Sickle Cell Disease

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Sickle Cell Disease Case Study
Patient’s Chief Complaints:
“My arms & legs hurt a lot more than usual today. The ibuprofen has stopped working and I need something stronger. I may have overdone it at the gym.”
History of Present Illness:
Carla is an 18 old female with sickle cell disease who presents with a one-day history of increasing pain localized to her arms and legs. Her pain has not been relieved with 400 mg of ibuprofen every 6 hours for the past 24 hours. She rates her current pain intensity level as 8 out of 10. She reports that she always seems to have some pain in her arms, legs, and back, but recently with the cold weather it has gotten worse. The pain really intensified approximately 36 hours after a workout at the gym that was more vigorous than usual. “I know that I shouldn’t have done that,” she confesses, “but the girls needed a 6th player for a game of 3-on-3. And, on top of that, I forgot to take my water bottle to the gym and haven’t been good about drinking water since.”
Past Medical History:
The patient was diagnoses with homozygous HbSS disease (HbSS genotype) at age 11 months. She first presented with a severe case of dactylitis at 10.5 months with significant swelling and pain in both hands and fee.
At age 16 months, the patient was hospitalized with acute sequestration syndrome and splenomegaly, treated, and released. At age 30 months and again at age 34 months, the patient was hospitalized for Streptococcus pneumoniae pneumonia, treated with IV antibiotics, and released. She also experienced one episode of acute staphylococcal osteomyelitis of the left knee at age 13. Since the age of 3 years, the patient has averaged three painful crises per year but has had as many as 10 attacks in a year. She has experienced chronic low-grade pain in his arms, legs, and back since becoming a teenager but has been able to cope by taking ibuprofen when needed.
Other medical conditions and surgeries of note include:
• Tonsillectomy as a child
• Childhood asthma that resolved at puberty
• Chronic sinus drainage/rhinitis x 2 years
Family & Social History:
• Single female who lives at home with her mother and brother during the summer and will reside in a college dormitory during the next academic year
• Patient identifies as African American; she has Nigerian genetic ancestory.
• Recently graduated from high school with honors and hopes to pursue a college education and major in business
• Works part-time at Chipotle
• Does not smoke, drink alcohol, or use illicit drugs “except for one trial of pot 2 years ago”
• Tries to maintain a healthy and balanced diet
• Consumes 2-3 caffeinated soft drinks per day
Review of Systems:
• Denies headache, cough, fever, chills, dizziness, lightheadedness, nausea, vomiting, diarrhea, shortness of breath, blurred vision, chest pain, blood in the urine, abdominal pain, and painful urination

• Admits to feeling tired much of the time but has generally been able to tolerate it
Physical Examination and Laboratory Tests:
General Appearance
The patient is a tall, thin, African American female in moderate-to-severe pain.
Vital Signs

BP 95/60 RR 18 BMI 17.7
P 58 T 98.5 O2 Sat 96% on room air
Skin & Hair
• Warm and dry with poor turgor/some tenting
• (-) rashes, bruises, or lesions
• Hair quantity, distribution, and texture unremarkable
Head, Eyes, Ears, Nose, & Throat
• Normocephalic and atraumatic
• Pupils equal at 3 mm, round, and reactive to light
• Extra-ocular muscles intact without nystagmus
• Normal sclerae
• Funduscopic exam revealed sharp optic disc margins with no arteriolar narrowing or hemorrhages
• External auricular canals clear
• Tympanic membranes gray and reveal good cone of light bilaterally
• Nasal mucous membranes dry
• Oral mucosa dry and without erythema
• No oropharyngeal lesions
• Lips dry
Neck & Lymph Nodes
• Neck supple
• (-) cervical, axillary, and inguinal nodes bilaterally
• (-) thyromegaly, nodules, carotid bruits, and jugular vein distension
Lungs and Thorax
• Clear to auscultation throughout with good breath sounds
• No costovertebral angle tenderness or spinal tenderness
Heart
• Regular rate & rhythm
• (-) rubs and gallops
• Systolic ejection murmur is prominent
Abdomen
• Normoactive bowel sounds in all four quadrants
• Soft, non-tender, and non-distended without guarding
• (-) organomegaly, masses, and bruits
Musculoskeletal & Extremities

• 2+ peripheral pulses in dorsalis pedis and tibialis pedis bilaterally
• (-) edema, ulcers, and clubbing
• Normal strength
• Limited range of motion in elbows, wrists, knees, and ankles
Neurological
• Alert and oriented x 3
• Cranial nerves II-XII intact
• Deep tendon reflexes intact throughout
• Sensory and motor levels intact
• (-) focal abnormalities
• Negative Babinski sign
Laboratory Blood Test Results

Na 141 meq/L Hct 28.1% Bilirubin – total 1.4 mg/dL
K 3.6 meq/L Plt 225 x 103/mm3 Bilirubin – indirect 0.9 mg/dL
Cl 101 meq/L WBC 7.0 103/mm3 Alb 3.7 mg/dL
HCO3 22 meq/L MCV 82.1 fL Protein – total 6.3 mg/dL
BUN 13 mg/L Retic 6.4% Ca 9.3 mg/dL
Cr 1.2 mg/L AST 25 IU/L Mg 1.9 mg/dL
Glu, fasting 87 mg/L ALT 22 IU/L PO4 4.0 mg/dL
Hb 10.9 mg/L Alk phos 75 IU/L Folic acid 515 ng/mL

Peripheral Blood Smear
• (+) sickled and crescent forms and target cells
Chest X-rays
• Clear Electrocardiogram Normal sinus rhythm Echocardiogram
Normal left ventricular function, normal left ventricular wall thickness, mild dilation of right ventricle
Urinalysis
(-) blood and protein
[Case adapted from: Bruyere, H. (2009). 100 Case studies in pathophysiology. Philadelphia, PA: Lippincott.]

Case Study Questions
Question 1:
Identify 2 risk factors that are likely contributing to Carla’s current clinical presentation? (2 points)

Question 2:
What are the pathophysiological mechanisms likely contributing to Carla’s clinical presentation? (4 points)

Question 3:
What genetic mutation led to Carla’s development of Sickle Cell Disease? Explain how the genetic mutation contributes to the development of Sickle Cell Disease. (Hint: Think about the functional consequence of the mutation.) (2 points)

Question 4:
If Carla has offspring with someone who has Sickle Cell Trait, what is the likelihood (risk) their offspring would have Sickle Cell Disease? What is the likelihood their offspring would have Sickle Cell Trait? (2 points)