

The incidence of type 2 diabetes in adolescents and young adults is increasing due to rising childhood obesity. Excess adiposity contributes to insulin resistance, which is further aggravated by pubertal growth hormone levels. Other findings associated with insulin resistance include acanthosis nigricans, central obesity, hypertension, and lipid abnormalities.

Hyperprolactinemia Due to Antipsychotic Use

This patient’s history of paranoia, social isolation, and disorganized behavior suggests psychosis, likely being treated with an antipsychotic medication. Antipsychotic drugs block dopamine, and since dopamine inhibits prolactin release, dopamine blockade in the tuberoinfundibular pathway can lead to hyperprolactinemia. This can result in gynecomastia, galactorrhea, menstrual dysfunction, and decreased libido.

Risperidone, a commonly used second-generation antipsychotic (SGA), is known for its high frequency of prolactin elevation and is the most likely cause of this patient’s symptoms.

Differential Diagnoses

• (Choice A) Aripiprazole

  • Functions as a dopamine D2 receptor antagonist and partial agonist
  • Due to its partial agonism, it is less likely to cause hyperprolactinemia

• (Choice B) Galactocele

  • A benign milk collection in lactating women, usually due to a blocked duct
  • This patient’s pregnancy test is negative, and there is no indication of breastfeeding

• (Choice C) Hypothyroidism

  • Can predispose to hyperprolactinemia, but typically presents with:
    • Lethargy
    • Dry skin
    • Cold intolerance
  • This patient has none of these symptoms, and her TSH level is normal

• (Choice D) Polycystic Ovary Syndrome (PCOS)

  • Associated with elevated androgens, leading to:
    • Acne
    • Hirsutism
    • Menstrual irregularities
  • Can occasionally cause elevated prolactin levels, but this patient lacks symptoms of hyperandrogenism

• (Choice E) Prolactinoma

  • A benign pituitary tumor causing:
    • Headaches
    • Visual disturbances (due to mass effect)
  • Can lead to extremely high prolactin levels (>200 ng/ml)
  • In contrast, medication-induced hyperprolactinemia typically results in prolactin levels between 25-100 ng/ml

• (Choice G) Valproate

  • An anticonvulsant used for:
    • Bipolar disorder
    • Seizures
  • Does not cause galactorrhea, but is associated with:
    • Blood dyscrasias
    • Liver toxicity

Learning Objective

Antipsychotic medications can cause hyperprolactinemia due to dopamine blockade in the tuberoinfundibular pathway. Risperidone has a particularly high risk of prolactin elevation. In contrast, prolactinomas typically produce very high prolactin levels (>200 ng/ml), whereas antipsychotic-induced hyperprolactinemia generally results in levels between 25-100 ng/ml.

Short Stature and Constitutional Growth Delay

This patient has short stature, defined as height below the 2nd percentile for sex and age. The most common causes of short stature are constitutional growth delay and familial short stature.

Constitutional Growth Delay

• Recognized by a delayed bone age and a normal linear growth velocity starting around age 3
• Affected children typically have a normal birth weight and height but exhibit slowed linear growth velocity between 6 months and 3 years, leading to a height below the 2nd percentile
• After age 3, growth resumes at a normal rate (ie, normal growth velocity), with the growth curve remaining below but parallel to the lowest percentile line
• Delayed puberty, including late adolescent growth spurt
• Bone age (skeletal maturation) is delayed relative to chronological age
• Ultimately, patients experience a normal growth spurt and achieve a normal adult height

Management

• Reassurance and monitoring of linear growth velocity

Differential Diagnoses

• (Choice A) Celiac Disease

  • Can cause short stature and delayed bone age
  • Typically presents with weight loss and gastrointestinal symptoms (eg, diarrhea, abdominal distension)
  • This patient has appropriate weight gain and no gastrointestinal symptoms

• (Choice C) Familial Short Stature

  • Bone age is normal and matches chronologic age
  • Puberty is not delayed
  • Patients have a normal linear growth velocity (stable percentile), similar to constitutional growth delay
  • One or both parents also have short stature (not the case in this patient)
  • Final adult height remains low

• (Choice D) Growth Hormone Deficiency

  • Causes short stature, delayed puberty, and delayed bone age
  • Slowed linear growth velocity, with height percentiles crossing 2 major percentiles downward (eg, from 50th to 25th)
  • This patient’s height percentile is stable, suggesting normal linear growth velocity

• (Choice E) Hypogonadism (Testosterone Deficiency)

  • Can be congenital (eg, Klinefelter syndrome) or acquired (eg, testicular trauma or infection)
  • Delayed puberty, but normal bone age
  • Most patients have gynecomastia, which is not present in this case
  • Often associated with increased LH, FSH, and estradiol due to lack of testosterone’s negative feedback

• (Choice F) Hypothyroidism

  • Causes declining linear growth velocity and pubertal delay
  • This patient’s linear growth velocity is normal
  • No symptoms of hypothyroidism (eg, fatigue, constipation, cold intolerance)

Learning Objective

Constitutional growth delay is characterized by short stature (height below the 2nd percentile), delayed bone age, and a normal linear growth velocity after age 3. Delayed puberty is common, but patients eventually experience a normal growth spurt and achieve a normal adult height.

Nutritional Rickets

Nutritional rickets is most commonly caused by vitamin D deficiency, which is essential for calcium metabolism and skeletal growth. Risk factors include limited sun exposure and increased skin pigmentation. Exclusively breastfed infants who do not receive vitamin D supplementation, as in this case, are at high risk because breast milk alone contains inadequate vitamin D.

Deficiency of vitamin D and calcium results in poor bone mineralization and growth plate cartilage accumulation. Clinical features include:

• Craniotabes (skull bones that depress with pressure), as seen in this infant
• Widened wrists due to growth plate enlargement
• Radial/ulnar bowing
• Delayed fontanel closure
• Lower extremity bowing (genu varum) once the child begins weight-bearing

Diagnosis & Imaging

X-ray of rapidly growing skeletal areas (eg, wrists, knees) is helpful for diagnosis. Classic findings include:

• Metaphyseal widening with cupping and fraying (white arrow), as seen here
• Costochondral joint widening

Treatment

Treatment involves vitamin D and calcium supplementation.

Differential Diagnoses

• (Choice A) Systemic Juvenile Idiopathic Arthritis (JIA)

  • Autoimmune inflammatory disorder
  • Presents with fever, arthritis, and rash (none of which are present here)
  • X-rays show soft tissue swelling and loss of joint space, not metaphyseal changes

• (Choice B) Hurler Syndrome

  • Autosomal recessive lysosomal storage disease
  • Characterized by dysostosis multiplex (shortened, thickened long bones)
  • Other features include coarse facial features (wide nasal bridge, flat midface), developmental delay, and frequent infections, none of which are seen here

• (Choice C) HIV

  • Can be transmitted via breast milk
  • Presents with hepatosplenomegaly, lymphadenopathy, and failure to thrive, rather than bony abnormalities
  • Milk banks screen donors for infectious diseases and pasteurize milk to destroy pathogens, including HIV

• (Choice D) Congenital Syphilis

  • Often asymptomatic at birth, but may cause skeletal abnormalities
  • Can present with craniotabes and osseous destruction of long bones, but not metaphyseal cupping and fraying
  • Other findings (eg, hepatosplenomegaly, rash, lymphadenopathy) are absent in this case

• (Choice E) Nonaccidental Trauma

  • Can present with localized swelling without reported trauma
  • New and/or old fractures would be expected on x-ray
  • Craniotabes would not be present in nonaccidental trauma cases

Learning Objective

Nutritional rickets classically occurs in exclusively breastfed infants who do not receive vitamin D supplementation. It presents with craniotabes (soft skull bones) and forearm deformities (widened wrists, radial/ulnar bowing). Lower extremity bowing develops once the child starts weight-bearing.