All the following matching are true EXCEPT
Rationale:
Abduction is incorrectly matched as movement toward midline.
Abduction is actually movement away from the midline of the body, not toward it. Adduction is the term for movement toward the midline. Therefore, the pairing "abduction = movement toward midline" is anatomically incorrect, making it the exception among the given options, which are all true statements. This fundamental anatomical definition is crucial.
A: pes cavus = high medial arch of the foot
Pes cavus precisely describes a foot condition characterized by an abnormally elevated longitudinal arch, often leading to altered weight bearing and biomechanical stress.
B: pes planus = flat foot
Pes planus accurately identifies a condition where the arch on the inside of the foot collapses, resulting in the entire sole making contact with the ground.
C: subluxation = displacement of bones at a joint
Subluxation accurately defines a partial or incomplete dislocation, where articular surfaces of a joint are misaligned but still maintain some degree of contact.
A 9-year-old presents with paresis of the upper and lower portions of the face, and loss of taste on the right side of the anterior portion of the tongue. On physical examination, the corner of the mouth droops, and he is unable to close the right eye tightly. The remainder of the physical examination is normal. Which is the most likely diagnosis?
Rationale:
Bell palsy is the most likely diagnosis given the patient's symptoms.
Bell palsy is an acute idiopathic unilateral facial nerve paralysis. The patient's presentation of sudden onset right-sided upper and lower facial paresis, including mouth droop and inability to close the eye tightly, along with ipsilateral loss of taste on the anterior tongue, are characteristic signs. These findings indicate a lesion affecting the facial nerve (C
ECG changes in hypomagnesaemia is characterized by
Rationale:
ECG changes in hypomagnesaemia are characterized by prolonged PR, QRS, and QT intervals.
Hypomagnesaemia impairs normal cardiac electrical activity. Magnesium plays a crucial role in
The critical site for the renal regulation of sodium balance is the
Rationale:
The critical site for the renal regulation of sodium balance is the distal tubule.
The distal tubule and collecting duct are crucial for fine-tuning sodium reabsorption, responding to hormonal signals
Match the following terms with the common names - Talipes equinovarus
Rationale:
Talipes equinovarus is commonly known as Clubfoot.
Correct Option Explanation:
Talipes equinovarus is the precise medical term for clubfoot, a congenital deformity characterized by the foot being severely twisted inward and downward at birth. This complex condition involves structural abnormalities in the bones, muscles, tendons, and ligaments of the foot and ankle. Successful treatment often involves serial casting, bracing, or surgical intervention to gradually correct the foot's position and enable normal function and mobility.
Incorrect Options Explanation:
A: Wryneck Wryneck, or torticollis, is a medical condition involving a twisted neck that causes the head to tilt to one side. This muscular issue affects the sternocleidomastoid muscle, leading to restricted neck movement, and is entirely unrelated to foot deformities.
C: Bowlegs Bowlegs, or genu varum, describes a condition where a person's legs curve outward at the knees, resembling an arch. This developmental alignment is often normal in infants but distinct from a foot's inward rotation.
D: Knock-knees Knock-knees, or genu valgum, occurs when a person's knees touch while their ankles remain separated when standing. This skeletal alignment issue, common in young children, differs significantly from a congenital foot malformation.
The Creatine kinase (CK) which is found in only 3 organs and may be separated into corresponding isozymes: MM for skeletal muscle, MB for cardiac muscle, and BB for brain. Of the following, the CK level is characteristically elevated in
Rationale:
Duchenne muscular dystrophy characteristically elevates Creatine kinase (CK) levels.
Duchenne muscular dystrophy is a severe X-linked genetic disorder primarily affecting skeletal muscles, leading to progressive muscle degeneration. The extensive muscle damage results in the leakage of intracellular enzymes, including Creatine kinase (CK-MM), into the bloodstream. Consequently, the characteristic elevation of CK levels serves as a crucial diagnostic marker for this debilitating condition, reflecting ongoing muscle breakdown.
A: Myasthenia gravis This autoimmune neuromuscular disorder primarily affects acetylcholine receptors at the neuromuscular junction, not causing direct muscle fiber destruction; consequently, CK levels typically remain within the normal range.
B: Guillain-Barré syndrome This acute inflammatory demyelinating polyneuropathy primarily targets peripheral nerves, sparing the muscle cells themselves from direct necrotic damage that would release significant CK enzymes.
C: Werdnig-Hoffmann disease This severe form of spinal muscular atrophy involves degeneration of motor neurons, leading to muscle atrophy from disuse rather than primary muscle cell necrosis that elevates CK.
Fractures are the second most common manifestation of child abuse after skin injury (bruises, burns/abrasions). All of the following fractures suggest nonaccidental injury EXCEPT
Rationale:
Distal humeral fractures are the exception among the listed fractures that strongly suggest nonaccidental injury.
Distal humeral fractures, while requiring investigation, are common accidental injuries in children, particularly from falls onto an outstretched arm. Their occurrence doesn't inherently trigger the same high suspicion for abuse as other specific fracture types. Unlike metaphyseal or posterior rib fractures, their mechanism often aligns with typical childhood accidents, making them less specific indicators of inflicted trauma without additional suspicious findings.
A: femur fractures in nonambulatory children Femur fractures in infants too young to walk are highly suspicious for abuse because significant force is required, and accidental mechanisms are extremely rare in this age group.
B: distal femoral metaphyseal corner fractures Metaphyseal corner fractures, also known as classic metaphyseal lesions, are pathognomonic for child abuse, typically resulting from violent shaking or pulling forces applied to a limb.
C: posterior rib fractures Posterior rib fractures are virtually diagnostic of abuse, caused by forceful compression of the chest, often from squeezing or blunt trauma, which is inconsistent with common accidental mechanisms.
Which is the etiology of most cases of myasthenia gravis?
Rationale:
Autoimmune disorder is the etiology of most cases of myasthenia gravis.
Myasthenia gravis is predominantly an acquired autoimmune condition where the body's immune system mistakenly produces antibodies that attack and destroy or block acetylcholine receptors at the neuromuscular junction. This immune-mediated attack impairs nerve-muscle signal transmission, leading to characteristic muscle weakness and fatigue. While genetic susceptibility plays a role, the disease itself is not directly inherited in the vast majority of instances.
A: Inheritance as a recessive trait Myasthenia gravis is not typically inherited as a simple Mendelian recessive trait; it's an acquired autoimmune condition. Genetic factors might increase susceptibility, but direct recessive inheritance is not its primary etiology.
B: Inheritance as an X-linked trait Myasthenia gravis is not an X-linked genetic disorder. While some congenital forms exist, the vast majority of cases are acquired autoimmune diseases, not linked to sex chromosomes for their primary inheritance pattern.
C: Postinfectious, usually after either influenza or chickenpox While infections can sometimes trigger or exacerbate autoimmune responses, myasthenia gravis is not primarily classified as a postinfectious disorder following specific common viral illnesses like influenza or chickenpox.
Infants are born with maximum genu varum. The lower extremity straightens out around the age of
Rationale:
The lower extremity straightens out around the age of 24 months.
Physiological genu varum, prominent at birth, typically begins resolving as infants bear weight and walk. By approximately 2
Gowers sign is fully expressed by the age of
Rationale:
Gowers sign is fully expressed by the age of 5 yr.
The characteristic Gowers sign, indicative of proximal muscle weakness, becomes distinctly and consistently observable around five years of age. Children with conditions like Duchenne muscular dystrophy often develop this compensatory maneuver to stand up from the floor, using their hands to "climb up" their legs, as the progressive weakness significantly impacts their motor function by this age.
A: 3 yr: While early signs of muscle weakness may be present, the full, characteristic Gowers maneuver involving distinct limb-climbing is typically not yet fully developed or consistently observed at three years.
C: 7 yr: By seven years, Duchenne muscular dystrophy often progresses to a point where Gowers sign might be less consistently observed as ambulation becomes severely compromised or lost, making the full expression less relevant.
D: 9 yr: At nine years, children with Duchenne muscular dystrophy are usually non-ambulatory, meaning Gowers sign would no longer be observable as they are unable to stand up from the floor independently.
Which medical condition is regarded a contraindication for sport participation?
Rationale:
Atlantoaxial instability is regarded a contraindication for sport participation.
Atlantoaxial instability presents a significant risk of severe spinal cord injury during sports, especially those involving contact or hyperextension of the neck. Trauma to the unstable cervical spine can lead to irreversible neurological damage, including paralysis or death. Therefore, restricting participation in sports is crucial to protect the athlete from catastrophic consequences.
B: splenomegaly Splenomegaly, while potentially increasing rupture risk in contact sports, isn't a universal contraindication for all sport participation; many non-contact activities remain permissible with appropriate medical guidance.
C: carditis Carditis, or inflammation of the heart muscle, often necessitates temporary activity restriction during the acute phase but typically doesn't preclude future sport participation once resolved and medically cleared.
D: long-QT syndrome Long-QT syndrome is a serious cardiac condition requiring careful management and sometimes activity modification, but it doesn't automatically contraindicate all sport participation; some individuals can participate under strict medical supervision.
Asymptomatic hyponatremia is seen in
Rationale:
Hyperglycemia can lead to asymptomatic hyponatremia.
Hyperglycemia causes an osmotic shift of water from the intracellular to the extracellular compartment, diluting serum sodium. This is known as pseudohyponatremia or dilutional hyponatremia. The increased glucose concentration effectively pulls water out of cells, lowering the measured sodium concentration without necessarily indicating a true deficit of total body sodium. This shift typically prevents severe neurological symptoms, maintaining an asymptomatic state.
A: cirrhosis Cirrhosis often causes dilutional hyponatremia due to impaired free water excretion and increased ADH, leading to symptomatic fluid overload and more pronounced electrolyte imbalance.
B: tap water enema Tap water enemas introduce hypotonic fluid into the colon, which can be rapidly absorbed, causing acute, often symptomatic, severe dilutional hyponatremia and water intoxication.
C: child abuse Child abuse is not a direct physiological cause of hyponatremia; however, forced water ingestion (water intoxication) as a form of abuse can induce severe, symptomatic hyponatremia.
In treatment of hyperkalemia, which measure removes potassium from the body?
Rationale:
Loop diuretic (IV or PO) directly removes potassium from the body.
Loop diuretics, such as furosemide, enhance renal excretion of potassium by inhibiting the reabsorption of sodium and chloride in the thick ascending limb of the loop of Henle. This action promotes increased urine flow and subsequent elimination of potassium through the kidneys, effectively lowering serum potassium levels in hyperkalemia. This is a definitive removal mechanism.
A: sodium bicarbonate administration (IV) Sodium bicarbonate shifts potassium intracellularly by correcting acidosis, but it does not facilitate its removal from the body. This measure redistributes potassium without eliminating it.
C: insulin and glucose (IV) Insulin, aided by glucose to
In Guillain-Barré syndrome, the paralysis usually follows a nonspecific gastrointestinal or respiratory infection by approximately 10 days. Of the following, the MOST likely respiratory infection that triggers the disease is
Rationale:
Mycoplasma pneumoniae is the MOST likely respiratory infection that triggers Guillain-Barré syndrome.
Mycoplasma pneumoniae is a well-established antecedent infection frequently linked to the development of Guillain-Barré syndrome. Its atypical pneumonia often precedes neurological symptoms by days to weeks, initiating an autoimmune response that targets peripheral nerves. The molecular mimicry between Mycoplasma antigens and gangliosides on nerve cells is a primary mechanism driving this post-infectious demyelination, making it a significant trigger for the disease.
A: Chlamydia trachomitis Chlamydia trachomitis primarily causes sexually transmitted infections or ocular infections, not typically a respiratory infection leading to Guillain-Barré syndrome. Its pathogenic mechanisms rarely involve the systemic autoimmune mimicry seen with respiratory pathogens triggering GBS.
B: Staphylococcal aureus Staphylococcal aureus is a common bacterial pathogen causing various infections, but it is not a recognized or frequent antecedent respiratory infection specifically associated with triggering Guillain-Barré syndrome development. Its infections seldom precipitate this specific post-infectious neuropathy.
C: Haemophilus influenzae Haemophilus influenzae can cause respiratory infections, yet it is not commonly identified as a primary trigger for Guillain-Barré syndrome. While other bacterial infections can precede GBS, Haemophilus does not share the strong epidemiological link observed with Mycoplasma pneumoniae.
Syndactyly is one of the common anomalies observed in the upper limb. All the following syndromes are associated with syndactyly EXCEPT
Rationale:
Laurence-Moon-Biedl syndrome is the exception among the listed conditions, as it is not typically associated with syndactyly.
This syndrome primarily presents with retinal degeneration, obesity, intellectual disability, hypogonadism, and polydactyly, not syndactyly. While polydactyly involves extra digits, syndactyly is the fusion of digits. Therefore, Laurence-Moon-Biedl syndrome stands out as not featuring syndactyly among its characteristic limb anomalies, distinguishing it from the other syndromes which do.
A: Carpenter syndrome Carpenter syndrome is an acrocephalopolysyndactyly disorder, characteristically involving craniosynostosis, heart defects, and notable cutaneous syndactyly, particularly of the third and fourth fingers, and fusion of toes.
B: Ellis-van Creveld syndrome Ellis-van Creveld syndrome, also known as chondroectodermal dysplasia, frequently manifests with short limbs, narrow chest, heart defects, and a high incidence of postaxial polydactyly and partial syndactyly.
D: Trisomy 13 Trisomy 13, or Patau syndrome, is a severe chromosomal disorder. Infants often exhibit profound developmental anomalies, including microphthalmia, cleft lip/palate, cardiac defects, and frequently demonstrate postaxial polydactyly and mild syndactyly.
Increased production of CO2 occurs in all the following EXCEPT
Rationale:
Emesis does not lead to increased CO2 production.
Emesis, or vomiting, primarily involves the expulsion of stomach contents and is not directly associated with an increase in metabolic rate or cellular respiration. While it can be a strenuous activity, the physiological mechanisms driving emesis do not inherently elevate systemic CO2 generation. Instead, conditions like metabolic alkalosis might result from significant fluid and acid loss, which is distinct from CO2 production.
A: fever Fever elevates the body's metabolic rate, increasing cellular respiration and oxygen consumption. This heightened metabolic activity directly results in greater carbon dioxide production as a byproduct of energy metabolism throughout the body's tissues.
C: excess caloric intake Consuming excess calories, particularly carbohydrates and fats, leads to increased substrate oxidation and energy expenditure. This heightened metabolic processing within cells generates more carbon dioxide as a waste product of nutrient breakdown.
D: increased respiratory muscle work Elevated respiratory muscle exertion, such as during strenuous breathing or respiratory distress, demands significant ATP. The metabolic processes supplying this energy produce substantial amounts of carbon dioxide as a byproduct of muscle cell activity.
On a global basis, poor bioavailability secondary to phytic acid is thought to be a more important factor than low intake in the widespread occurrence of
Rationale:
The widespread occurrence of zinc deficiency is thought to be more influenced by poor bioavailability secondary to phytic acid than low intake.
Phytic acid, commonly found in plant-based foods like grains and legumes, strongly chelates divalent cations such as zinc. This binding significantly inhibits zinc absorption in the human gut, making its bioavailability a critical determinant of nutritional status globally. Consequently, even with adequate dietary intake, high phytic acid consumption frequently precipitates widespread zinc
Malignant hyperthermia is an acute hypermetabolic syndrome that is triggered by inhalational anesthetic agents and succinylcholine. Of the following, which myopathy is consistently associated with malignant hyperthermia?
Rationale:
Central core myopathy is consistently associated with malignant hyperthermia.
Central core myopathy is the most frequently identified congenital myopathy linked to malignant hyperthermia susceptibility (MHS). This association stems from shared genetic defects, often involving mutations in the ryanodine receptor (RYR1) gene, which plays a critical role in calcium release within muscle cells. These mutations predispose individuals to the uncontrolled calcium efflux characteristic of MH upon exposure to triggering agents, leading to the hypermetabolic state.
B: Myotubular myopathy Myotubular myopathy presents with severe muscle weakness and often X-linked inheritance, primarily affecting muscle development. It lacks a consistent or direct genetic link to the RYR1 gene defects or the calcium dysregulation pathways specific to malignant hyperthermia susceptibility.
C
All the following are features of chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs) EXCEPT
Rationale:
CSF shows pleocytosis and high protein is NOT a feature of chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs).
CIDP characteristically shows elevated CSF protein without significant pleocytosis, typically fewer than 10 cells/mm³. This 'albumino-cytological dissociation' is a hallmark. The presence of both significant pleocytosis and high protein is atypical for CIDP, suggesting alternative diagnoses or complicating factors, thus making it the feature that is NOT characteristic of CIDP.
A: motor deficits in 94% Motor deficits, including progressive weakness and impaired ambulation, are
A school age child presented with a mass behind the knee. Physical examination reveals a firm mass in the popliteal fossa, medially located and distal to the popliteal crease. The mass is most prominent when the knee is extended. Knee radiographs are normal. Of the following, the MOST likely diagnosis is
Rationale:
A popliteal cyst is the most likely diagnosis.
A popliteal cyst, or Baker's cyst, typically presents as a firm, medially located mass in the popliteal fossa
Matching: Flexible flatfeet
Rationale:
Flexible flatfeet are usually painless.
Flexible flatfeet frequently present without any associated discomfort or functional limitation, especially in children and adolescents. This common variant of foot posture often allows for normal participation in physical activities, with the arch reappearing when non-weight-bearing. Intervention is typically unnecessary unless symptoms develop, making "usually painless" an accurate description of its presentation.
A: Soft tissue surgical release required
Soft tissue surgical release is rarely indicated for flexible flatfeet, as most cases are asymptomatic and resolve or accommodate naturally without invasive procedures.
C: Peripheral neuropathy
Peripheral neuropathy is an unrelated neurological condition affecting nerve function, not a direct cause or characteristic feature of flexible flatfeet.
D: Fusion or failure of segmentation
Fusion or failure of segmentation describes tarsal coalition, a rigid foot deformity distinct from the flexible nature of typical flexible flatfeet.
Bilateral developmental dysplasia of the hip (DDH) presents a diagnostic dilemma. Of the following, the MOST useful test in this situation is
Rationale:
The MOST useful test in this situation is Galeazzi sign.
Bilateral developmental dysplasia of the hip makes dynamic tests like Ortolani and Barlow difficult to interpret due to the absence of a stable, unaffected hip for comparison. The Galeazzi sign, which observes limb length discrepancy, becomes particularly valuable in bilateral cases. It reveals the relative shortness of the thigh on the affected side when the knees are flexed and feet are flat, indicating femoral head displacement.
A: Ortolani test This maneuver detects a dislocated hip by reducing it, producing a clunk. In bilateral DDH, the absence of a stable reference hip complicates the interpretation of hip reduction, making its utility limited.
B: Klisic test This observational test assesses hip dislocation by drawing a line from the greater trochanter to the umbilicus. While suggestive, it is primarily a screening tool and lacks the diagnostic precision required for definitive bilateral DDH assessment.
C: Barlow test This maneuver attempts to dislocate an unstable hip by adducting and posteriorly pushing the femur. In bilateral DDH, the lack of a stable contralateral hip for comparison makes detecting subtle instability challenging and less informative.
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by
Rationale:
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by euvolemic hyponatremia.
SIADH involves excessive antidiuretic hormone, causing water retention and dilutional hyponatremia. Despite increased total body water, the body's compensatory mechanisms, including natriuresis and ANP release, prevent significant extracellular volume expansion. This results in a clinically euvolemic state where patients do not exhibit overt signs of fluid overload like edema, while still experiencing low serum sodium.
A: extravascular volume expansion While SIADH increases total body water, compensatory mechanisms like natriuresis often maintain a euvolemic state without significant extravascular fluid accumulation, making overt expansion uncommon.
B: high serum uric acid SIADH typically causes hypouricemia, not hyperuricemia, due to enhanced renal uric acid clearance, which is a consequence of expanded plasma volume and reduced proximal tubular reabsorption.
C: high blood urea nitrogen SIADH usually leads to a low or normal blood urea nitrogen (BUN) because the increased water retention dilutes BUN, and enhanced renal perfusion improves urea excretion.
Bell palsy is an acute unilateral peripheral facial nerve palsy that is not associated with other cranial neuropathies or brainstem dysfunction. Of the following, the MOST traditional treatment is
Rationale:
The MOST traditional treatment for Bell palsy is prednisone.
Prednisone, a corticosteroid, is widely considered the cornerstone of Bell palsy management, traditionally initiated within 72 hours of symptom onset. Its anti-inflammatory properties significantly reduce facial nerve swelling, thereby promoting faster recovery and improving the likelihood of complete resolution. Early steroid intervention is crucial for mitigating nerve damage and enhancing functional outcomes in affected individuals.
A: acyclovir Acyclovir, an antiviral, is sometimes co-administered with corticosteroids but lacks strong evidence as a standalone traditional treatment for Bell palsy. Its efficacy in improving outcomes beyond steroids alone remains debated in clinical practice.
C: laser therapy Laser therapy for Bell palsy is an unconventional and emerging modality, not a traditional or widely accepted primary treatment. Its role in nerve regeneration or inflammation reduction is still largely experimental and unproven.
D: physiotherapy Physiotherapy is a supportive intervention, often recommended for facial muscle re-education during recovery, but it is not the initial, traditional pharmacological treatment for acute nerve inflammation. It assists functional restoration later.
A 10-year-old female has had diplopia and ptosis and weakness of her neck flexors for 2 months. Symptoms are worse in the evening and are usually partially improved on awakening in the morning. She has no fasciculations or myalgias, and her deep tendon reflexes are 1-2+. The most likely diagnosis is
Rationale:
Myasthenia gravis is the most likely diagnosis.
Myasthenia gravis characteristically presents with fluctuating muscle weakness, worsening with activity and improving with rest, as seen with evening exacerbation and morning improvement. Ocular symptoms like diplopia and ptosis are common initial manifestations. Normal reflexes and absence of fasciculations further support this autoimmune neuromuscular junction disorder.
A: hysterical weakness Hysterical weakness typically lacks objective neurological signs and a consistent diurnal pattern of worsening and improvement, unlike the clear physical symptoms presented here.
B: muscular dystrophy Muscular dystrophy involves progressive muscle degeneration, not fluctuating weakness that improves with rest, and often includes myalgias or elevated creatine kinase, which are absent here.
C: spinal muscular atrophy Spinal muscular atrophy causes progressive motor neuron degeneration, leading to fasciculations and profound muscle atrophy, symptoms completely unobserved in this patient's presentation.
In infants, radiographs and advanced imaging are rarely necessary for assessment because their tarsals have incomplete ossification. The navicular ossifies in boys at the age of about
Rationale:
The navicular ossifies in boys at the age of about 4 years.
The navicular bone, a key tarsal bone, completes its ossification process in boys around the age of four years. This developmental milestone is crucial for foot structure and function. Before this age, its cartilaginous state contributes to the challenge of radiographic assessment in infants, as mentioned in the question's context, making advanced imaging less informative due to incomplete bone formation.
A: 2 years The navicular typically remains cartilaginous at two years old, making full ossification at this early stage atypical. Skeletal maturation progresses more gradually for this specific tarsal bone.
B: 3 years While some ossification may begin, the navicular is generally not fully ossified in boys by three years of age. Its complete bony transformation usually occurs later in childhood development.
D: 5 years By five years, the navicular is typically already ossified in most boys, meaning four years represents a more accurate average onset for its completion. This age often indicates a fully formed bone.
An adolescent athlete complains of an insidious onset of low back pain persisting over 6 weeks. The pain tends to worsen with activity and with extension of the back and improves with rest, the pain radiated to the buttocks. Of the following, the MOST likely cause is
Rationale:
Spondylolisthesis is the MOST likely cause of the adolescent athlete's insidious low back pain.
Spondylolisthesis, particularly in adolescent athletes, frequently presents with insidious low back pain exacerbated by activity and lumbar extension, often relieved by rest. The pain radiating to the buttocks is a common symptom due to nerve root irritation or referred pain from facet joint stress. This condition involves a vertebral slip, commonly L5-S1, making it highly consistent with the described mechanical pain pattern in an active youth.
A: diskitis Diskitis typically presents with severe, constant back pain, often accompanied by fever and systemic illness, which does not align with the insidious, activity-related pain described here.
B: ankylosing spondylitis Ankylosing spondylitis usually causes inflammatory back pain, characterized by morning stiffness that improves with activity, not worsening, and often affecting younger adults.
C: vertebral osteomyelitis Verte
Matching: Episodic paralysis
Rationale:
Episodic paralysis is associated with hypokalemia. Hypokalemic periodic paralysis features transient muscle weakness linked to low potassium levels, causing episodic paralysis attacks. This condition involves ion channel dysfunction affecting muscle excitability, explaining the periodic nature of symptoms. The other options involve metabolic or mitochondrial disorders with different clinical presentations, unrelated to potassium-induced episodic muscle weakness characteristic of hypokalemic paralysis.
B: Pompe disease involves glycogen storage leading to progressive muscle weakness rather than episodic paralysis; it does not feature potassium-related episodes characteristic of hypokalemic periodic paralysis.
C: McArdle syndrome presents with exercise intolerance and muscle cramps due to glycogen breakdown defects, lacking the potassium imbalance and episodic paralysis typical of hypokalemic conditions.
D: MELAS is a mitochondrial disorder causing stroke-like episodes, seizures, and muscle weakness, but it does not produce episodic paralysis linked to potassium disturbances like hypokalemic periodic paralysis.
A 15-year-old male has lost his ability to walk. On physical examination, his ankle and knee deep tendon reflexes are noted to be diminished. The weakness is greatest in peripheral muscles. Cranial nerves all are normal. One week before these symptoms arose, he returned from a camping trip. The most likely diagnosis is
Rationale:
The most likely diagnosis is tick paralysis.
Tick paralysis typically presents with ascending flaccid paralysis, diminished deep tendon reflexes, and preserved cranial nerve function, mirroring the patient's symptoms. The history of
Septic arthritis in infants and children has the potential to damage the synovium, adjacent cartilage, and bone causing permanent disability. All the following statements regarding its epidemiology are true EXCEPT
Rationale:
"Half of all cases occur by 5 yr of age" is the statement that is NOT true regarding the epidemiology of septic arthritis.
The epidemiology of septic arthritis typically shows a higher incidence