Cardiomegaly, OHA, Hypoglycemia

1. What is the criteria to say a patient to have cardiomegaly based on CXR? (clue: cardiothoracic ratio)
2. If you are working in district hospital as a MO, would you give OHA to a pregnant woman? Why not?
3. A patient came to you with hypoglycemia. His DXT was 2.0mmol/L. For the past 5/7, he c/o (complaint of) dysuria and increased frequency of micturination, vomiting and low grade fever x 5/7. He noted his urine was cloudy. He claimed that daily he took 2 types of OHA - one was round-shaped,(roughly) 1cm sized white tablet and another one is small, oval shaped white tablet.
Q:
a. What would be your complete diagnosis then?
b. Let us guess what OHA he was taking, based on his description of the OHA tablets.
c. What would be your first step when the patient's DXT 2.0mmol/L and he is unconscious.

1. Cardiomegaly's criteria on CXR: When Cardiothoracic ratio > 0.5, i.e. the maximal transverse diametre of heart is >50% of the maximal transverse diametre of the thoracic cavity.

2. OHA shouldn't be given to pregnant woman as there are no data regarding safety of OHA usage in pregnant women. If the DXT is uncontrolled by diet and exercise then insulin is considered to control DM during pregnancy.

3. Hypoglycemia

a. Diagnosis: Hypoglycemic attack secondary to UTI. 

Although infection is the usually cause for hyperglycemia due to increased requirement of insulin, but infection can cause hypoglycemia by the following causes:

• Infection causes loss of appetite (LOA) and cause patient reduces food intake.
• Infection causes decrease of DXT by increased metabolism.

These result in relative insulin overdose if the patient still take the same dose of OHAs.

b. Possible OHA is metformin and glicazide or glibenclamide, as these drugs are white tablets, available in either round or oval shape, and the combination of metformin + sulfonylurea is a common treatment.

c. Immediate action to restore back the DXT to normal is needed. Dextrose 50% 25-50ml IV till recovering of consciousness, followed by D5 infusion or glucose drink PO. If IV access not possible, can consider glucagon 1mg IM / SC. 

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Answer.

1. Cardiothoracic ratio will determine whether a patient to have cardiomegaly. Normal CTR should be less than 0.5. In the CXR, we take the length of heart and length of whole thorax in longitudinal direction. Then we divide the cardiac length with thoracic one. If the value exceeds 0.5, then it is cardiomegaly. Do remember that we can only measure CTR from CXR in PA erect. CXR in supine PA or AP can give you wrong view of heart position.

2. OHA is recommended for pregnant women. Firstly blood sugar must be controlled well during pregnancy to prevent hyperglycemic complications. (You shall find out about it-> polyamnio, congenital defects, macrosomia, post-partum fetal hypoglycemia etc. You also must know how post-delivery fetal hypoglycemia can develop and how to prevent it post-partumly.) Secondly, OHA may have teratogenic effect but it is not completely proven.

3. (hint: DXT means dextrostick. )

a. Diagnosis would be Hypoglycemic attack secondary to UTI(urinary tract infection).

b. White rough big tablet is metformin; usually small round tablet is gliclazide. Sometimes, gliclazide is small oval-shaped. Most of the time, glibenclamide is small oval shaped. All of them are white in colour.

c. If a patient develops hypoglycemic attack and is unconscious, we must give intravenous(IV) bolus Dextrose 50%(D50%) 50cc. IV D50% is given till the patient regains consciousness. Then we must maintain the blood sugar level with IV drip D10%/D5% (depending on the DXT). IM glucagon can be given if there is no IV access.

(You shall find out what is neuroglucopenia)